The prevalence, correlates and treatment of pain in

Current Medical Research & Opinion
0300-7995
doi:10.1185/03007995.2010.542136
Vol. 27, No. 2, 2011, 463–480
Article FT-0154.R1/542136
All rights reserved: reproduction in whole or part not permitted
P.C. Langley
Abstract
University of Minnesota, Minneapolis, MN, USA
Address for correspondence:
Paul C. Langley PhD (for the CHANGE PAIN
International Advisory Board), University of Minnesota,
7-159 Weaver-Densford Hall, 308 Harvard St SE,
Minneapolis, MN 55455, USA.
Tel.: þ1 520 577 0436; Fax: (612) 624-2974;
[email protected]
Key words:
HRQoL – Pain – Prevalence – Severity
Accepted: 18 November 2010; published online: 3 January 2011
Citation: Curr Med Res Opin 2011; 27:463–80
CHANGE PAIN International Advisory Board members:
K Ahlbeck, Karolinska University Hospital Solna, Stockholm,
Sweden
D Aldington, Churchill Hospital, Oxford, UK
E Alon, Universitätsspital Zurich, Zurich, Switzerland
M Berti, A.O. Ospedaliero-Universitaria Parma, Parma, Italy
B Collett, University Hospitals of Leicester, Leicester, UK
F Coluzzi, Sapienza Università di Roma, Rome, Italy
F Huygen, University Hospital Rotterdam, Rotterdam,
The Netherlands
W Jaksch, Wilhelminenspital der Stadt Wien, Vienna,
Austria
E Kalso, Helsinki University Central Hospital, Helsinki,
Finland
M Kocot-Ke˛pska, Poradnia Leczenia Bólu University
Hospital, Kraków, Poland
A Mangas, Hospital de Santo André, Leiria, Portugal
C Margarit, Hospital General Universitario de Alicante,
Alicante, Spain
P Mavrocordatos, Clinique Cecil, Lausanne, Switzerland
B Morlion, University Hospitals Leuven, Pellenberg, Belgium
G Müller-Schwefe, Schmerz- und Palliativzentrum
Göppingen, Göppingen, Germany
A Nicolaou, St Georges Hospital, London, UK
C Pérez Hernández, Hospital Universitario de la Princesa,
Madrid, Spain
J Pergolizzi, School of Medicine, Johns Hopkins University,
Baltimore, MD, USA
M Schäfer, Campus Virchow Klinikum, Charité Berlin, Berlin
P Sichère, Paris, France
G Varrassi, Università degli Studi di L’Aquila, L’Aquila, Italy
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Original article
The prevalence, correlates and treatment of pain
in the European Union
Objectives:
To report on the results of a recent large-scale, internet-based survey of the population, prevalence and
attributes of pain experience in the United Kingdom (UK), France, Spain, Germany and Italy.
Methods:
The results reported here are taken from the internet-based, 2008 National Health and Wellness Survey
(NHWS). In addition to detailing the prevalence of pain, the survey reports on the correlates of pain – sociodemographic characteristics of respondents, health status and health related quality of life, pain associated
comorbidities, satisfaction with care, employment and productivity and utilization of health care resources.
In addition, the survey also captures treatment patterns, satisfaction with medications (both prescription and
over the counter [OTC]) and adherence experience.
Results:
An estimated 49.7 million persons in these five countries reported pain by both its severity and frequency in
the previous month. Of these, 11.2 million reported severe pain, 29.4 million reported moderate pain and
9.0 million reported mild pain. The population prevalence of daily pain is 8.85% with 3.47% reporting severe
daily pain and 4.70% moderate daily pain. The cumulative burden of pain is demonstrated in terms of
HRQoL, employment status and workforce activities as well as in healthcare resource utilization. The most
striking impacts are seen in the impact of severe and frequent pain on HRQoL. Of the measures employed,
the impact on the physical component score (PCS) of the SF-12 and the SF-6D absolute utility scores are
substantial. The presence of severe and daily pain not only reduces the PCS score against that reported for
the no pain population by over 20 points (or approximately 40%) but the impact on the absolute utility score
is to reduce it from a no pain average of 0.74 to a score of 0.54. As far as productivity losses to the
community are concerned the impact of severe pain is equally dramatic.
Conclusions:
The reported prevalence of pain in these five countries represents a substantial burden to individuals,
employers, healthcare systems and society in general. The fact that one in five of the adult population has
experienced pain presents a major policy challenge. This would involve not only reducing the prevalence
of pain – where chronic pain may be considered a disease in its own right – but to co-ordinate pain
management programs across a range of disease states and socio-economic groups.
Introduction
Comprehensive, pan-European assessments of the prevalence, characteristics,
correlates and burden of pain are limited – both in their scope and in the attributes of pain treatment and experience that are captured. With few exceptions,
little is known at this level of the societal burden of pain in terms of its impact on
HRQoL, workforce status and productivity, and healthcare resource utilization.
Even less is known about the characteristics that distinguish those experiencing
The prevalence, correlates and treatment of pain Langley
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Current Medical Research & Opinion Volume 27, Number 2
February 2011
pain from those who are not experiencing pain; a distinction that is critical to an assessment of the societal burden.
The purpose of this paper is to report, in general terms,
on the results of a recent pan-European study of pain in five
countries: the UK, France, Spain, Germany and Italy. Data
for this study are from the 2008 NHWS1.
Until the present study, the most comprehensive assessment of the prevalence, severity, treatment and impact of
pain in Europe is from Breivik et al.2. This computer assisted telephone survey covered 15 European countries and
Israel. Overall, some 46,934 respondents agreed to participate (a refusal rate of 46%); they had to have suffered from
pain for six months or more, experienced pain in the last
month and several times in the last week. Respondents
were only included if their reported pain intensity was
5 on a 10-point numeric rating scale. In depth interviews
with 4839 respondents found 66% reporting moderate pain
and the balance reporting severe pain. The study results
focused on exploring the demographics of pain, correlates
of pain experienced, the impact of defined chronic pain on
quality of life and daily activities, understanding current
treatment practices and satisfaction with treatment, as
well as exploring attitudes towards pain.
Another large-scale study of pain in Europe that is
worth noting is McDermott et al.3 on the burden of neuropathic pain. This study, with a relatively small convenience sample across six European countries recruited from
physician practices, evaluated pain severity, HRQoL,
overall health, productivity, non-prescription medication
use and frequency of physician visits. Other community
pain studies include two by Rustøen et al.4,5, reporting in
two papers on the prevalence and characteristics of
chronic pain in Norway; Gerdle et al.6, reporting on the
prevalence of pain and its impact on work status in
Sweden, and the Brattberg et al.7 study of pain prevalence
also in Sweden; a study by Bassols et al.8 on pain prevalence in Catalonia, and the prevalence of pain in older
adults in Catalonia by Miró et al.9; Smith et al.10 reporting
on the community impact of pain in the Grampian region
of Scotland; the Eriksen et al.11 study of chronic pain in
Denmark; and the more recent German study of chronic
pain in primary care by Frießem et al.12. To these would be
added the recent pan-European review by Juniper et al.13 of
the impact of chronic low back pain.
The present study is designed to complement two
recently published studies which, using the same data
set, have evaluated the impact of the severity and frequency of pain on health related quality of life and healthcare resource utilization14, and employment status,
absenteeism and presenteeism15.
Outside of the European Union there have been a large
number of pain prevalence studies published and some systematic reviews. The most comprehensive studies are
those undertaken by national agencies with surveys such
as the National Health Interview Survey in the US16.
464
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In the case of systematic reviews a key reference is the
Ospina and Harstall17 review of the prevalence of chronic
pain in 2002, together with earlier studies, cited by Ospina
and Harstall, namely Verhaak et al. in 199818 and Nickel
and Raspe in 200119. There was little overlap in the studies
selected for these various reviews, reflecting both definitions adopted and the diversity in study design. In the 13
studies selected by Ospina and Harstall it was impossible
to come to any consensus on the prevalence of chronic
pain with estimates in the range 10.1% to 55.2%. It was
possible, however, to come to a consensus view on the
prevalence of severe chronic pain with a range from 10%
to 13%.
Using the IASP definition of chronic pain20, four studies reviewed by Ospina and Harstall yielded an estimate of
the weighted mean prevalence of chronic pain at 35.5%
(range 11.5% to 55.2%)17.
The present study differs in a number of important
respects from previous cross-section studies of the prevalence of pain in Europe. First, it focuses on the current
experience of pain – pain experienced in the past month.
