Incidence and risk factors of warfarin therapy complications in community hospitals, central and eastern regions, Thailand: a retrospective, multicenter, cohort study

Warfarin, like many other anticoagulants, has been linked to an elevated risk of bleeding proportional to the amount of anticoagulation used. Not only was the incidence of bleeding raised by the dosage, but the subtherapeutic international normalized ratio (INR) was also associated with increased thrombotic events. This retrospective cohort and multi-center study evaluated the incidence and risk factors of warfarin therapy complications in community hospitals in Thailand's central and eastern regions from 2016 to 2021. Among 335 patients (683.90 person-year of follow-up), The incidence rate of warfarin complications was 4.91 events per 100 person-year. The independent factor associated with warfarin therapy complications was propranolol prescription (Adjusted RR: 2.29, 95%CI: 1.12-4.71). The secondary analysis was divided according to the outcome of the major bleeding and thromboembolic event. Major bleeding events, hypertension (Adjusted RR: 0.40, 95%CI: 0.17-0.95), amiodarone prescription (Adjusted RR: 5.11, 95%CI: 1.08-24.15), and propranolol prescription (Adjusted RR: 2.86, 95%CI: 1.19-6.83) were the independent risk factors. While in the major thrombotic event, non-steroidal anti-inflammatory drugs (NSAIDs) prescription was an independent factor (Adjusted RR: 10.65, 95%CI: 1.26-90.35).