Prognostic factors for the development of fibromyalgia in women with self-reported musculoskeletal pain. A prospective study

Objective. To estimate the risk of developing fibromyalgia (FM) in women wi th self-reported pain and to estimate the relative risk of a series of vari ables. Methods. As part of a population study, 214 women with self-reported pain w ere interviewed and examined in 1990 and 1995, In 1990, 39 of these women f ulfilled the American College of Rheumatology criteria for FM. The other 17 5 women represented a continuum of pain extent from nonchronic pain to chro nic widespread pain, and were assessed as individuals at risk for developin g FM. Potential risk factors for FM were registered in 1990 and analyzed by bivariate and multiple statistical methods in the total sample and also in a subgroup of 115 women with limited pain. Results, Forty-three (25%) women developed FM. Having greater than or equal to 4 associated symptoms, pain of greater than or equal to 6 years' durati on, back pain, alternately hard/loose stools, and self-assessed depression were found to be predictors. Pain in the lower arm and a feeling of swellin g were more weakly associated. In women with limited pain, pain greater tha n or equal to 6 years' duration, greater than or equal to 4 associated symp toms, not feeling refreshed in the morning, and paresthesia were found to b e predictors. A weaker association was found with self-assessed depression and a lack of formal education. Conclusion, A high cumulative incidence: of FM was found and a diversity of predictors for FM were identified in the total sample and also in women wi th limited pain. Of the variables that were part of the FM syndrome, back p ain predicted FM, while tender points and pain in the neck did not. Moreove r, greater than or equal to 4 associated symptoms, self-assessed depression , and longlasting pain were shown to be important predictors.