Second, as it is based on a general health status survey, it
allows a comparison between those experiencing pain and
those not reporting pain in the last month. Third, the study
captures two key dimensions of pain: self-reported pain
severity and the frequency with which pain has been experienced. Fourth, while the study asks respondents how long
they have been taking prescription pain drugs, it does not
attempt to impose an arbitrary distinction between
chronic and acute pain. Finally, the study focuses on
three complementary outcomes of the experience of
pain: HRQoL, employment status and workplace productivity, and healthcare resource utilization. The ability to
benchmark against those respondents not experiencing
pain allows a comprehensive assessment of the individual
and societal burden of pain.
Methods
The purpose of the present analysis is to provide an overview of the results of the 2008 NHWS1 as they relate to the
dimensions of pain reported, the prevalence of pain, its
correlates and the association between pain and measures
of the societal burden of pain.
National Health and Wellness Survey
The NHWS is an internet based, cross-sectional study of
the healthcare attitudes, behaviors, and characteristics of
the adult population in the United States, Japan and five
European countries1. The survey is designed to be representative of the population 18 years and over in each country. Since its initiation in 1998, over 600,000 survey
responses across approximately 140 conditions have been
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Current Medical Research & Opinion Volume 27, Number 2
collected. Core reports for each country can be purchased
to give bivariate results. Multivariate analyses of results
and special supplementary surveys are also available.
The present analysis is based on the results of the 2008
NHWS for the European Union. Five countries are
included – the UK, France, Italy, Germany and Spain.
A total of 53,524 persons 18 years of age and over
were interviewed, yielding an age/gender weighted or estimated population of 247.3 million for these five EU
countries.
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Dimensions of pain reported
The dimensions of pain identified in the NHWS include:
Pain experienced in the past month
Frequency with which pain is experienced
Pain type and associated health status
Medication utilization and satisfaction
Medication adherence
Type of pain medication
Duration of pain medication utilization
Satisfaction with pain medication
Side effects of pain medication
Pain experienced in the last month
Overall, the 2008 NHWS sample comprised 53,524
respondents. After adjusting to exclude a number of
minor or acute pain categories, which were assigned back
to the no pain category, a total of 11,891 respondents were
identified as reporting pain in the last month. As a
weighted population for the five EU countries in the
NHWS (247.3 million), a total of 51.8 million reported
pain (20.9%) or just over one in five of the population
18 years of age and over. Severe pain was reported by
11.3 million, moderate pain by 29.4 million and mild
pain by 9.0 million. An estimated 2.0 million failed to
report pain frequency. Note that respondents were asked
only to report subjectively assessed ‘severe’, ‘moderate’ and
‘mild pain’; pain scales were not used. Respondents were
not asked how long they had experienced pain; rather they
were asked how long they had taken specific prescription
and/or OTC pain medications. Although there is no
unique, clinically based measure of pain, there is a relatively high correlation between self-reported pain status
and, for example, pain scales.
Frequency of pain experienced
Respondents to the NHWS were asked to report the
frequency with which they had problems with pain.
Options ranged from daily pain to those who experienced
pain once a month or less. For the purposes of this analysis
the six categories identified in the NHWS have been
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February 2011
collapsed to four: ‘daily’, ‘2–4 times a week’, ‘5–6 times a
week’, and ‘weekly or less’. These responses can be combined with pain severity to yield ranked combinations
from ‘severe pain and daily frequency’ to ‘mild pain’ experience weekly or less. In this study persons only reporting
severity of pain (and not frequency of pain) are excluded
from the analysis.
Pain type and associated health status
The NHWS asks respondents reporting pain in the last
month which of a list of conditions caused them to feel
pain in the last month. These include the most commonly
identified causes of pain – back problems, joint pain, neck
and migraine – as well as experience of neuropathic pain.
At the same time all respondents are also asked which of a
number of conditions (n ¼ 34) they have experienced in
the last 12 months. These include health states often associated with pain – depression, anxiety, generalized anxiety
disorder and sleep difficulties.
Medication utilization and satisfaction
Respondents were asked if they used prescription or OTC
medications to treat their pain. If the response is yes, then
for the prescription medications, they are asked to identify
from pre-assigned lists for each country in the NHWS the
prescription medications they currently use. Pre-assigned
lists are not used for OTC medications; respondents are
asked to write in the products used.
Respondents were also asked, for each of the prescription and OTC medications used, to indicate for how many
months/years they had been using prescription medication
for pain. As respondents could reply to this question for
each medication reported, the responses are collapsed to
capture the longest time (in months) that a prescription or
OTC medication had been taken. Rather than include the
actual number of months, the responses were categorized
into those who had taken one or more prescription medications for less than three months and those who had taken
medications for three or more months.
For each of the prescription and OTC pain medications
identified, respondents were asked to indicate how satisfied they were with the product. Responses (seven in all)
ranged from ‘extremely dissatisfied’ through ‘neither dissatisfied nor satisfied’ to ‘extremely satisfied’. Although the
majority of respondents were on one prescription medication, it was decided to collapse the responses to allow the
following categories:
Extremely dissatisfied, very dissatisfied or somewhat
dissatisfied with all prescription/OTC medications
Extremely satisfied, very satisfied or somewhat satisfied
with all prescription/OTC medications
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Neither dissatisfied nor satisfied with all prescription/
OTC medications
Mixed response for those taking more than one prescription/OTC medication
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Medication adherence
Adherence to prescription medications is captured
through the application of the Morisky scale21. The four
items in the scale focus on barriers to medication taking.
The items are:
Have you ever forgotten to take your medication?
Are you careless at times about taking your
medication?
When you feel better do you sometimes stop taking
your medication?
Sometimes if you feel worse when you take the medicine, do you stop taking it?
As a ‘yes’ response is scored as one and no is scored as zero,
the scale can take values from zero (no ‘yes’ responses) to 4
for the least adherent. These results are presented as averages for the integer valued respondent Morisky score in
each of the pain and medication groups.
Health related quality of life
The instrument selected to measure HRQoL in the
NHWS is the SF-12 (version 2)22. The SF-12 is a multipurpose short-form with 12 questions. These questions are
all selected from the SF-36 health survey23,24. The SF-12 is
a generic measure. A key objective in developing the SF12 in the early 1990 s was to construct the shortest possible
form that would replicate the physical and mental health
summary scores generated from the SF-36 with at least
90% accuracy. To support this, a further objective was to
replicate each of the eight SF-36 health concepts with at
least one questionnaire item to set the stage for scoring an
eight-scale profile from SF-12 responses. The eight health
concepts common to both the SF-36 and SF-12 are:
Physical functioning
Role physical (accomplishment)
Bodily pain
General health
Vitality (energy level)
Social functioning
Role emotional (accomplishment)
Mental health (feeling)
It is worth noting that the SF-12 bodily pain item does not
ask respondents to indicate either the severity or the frequency with which pain is experienced. Rather the question asks respondents ‘How much did pain interfere with
your normal work (including both work outside the home
and housework)’ with the response choice (five items)
from ‘not at all’ to ‘extremely’.
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The prevalence, correlates and treatment of pain Langley
While it is possible to develop a health profile utilizing
the item responses corresponding to these eight concepts,
the focus here is on the two summary scores that can be
generated from the respective item responses. These are (i)
the physical component summary (PCS) and (ii) the
mental component summary (MCS). The former captures
the first four elements in the bullet point above, the latter
the last four elements. Details of how the links are established and the scoring algorithms are given in Ware et al.22.
For the purpose of the present analysis the PCS and
MCS summary scores are utilized as normed scores. This
is achieved by transforming the raw scores for the items
to a mean of 50 and a standard deviation of 10 for the US
population. Normed scores can be calculated for both the
eight SF-12 scales as well as for the PCS and MCS summary scores. Although country-specific scoring algorithms
are available outside the US, the argument has been that it
is more appropriate to use a standard scoring algorithm as
scores can then be compared across countries. The appropriateness of using the US as a standard benchmark has
been demonstrated for nine European countries (including
the five countries in the NHWS)22. Given the cross-country nature of the present analysis, the US standard scoring
algorithms are used.
As well as generating profile and summary PCS and
MCS scores, the SF-12 can also be used to generate
health state utilities. This is achieved through application
of the SF-6D. The SF-6D provides a means for using the
SF-36 and SF-12 in economic evaluation by estimating a
preference-based single index measure for health from
these data using general population values25,26. Any
patient who completes the SF-36 or the SF-12 can be
uniquely classified according to the SF-6D. The SF-6D
describes 18,000 health states in all. It comes with a set
of preference weights obtained from a sample of the general population using the recognized valuation technique
of standard gamble. The SF-6D allows the analyst to obtain
quality adjusted life years (QALYs) from the SF-36 or
SF-12 for use in cost utility analysis. The index has interval
scoring properties and yields summary scores on a 0–100
scale. The preference weights, which have recently been
revised, are those for a UK population27.
