Does Estrogen Replacement Cause Lupus Flares?

Flares of disease activity in patients with systemic lupus erythematosus (SLE) have been reported during treatment with estrogens, but does estrogen cause such flares? In this U.S. multisite trial, investigators enrolled 351 menopausal women with SLE (inactive or stable disease on low-dose prednisone or stable doses of other immunosuppressive drugs). Patients were randomized to receive either conjugated estrogen (0.625 mg) plus medroxyprogesterone (5 mg) or placebo daily for the first 12 days of each month for 12 months. Patients with the lupus anticoagulant, anticardiolipin antibodies, or arterial or venous thrombotic disease were excluded. The study was stopped (although largely completed) when the Women’s Health Initiative investigators …