Low fibrinogen level: A predisposing factor for venous thromboembolic events with hormone replacement therapy

Several studies have reported an association between hormone replacement th erapy (HRT) in postmenopausal women and increased risk of idiopathic venous thromboembolic events (VTEs), Given the widespread use of HRT, it is impor tant to identify factors that may predispose women on HRT to VTEs, To addre ss this concern, we examined potential risk factors for VTEs in women assig ned to HRT in the Postmenopausal Estrogen/Progestin Interventions (PEPI) st udy, a three-year, double-blinded, placebo-controlled trial of 875 postmeno pausal women designed to assess the effects of HRT on heart disease risk fa ctors (HDL cholesterol, fibrinogen, blood pressure, and insulin). Women wit h a history of estrogen-associated VTEs were excluded from the trial. Ten w omen, all assigned to HRT, had a VIE during PEPI, Only baseline fibrinogen varied significantly between those who did (mean = 249.0 mg/dl) and did not (mean = 280.8 mg/dl) have a VTE while assigned to HRT (P < 0.03), Adjustin g for covariates including age, smoking, body mass index, lipid levels, blo od pressure, alcohol, exercise, and prior HRT or oral contraceptive use did not affect this finding, The significantly lower fibrinogen levels seen am ong women subsequently reporting VTEs may be a marker for a specific, but a s yet undefined, coagulopathy that is magnified in the presence of exogenou s hormones. However, larger studies are needed to confirm this finding. (C) 1999 Wiley-Liss, Inc.