Labor force participation, absenteeism and
presenteeism
The NHWS asks individuals to state their current employment status. Four employment status categories are identified, together with job seeking and reasons for not
working. In the present analysis a total of five categories
are used to assess the impact of pain. These are:
Employed full time
Employed part time
Self-employed
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Unemployed (actively looking for work)
Not in the labor force
The NHWS uses the Workplace Productivity and Activity
Impairment Scale (WPAI)28 to measure the impact of
health status on employment related activities. The
WPAI questionnaire measures work time missed and
work and activity impairment because of a specified
health problem during the past 7 days28. The validity
and accuracy of the instrument has been established in a
number of disease states (e.g., irritable bowel syndrome,
asthma, dermatitis, Crohn’s disease)29,30.
The WPAI absenteeism and workplace questions are
only relevant to those in employment – where the
NHWS identifies persons who are currently employed
full-time, employed part-time or self-employed.
Respondents are asked to indicate:
During the past seven days, how many hours did you
miss from work because of your health problems?
(Range 0 to 112 hours.)
During the past seven days, how many hours did you
miss from work because of any other reason such as
vacation, holidays, time off to participate in this
study? (Range 0 to 112 hours.)
During the past seven days, how many hours did you
actually work? (Range 0 to 112 hours.)
During the past seven days how much did your health
problems affect your productivity while you were working? (Response on a 0–10 scale from ‘health problems
had no effect on work’ to ‘health problems completely
prevented me from working’.)
During the past seven days, how much did your health
problems affect your ability to do your regular daily
activities, other than work at a job? (Response on a
0–10 scale from ‘health problems had no effect on
my daily activities’ to ‘health problems completely
prevented me from doing my daily activities’.)
Two measures of employment impact are presented in this
analysis. These are:
(i) Absenteeism: percentage of work time missed in the
past seven days
(ii) Presenteeism: percentage of hours worked impacted
by impaired productivity
February 2011
Provider visits, emergency room visits and
hospitalizations
The 2008 NHWS also asks respondents about their use of
healthcare resources. Resource utilization is considered in
terms of visits or events as they relate to:
Emergency room visits in the last six months
Number of times hospitalized in the last six months
Number of visits in the last six months to traditional
healthcare providers
The number of visits for each type of traditional healthcare
provider is also identified, but this level of detail is not
considered in the present analysis. Traditional healthcare
providers include general practitioner/family practitioner,
nurse practitioner/physician assistant as well as medical
specialists. Non-traditional or excluded providers include
acupuncturist, chiropractor, herbalist, physical therapist,
nutritionist, massage therapist and occupational therapist.
Results
Prevalence, severity and frequency of pain
Estimates of the prevalence of pain reported in the previous month by severity and frequency for the five countries
are given in Table 1. Overall, out of an estimated total
population 18 years of age and over of 245.3 million, an
estimated 20.27% (49.7 million) reported both pain severity and the frequency of pain experienced in the last
month. Among these 22.47% (11.17 million) report
having severe pain and 59.20% (29.42 million) moderate
pain. The population prevalence of persons reporting
severe pain was 4.61% and moderate pain 12.0%; daily
pain was reported by 8.85% of the population.
In the severe pain category, the overwhelming majority
reported experiencing daily pain (75.16%). This contrasts
with only 39.90% in the moderate pain category and
16.12% in the mild pain category.
The population prevalence of pain by age, gender, education and household income is detailed in Table 2. The
prevalence of pain is greatest in the 40 to 59 year age group.
As expected, the population prevalence of pain among
Table 1. Population prevalence of pain by severity and frequency, NHWS 2008*.
Frequency of
pain reported
Daily
4–6 times a week
2–3 times a week
Weekly or less
Total pain population
Total big 5 EU population
Severe
pain (%)
Moderate
pain (%)
Mild
pain (%)
Total pain
population (%)
3.47
0.40
0.30
0.45
4.61
22.47 (11.17 m)
4.79
1.69
2.47
3.06
12.00
59.20 (29.42 m)
0.59
0.32
0.74
2.00
3.66
18.06 (8.98 m)
8.85
2.41
3.51
5.51
20.27
20.27 (49.7 m)
*UK, France, Spain, Germany, Italy.
Source: NHWS, 2008.
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Table 2. Pain population prevalence distribution by severity, age, gender,
education and household income, NHWS 2008.
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Characteristics
Age
18 to 39 years of age
40 to 59 years of age
60 years and over
Gender
Males
Females
Education
University
High school
Other
Household income
Under E20,000
E20,000 to E39,999
E40,000 and above
No response
Severe
pain
(%)
Moderate
pain
(%)
Mild
pain
(%)
Total pain
population
(%)
0.87
2.30
1.45
3.42
4.84
3.74
1.57
1.31
0.77
5.86
8.45
5.96
1.58
3.04
4.41
7.59
1.99
1.67
7.98
12.30
0.92
2.23
1.46
2.97
5.90
3.14
1.20
1.84
0.62
5.09
9.97
5.22
1.78
1.46
0.69
0.69
3.95
4.06
2.19
1.80
0.98
1.36
0.87
0.44
6.70
6.89
3.75
2.93
Table 3. Pain population, distribution of severe, moderate and mild pain by
age, gender, education and household income, NHWS 2008.
Characteristics
Severe
pain (%)
Moderate
pain (%)
Mild
pain (%)
Total
(%)
14.80
27.16
24.33
58.35
57.29
62.75
26.85
15.55
12.92
100.0
100.0
100.0
19.76
24.71
55.28
61.75
24.97
13.54
100.0
100.0
18.16
22.40
27.94
58.30
59.18
60.12
23.54
18.42
11.95
100.0
100.0
100.0
26.49
21.22
18.38
23.45
58.93
59.02
58.32
61.38
14.57
19.76
23.30
15.17
100.0
100.0
100.0
100.0
Age
18 to 39 years of age
40 to 59 years of age
60 years and over
Gender
Males
Females
Education
University
High school
Other
Household income
Under E20,000
E20,000 to E39,999
E40,000 and above
No response
Source: NHWS, 2008.
Source: NHWS, 2008.
females is substantially greater than for males (overall
12.30% vs. 7.98%). The case for mild pain is less clear
cut. Persons with university education report a lower prevalence of pain that those with high school education
while the prevalence of pain tends to decline with
higher household income; notably among those with
severe pain.
Distribution of pain
Within the pain population, the distribution of pain level
by age, gender, education and household income is dominated by those reporting moderate pain (Table 3). Within
the pain population females report more severe (24.71%)
and moderate (61.75%) pain than males. The proportion
reporting severe pain increases with lower educational
attainment (which is inversely related to mild pain). A
similar gradient is found in the case of household income
with the percentage reporting severe pain declining the
higher the level of income reported.
with that pain type, with 25% reporting severe pain and
15% mild pain. In the case of back pain, for example,
60.33% report experiencing it as a moderate pain while
24.53% report it as a severe pain.
Associated health status
Associated health conditions experienced in the past 12
months by the pain population are detailed in Table 5.
Overall, in rank order, the most commonly stated health
status categories are headache (63.65%), sleep difficulties
(46.55%), abdominal pain (38.15%), insomnia (37.27%)
and anxiety (35.97%). At the same time the pain population prevalence of associated health states also shows a
relationship with pain severity. The prevalence of depression, for example, is 35.38% for those with severe pain,
falling to 19.74% for those with mild pain. A similar pattern is found in respect of sleep difficulties, reported anxiety, generalized anxiety disorder, insomnia and panic
disorders.
Conditions causing pain
Conditions causing pain among the pain population are
detailed in Table 4. The categories are not mutually exclusive. The most frequently reported condition causing pain
is back pain with almost two-thirds of respondents citing
this condition (65.56%). The next most frequently cited
condition is joint pain (51.66%) followed by neck
pain (32.20%). Among all pain conditions noted, the largest single category is for moderate pain experience,
followed by severe pain. That is, approximately 60% of
respondents have experienced moderate pain associated
468
The prevalence, correlates and treatment of pain Langley
Medication utilization
Medication utilization is considered from three perspectives. First, the distribution of reported pain experience
by medication class (Table 6); second, the distribution of
medication reported within disease severity class
(Table 7); and third, the distribution of prescription
medication use within disease severity class (Table 8).
Medication status is categorized by reported utilization of
one or more prescription or OTC pain medications.
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Table 4. Pain population, prevalence of conditions causing pain by pain severity, NHWS 2008.
