Use of antipsychotics and risk of venous thromboembolism in postmenopausal women A population-based nested case-control study

Despite continued uncertainty of venous thromboembolism (VTE) caused from antipsychotic agents, this safety issue has not been examined in postmenopausal women, a population with high usages of anti psychotics and at high risk for VTE. We assessed whether antipsychotic use was associated with an increased VTE risk in women after menopause. We conducted a nested case-control study of all Taiwanese women aged >= 50 years (n = 316,132) using a nationwide healthcare claims database between 2000 and 2011. All newly diagnosed VTE patients treated with an anticoagulant or thrombectomy surgery were identified as cases (n = 2,520) and individually matched to select controls (n = 24,223) by cohort entry date, age, cancer diagnosis and major surgery procedure. The odds ratios (ORs) and 95 % confidence interval (CI) of VTE associated with antipsychotics were estimated by multivariate conditional logistic regressions. Current use of antipsychotics was associated with a 1.90-fold (95 % CI = 1.64-2.19) increased VTE risk compared with nonuse in postmenopausal women. The VTE risk existed in a dose-dependent fashion (test for trend, p<0.001), with a more than quadrupled risk for high-dose antipsychotics (adjusted OR = 4.60; 95 % CI = 2.88-7.33). Current parenteral administration of antipsychotics also led to a 3.46-fold increased risk (95% CI = 2.39-5.00). Conversely, there was no increased VTE risk when antipsychotics were discontinued for >30 days. In conclusion, current use of antipsychotics is significantly associated with a dose-dependent increased risk of VTE in postmenopausal women, especially for those currently taking high-dose or receiving parenteral antipsychotics.