Population-based study of pain in elderly people: a descriptive survey

Age and Ageing 1998; 27: 279-284 Population-based study of pain in elderly people: a descriptive survey BRUNO BROCHET PHILIPPE MICHEL 1, PASCALE BARBERGER-GATEAU 1, JEAN-FRANCOIS DARTIGUES 1 Unite de Traitement des Douloureux Chroniques, Departement de Neunologie, Hopital Pellegrin, CHU de Bordeaux, 33076 Bordeaux cedex, France 'INSERM U330, Universrte de Bordeaux II, 33076 Bordeaux cedex, France Address correspondence to: B. Brochet Fax (+33) 5 56 79 60 25. email: bbrochet@bb-luni.u-bordeaux2.fr Abstract Aim: to establish the prevalence of pain and persistent pain in an elderly community-based population. Methods: an epidemiological study of pain complaints in a population-based sample of elderly people in Southwestern France. Results: among the 741 subjects, 530 (71.5%) reported pain somewhere, 244 (32.9%) persistent pain (defined as daily pain for more than 6 months) and 241 (32.5%) reported episodic pain. The commonest locations were limb joints and back. The prevalence of pain was 44.5% for limb joints,.6% for back, 11.6% for neck and 11.3% for limbs (joints excepted). The prevalence for persistent pain was 19-4% for limb joints, 12% for back and 10.4% for limbs (joints excepted). The frequency of persistent pain increased slightly with age in both sexes but was higher in women. A higher prevalence of persistent pain in limb joints and back in women explained the difference. By contrast, the prevalence of episodic pain was statistically higher in men over 75. Conclusion: persistent pain is an important health problem in elderly subjects Keywords: France, pain, persistent pain, population study Introduction In a recent editorial, Crombie et al. [1] called for epidemiological studies providing detailed information on the nature of pain problems in the community, the adequacy of their current management and optimal care requirements. Although pain is common in elderly patients, it has not been considered an important health problem and the literature is sparse [2]. Few data are available on the size of the problem. The main epidemiological pain studies are not large enough to study pain specifically in old age [3-8]. Several studies have addressed the problem of pain in elderly residents of nursing homes [9], but little is known about pain in elderly people living at home. In a previous epidemiological survey of elderly subjects living at home in South-Western France [10], we observed high prevalences of joint and back pain. Moreover, these complaints were associated with disability and depressive symptoms. However, this study gave little information about other pain sites or about chronic pain. To establish the prevalence of pain according to sites and temporal patterns, we designed and carried out a study in the same population 3 years later. Here we present the results of this descriptive survey of pain and persistent pain in an elderly population. Methods This work was part of a large cohort study of elderly people living in the community in the Gironde (10000 km 2, 1127 546 inhabitants), France (the PAQUID study) [11]. The aim of PAQUID was to study dementia, ageing and disability in this target population. The general methodology of the PAQUID study has previously been published [11, 12]. Briefly, a representative sample of people aged 65 and over living in the community was randomly selected from electoral registers of 37 parishes. After written informed consent, subjects were interviewed by psychologists using a closed questionnaire. These psychologists were specifically trained and had experience in interviewing elderly subjects. The sample population, aged 65 years and over on 31 December 279

B. Brochet et al. 1987 was folio wed-up and interviewed each year from 1988. The third-year follow-up interview involved 1726 subjects from the same 37 parishes, selected randomly from the original sample. A specific questionnaire on pain was included in the general questionnaire and administered at home to a subgroup of 741 subjects, randomly selected according to the size of their parish, representative of the general elderly population in the Gironde and living in 32 different parishes. The 741 subjects were therefore a subgroup of the population of the PAQUID cohort study which did not significantly differ in demographic characteristics. All subjects were living at home at the start of the study (31 December 1987) but 3 years later 4.5% were in a nursing home and 3-4% in a residential home. By this time only 40.7% of subjects lived alone. The main issues addressed by the questionnaire were: 1. Frequency of pain (annual prevalence), estimated by the question: 'During the previous year, did you feel pain anywhere?' 