Chronic widespread pain: a three year followup of pain distribution and risk factors

Abstract

Objective: To describe the change of pain reports over time in 3 cohorts derived from the general population: (1) no chronic pain (NCP; n = 1156); (2) chronic regional pain (CRP; n = 502); and (3) chronic widespread pain (CWP; n = 242). To identify risk factors that predict the development or persistence of chronic widespread pain.

Methods: A 3-year followup from 1995 to 1998 with postal questionnaire to 2425 subjects of both sexes aged 20-74 years on the west coast of Sweden.

Results: At followup, a larger proportion of subjects with initial CRP compared to initial NCP reported CWP (16.4 and 2.2%, respectively; p < 0.001). The majority of subjects (56.9%) who primarily reported CWP remained in that group at followup, but 26.8% had changed status to CRP and 16.3% to NCP. The number of painful regions (7-12 vs 0 regions) reported at baseline was the strongest predictor for the development of CWP with an odds ratio (OR) of 12.13 (95% CI 4.47-32.88). The development of CWP was also predicted by higher age (OR = 3.13, 95% CI 1.47-6.69, age-group 59-74 years vs age-group 20-34 years), and a family history of chronic pain (OR = 1.87, 95% CI 1.14-3.07). A habit of drinking alcohol weekly (OR = 0.42, 95% CI 0.21-0.85) compared to the habit of never or seldom drinking alcohol was protective, as well as having personal social support (OR = 0.49, 95% CI 0.28-0.85). The persistence of CWP was predicted by the number of painful regions (13-18 vs 1-6 regions) at baseline (OR = 7.56, 95% CI 2.17-26.30), and being an immigrant (OR = 3.22, 95% CI 1.33-7.77).

Conclusion: Although the overall prevalence of CWP was stable over a 3-year period there was a considerable variation on an individual basis. This variability in expressing CWP was moderately predicted by a combination of risk factors, the most important being the number of painful regions at baseline. Future research will need to show how useful the identified factors are in clinical practice and whether intervention aimed at changing these factors will improve pain outcome.