Pain experienced
Back pain
Joint pain
Neck pain
Headache
Arthritis pain
Migraine
Dental pain
Menstrual pain
Sprains or strains
Surgery or medical procedure pain
Severe
pain (%)
Moderate
pain (%)
Mild
pain (%)
Prevalence of pain experienced
in pain population (%)
24.53
25.07
25.01
21.26
32.22
25.15
19.41
15.87
14.92
37.75
60.33
59.73
60.80
60.96
57.97
62.19
62.37
65.44
58.10
51.43
15.15
15.20
14.19
17.78
9.81
12.66
18.22
18.69
26.98
10.82
65.56
51.66
32.20
31.36
17.50
14.34
12.21
22.95
9.55
7.19
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Source: NHWS, 2008.
Table 5. Population prevalence and distribution of health conditions experienced in past 12 months and pain severity, NHWS 2008.
Associated health status
Severe
pain (%)
Moderate
pain (%)
Mild
pain (%)
Total pain
population (%)
64.50
57.57
38.96
47.42
41.96
31.12
34.72
35.38
17.39
14.56
18.69
14.90
16.45
15.97
13.78
15.86
10.45
12.90
12.15
11.84
8.22
8.58
6.83
5.67
4.53
9.43
7.63
3.60
3.27
62.98
44.89
38.34
35.87
34.65
33.60
29.59
22.97
15.12
14.92
14.16
13.53
10.91
10.25
11.02
9.40
9.33
9.08
8.99
7.21
7.49
7.57
5.42
4.86
4.31
3.30
3.48
2.80
2.37
64.76
38.11
36.53
29.07
32.77
31.50
25.98
19.74
16.62
15.21
11.54
13.59
8.58
7.97
8.20
5.37
10.15
7.70
7.92
5.43
7.82
5.17
4.07
5.57
5.88
0.83
2.18
0.90
2.66
63.65
46.55
38.15
37.27
35.97
32.66
30.11
25.21
15.91
14.89
14.72
13.85
11.75
11.14
11.14
10.14
9.73
9.70
9.52
7.95
7.72
7.37
5.50
5.17
4.64
4.25
4.19
2.64
2.63
Headache
Sleep difficulties
Abdominal pain
Insomnia
Anxiety
Abdominal bloating
Migraine
Depression
Nasal allergies/hayfever
Gingivitis
Generalized anxiety disorder
Diarrhea (frequent)
Restless legs syndrome
Gastroesophageal reflux disease (GERD) or acid reflux
Irritable bowel syndrome
Chronic constipation
Fungal infections of the skin
Asthma
Social anxiety disorder
Panic disorder
Eczema
Nail fungus
Anemia
Phobias
Dermatitis
Fibromyalgia
Post-traumatic stress disorder (PTSD)
Gout
Attention deficit disorder (ADD)
Source: NHWS, 2008.
Table 6. Pain population, distribution of pain severity by medication utilization, NHWS 2008.
Medication status
Only prescription pain medications
Only OTC pain medications
Prescription and OTC pain medications
No pain medication
Severe
pain (%)
Moderate
pain (%)
Mild
pain (%)
Total
(%)
41.84
10.86
33.01
11.53
52.07
65.02
58.79
59.32
6.08
24.13
8.20
29.15
100.0
100.0
100.0
100.0
Source: NHWS, 2008.
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Current Medical Research & Opinion Volume 27, Number 2
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Table 7. Pain population, distribution of medication utilization by pain severity, NHWS 2008.
Medication status
Severe
pain (%)
Moderate
pain (%)
Mild
pain (%)
Total pain
population (%)
Only prescription pain medications
Only OTC pain medications
Prescription and OTC pain medications
No pain medication
Total pain population
53.89
17.31
17.48
11.31
100.0
25.79
39.86
11.97
22.38
100.0
9.89
48.55
5.48
36.09
100.0
29.32
36.30
12.05
22.33
100.0
Source: NHWS, 2008.
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Table 8. Pain population, prescription medication utilization by pain severity NHWS, 2008.
Medication status
Severe
pain (%)
Moderate
pain (%)
Mild
pain (%)
Total pain
population (%)
Strong opioids*
Weak opioids**
Other prescription medication only***
No prescription medication
Strong opioids and OTC pain medication*
Weak opioids and OTC pain medication**
Other prescription and OTC pain medication***
No prescription but used OTC medication
Persons with prescription and/or OTC medications
10.96
27.57
15.36
11.31
2.34
7.49
7.65
17.31
100.0
1.11
10.97
13.70
22.38
0.39
3.70
7.89
39.86
100.0
0.47
2.69
6.73
36.09
0.14
1.37
3.96
48.55
100.0
3.24
13.26
12.82
22.33
0.79
4.14
7.13
36.30
100.0
*Includes weak opioids and other prescription medications.
**Includes other prescription medications but excludes strong opioids.
***Excludes strong and weak opioids.
Source: NHWS, 2008.
Persons reporting severe pain tend to focus on either
taking only prescription pain medications or combining
these with over the counter (OTC) medications.
Within the medication groups, 52.07% of those taking
only prescription medications were experiencing moderate pain compared to 41.84% for those with severe pain
(Table 6). The corresponding figures for those only taking
OTC medications are 65.02% and 10.86% respectively.
A total of 33.01% of those taking both prescription and
OTC medications are in the severe pain group.
The distribution of medication utilization within the
total pain population clearly favors those only taking
OTC medications (36.30%), with 29.32 only taking prescription medications (Table 7). Just over one in five
(22.33%) took neither prescription nor OTC pain medications. Turning to the distribution of medications by pain
severity category we find of those reporting severe pain
53.89% reported only taking prescription medications,
with 17.31% only taking OTC medications. Among
those with moderate pain, persons only taking OTC medications predominate (39.86%), with a much higher figure
for mild pain (48.55%).
Prescription medication utilization by drug class –
strong opioids, weak opioids and other prescription medication – is presented as a hierarchy (Table 8). The first
470
The prevalence, correlates and treatment of pain Langley
group is persons who report strong opioids including, if
reported, weak opioids and other prescription medications.
The second group is those who report weak opioid use and,
if reported, other prescription medications but no strong
opioids. The third group is those who take prescription
medications but not strong or weak opioids. These distinctions carry over when OTC medications are added to these
three prescription drug categories.
Within the pain population only 3.24% report taking
strong opioids with possibly weak opioids and other prescription medications; with 10.96% in the severe pain
group. Persons who do not report strong opioids but
report weak opioids and possibly other prescription medications are 13.26% in the total pain population but
27.57% in the severe pain population. A total of 12.82%
report taking non-opioid prescription medications. A
total of 36.30% of the pain population report taking only
OTC products. This figure is highest in the mild pain category (48.55%) and lowest in the severe pain category
(17.31%).
Duration of pain medication utilization
Table 9 reports the duration of medication utilization by
medication utilization status. The medication utilization
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Table 9. Pain population, duration of pain medication utilization by pain severity, NHWS 2008.
Medication status
Duration of medication utilization
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Strong opioids*
Weak opioids**
Other prescription medication***
Strong opioids and OTC pain medication*
Weak opioids and OTC pain medication**
Other prescription and OTC pain medication***
Persons with prescription and/or OTC medications
Severe pain (%)
Moderate pain (%)
Mild pain (%)
Under
3 months
3 months
or more
Under
3 months
3 months
or more
Under
3 months
3 months
or more
7.48
28.75
32.07
2.91
6.52
22.26
100.0
16.36
39.90
20.17
3.33
11.00
9.24
100.0
1.63
17.62
45.11
1.09
7.31
27.25
100.0
3.14
30.72
35.01
1.01
10.15
19.97
100.0
0.00
22.03
37.83
1.32
6.27
32.55
100.0
3.89
16.25
45.43
0.81
9.64
23.97
100.0
*Includes weak opioids and other prescription medications.
**Includes other prescription medications but excludes strong opioids.
***Excludes strong and weak opioids.
Includes people reporting pain and using a prescription medication because duration was only collected in the NHWS for persons reporting one or more prescription
medications.
Source: NHWS, 2008.
Table 10. Pain population, average Morisky score by pain severity and medication utilization, NHWS 2008.
Medication status
Strong opioids*
Weak opioids**
Other prescription medication***
Strong opioids and OTC pain medication*
Weak opioids and OTC pain medication**
Severe pain
Moderate pain
Mild pain
Total pain population
0.694
0.983
1.193
0.925
1.505
1.323
1.068
1.302
1.813
1.713
0.964
1.063
1.555
0.501
1.656
0.829
1.027
1.296
1.169
1.624
Morisky score takes values from 0 to 4 (where 0 is adherent).
*Includes weak opioids and other prescription medications.