2. Location of pain, elicited by the open question: 'Where?' [The psychologists had specific training with a pain specialist to enable them to classify the answer as head, neck, back, limb joints, limb pain outside joints, chest or abdomen.] 3- Temporal pattern of each pain (episodic, with attacks daily for less than a month, daily for less than 6 months and more than 1 month or daily for more than 6 months; or persistent). Episodic pains occurring more often than once a month were distinguished from those occurring once or fewer times a month. [We will avoid the term 'chronic' and use 'persistent' pain since 'chronic pain' is often misunderstood as meaning a chronic pain syndrome (or pain-related disability) which is not addressed in the current survey.] The severity of each incident of pain was assessed by a verbal scale ('Was severity of the last 'usual' episode mild, moderate, severe or very severe?') The number of subjects with episodic pain plus the number with pain lasting more than 6 months is less than the total number of subjects with pain because it does not include subjects with pain lasting less than 6 months. We do not present the results on the latter group which is very heterogeneous and includes subjects with resolving subacute pain and those with persistent pain before the study started. The number of subjects in each group varies from one question to another because it represents the number of subjects answering that question. The x 2 was test used to compare qualitative variables. Results Demographic characteristics of the sample The sample was composed of women (60.2%) and 5 men (39.8%). The mean age (SEM) on 31 December 1987 was 74.2 years (0.24). The majority (54.5%) lived in a city (>50 000 inhabitants). Prevalence and temporal pattern of pain syndromes by sites Among the 741 subjects, 530 (71.5%) reported pain somewhere: 303 (40.9%) in one place, 157 (21.2%) in two places, 50 (6.7%) in three places, 13 (1.8%) in four places, three (0.4%) in five places, three (0.4%) in six places and one (0.1%) in eight places. The commonest complaint in this sample was pain in the peripheral joints, followed by back pain and non-joint leg pain. Table 1 shows the prevalence of elderly subjects reporting pain in the previous year for each site. Two hundred and forty-four subjects (32.9%) reported persistent pain (denned as daily pain for more than 6 months) and 241 (32.5%) reported episodic pain. Table 1 also shows the number of elderly subjects reporting persistent pain for each site. Here, again, the commonest site was limb joints (57.7% Table I. Prevalence of pain according to location (n 741) Location Head Face Neck Back limb joints Chest Abdomen limb except joints Prevalence, % (95% confidence interval) Pain 5.1 (3.5-6.7) 0.4 (0-0.9) 11.6(92-14).6(26.2-330) 44.5 (40.8-48.2) 2.4(1.3-3.5) 5.1 (3.5-6.7) 17.3 (14.6-20.0) Persistent pain 1.5 (0.6-2.4) 0.0 4.7(3.1-6.3) 12.0(9.6-14-4) 194(17.0-21.8) 0.7 (0-3.6) 1.9(1.3-2.5) 10.4(8.2-12.6) 280

Table 2. Proportion of each temporal pattern for each pain location Population-based study of pain in elderly people Proportion of cases by temporal pattern Episodic Daily, for Location Head Neck Back Limb joints limb other Chest Abdomen n a 38 219 330 128 19 38 > I/month 36.8 26.7 26.5 23.0 15.6 21.1 21.1 < I/month 31.7 1 28.3 26.4 17.2 42.1 39.5 <6 months 2.6 3.5 4.6 7.0 7.0 5.3 2.6 >6 months 28.9 40.7 40.6 43.6 60.2 26.3 36.8 "The total number is 741 for the 530 subjects because some subjects reported pain In several sites. of patients with persistent pain), followed by back (35.9%) and limb pain outside joints (30.6%). Table 2 shows the temporal pattern of pain according to each site. Head, chest and abdominal pain occurred mainly by attacks, although articular, spinal and leg pain were more persistent. Severity of pain Table 3 shows the severity of pain most of the time. A trend suggesting that head pain was more severe and joint, chest and abdomen pain less severe was observed but did not reach statistical significance (x 2 test comparing severity of pain at each site with severity of pain at all other sites). Persistent back and joint pains were significantly more severe than episodic back and joint pains (P<0.01 for each site, x 2 test). No significant difference by gender was observed for severity of pain. Age and gender of elderly subjects with and without pain A