Assessing the Rate of Antipsychotic Use in Ambulatory Care Patients With a Venous Thromboembolism.

Background: Evidence regarding the use of antipsychotics and associated venous thromboembolism (VTE) risk is inconclusive. Studies finding a relationship lack in-depth analysis; thus, the VTE risk among those treated with antipsychotic remains largely unknown. Objectives: The primary objective of this investigation was to compare the incidence of antipsychotic use in patients who developed a VTE versus those who did not. Methods: Data were collected via retrospective chart review from an ambulatory care clinic between January 2012 and August 2017. All active clinic patients within the study period were included unless they met the following criteria: age <18 years, pregnancy within the study period, and/or current or historical malignancy. The odds ratio (OR) of developing a VTE was determined using multivariate regression analysis controlling for age, gender, obesity, and smoking. Secondary end points were reviewed for participants who were exposed to an antipsychotic and subsequently developed a VTE within the study period. Results: A total of 7079 patients were included in the analysis, of whom 314 developed a VTE. Of these, 45 were exposed to an antipsychotic prior to VTE development. Nearly 25% of patients receiving an antipsychotic did not have a primary psychiatric diagnosis. Results suggest that antipsychotic use was significantly associated with increased risk of VTE development (OR = 1.481 [95% CI = 1.067 to 2.055]). Conclusion and Relevance: The results of this study suggest an association between antipsychotic use and VTE development. This association should be considered when prescribing antipsychotics and treating patients who develop a VTE after antipsychotic exposure.