**Includes other prescription medications but excludes strong opioids.
***Excludes strong and weak opioids.
Source: NHWS, 2008.
hierarchy is the same as for Table 8. Duration is defined in
terms of the longest period reported for any given medication within the medication class and is presented as the
percentage of respondents reporting duration of use (but
not compliance or adherence) for periods under 3 months
and for 3 months or more by pain severity and medication
status. For persons with severe pain who report a duration
of 3 months or more, 16.36% report a strong opioid with
possible weak opioid and other prescription medication
use. The corresponding figure for those with a weak
opioid (no strong opioid) and other possible prescription
medication is 39.90% for a duration of 3 months or more.
The corresponding figures for those with moderate pain
are 30.72% for weak opioids and 3.24% for strong
opioids. Again, for those with severe pain 20.17% report
taking other prescription medications for 3 months or
more compared to 35.01% for those reporting moderate
pain.
Prescription medication adherence
Morisky scores for prescription adherence by medication
status and pain severity are presented in Table 10 for the
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same medication hierarchy reported in Tables 8 and 9.
These are the average of respondent integer valued
scores (range 0–4) across all respondents in the respective
cells. The lower the score the greater the adherence. For
the total pain population the Morisky scores vary from
0.829 in the case of those using strong opioids to 1.624
in the case of those using weak opioids and OTC pain
medications. The greatest adherence reported, a Morisky
score of 0.694, is for those with severe pain and utilizing
strong opioids (to include weak opioids and other prescription medications).
Satisfaction with pain medications
Overall, the overwhelming majority of persons taking
prescription pain medications report they are satisfied
with all medications taken (Table 11). Taking account
of the substantial proportion of the pain population who
do not take prescription medications (58.63%), 29.63%
report being satisfied with all prescription medications.
Among those with severe pain, where those not taking
prescription medications account for only 28.62% of the
The prevalence, correlates and treatment of pain Langley
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Table 11. Pain population, satisfaction with prescription and OTC pain medications by pain severity, NHWS 2008.
Satisfaction
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Satisfaction with prescription pain medications
Satisfied with all prescription pain medication
No view on all prescription pain medication
Dissatisfaction with all prescription pain medications
Other
No prescription pain medication
Satisfaction with OTC pain medications
Satisfied with all OTC pain medication
No view on all OTC pain medication
Dissatisfaction with all OTC pain medications
Other
No OTC pain medication
Not asked
Severe
pain (%)
Moderate
pain (%)
Mild
pain (%)
Total pain
population (%)
47.96
7.23
7.4
8.79
28.62
100.0
27.9
3.73
3.28
2.85
62.24
100.0
12.2
1.18
1.14
0.85
84.63
100.0
29.63
4.07
3.83
3.84
58.63
100.0
12.15
2.97
1.48
0.88
28.62
53.89
100.0
9.11
1.33
0.76
0.78
62.24
25.79
100.0
4.82
0.14
0.26
0.26
84.63
9.89
100.0
9.03
1.49
0.83
0.71
58.63
29.32
100.0
Source: NHWS, 2008.
severe pain population, 47.96% report being satisfied with
all prescription medications.
Societal burden of pain
Three aspects of the societal burden of pain are considered.
These are:
Health related quality of life
Labor force participation and productivity
Healthcare resource utilization
HRQoL
HRQoL results are presented in Table 12. Estimates for the
mental and physical component scores for the SF-12 show
a disparity between PCS and MCS measures with the deficit impact of pain substantially greater for the former
measure.
Against an implicit norm of 50, persons reporting no
pain had a PCS of 50.96 (SD 8.42) while those reporting
pain had a corresponding score of 44.26 (SD 11.60).
Within the pain population persons reporting severe
pain have the greatest deficit in PCS (32.03; SD 11.53),
followed by those reporting moderate pain (42.27; SD
10.62). Within the severe pain category, those reporting
daily pain report a PCS of only 29.220 (SD 10.45).
The MCS for the total pain population (44.26, SD
11.60) is substantially below that for the no pain population (50.96; SD 8.42). Even so, MCS by pain severity and
frequency categories are not markedly different from each
other.
The impact of pain on SF-6D health utility scores is
most clearly seen in respect of severe pain. Against a no
pain group absolute utility of 0.74 (SD 0.13), persons
experiencing severe pain have an estimated absolute
472
The prevalence, correlates and treatment of pain Langley
utility score of 0.56 (SD 0.12). Corresponding scores for
moderate pain are 0.66 (SD 0.12) and mild pain 0.72
(SD 0.12). The impact of frequency is seen most dramatically in the severe pain category. Persons reporting severe
daily pain have a utility of 0.54 (SD 0.11) compared to
those with moderate daily pain reporting a utility of 0.64
(SD 0.64).
Responses to each of the eight SF-12 scales are detailed
in Table 13 for each of the pain severity groups and the no
pain population. There is a deficit recorded for each scale
between the pain and no pain populations. The deficit is
greatest for bodily pain and for general health. The deficit
pattern is repeated for each level of pain severity; the
greater the reported pain severity the greater the deficit
for each scale. In the severe pain category, the deficit is
greatest for bodily pain (28.71 vs. 49.99 in the no pain
group).
Labor force participation and productivity
The association between labor force participation (LFP)
and pain severity is detailed in Table 14. The LFP in the no
pain population is 64.46%. The LFP in the pain population
is 55.93%, falling to 44.67% in the severe pain group. This
decline in LFP occurs for all employed components of
LFP but not for the unemployed (i.e., those actively looking for work).
Absenteeism and presenteeism
Patterns of absenteeism and presenteeism mirror those for
labor force participation (Table 15). Rates of absenteeism
over the previous week increase along with presenteeism as
pain increases in severity. In the case of absenteeism, with
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Table 12. Population health related quality of life: pain severity and frequency by SF-12 mental and physical summary scores and
SF-6D utilities, NHWS, 2008.
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Frequency of
pain reported
SF-12 MCS
Once a day
4–6 times a week
2–3 times a week
Weekly or less
Total pain population
SF-12 PCS
Once a day
4–6 times a week
2–3 times a week
Weekly or less
Total pain population
SF-6D utilities
Once a day
4–6 times a week
2–3 times a week
Weekly or less
Total pain population
Persons not reporting pain
MCS
PCS
SF-6D utilities
Severe
pain (SD)
Moderate
pain (SD)
Mild
pain (SD)
Total pain
population
41.36 (12.57)
40.63 (11.86)
41.36 (12.19)
44.96 (10.90)
41.65 (12.38)
45.32 (11.85)
44.20 (11.39)
43.74 (11.22)
44.87 (10.62)
44.72 (11.37)
46.71 (11.82)
45.47 (10.96)
44.54 (11.43)
46.43 (10.05)
46.01 (10.75)
43.86 (12.30)
43.78 (11.50)
43.71 (11.38)
45.44 (10.46)
44.26 (11.60)
29.20 (10.45)
35.88 (10.02)
40.09 (9.16)
45.10 (9.37)
32.03 (11.53)
37.56 (10.53)
42.05 (9.99)
43.96 (9.38)
48.41 (8.26)
42.27 (10.62)
45.40 (10.04)
46.27 (8.70)
47.01 (8.88)
50.40 (7.77)
48.54 (8.74)
34.81 (11.56)
41.61 (10.25)
44.28 (9.43)
48.86 (8.31)
41.07 (11.85)
0.54 (0.11)
0.58 (0.10)
0.62 (0.11)
0.67 (0.12)
0.56 (0.12)
Score
47.00 (10.64)
50.96 (8.42)
0.74 (0.13)
0.64 (0.12)
0.66 (0.11)
0.67 (0.11)
0.70 (0.11)
0.66 (0.12)
0.72 (0.13)
0.70 (0.12)
0.69 (0.11)
0.73 (0.11)
0.72 (0.12)
0.60 (0.13)
0.65 (0.11)
0.67 (0.11)
0.71 (0.11)
0.65 (0.13)
MCS: mental component score; PCS: physical component score; SD: standard deviation.
Source: NHWS, 2008.
Table 13. Population average scores to SF-12 scales by pain severity, NHWS 2008.
SF-12 scale
SF12 physical functioning
SF12 role physical
SF12 bodily pain
SF12 general health
SF12 vitality
SF12 social functioning
SF12 role emotional
SF12 mental health
Severe pain
Moderate pain
Mild pain
Total pain population
No pain population
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Mean
SD
36.94
34.07
28.71
32.40
41.52
36.20
37.28
40.86
12.19
10.07
10.77
11.44
9.99
11.62
13.92
11.34
45.45
42.24
40.11
40.50
46.27
42.76
42.79
44.98
10.72
9.69
9.87
10.79
9.34
10.58
11.81
10.20
50.24
47.24
46.64
45.84
49.22
45.81
45.07
47.48
9.06
8.95
8.47
9.83
8.94
10.23
11.17
9.47
44.37
41.28
38.69
39.62
45.72
41.82
41.95
44.49
11.67
10.58
11.50
11.64
9.75
11.25
12.51
10.58
51.32
48.72
49.99
47.48
51.51
46.74
45.97
48.82
8.64
8.95
9.18
9.87
9.18
10.31
11.03
9.76
SD: standard deviation.
