Purpose: This study examined and compared health-related quality of life (QoL) in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).
Methods: We included patients from two multicentric cohorts, the Swiss SLE cohort study (SSCS) and the Swiss Clinical Quality Management Program for RA (SCQM-RA). Patients were matched by age, sex and disease duration using the propensity score. Disease activity was assessed by SELENA-SLEDAI in SLE and by DAS-28 in RA. QoL was captured by the short-form 36 (SF-36). The primary outcomes were physical component summary (PCS) and mental component summary (MCS) of the SF-36. Generalized estimating equation models were used to assess evolution over time.
Results: We analyzed 267 SLE patients and 267 matched RA patients. More patients with RA had active disease and more patients with SLE had immunosuppressant therapies at baseline. The median [interquartile range (IQR)] MCS and PCS scores were 45.1 [33.7-52.6] and 45.6 [38.0-53.0] in SLE and 48.8 [37.6-56.7] and 34.7 [26.8-43.0] in RA, respectively (ps < 0.001). Over one year the differences persisted, although PCS and MCS increased in RA (ps < 0.001) but not in SLE in the univariate analysis. The differences in MCS and PCS scores between RA and SLE remained qualitatively similar after adjustment for patient characteristics, treatment, and activity disease.
Conclusions: SLE and RA both affect QoL. Patients with SLE have lower MCS, whereas patients with RA have lower PCS. These differences remained over 1 year of follow up, suggesting fundamental dissimilarities between SLE and RA in their impact on QoL.
Keywords: DAS-28; QOL; Rheumatoid arthritis; SF-36; SLEDAI; Systemic lupus erythematosus.