Prescription trends for combined oral contraceptives and thromboembolism incidence in Japan before and after public awareness events in 2013–2015

OBJECTIVE: Combined oral contraceptives (COCs) for dysmenorrhea management have been covered by the Japanese universal health insurance system since 2008. Several public awareness events regarding COC prescriptions for dysmenorrhea were implemented between 2013 and 2015, including media reports on COC-related fatalities in 2013, drug safety alerts in 2014, and new clinical guidelines in 2015. This study aimed to examine the trends in patient characteristics, coagulation testing, and thromboembolism incidence before and after these events. METHODS: We used the JMDC claims database to identify patients with dysmenorrhea prescribed COCs between 2009 and 2021. We evaluated the annual trends in guideline-listed thromboembolism risk factors (age ≥ 40 years, obesity, and smoking), frequency of patients undergoing coagulation testing among patients prescribed COCs, and thromboembolism incidence. RESULTS: Of 860 840 patients with dysmenorrhea, 173 502 received COCs. The proportion of patients prescribed COCs decreased temporarily from 12.2% to 11.2% in 2014. The proportion of new COC prescriptions increased for women aged