Source: NHWS, 2008.
Table 14. Labor force participation by pain severity, NHWS 2008.
Labor force status
Employed full-time
Employed part-time
Self-employed
Unemployed
In the labor force
Not in the labor force
Severe
pain (%)
Moderate
pain (%)
Mild
pain (%)
Total pain
population (%)
No pain
population (%)
25.98
9.81
3.79
5.08
44.67
55.33
34.44
10.83
5.72
5.15
56.14
43.86
47.39
10.75
7.25
4.05
69.44
30.56
34.85
10.59
5.56
4.93
55.93
44.07
44.52
9.80
6.11
4.03
64.46
35.54
LFP is defined as the number of persons in each labor force category divided by the total population 18 years of age and over.
Source: NHWS, 2008.
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The prevalence, correlates and treatment of pain Langley
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Current Medical Research & Opinion Volume 27, Number 2
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Table 15. Employed population absenteeism and presenteeism by pain severity, NHWS 2008.
Average number of hours
impacted last week (SD)
Absenteeism
Presenteeism
Severe pain
Moderate pain
Mild pain
No pain population
22.97 (37.10)
37.49 (28.58)
7.77 (22.26)
24.88 (24.90)
4.76 (16.35)
18.71 (22.77)
4.09 (16.11)
13.76 (21.17)
Source: NHWS, 2008.
Table 16. Population health care utilization: traditional provider visits, emergency room visits, hospitalizations, NHWS 2008.
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Average number of visits past 6 months (SD)
Traditional provider visits
Emergency room visits
Hospitalizations
Severe pain
Moderate pain
Mild pain
No pain population
11.83 (12.00)
0.50 (1.47)
0.59 (3.67)
7.82 (8.90)
0.32 (1.33)
0.22 (1.75)
5.51 (6.93)
0.22 (0.67)
0.16 (0.64)
4.39 (6.08)
0.18 (1.03)
0.14 (1.25)
Source: NHWS, 2008.
the no pain population as the reference point (4.09%
absenteeism) those with mild pain report an absenteeism
rate of 4.76% climbing to 22.97% for those with severe
pain. The corresponding presenteeism estimates increase
from 18.71% in the mild pain group to 37.49% in the
severe pain group compared to 13.76% in the no pain
population.
Healthcare resource utilization
Healthcare resource utilization is considered in terms of:
(i) traditional provider visits; (ii) emergency room visits;
and (iii) hospitalizations. Comparing the no pain to the
pain population there is a clear demarcation in terms of
resource utilization (Table 16). This is most clearly seen in
respect of those experiencing severe pain where a substantially higher average number of traditional provider visits
(11.83 vs. 4.39), emergency room visits (0.50 vs. 0.18) and
hospitalizations (0.59 vs. 0.14) is observed. These differences reduce as pain severity declines.
Discussion
In the pain population, the most frequently reported conditions causing pain are back pain (65.56%) joint pain
(51.66%), neck pain (32.20%) and headache (31.36%)
(Table 4). The categories are not mutually exclusive.
These results are entirely consistent with previous studies
reporting over half the respondents having back pain,
some 40% with joint pain and 20% with neck pain. The
estimates given here are somewhat higher than those
reported by Breivik et al.2, which probably reflects
Breivik’s focus on chronic pain. What is of interest to
note, however, is that the distribution of the severity of
pain reported is similar across all top four pain condition
474
The prevalence, correlates and treatment of pain Langley
groups with the majority reporting moderate pain and
approximately one in four reporting severe pain.
A key distinction between the present survey of pain
experience and previous national surveys is in the assessment of the severity, frequency and duration of pain experienced. The present survey is not intended, for example,
to focus on chronic pain per se but on the current experience of pain in a representative European population. This
includes, by definition, persons who are receiving treatment for their pain condition. In this context, a major
objective of the survey is to assess the extent and correlates
of the individual and societal burden of pain; i.e., the
extent to which current pain experience impacts health
related quality of life, workforce status and productivity,
and healthcare resource utilization. While this does not
mean that the duration and intensity of pain experienced
are not potentially important attributes, the focus is on
perceived pain severity and its frequency.
In the Breivik study, the screening questions exclude
all persons who do not meet its definition of chronic
pain2: experienced pain for at least six months, had experienced pain in the last month, had experienced pain at
least twice a week and rated their pain as at least 5 on a
10-point numeric rating scale. This is, of course, not the
only definition of chronic pain found in the literature.
Smith et al.10 differentiated ‘any chronic pain’ from ‘significant chronic pain’ and ‘severe chronic pain’ – all of
which had a common element of pain duration of at least
3 months. This follows from the IASP definition of
chronic pain as ‘ . . . pain which persists past the normal
time of healing . . . With nonmalignant pain, three
months is the most convenient point of division between
acute and chronic pain, but for research purposes six
months will often be preferred’’20. A recent study of
pain in primary care by Frießem et al. in 200912 defines
chronic pain as recurring or constant pain lasting longer
than six months.
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A further consideration in avoiding screening questions
that arbitrarily differentiate pain groups is the identification of the type of pain experienced and the extent to
which respondents suffer from widespread pain and the
duration of that pain. This points to the multidimensional
nature of pain and further aspects of the societal burden of
pain. Gerdle et al.6 report on a population study in Sweden
of the prevalence of widespread pain and its impact on
work status. They find that widespread pain under the
ACR criteria31 gives an overall population prevalence of
4.8% while the Manchester definition32 yields a population prevalence of 7.4%.
More recently Von Korff and Dunn33 have argued that
the duration approach to the definition of chronic pain is
less than optimal. Defining chronic pain solely by duration
has not produced reliable or valid methods for the differentiation of chronic from acute pain in either clinical or
epidemiological research. The key point is that pain, in
particular chronic pain, is multidimensional. Taking a prospective approach to defining chronic pain the authors
propose a risk scoring algorithm to predict probabilities
of chronic pain 1 to 5 years ahead. A comparison of the
risk score with pain days experienced across pain conditions showed less than moderate agreement. The two
approaches differed in their profile of chronic pain across
pain conditions. Risk score patients, however, with possible and probable chronic pain differed from low-risk
patients in both reported intensity and duration. Risk
scores had improved predictive power for future severe
pain over pain days across all pain conditions assessed.
The authors suggest that chronic pain should be defined
by the likelihood that the pain will continue into the
future, not by duration of pain experience. In the general
practitioner setting, however, it might be easier to distinguish chronic pain by duration rather than apply risk
scores.
While the NHWS does not allow estimation of the
proposed Von Korff and Dunn33 risk score, the key point
to note is the multidimensional nature of pain and the
need to generate an estimate of the likelihood of chronic
pain that is consistent across pain conditions. The advantage of the approach taken here in the classification of pain
experience is one of flexibility. It allows various profiles of
pain experience to be constructed and their impact
assessed – as well as the independent contributions of
pain frequency and pain severity combinations. For example, if chronic pain is defined as persons experiencing
severe or moderate pain at least 4 to 6 times a week then
an estimated 10.35% of those 18 years and over in the five
EU countries would be classified as experiencing chronic
pain. However, if the duration of prescription pain medication utilization is added, where the respondent must
have taken at least one branded pain medication for at
least 3 months, then this would yield a lower estimate.
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Rather than attempt to base an analysis of the prevalence and correlates of pain experience on an arbitrary
distinction between persons experiencing acute and
chronic pain – or on a risk score approach to assess the
likelihood of chronic pain – the analysis presented here
focuses on reported pain severity and pain frequency and
the relationship between the pain and no pain populations
in the five EU countries. While the emphasis has been on
the correlates of those reporting pain severity, it could be
extended to combine pain frequency with pain severity.
This is most effectively assessed in the context of multivariate modeling. The potential importance of integrating
these two dimensions of current pain experience is seen,
first, in the relationship between severity of pain reported
(Table 1) and, second, in the relationship between severity
and frequency on the distribution of physical and mental
summary scores from the SF-12 instrument and on the
estimated SF-6D health utilities (Table 12). In the
former case, the majority of persons reporting severe pain
also report experiencing daily pain. The frequency of pain
reported is more diffuse for both the moderate and, in particular, the mild pain groups. In the latter case, there is a
clear relationship between the deficits reported for the
three health related quality of life measures and the
increasing severity and frequency of pain reported.
This is seen most dramatically in the SF-12 physical summary scores for persons in the severe pain category.
