Risks of thromboembolism associated with hormonal contraceptives related to body mass index and aging in Japanese women

Objective: The aim of this study is to estimate the risk of thromboembolism related to body mass index (BMI) and aging among users of hormonal contraceptives in Japan. Methods: A case-control study of the risk of obesity and a descriptive study of the risk of age were conducted. We used the Pharmaceuticals and Medical Devices Agency database, and extracted thromboembolic events of combined oral contraceptive (COC) products. Control data were from the National Health and Nutrition Survey in Japan. Denominator of descriptive study was from IMS Health, JPM. Results: A total of 306 thromboembolic events and 6423 controls were analyzed. The odds ratios (95% confidence interval) of the obesity groups (BMI >= 25) were 2.32 (1.71-3.15) for venous thromboembolism(VTE), 1.16 (0.62-2.18) for arterial embolism and thrombosis (ATE), and 1.83 (1.38-2.43) for overall thromboembolic events compared with the standard group (BMI of 18.5-24.9) as a reference. The estimated incidence rates of VTE, ATE and overall thromboembolic events per 10,000 person-years in users of therapeutic remedies for dysmenorrhea (35 mu g ethinylestradiol combined with norethisterone, 20 mu g ethinylestradiol combined with drospirenone and dienogest) among women aged 10-59 years from 2009 to 2013 were 2.38 (2.08-2.74), 0.63 (0.48-0.82), and 3.17 (2.81-3.57), respectively. This tendency was not seen for dienogest. Conclusions: The risk of VTE in the obesity group among COC users was more than 2 times higher than in the standard group. The incidence rates of VTE in Japanese users of all remedies for dysmenorrhea except dienogest were as high as in people in Western countries. (C) 2015 Elsevier Ltd. All rights reserved.