Health-related quality of life in fibromyalgia patients: a comparison with rheumatoid arthritis patients and the general population using the SF-36 health survey

Objective. To compare health-related quality of life (HRQL) in fibromyalgia (FM) patients with that of patients with rheumatoid arthritis (RA) and the general population, and investigate if the factors are associated with the greater impact of FM. Methods. This cross-sectional study involved 380 patients with FM, 693 patients with RA and 1579 healthy controls. HRQL was evaluated using the Medical Outcome Study Short-Form 36 (SF-36), and the measures included disease-related characteristics, demographic variables and comorbidities. S-scores were calculated for comparisons with the norm, and multivariate analyses were used to assess the relationships between HRQL and clinical and demographic variables. Results. In comparison with the general population, the FM patients showed significant impairment in relation to all of the eight scales of the SF-36(p<0.0001), as well as the physical and mental component summary scores (PCS and MCS) (p<0.0001). The mean PCS and MCS of the FM patients were 38.5 (SD=6.9) and 32.8 (SD=10.9), whereas those of the RA patients were, 33.5 (SD=6.4) (p<0.01) and 40.2 (SD=11.9) (p<0.001). The dimensions typical 67 affected by FM were vitality (s-score, -1.61), mental health (s-score -1.46) and general health (s-score-1.47), whereas physical functioning (s-score-1.63) and role limitations due to physical function (s -score -0.94) were more impaired in the RA patients; the bodily pain scores were similar in the two groups. The PCS was lower than the MCS in the RA patients (s-scores -1.80 vs. -0.62), but the two scores were similar in the FM patients (s-scores -1.20 vs. -1.08). Multiple regression models showed that the physical component of the SF-36 was associated with widespread pain (the SAPS score) (p<0.0001), educational level (p=0.0017), and the body mass index (p=0.007), and the mental component was associated with the widespread pain (p=0.0005), sleep abnormalities (p=0.0033), physical function (p=0.015), fatigue (p=0.029), gender (p=0.014) and a low educational level (p=0.0007). Conclusion. Patients with FM see the disease as having a worse health than RA patients and the general population, especially in terms of mental health.