As far as the overall prevalence of pain in these five EU
countries is concerned, the NHWS survey finds that one in
five of the population experienced pain in the previous
month (Table 1). The majority report experiencing moderate pain, a population prevalence of 12.0%, with a population prevalence for severe pain of 4.61%. These
estimates are not inconsistent with previous estimates of
the population prevalence of pain and estimates of the
prevalence of chronic pain. Under the Breivik2 criteria
19% of the population of the 16 countries in their telephone survey reported moderate or severe chronic pain –
with a range across the individual countries from 12% to
30%. The overall ratio of severe to moderate pain was 1:2,
although (once again) there were significant differences in
the relative importance of severe vs. moderate pain
between the various countries. Using the IASP definition,
however, Ospina and Harstall estimate a mean prevalence
of chronic pain of 35.5% (range 55.2% to 11.5%) with a
weighted mean prevalence under the ACR definition of
11.8% (range 10.1% to 10.5%)17. Even so, more recent
estimates of the population prevalence pain and the prevalence of chronic severe pain point to the disparities than
can exist. Gerdle et al.6 in their Swedish population study
(age group 18 to 74 years) estimated a population prevalence for those reporting pain in the last week of 63.2%,
with 4.8% to 7.4% reporting widespread chronic pain.
A feature of the present study which is not found in
previous studies is the frequency with which pain is
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experienced. While some studies report the experience of
constant as opposed to intermittent pain2, the detail provided by the NHWS is not found. In the case of severe
pain, some four out of five respondents report severe daily
pain, while only two out of five respondents report daily
moderate pain. This would qualify attempts to define
chronic pain solely in terms of duration.
What is of interest in the present study, however, is the
apparently low population prevalence of mild pain. As
previous studies have focused on moderate and severe
pain, notably in respect of chronic pain and neuropathic
pain, the experience of mild pain has tended to be overlooked. In McDermott’s study of neuropathic pain report3,
using the Brief Pain Inventory score, that most patients
reported moderate pain (54%) followed by severe pain
(25%) and the balance mild pain.
The impact of gender on the reporting and experience
of pain has been extensively documented. Pain prevalence
studies have consistently shown the impact of gender with
women reporting more pain than men, reporting more
severe and persistent pain and reporting pain in more
body regions. General population studies have shown statistically significant gender differences16, thoracic spine
pain34 and with even greater disparities for chronic widespread pain and fibromyalgia35. In the present analysis the
difference in pain prevalence and gender is clear-cut both
at the population pain prevalence level (Table 2) and
within the pain population (Table 3). There is, however,
one qualification: the gender difference favoring females
only holds for severe and moderate pain; males report more
mild pain. Within the pain population females, unlike
males, are more likely to report severe and moderate pain.
The impact of age on pain is also less clear cut. Rather
than a simple gradient where the prevalence of pain across
all pain severity categories increases with age, the results
(at least for severe and moderate pain) point to the highest
prevalence in the 40 to 59 years of age group (Table 2).
Indeed, within the pain population, persons 40 to 59 years
of age are more likely to report severe pain than the other
age groups (Table 3).
Although there seems to be a consensus view that there
exists a strong social gradient between social status and the
experience of pain, notably with educational attainment
and household income36,37, the population prevalence
results reported here do not support that proposition. At
the population prevalence level, the percentage reporting
pain is highest in the 40 to 59 years age group (9.97%) and
in the intermediate household income (E20,000 to
E39,999 group (6.89%). Severe pain is a possible exception. Within the pain population there is no evidence for
the likelihood of moderate pain experience being different
across income or education groups. Again, severe pain is a
possible exception with the frequency reported being
inversely related to both education and household income.
476
The prevalence, correlates and treatment of pain Langley
It is important to distinguish patient or physician
assessed conditions that are associated with self-reported
pain from the comorbidities reported by patients
experiencing pain. Indeed, the term comorbidity could
be extended to include health risk behaviors and even
socio-demographic and employment related characteristics – which may map into scales or instruments such as
the SF-36. Current and former smokers, for example, have
been found to have a higher prevalence or incidence,
albeit modest, of low back pain38. While there is a growing
literature on the comorbidities or health states that are
associated with pain there is no consensus on the principal
comorbidities – even when particular pain types of disease
states associated with severe or moderate pain are the
focus. This reflects, in part, the limitations of patient self
reporting, the lack of an agreed classification system for
reporting comorbidities and the lack of comprehensive
clinical assessment of comorbidities in pain prevalence
studies. The NHWS is no exception as respondents are
merely asked to report on conditions they have experienced in the last 12 months – without reference to pain
(Table 5). As it stands, the conditions reported are somewhat heterogeneous combining both direct pain experience with comorbidities which may or may not be
argued to be linked to pain (e.g., nasal allergies/hayfever).
Even so, the conditions ranked as having the highest prevalence in the pain population are clearly associated with
pain experience – headache, abdominal pain, sleep difficulties, insomnia. At the same time there are a number of
high prevalence conditions often associated with the existence of pain – anxiety and depression39 and migraine40. It
is worth noting that the population prevalence of anxiety
is 35.97% and depression is 25.21% with recent studies
pointing to the role of psychosocial factors in amplifying
the perception of pain severity, coping adequacy and mediating response41. As these responses are not mutually
exclusive, it is of interest to speculate whether or not clinically distinguishable constructs or subgroups of conditions
which may have distinct pathophysiological mechanisms
of pain generation and response42. Of some note is the
relationship between the pain population prevalence of
psychiatric disorders with pain severity. As pain increases
in severity the prevalence of depression, anxiety, generalized anxiety disorder and panic disorder increases
significantly.
Patterns of medication utilization point to an increased
utilization of prescription pain medications with increased
pain severity (Tables 6 and 7). There is little difference in
patterns of use for those only reporting prescription medications between those reporting severe or moderate pain.
There are, not surprisingly, relatively few respondents with
severe pain who are only on OTC products. Even so there
is a substantial proportion of respondents with severe pain
who reportedly take no pain medications, a proportion
that increases with moderate and then mild pain.
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Care has to be taken in interpreting opioid use. In the
NHWS survey respondents could choose from pre-selected
lists of prescription medications as well as detailing OTC
medication utilization. In the results presented here a hierarchy of drug utilization is employed. At the apex are those
persons who report strong opioids utilization with the possible addition of weak opioids and other prescription medications. At the next level are those who report weak
opioids utilization and possibly other prescription medications but no strong opioids. Given this, it is noteworthy
that almost 40% of those with severe pain who report
taking prescription and/or OTC medications take at least
a strong or a weak opioid; at the same time 17.31% report
only taking OTC medications. This contrasts with utilization patterns among those with moderate or mild pain
where opioids and other prescription drug use declines substantially, to be overtaken by exclusive non-prescription
drug utilization.
One feature of duration of medication utilization that
stands out is the percentage of respondents who report long
term utilization of opioids – in particular the use of weak
opioids – in conjunction with other prescription medications (Table 9). Among respondents who have severe pain
and who report 3 months or more of medication utilization, 39.90% report taking weak opioids and 16.36%
strong opioids (together with other prescription medications). Among the severe pain group relatively few report
long term utilization of combinations involving OTC
products. Among those with moderate pain, for those
with a duration of 3 months or more, sole utilization of
prescription medications are still the largest categories.
This holds for those reporting mild pain.
A recent review by Broekmans et al.43 provides a useful
overview of the degree of medication adherence in chronic
non-malignant pain. The review found that lack of adherence is common, to include both medication overuse and
underuse. A recent Taiwanese study assessed the Morisky
score as a measure of adherence in chronic cancer pain
where just over 50% of patients were non-adherent44.
The results of the present study, in reporting average
Morisky scores by medication status and pain severity,
paint a somewhat different picture (Table 10). Persons
who are experiencing severe pain are consistently more
adherent to their medication, whether prescription or
OTC, than those who are experiencing only moderate
pain. As well, persons who report only strong or weak
opioid utilization report consistently higher adherence
compared to other pain medication groups, with persons
on strong opioids and experiencing severe or moderate
pain reporting the highest adherence rates. As Table 9
demonstrates, this adherence is on a relatively long term
basis. Clearly, before blanket statements are made as to
adherence experience, the potential impact of choice of
medication and pain severity needs to be factored into the
analysis.
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The level of satisfaction with pain medications, notably
for prescription pain medications, is high (Table 11).
Among the severe pain population, 47.96 report being satisfied with all prescription medications taken (with
28.62% not taking prescription pain medications).
Ignoring this latter group, this figure translates to
67.19% or two out of three respondents.
