Is reduced health-related quality of life a primary manifestation of fibromyalgia? A comparative study with Rheumatoid arthritis

Background: Fibromyalgia syndrome (FMS) is a chronic pain condition associated with a significant reduction in health-related quality of life (HRQoL). This study compared the different components of HRQoL between FMS and rheumatoid arthritis (RA) patients, and evaluated the relationships between HRQoL and clinical and emotional factors in FMS and RA patients. Method: Women with FMS (n=80), RA (n = 43) and healthy women (n = 67) participated in the study. HRQoL was assessed by the SF-36 survey. Associations between HRQoL and symptom severity were assessed by correlation and multiple linear regression analyses. Results: FMS patients displayed lower values for all SF-36 variables than RA patients and healthy participants, while RA patients showed lower values for all SF-36 variables than healthy participants. These group differences persisted after statistically controlling for demographic, clinical and emotional variables. Clinical and emotional factors were inversely associated with SF-36 scores in the overall FMS + RA sample. Depression and fatigue were the strongest negative predictors. However, after the statistical control of the effect of diagnosis (FMS vs. RA) in the regression analysis, most of the associations disappear. Conclusions: The fact that group differences in HRQoL remained highly significant after statistically controlling of group differences in clinical symptom severity, and that associations between clinical symptoms and HRQoL disappear when the type of diagnosis was considered in the regression analysis, suggest that impairment of HRQoL could be considered a primary feature of FMS.