statistically significant difference was observed in the prevalence of pain sufferers among women (74.7%) Table 3. Severity of pains according to location, assessed by a verbal scale Location Head Neck Back Joint limb Chest Abdomen Percentage of cases, by severity Mild 5.4 11.8 7.3 11.5 11.7 11.1 7.9 Moderate 32.4 38.8 43.8 50.3 47.7 66.7 50.0 Intense 54.1 48.2 43.4 34.2 36.7 22.2 31.6 Very severe 8.1 1.2 5.4 3.9 3.9 0 10.5 compared with men (66.8%; 7><0.02). We found an opposite effect according to the type of pain: since 40.1% of women reported persistent pain against 23.7% of men (P< 0.001), although 28.3% of women reported episodic pain against 39% of men (P< 0.01). The frequency of persistent pain increased slightly with age in both sexes but remained higher in women. The prevalence of episodic pain was statistically higher in men after 75 (Table 4). The high frequency of persistent limb (at and outside joints) and back pain in women may account for this difference (Table 5). There is no statistically significant difference for frequency of back, joint and limb episodic pain according to gender (Table 5). Table 5 also shows that the frequency of persistent joint pains in the limbs did not vary with age after 65, but that the frequency of persistent back and non-articular limb pains increased with age in men and women. Frequencies of episodic chest, head and abdominal pain did not differ significantly between women and men, with values of 4.0 and 2.7%, 1.3 and 2.0%, and 3-1 and 31% respectively ( women and 5 men). Discussion This study provides a general overview of pain complaints in an elderly population. To our knowledge, this is the first prevalence study of pain in a nonselected community-dwelling sample in this age range. The Iowa study addressed the prevalence of pain in a community elderly population but focused on leg and back pain [13, 14]. The quality of our data was ensured by the fact that location, duration, type and intensity were assessed by specifically-trained psychologists. We confirm that pain, whatever the type, is common in this age group (71-5%), as is persistent pain: about 33% of elderly subjects reported pain lasting more than 6 months. Roy and Thomas [15] in a telephone survey of 205 elderly people in Winnipeg, Canada, found a similar prevalence of 69.8%. In a nursing home, Ferrell 281

B. Brochet et al. Table 4. Prevalence of pain according to gender and age (n 741) Age group (years) No. of subjects Women Men Percentage of group Women Men Percentage of group Women Men with episodic pain 35.6 41.7; n.s. with persistent pain 33.3 19.7 b 23-9 35.1 a 42.8 25.4 b 23.3 44.8 a 48.8 34.5 5 28.3 39.0 b 40.1 23.7* Statistical significance using x 2 test between women and men of a particular range of age: 'P < 0 03; b P < 0.01; C P < 0.001; n.s., not significant. etal. [9] found a prevalence of 71% for pain. In a postal survey of pain prevalence in the general population in Sweden, Brattberg et al. [6] studied 183 people over 65; in this section of their sample they observed 36.1% with 'obvious' pain of at least 6-months duration. The commonest pains are of presumably musculoskeletal origin: joints and back pain (44.5 and 30% respectively). However, this kind of epidemiological study has obvious limitations and we cannot address aetiology or pathophysiology in such an interview study. The term 'joint-pain' does not necessarily means that the pain originates from the musculo-skeletal system, although one can assume that most of the so-called joint pain does originate from joints. By comparison, 55% of community-dwelling elderly people in the USA reported arthritis [16]. These pain Table 5. Prevalence of joint, back and limb pain according to gender and age % of subjects, by pain type No. of subjects Episodic Persistent Age group (years) F M F M F M Limb joint pain Overall prevalence (%) 48.9 5 38.0 c 25.6 15.6 18.6 20.2 23.5; n.s. 23.8; n.s. 34.5; n.s. 24.7; n.s. 21.7 26.7 27.9 24.9 10.6 c 11.9 C 10.3; n.s. 11.2 d Back pain Overall prevalence (%) 318 5 26.1; n.s. 21.1 13-3 10.5 15.9 15.2; n.s. 17.2; n.s. 20.7; n.s. 16.6; n.s. 11.1 16.7 17.4 14.6 5.3; n.s. 10.4; n.s. 10.3; n.s. 8.1 C Limb pain except joint Overall prevalence (%) 19.7 5 13.6 a 7.2 5.6 0 5.2 6.1; n.s. 6.7; n.s. 6.9 b 6.4; n.s. 7.8 16.1 18.6 13.2 3.8; n.s. 6.0 c 17.2; n.s. 6.1 C Statistical significance using x 2 test between women and men: *P < 0.04; b P < 0.02; C P < 0.01; d P < 0.001; n.s., not significant. F, female; M, male. 282

