Abstract
Background Use of Hydroxychloroquine (HCQ) is known to be associated with less disease activity, flares, damage and better survival in patients with Systemic Lupus Erythematosus (SLE). It is not known if its use is also associated with better patient reported health outcomes, a core outcome in SLE.
Methods International data from Study on Outcomes of Lupus (SOUL) on LupusPRO, a patient reported disease targeted Quality of life (QOL) tool, from 2,157 patients with SLE, were compared based on use HCQ. Disease activity and damage were assessed using SELENA-SLEDAI and SLICC-ACR/SDI. T tests and Chi square tests were used for comparisons. Linear regression analyses were undertaken with summary LupusPRO health (HRQOL), non-health (NHRQOL) and Lupus Impact Tracker (LIT) scores as the dependent variables, and HCQ as the independent variable. LIT scores were derived from LupusPRO data. Similar analysis for damage was also conducted.
Results Mean age was 40.5 ± 12.8 years. Ninety-three percent were women. HCQ use 798/2157 (37%) was inversely associated with age, Asian race, disease duration, lupus nephritis, neurological and hematologic manifestations, and damage. HCQ use was directly associated with presence of photosensitivity. On univariate analysis, HCQ use was associated with better QOL (β 6.19, 95% CI 4.15, 8.24, P ≤0.001 for LupusPRO-HRQOL) and less impact on daily life (β -9.37, 95% CI -12.24, -6.50, P ≤0.001 for LIT). Other predictors for QOL and LIT were age, education, Asian race and disease activity. On multivariate analyses (adjusted for age, education, Asian status) use of HCQ was independently associated with better outcomes (LupusPRO-HRQOL and LIT). However, addition of disease activity variable to the models resulted in loss of independent association of HCQ use with better outcomes, suggesting mediation through disease activity (table 1). Similarly, mediation was seen for beneficial effects of HCQ use on damage through disease activity.
Conclusions HCQ use in SLE is associated with better health outcomes (LupusPRO-HRQOL, impact on daily life, damage), and the effects are mediated through disease activity modification.
Acknowledgements Behalf of SOUL group.