The impact of neuropathic pain on HRQoL has
been the subject of community studies45 and recent
reviews45–47. Smith et al. found that those experiencing
neuropathic pain in three UK communities recorded significant differences on all dimensions of the SF-36 compared to those reporting no pain45. In reviews by both
Jensen and O’Connor neuropathic pain was associated
with significant HRQoL deficits in multiple domains –
including physical and emotional suffering46,47. Utilizing
the EQ-5D instrument as reference point, McDermott
et al. point to substantial differences in the deficits associated with levels of pain severity although direct evidence
for deficits compared to no pain populations have focused
on hypothetical pain free states rather than direct observation. Unfortunately, relatively few of these studies have
used a validated generic instrument to assess quality of
life3. While Smith et al.10 utilize the SF-36, more recent
studies which have taken a broader perspective2,3 have not
included a validated instrument. In the present survey, as
already noted this is recognized and the SF-12 instrument
is used to assess HRQoL. The use of a validated instrument
is important because it not only allows comparisons across
studies but in the case of the SF-6D health utilities can be
estimated.
In terms of the scores reported for the SF-12 instrument,
the deficit impact of pain is most clearly felt in terms of the
PCS (Table 12). While there is a substantial deficit associated with the MCS, there is little variation between the
pain severity and frequency categories. This is in contrast
to the variability shown for the PCS, with severe daily pain
showing the greatest deficit. The differential impact of
pain on the PCS and MCS is most readily explained in
terms of the components of the scores. The components of
the PCS are of interest with the deficit in scores most
clearly seen in respect of bodily pain. Even so, it is worth
noting again that the SF-12 bodily pain item does not ask
respondents to indicate either the severity or the frequency
with which pain is experienced. Rather the question asks
respondents ‘How much did pain interfere with your
normal work (including both work outside the home and
housework)’ with the response choice (five items) from
‘not at all’ to ‘extremely’. While depression has often
been identified as a key element in the negative impact
of pain on HRQoL it does not stand out in this analysis –
even for severe pain.
As well as evaluating the impact of pain on HRQoL, the
present survey also allows an assessment of its impact on
employment status and workplace productivity. There is
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now an extensive literature on the impact of pain and
disability on employment status and the likelihood of
returning to work. There are, however, relatively few studies that have considered the relationship between pain
severity and factors such as pain duration on labor force
status. Those studies that have considered the relationship
point to the adverse impact on employment status48,49. In
the present study, the presence of both severe and moderate pain is associated with reduced labor force participation (Table 14). Compared to the no pain population,
severe pain respondents report an almost 20 point deficit
in the percentage in full-time employment. While it is not
possible to assign this deficit directly to the experience of
pain as there may be other factors contributing to the
employment decision, the deficit is clearly substantial
and could be interpreted as one of the more significant
community burdens associated with the experience of
pain. Although the numbers are small, it is worth noting
that while the percentage of those employed declines with
pain, the percentage actively looking for work increases.
The impact of pain on both absenteeism and presenteeism has been considered in a number of studies. These
include the Stewart et al. assessment of lost productive
time due to common pain conditions – impacting 13%
of the US workforce50 – with the major losses due to presenteeism rather than absenteeism; the Roy assessment of
the loss of productive time due to pain in the US51; and
more recently, for pain associated with particular disease
states, the review by Manchikanti et al. of the impact of
spinal pain52 and the Sullivan et al. review of the impact of
rheumatoid arthritis53. The results of the present study, not
surprisingly, support the consensus view on the negative
impact of pain on productivity in pointing to the impact
of pain on both rates of absenteeism and presenteeism
(Table 15).
Finally, it should also come as no surprise that the
presence of pain negatively impacts health care resource
utilization (Table 16). This is seen in traditional provider visits, emergency room visits and hospitalizations.
The impact is most pronounced in the severe pain
category.
Limitations of the analysis
The results detailed here are essentially descriptive. In
reporting on the key findings for the prevalence, correlates and outcomes associated with the severity and frequency of pain, little can be said as to the underlying
causes for the observed patterns or the relative importance of pain severity and frequency, for example, on
the HRQoL, workforce status and productivity and
healthcare resource utilization. This would require a multivariate analysis that captured possible confounding factors – socio-demographic characteristics, health risk
478
The prevalence, correlates and treatment of pain Langley
factors and the presence of comorbidities. Two complementary studies utilizing the same data set have already
evaluated the quantitative impact of the severity and
frequency of pain on HRQoL and healthcare resource
utilization14 and the impact of pain on employment
status, absenteeism and presenteeism15. Both point to
the dominant impact of pain severity and frequency on
these aspects of the burden of pain compared to socioeconomic characteristics, health risk behaviors and
comorbidities. Other aspects that could be explored in
similar analyses would be the determinants of gender differences in pain reported, the impact of pain prevalence
within disease groups, medication utilization patterns and
pain severity and frequency, adherence patterns and
duration of utilization, and satisfaction with care. Even
so, the results presented here point, not only to the pervasive presence of pain in these five EU countries, but to
the potential importance of factoring in both pain severity and the frequency of pain experienced in understanding the burden of pain in the community.
There are other limitations to this analysis that should
be noted. First, the NHWS is an internet based survey
and may not be representative of the five EU countries
covered in the sample – particularly if there are potential
biases in the extent to which internet access is available.
Even so, over 50% of the EU population in all countries
has internet access. The clear advantage of internet based
surveys such as the NHWS is in their flexibility, timeliness and cost in identifying key aspects of the burden of
disease – in particular, in the present case, the ability to
identify a ‘no-pain’ control group. Given that the NHWS
covers some 140 disease areas, it offers a robust vehicle
for the analysis of pain. Second, respondents are asked to
report their experience of pain. There is no separate clinical confirmation of the presence of pain and reported
conditions and attributes that may be associated with
pain experience. Third, the study is focused on the experience of pain. It has not been concerned with the
broader issue of whether the experience of chronic pain
should be considered as a disease in its own right54. If
pain is considered as a disease in its own right, the sheer
burden of pain would point to the need to evaluate the
commitment to national pain management strategies, a
need for more education to acquaint stakeholders with
the burden of pain and the need to take a global perspective in management strategies.
Conclusions
The experience of pain – notably moderate and severe
pain – is common in the adult population. With over
one in five of the estimated 5 country adult population
of some 250 million persons reporting having experienced
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Current Medical Research & Opinion Volume 27, Number 2
pain in the last month, notably moderate and severe
pain, the burden of pain experience is substantial for
both the individual and for the community as a whole.
The burden imposed comprises not only pain severity, to
exclude acute pain presentations associated with
migraine, dental pain, menstrual pain and headache,
but also the frequency of pain reported. Almost one in
two of those experiencing pain, even with the range of
pain modalities and treatment options open, report daily
severe or moderate pain. Pain experience is dominated by
back and joint pain, but with almost one in three also
reporting neck pain and headaches ancillary to other
pain conditions. Indeed, ancillary headache experience
is reported by two out of three respondents. Not surprisingly respondents reporting severe pain also report the
highest utilization of prescription pain medications, in
particular the use of weak opioids. Overall, respondents
are satisfied with their pain medications and are strongly
adherent in medication utilization, notably among those
experiencing severe pain.
The cumulative burden of pain is amply demonstrated
in terms of HRQoL, employment status and workforce
activities as well as in healthcare resource utilization.
Perhaps the most striking impacts are seen in the
impact of severe and frequent pain on HRQoL. Of the
three measures employed, the impact on the PCS component of the SF-12 and the SF-6D absolute utility
scores are substantial. The presence of severe and daily
pain not only reduces the PCS against that reported for
the no pain population by over 20 points (or approximately 40%) but the impact on the absolute utility score
is to reduce it from a no pain average of 0.74 to a score
of 0.54. Both imply a substantial pain related clinical
deficit. As far as productivity losses to the community
are concerned the impact of severe pain is equally dramatic. Labor force participation for the severe pain group
is some 20 points lower than for the no pain population
while rates of absenteeism and presenteeism are over five
time and three times greater respectively than those
reported for the no pain population.
The fact that one in five of the adult population of
these five European countries reports experiencing pain
in the past month presents a major challenge for both
policies to reduce the incidence and prevalence of
chronic pain in the community as well as policies to
manage pain populations. Whether pain should be considered a disease in its own right, or managed as part of
traditional disease intervention strategies where pain is a
significant comorbidity, is an issue which has yet to be
resolved. A lack of appreciation of the need to manage
pain effectively in the long-term would be a major concern. Even so, the benefits of effective pain prevention
and pain management strategies would appear to be
substantial.
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February 2011
Transparency
Declaration of interest
This study was supported by Grünenthal GmbH, Aachen,
Germany.
Declaration of financial/other interests
P.C.L. has disclosed that he is a consultant for Kantar Health, a
company that undertook this analysis on behalf of Grünenthal.
Acknowledgments
No assistance in the preparation of this article is to be declared.
The author would like to acknowledge comments on earlier drafts
from members of the CHANGE PAIN International Advisory
Board.
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