Population-based study of pain in elderly people sites are also the most frequently mentioned for persistent pain. About 40% of elderly subjects reporting musculo-skeletal pain had daily pain for more than 6 months. In their study in a nursing home, Ferrell et al. [9] found that back pain and other 'arthritic' pains are the two most common sources of pain in elderly institutionalized people. In the National Health and Nutrition Epidemiologic Follow-up Study, Magni et al. [8] studied the prevalence of chronic musculo-skeletal pain (denned as pain in the neck, back, hip or knee most days for at least 1 month in the previous 12 months). Their sample included 519 subjects over 65 and the prevalence (calculated from the table published) was 37.6%. This is consistent with our results using the same definition (41.0%). The prevalence of back pain in our study (.6%) is slightly higher than in the Iowa 65+ Rural Health Study (23.6%) but in the latter only low back pain was studied [14]. A third type of pain appears to be very common: non-articular pain in the limbs. This is most frequently persistent. In a survey of non-institutionalized people aged 65 and over in two rural Iowa counties, Herr et al [13] reported prevalences of 63-6% for leg pain, 56.4% for leg pain during the night and 21.2% for pain while walking. In this study a relationship was observed between leg pain and arthritis and between leg pain and back pain. In our study we did not find such an association. In this study neck pains were considered separately from headaches and back pain. The high frequency of neck pain may explain in part the very low number of subjects reporting pain in the head. In a previous study on the same sample [10], 22.5% of subjects reported headache. Several further points may explain the discrepancy between these results. The main one is the difference between the questions: "Do you get headaches?" and "During the previous year, have you felt pain somewhere?" One explanation is that more subjects, headache-free at the time of the interview but with a long history of migraine, answered yes to the first, more focused question. Headache prevalence is usually found to be less than 5% in this age group [17]. It is, however, also possible that some patients with headache may not consider it as 'pain'. More than 5% of subjects reported abdominal pain. It is not surprising that chest and abdominal pains were more likely to be episodic. Recently there has been interest in the relationships between gender and pain [18]. Our study shows some differences for pain between women and men after 65. Women reported significantly more pains (74.7 versus 66.8%). We found that this difference is explained by the higher prevalence of persistent pain in women, limb joint pain was the main cause of different frequency of persistent pain between elderly women and men. Roy and Thomas [15] did not find such a difference: 70.5% of men and 70.4% of women reported pain in their study. By contrast, episodic pains were more common in men. In terms of severity, no major differences were observed between pain sites, but in the two most frequent pain sites persistent pains were more severe than episodic. They were classified as severe by 55% of subjects with back pain, a result similar to that of the Iowa study [14]. In conclusion, this study shows the high prevalence of pain in elderly people. Furthermore, it provides estimates of the prevalence of pain according to type, duration, location and gender. It shows that persistent pain, especially of the musculo-skeletal type, is very common in the elderly. As the size of the elderly population grows rapidly in Western countries, adequate health policies are needed to provide these people with appropriate care for their symptoms. This work may provide useful information for care providers, for planning strategies and for health and social policies, since the symptoms may have an impact on autonomy and health-care resource utilization. These points will be addressed in a forthcoming paper. Acknowledgements The authors thank H. Brochet for technical assistance. The PAQUID research programme is funded by the 'Fondation de France', Sandoz Laboratories, AXA Insurance Company, the French Ministry of Research and Technology, the National Medical Insurance Companies CNAMTS and MSA, the Brain Institute (ARMA), the Regional Council of Aquitaine, the General Councils of Gironde and Dordogne, the Regional Direction of Sanitary and Social Affairs of Aquitaine, the Inter-Firms pension aid fund, CAPIM- MEC and INSERM, the National Institute of Medical Research. 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