Alison M Elliott

The epidemiology of chronic pain in the community

BACKGROUND Chronic pain is recognised as an important problem in the community but our understanding of the epidemiology of chronic pain remains limited. We undertook a study designed to quantify and describe the prevalence and distribution of chronic pain in the community. METHODS A random sample of 5036 patients, aged 25 and over, was drawn from 29 general practices in the Grampian region of the UK and surveyed by a postal self-completion questionnaire. The questionnaire included case-screening questions, a question on the cause of the pain, the chronic pain grade questionnaire, the level of expressed needs questionnaire, and sociodemographic questions. FINDINGS 3605 questionnaires were returned completed. 1817 (50.4%) of patients self reported chronic pain, equivalent to 46.5% of the general population. 576 reported back pain and 570 reported arthritis; these were the most common complaints and accounted for a third of all complaints. Backward stepwise logistic-regression modelling identified age, sex, housing tenure, and employment status as significant predictors of the presence of chronic pain in the community. 703 (48.7%) individuals with chronic pain had the least severe grade of pain, and 228 (15.8%) the most severe grade. Of those who reported chronic pain, 312 (17.2%) reported no expressed need, and 509 (28.0%) reported the highest expressed need. INTERPRETATION Chronic pain is a major problem in the community and certain groups within the population are more likely to have chronic pain. A detailed understanding of the epidemiology of chronic pain is essential for efficient management of chronic pain in primary care.

The course of chronic pain in the community: results of a 4-year follow-up study

&NA; Little is known about the course of chronic pain in the community. Such information is needed for the prevention and management of chronic pain. We undertook a 4‐year follow‐up study of 2184 individuals living in Grampian, UK to describe patterns and predictors of change in chronic pain over time. In October 2000, participants completed a postal questionnaire including case definition questions, the chronic pain grade questionnaire, the SF‐36 and socio‐demographic questions. Information from this questionnaire was compared to information collected from a similar questionnaire in 1996. A response rate of 83% was achieved for the follow‐up study. The overall prevalence of chronic pain (pain or discomfort present either all the time or on and off for 3 months or longer) increased from 45.5% at baseline to 53.8% at follow‐up. Seventy‐nine percent of those with chronic pain at baseline still had it at follow‐up. The average annual incidence was 8.3% and the average annual recovery rate was 5.4%. Individuals in the study samples who are in lowest quartile of SF‐36 domains–physical functioning, social functioning and bodily pain at baseline–were more likely to develop chronic pain at follow‐up, and respondents who were retired were less likely to develop chronic pain. Individuals in the study samples in the lowest quartile of SF‐36 domains, bodily pain and general health at baseline, were less likely to recover from their chronic pain, as were those aged 45–74 compared with those aged 25–34. We concluded that chronic pain is a common, persistent problem in the community with relatively high incidence and low recovery rates. The lack of association between onset or recovery from chronic pain and most traditional socio‐demographic factors, highlights the need to broaden the range of factors included in studies of chronic pain aetiology.

Rural and urban differences in stage at diagnosis of colorectal and lung cancers

There is evidence that patients living in outlying areas have poorer survival from cancer. This study set out to investigate whether they have more advanced disease at diagnosis. Case notes of 1323 patients in north and northeast Scotland who were diagnosed with lung or colorectal cancer in 1995 or 1996 were reviewed. Of patients with lung cancer, 42% (69/164) living 58 km or more from a cancer centre had disseminated disease at diagnosis compared to 33% (71/215) living within 5 km. For colorectal cancer the respective figures were 24% (38/161) and 16% (31/193). For both cancers combined, the adjusted odds ratio for disseminated disease at diagnosis in furthest group compared to the closest group was 1.59 (P = 0.037). Of 198 patients with non-small-cell lung cancer in the closest group, 56 (28%) had limited disease (stage I or II) at diagnosis compared to 23 of 165 (14%) of the furthest group (P = 0.002). The respective figures for Dukes A and B colorectal cancer were 101 of 196 (52%) and 67 of 172 (39%) (P = 0.025). These findings suggest that patients who live remote from cities and the associated cancer centres have poorer chances of survival from lung or colorectal cancer because of more advanced disease at diagnosis. This needs to be taken into account when planning investigation and treatment services.

