Clinical Question: What is the optimal management of antiphospholipid antibody syndrome?

Setting: Various (meta-analysis)

Study Design: Systematic review

Synopsis: Antiphospholipid antibodies are associated with an increased risk of thrombotic events and fetal loss. To fully evaluate this risk and potential treatments, the investigators systematically searched MEDLINE, the Cochrane Library, and reference lists from significant articles for randomized trials and cohort studies reporting on patients with antiphospholipid antibodies.

The risk of developing a new thrombosis in otherwise healthy patients with antiphospholipid antibodies without previous thrombotic events is low (less than 1 percent per year). Among other patients with antiphospholipid antibodies, the risk of a new thrombotic event is moderately increased in women with recurrent fetal loss without previous thrombosis (up to 10 percent per year), and it is highest in patients with a history of venous thrombosis who have discontinued anticoagulant drugs in the previous six months (greater than 10 percent per year).

Moderate-intensity anticoagulation (target International Normalized Ratio [INR] = 2 to 3) significantly reduces the risk of recurrent thrombosis; no additional benefit is gained with high-intensity anticoagulation (target INR = greater than 3).

Evidence is lacking to make clear recommendations for the following patients with antiphospholipid antibodies: those without previous thrombosis, those with recurrent thrombosis despite anticoagulation, those undergoing treatment of arterial thrombosis, and women with recurrent fetal loss.

Bottom Line: Patients who test positive for antiphospholipid antibodies are at an increased risk of thrombotic events. Pregnant women who test positive for antiphospholipid antibodies are at an increased risk of fetal loss. Moderate-intensity anticoagulation with warfarin (Coumadin) prevents recurrent venous thrombosis. The optimal management of other thrombotic aspects of patients with antiphospholipid antibodies remains uncertain. (Level of Evidence: 1a)