Impact of Disease Activity on Health-related Quality of Life in Systemic Lupus Erythematosus - a Cross-sectional Analysis of the Swiss Systemic Lupus Erythematosus Cohort Study (SSCS)

Background: To assess the impact of disease activity on health-related quality of life (HRQoL) in systemic lupus erythematosus (SLE).

Methods: Cross-sectional study of patients included in the Swiss SLE Cohort Study between April 2007 and June 2014. HRQoL outcomes were based on the Medical Outcome Study Short Form 36 (SF-36). Disease activity was assessed by the SLE Disease Activity Index score with the Safety of Estrogens in SLE National Assessment modification (SELENA-SLEDAI) and by the physican's global assessment (PGA).

Results: Of the 252 patients included, 207 (82%) were women. Median [interquartile range (IQR)] age was 43 [32-57] years. SLE was active in 125 patients (49.6%). Median [IQR] mental component summary (MCS) in active vs inactive SLE was 40.0 [30.2-51.0] compared to 47.3 [39.2-52.8] (p < 0.01) and median [IQR] physical component summary (PCS) 43.7 [37.0-52.8] compared to 49.1 [38.4-55.6], respectively (p < 0.05). Increase in SELENA-SLEDAI or increase in PGA were negatively correlated with PCS and/or MCS. After adjusting for gender, age and disease duration, disease activity impacted on both PCS and MCS and all subscales except general health. Active lupus nephritis and musculoskeletal involvement were associated with physical limitations and emotional problems, increased bodily pain and poor social functioning. Low complement and/or presence of anti-dsDNA antibodies were associated with increased fatigue and reduced mental health.

Conclusions: In patients with SLE, HRQoL is reduced in those with active disease. Impact of disease activity on HRQoL dimensions depends on SELENA-SLEDAI system components.