A LONG-TERM STUDY OF HYDROXYCHLOROQUINE WITHDRAWAL ON EXACERBATIONS IN SYSTEMIC LUPUS-ERYTHEMATOSUS

The ability of antimalarials to moderate severe disease activity in sy stemic lupus erythematosus (SLE) is plausible but undemonstrated. We e valuated the long-term effectiveness of maintaining treatment with hyd roxychloroquine sulphate (HCQ) to prevent major flares in quiescent SL E. Forty-seven patients with quiescent SLE who had been randomized to take HCQ (n = 25) or placebo (n = 22) as part of a 24-week withdrawal trial were evaluated for an additional 3 years. The primary outcome wa s time to a major flare of SLE which resulted in either the institutio n of or an increase in the current dosage of prednisone of 10 mg/day o r more, or institution of therapy with immunosuppressive agents. Secon dary outcomes included the specific subtype of these major flares (glo merulonephritis, vasculitis or other) and hospitalization for an exace rbation of SLE. An intent-to-treat analysis was conducted. Over the 42 months of study, 11 of 22 (50%) patients randomized initially to plac ebo, and seven of 25 (28%) patients randomized to continue treatment e xperienced a major flare. The relative risk of major flare for those r andomized to continue HCQ compared with controls was 0.43 (95% CI: 0.1 7, 1.12). The relative risks for subtypes of flares were 0.26 (95% CI: 0.03, 2.54) for nephritis, 0.51 (95% CI: 0.09, 3.08) for vasculitis a nd 0.65 (95% CI: 0.17, 2.41) for flares characterized by other symptom s. The relative risk of hospitalization for major flare for patients r andomized to continue hydroxychloroquine was 0.58 (95% CI: 0.13, 2.60) . While the results are not statistically significant, they are compat ible with the clinical belief that HCQ has a long-term protective effe ct against major disease flares in SLE and suggest that on average, HC Q use reduces major flares by 57% (95% CI: 83% reduction to 12% increa se).