Determinants of health-related quality of life in systemic lupus erythematosus: a monocentric, retrospective long-term observational study in Germany

Background. Improvement of health-related quality of life (HRQoL) is a prioritized treatment target in systemic lupus erythematosus (SLE). A retrospective chart review of patients with repeated HRQoL measurements from the outpatient department was conducted in order to better understand which factors drive HRQoL in established SLE. Of particular interest was the association between HRQoL and disease activity. Methods. The medical outcomes study short form 36 (SF-36), systemic lupus activity measure (SLAM) and routine clinical data of 169 patients (83% female, mean age 40.3 +/- 13 years, disease duration 9.4 +/- 7 years) over an average of 7.1 +/- 4.2 years were available for analysis by linear mixed modelling. Factors associated with the physical component summary (PCS) and mental component summary (MCS) of the SF-36 were assessed. The proportion of HRQoL which could be explained by the variables was estimated by marginal R-2 (mR(2)) and conditional R-2 (cR(2)). Results. At baseline, SLE patients showed a reduced HRQoL in all subscales of the SF-36 including PCS and MCS with the exception of vitality. A higher PCS over time was significantly associated with concurrent parameters, such as intake of antimalarial drugs, no glucocorticoid use, less fatigue, lower disease activity as well as to the baseline parameters of younger age and higher PCS (mR(2) 54.7%, cR(2) 59.9%). A higher MCS was associated with concurrent use of glucocorticoids and a higher baseline MCS (mR(2) 21.7%, cR(2) 25.1%). Conclusion. The use of antimalarial drugs and no glucocorticoid intake as well as low current disease activity are modifiable factors associated with a better physical HRQoL. The mental component of HRQoL was poorly represented by conventional parameters and not associated with parameters of disease activity in the present study cohort.