The incidence and prognosis of thromboembolism associated with oral contraceptives: Age‐dependent difference in Japanese population

AIM: We analyzed the incidence and prognosis of thromboembolism associated with combined oral contraceptives (COCs) by age groups in Japan. METHODS: A total of 581 events of venous thromboembolism (VTE) and arterial thromboembolism (ATE) associated with COCs were analyzed from the Pharmaceuticals and Medical Devices Agency database from 2004 to 2013. In a statistical analysis, a good‐prognosis group included recovery cases and a poor‐prognosis group involved unrecovered cases with some sequela and fatal cases. The significant difference between these two groups was calculated by Pearson's chi‐square test, and the age‐specific tendency and the trend of differences in prognosis according to different hormonal contraceptives were examined by Cochran–Armitage trend test. RESULTS: A total of 543 events were analyzed except 38 events due to unknown age, in which DVT only was the most frequent, followed by cerebral infarction, PE with DVT, PE only, cerebral vein thromboses. ATE ratio for overall thromboembolism tended to increase with advancing age (P = 0.0041). Good‐prognosis group was common (291 cases in VTE and 83 cases in ATE), followed by poor‐prognosis group (46 cases in VTE and 34 cases in ATE). All ATE cases had a significantly poorer prognosis in comparison with all VTE cases (P < 0.0001). Types of progestin and age difference, however, showed no trend in the differences between good‐prognosis group and poor‐prognosis group (P = 0.3548 and P = 0.6097). CONCLUSION: Thromboembolic events were the most frequent in the 40s. The ATE ratio for overall thromboembolism tended to increase with advancing age. All ATE cases had a significantly poorer prognosis in comparison with all VTE cases.