Effect of antimalarials on thrombosis and survival in patients with systemic lupus erythematosus

Antimalarials have shown beneficial effects on systemic lupus erythematosus (SLE) activity. Our aim was to investigate whether antimalarials protect against thrombosis and influence survival in SLE patients. A prospective cohort including 232 patients with SLE were included in the study at the time of lupus diagnosis. End points were documented thrombosis and death due to any cause. A Cox regression-multiple-failure time survival analysis model was fitted to establish the effect of antimalarials on the development of thrombosis. Kaplan-Meier survival curves and propensity score adjusted-Cox regression analysis were performed to investigate the effect of antimalarials use on survival. Of our subjects, 204 patients (88%) were women. 230 patients (99%) were white. 150 patients (64%) had ever received antimalarials. Median time on antimalarials was 52 months (range three to 228 months). The Cox multiple-failure time survival analysis showed that taking antimalarials was protective against thrombosis (HR 0.28, 95%CI 0.08-0.90), while aPL-positivity (HR 3.16, 95%CI 1.45-6.88) and previous thrombosis (HR 3.85, 95%CI 1.50-9.91) increased the risk of thrombotic events. Twenty-three patients died, 19 of whom (83%) had never received antimalarials. No patient treated with antimalarials died of cardiovascular complications. Cumulative 15-year survival rates were 0.68 for never versus 0.95 for ever treated patients (P < 0.001). Age at diagnosis and propensity score-adjusted HR for antimalarials ever versus never users was 0.14 (95%CI 0.04-0.48). Our study shows a protective effect of antimalarials against thrombosis and an increased survival of SLE patients taking these drugs. These data support the routine use of antimalarials in all patients with SLE.