PREVALENCE OF CHRONIC PAIN WITH NEUROPATHIC CHARACTERISTICS IN
THE GENERAL POPULATION
Didier Bouhassira, M.D, PhD (1,2), Michel Lantéri-Minet, M.D, PhD (3), Nadine Attal,
M.D, PhD (1,2), Bernard Laurent, M.D (4), Chantal Touboul (5)
1) INSERM U-792, Boulogne-Billancourt F-92100 France; CHU Ambroise Pare, APHP,
Boulogne-Billancourt, F-92100 France; 2) Université Versailles-Saint-Quentin, Versailles
F-78035, France; 3) CHU Pasteur, Centre d'Evaluation et Traitement de la Douleur, Nice,
F-06000 France; 4) CHU de Bellevue, Service de Neurologie, Saint-Etienne, F-42055
France; 5) TNS Healthcare SOFRES, Montrouge, F-92129 France
Correspondence to:
Didier Bouhassira
INSERM U-792
Centre de Traitement et d'Evaluation de la Douleur,
CHU Ambroise Paré
9, avenue Charles de Gaulle
92100 Boulogne-Billancourt cedex
telephone number: +33 1 49 09 45 56
fax number: +33 1 49 09 44 35
e-mail: didier.bouhassira@apr.aphp.fr
ABSTRACT
We conducted a large nationwide postal survey to estimate the prevalence of chronic
pain with or without neuropathic characteristics in the French general population.
A questionnaire aimed at identifying chronic pain (defined as daily pain for at least 3
months), evaluating its intensity, duration and body locations was sent to a representative
sample of 30,155 subjects. The DN4 questionnaire was used to identify neuropathic
characteristics.
Of the questionnaires, 24,497 (81.2%) were returned and 23,712 (96.8%) could be
assessed. 7,522 respondents reported chronic pain (prevalence =31.7%; [95%CI: 31.1-
32.3]) and 4,709 said the pain intensity was moderate to severe (prevalence= 19.9%;
[95%CI: 19.5-20.4]). Neuropathic characteristics were reported by 1,631 respondents with
chronic pain (prevalence= 6.9%; [95%CI: 6.6-7.2]), which was moderate to severe in
1,209 (prevalence= 5.1% [95%CI: 4.8-5.4]). A higher prevalence of chronic pain with
neuropathic characteristics was associated with middle age (50–64 years), manual
professions and those living in rural areas. It was more frequently located in the lower
limbs and its intensity and duration were higher in comparison with chronic pain without
neuropathic characteristics.
This large national population-based study indicates that a significant proportion of
chronic pain patients report neuropathic characteristics. We identified distinctive socio-
demographic profile and clinical features indicating that chronic pain with neuropathic
characteristics is a specific health problem.
1. Introduction
Neuropathic pain is caused by a lesion or dysfunction of the peripheral or central
nervous system (Merskey and Bogduk 1994). It is generally chronic and disabling, and is
among the most challenging to treat (Dworkin et al., 2003; Finnerup et al., 2005; Attal et
al., 2006). This may be related to the specificities of its pathophysiological mechanisms
(Woolf and Manion, 1999; Baron, 2006), but also to its being underestimated, particularly
in patients having no definite neurological condition (Harden and Cohen, 2003). There
have been considerable advances in the understanding of neuropathic pain syndromes
over the last decade (Jensen and Baron, 2003; Woolf, 2004). However, there is a lack of
general epidemiological information.
Major causes of neuropathic pain include: diabetes, shingles, spinal cord injury,
stroke, multiple sclerosis, cancer, and HIV infection, as well as common conditions, such
as lumbar or cervical radiculopathies, and traumatic or postsurgical nerve injuries. The
large range of etiologies indicates that the prevalence of neuropathic pain may be high in
the general population. This has also been suggested by studies based on cohorts seen
in specialized referral centers, which showed that considerable proportions of patients
with herpes zoster (Jung et al., 2004), diabetic polyneuropathy (Daousi et al., 2004;
Davies et al., 2006); multiple sclerosis (Osterberg et al., 2005), spinal cord injury (Siddall
et al., 2003), stroke (Andersen et al., 1995); HIV infection (Hewitt et al., 1997); cancer
(Caraceni et al., 1999) and persistent postsurgical pain (Kehlet et al., 2006), suffer
neuropathic pain. These studies did not allow estimation of the overall prevalence of
neuropathic pain in the general population, but crude estimates in the 1-3% range have
been proposed (Bowsher, 1991; Dworkin et al., 2003; Irving, 2005).
One major reason for the absence of population-based epidemiologic data on
neuropathic pain was the lack of a validated, reliable and simple clinical instrument that
can identify the characteristics of neuropathic pain. Recently, we developed and validated
the DN4 questionnaire based only on the analysis of the semiological characteristics of
pain (i.e. pain descriptors). We demonstrated that a relatively small number of items was
sufficient to discriminate pain due to a definite neurological lesion (Bouhassira et al.,
2005). Like other symptom-based screening tools vadidated recently (Bennett, 2001;
Krause and Backonja, 2003; Portenoy, 2006; Freynhagen et al., 2006a), the DN4
questionnaire has very good discriminative properties for the identification of neuropathic
pain characteristics. One of the chief research application of these questionnaires is
epidemiological studies (Bennett et al., 2007). A first population-based survey using the
Leeds Assessment of Neuropathic Symptom and Signs score (S-LANSS) estimated the
prevalence of chronic pain of predominantly neuropathic origin in six family practices in 3
UK cities (Torrance et al., 2006).
Here, we present the results of STOPNEP (Study of the Prevalence of Neuropathic
Pain), a postal survey carried out to estimate the prevalence of chronic pain with or
without neuropathic characteristics in a large representative sample of the French general
population.
2. Methods
The STOPNEP population-based survey was carried out from August to November
2004 by the poll institute TNS Healthcare Sofres. Although no nominative data were
recorded, the study was notified to the French personal data processing surveillance
authorities (Commission Nationale Informatique et Libertés, CNIL) and was conducted
according to the relevant national and European laws and consensus professional
guidelines.
2.1. Subjects
The survey was conducted among the "Access Santé" permanent polling base
representative of the French population. Individuals entered into this polling base are
recruited in several ways (face-to-face interviews, mailings, phone calls) to reduce
possible risk of selection bias associated with a particular methodology.
A questionnaire was sent to a randomly selected representative sample of
30,155 panellists aged 18 years and over. The representativeness of the sample with
respect to the French national population (INSEE, 2002) was checked for sex (2
categories), age (6 categories), socio-professional status (8 categories), region (5
categories) and community size (5 categories). Reminder letters were sent to non-
respondents to increase the response rate.
2.2. Survey questionnaire
To ensure maximal response rate, the questionnaire was deliberately simple and
short. As well as socio-demographic information, there were only 11 questions
concerning pain. The first two questions were used to identify chronic daily pain (question
1: Do you currently suffer with pain every day?; if yes, question 2: Have you had this daily