Mortality among contraceptive pill users: cohort evidence from Royal College of General Practitioners’ Oral Contraception Study

Objective To see if the mortality risk among women who have used oral contraceptives differs from that of never users. Design Prospective cohort study started in 1968 with mortality data supplied by participating general practitioners, National Health Service central registries, or both. Setting 1400 general practices throughout the United Kingdom. Participants 46 112 women observed for up to 39 years, resulting in 378 006 woman years of observation among never users of oral contraception and 819 175 among ever users. Main outcome measures Directly standardised adjusted relative risks between never and ever users for all cause and cause specific mortality. Results 1747 deaths occurred in never users of oral contraception and 2864 in ever users. Compared with never users, ever users of oral contraception had a significantly lower rate of death from any cause (adjusted relative risk 0.88, 95% confidence interval 0.82 to 0.93). They also had significantly lower rates of death from all cancers; large bowel/rectum, uterine body, and ovarian cancer; main gynaecological cancers combined; all circulatory disease; ischaemic heart disease; and all other diseases. They had higher rates of violent deaths. No association between overall mortality and duration of oral contraceptive use was observed, although some disease specific relations were apparent. An increased relative risk of death from any cause between ever users and never users was observed in women aged under 45 years who had stopped using oral contraceptives 5-9 years previously but not in those with more distant use. The estimated absolute reduction in all cause mortality among ever users of oral contraception was 52 per 100 000 woman years. Conclusion Oral contraception was not associated with an increased long term risk of death in this large UK cohort; indeed, a net benefit was apparent. The balance of risks and benefits, however, may vary globally, depending on patterns of oral contraception usage and background risk of disease.

Severe chronic pain is associated with increased 10 year mortality. A cohort record linkage study

Previous research has clearly demonstrated a link between chronic pain and poor health, and has suggested a link with increased mortality, though the latter is less consistent. In 1996 a cohort of 6940 individuals was recruited, and information collected, about reported chronic pain status, general health and socio‐demographic details. Ten years later, a record linkage was conducted between these data and the routinely collected national dataset for death registration. Primary cause of death was classified according to ICD‐10 codes. Survival analysis was conducted to obtain unadjusted and multi‐adjusted hazard ratios (HR) for all‐cause, system‐specific and disease‐specific mortality by chronic pain status. A total of 5858 (84.4%) of individuals from the original cohort were linked, including 1557 (26.6%) who had died. Survival analysis found significant associations between any reported chronic pain and all‐cause mortality (HR 1.32, 99% CI, 1.14–1.54) and a number of specific causes. However, when we adjusted for socio‐demographic factors and reported long‐term limiting illness, the significant association was lost. Survival among those reporting severe chronic pain was significantly worse than among those reporting mild or no chronic pain. After adjustment for socio‐demographic factors and reported long‐term limiting illness, severe chronic pain remained significantly associated with all‐cause mortality (HR 1.49, 99% CI 1.21–1.84) and all circulatory system disease deaths (HR 1.68, 99% CI 1.20–2.35). The evident association between any chronic pain and increased mortality can apparently be explained by confounding caused by socio‐demographic factors. However, severe chronic pain is associated with increased risk of mortality, independent of socio‐demographic factors.

Changes in chronic pain severity over time: the Chronic Pain Grade as a valid measure.

&NA; Our understanding of the natural history of chronic pain in the community is limited. This is partly due to the lack of a validated measure of chronic pain severity known to be responsive to change over time. The Chronic Pain Grade questionnaire has been shown to be valid and reliable for use in a general population as a self‐completion questionnaire. However, its reliability and validity for use in longitudinal studies and its responsiveness to change over time has not yet been assessed. We undertook a postal survey designed to test the responsiveness and the validity of the Chronic Pain Grade questionnaire over time. A random sample of 560 chronic pain patients, aged 25 years and over was drawn from an existing cohort and stratified for age, gender and chronic pain severity. Subjects were re‐surveyed by a postal self‐completion questionnaire consisting of the Chronic Pain Grade and the SF‐36 general health questionnaire, which is known to be responsive to change in health over time. To test whether changes in CPG scores correlated with changes in SF‐36 scores, Spearmans rank correlation coefficients were calculated. A response rate of 86% was achieved for the follow‐up study. The majority of SF‐36 scores changed in the hypothesized directions. Changes in CPG scores were significantly correlated with changes in most of the SF‐36 domains. We concluded that the CPG is a useful and valid objective instrument for measuring change in severity of chronic pain over time and could be used in longitudinal studies of chronic pain severity.

