Antipsychotic drugs and the risk of recurrent venous thromboembolism: A prospective cohort study

Background Numerous studies have suggested that antipsychotic drugs are associated with an increased risk for a first episode of venous thromboembolism (VTE). However, after anticoagulation discontinuation, the impact of antipsychotic drugs on the risk of recurrent VTE (rVTE) remains unknown. Objective To estimate the risk of rVTE in association with antipsychotic drugs. Methods Between May 2000 and December 2012, we included all consecutive patients with a first unprovoked symptomatic VTE and who discontinued anticoagulation. During follow-up, exposure to antipsychotic drugs was systematically assessed. Results A total of 736 patients with a first unprovoked symptomatic VTE were followed-up during a median period of 27.0 months (interquartile range (IQR) 6.2–60.0). Patients' median age was 66.0 years (IQR 49.0–76.0), 404 (54.9%) were men, and 61 (8.3%) were exposed to antipsychotics during follow-up. The incidence rate of r VTE was 12.1% person-year (95% CI 7.2–20.5) in antipsychotics users compared with 8.3% person-year (95% CI 7.1–9.8) in non-users (p = 0.20). Multivariate analysis showed a significant increased risk of recurrence associated with antipsychotic exposure (adjusted hazard ratio 1.9, 95% CI 1.1–3.3). Conclusions In this cohort study, exposure to antipsychotic drugs was found to be associated with an increased risk of rVTE among patients with a previous first unprovoked symptomatic VTE and who discontinued anticoagulation. Larger studies are needed to confirm and further explore this association.