Risk factors for persistent chronic widespread pain: a community-based study.

BACKGROUND: Chronic widespread pain is the cardinal clinical feature of the fibromyalgia syndrome, which, in the majority of clinic patients, is persistent. By contrast, in community-derived patients, pain is persistent in only half of the affected individuals, particularly those with psychological distress. Whether such distress is a consequence of the pain or a manifestation of a wider process of somatization which is associated with the persistence of pain is unclear. OBJECTIVES: We tested in a large, prospective, population-based study the hypothesis that features of somatization predict the persistence of chronic widespread pain. METHODS: In all, 252 (13%) of 1953 adult subjects selected from a population register were classified as having chronic widespread pain based on a detailed questionnaire which included a pain drawing. The patients also completed a number of psychosocial instruments which measure features known to be associated with somatization. Two hundred and twenty-five (91%) of the patients were successfully followed up after 12 months and provided data on pain status using the same instruments. RESULTS: In all, 126 (56%) patients reported chronic widespread pain at follow-up, 74 (33%) reported other pain and 25 (11%) reported no pain. Persistent chronic widespread pain was strongly associated with baseline test scores for high psychological distress and fatigue. In addition, these subjects were more likely to display a pattern of illness behaviour characterized by frequent visits to medical practitioners for symptoms which disrupt daily activities. The prevalence of persistent pain increased with the number of risk factors the subjects were exposed to. CONCLUSIONS: Although almost half of the cases of chronic widespread pain resolved within 1 yr, this study has demonstrated for the first time that those subjects who display features of somatization are more likely to have widespread pain which persists. These findings have implications for the identification and treatment of persons with persistent chronic widespread pain.