Rural factors and survival from cancer: analysis of Scottish cancer registrations.

In this survival study 63 976 patients diagnosed with one of six common cancers in Scotland were followed up. Increasing distance from a cancer centre was associated with less chance of diagnosis before death for stomach, breast and colorectal cancers and poorer survival after diagnosis for prostate and lung cancers.

Factors related to the onset and persistence of chronic back pain in the community: results from a general population follow-up study

Introduction. We compared the prevalence of chronic back pain (CBP) at two points 4 years apart and examined socio-demographic, health, and pain-related factors associated with its onset and persistence. Method. A random population sample of 2,184 adults was surveyed in 1996 and resurveyed in 2000. The questionnaire included chronic pain case definition questions (pain for 3 months or longer); the cause (1996) or site (2000) of any chronic pain; the Chronic Pain Grade questionnaire; the Level of Expressed Need (LEN) questionnaire; the SF-36 general health questionnaire; and demographic questions. Those with CBP in 1996 and 2000 had “persistent” CBP; those with CBP in 1996 but not 2000 had “recovered” CBP; those with CBP in 2000 but not 1996 had “new” CBP. Results. Corrected response rates were 82.3% (1996) and 83.0% (2000). The sample prevalence of CBP was 16% (1996) and 27% (2000). Factors in 1996 independently associated with “persistent” compared with “recovered” CBP were preexisting arthritis, high LEN, poor mental health, and not living alone. Factors independently predicting “new” CBP compared with no previous CBP were previous chronic pain elsewhere and poor physical health. “Persistent” CBP was associated with more severe pain, higher LEN, and poorer general health than “new” CBP. Discussion. CBP is a common and lasting problem, whose persistence and onset are predicted by clinical (especially pain) and help-seeking behavior factors, rather than socio-demographic. Prevention should focus on these factors.

Evidence-based clinical practice guidelines on management of pain in older people

Pain in older people is not only under-recognised, but is also under-treated. Many professional bodies have documented that pain in this rapidly growing population is poorly controlled [1–7]. This may be related to attitudes and beliefs held by older people, which in turn affects their reporting of pain [8] but also due to misconceptions and educational deficits by health professionals [9, 10]. Treatment when prescribed is often limited to basic medication seldom tailored to the individual [11–14]. There is also a general failure by professionals to consider alternative pain relief options [2]. No doubt more needs to done and national guidance on the management of pain in older people is long overdue. Older people are different; the bio-physiological changes that occur with ageing, the accumulation of co-morbidities and co-prescription of medication, frailty and psychosocial changes make older people rather unique when considering treatment modalities for pain control. The British Geriatric Society and British Pain Society have collaborated to produce the first UK guideline on the management of pain in older people. The recommendations follow an extensive systematic review of the available literature and will help health professionals consider the options available when managing pain in older patients. The guideline has been categorised into sections dealing with pharmacology, interventional therapies, psychological interventions, physical activity and assistive devices and complementary therapies. This article provides a summary of the recommendations. The full guideline is available in the supplement accompanying this issue of the journal.

Impact of deprivation and rural residence on treatment of colorectal and lung cancer.

For common cancers, survival is poorer for deprived and outlying, rural patients. This study investigated whether there were differences in treatment of colorectal and lung cancer in these groups. Case notes of 1314 patients in north and northeast Scotland who were diagnosed with lung or colorectal cancer in 1995 or 1996 were reviewed. On univariate analysis, the proportions of patients receiving surgery, chemotherapy and radiotherapy appeared similar in all socio-economic and rural categories. Adjusting for disease stage, age and other factors, there was less chemotherapy among deprived patients with lung cancer (odds ratio 0.39; 95% confidence intervals 0.16 to 0.96) and less radiotherapy among outlying patients with colorectal cancer (0.39; 0.19 to 0.82). The time between first referral and treatment also appeared similar in all socio-economic and rural groups. Adjusting for disease stage and other variables, times to lung cancer treatment remained similar, but colorectal cancer treatment was quicker for outlying patients (adjusted hazard ratio 1.30; 95% confidence intervals 1.03 to 1.64). These findings suggest that socio-economic status and rurality may have a minor impact on modalities of treatment for colorectal and lung cancer, but do not lead to delays between referral and treatment.