Coronary heart disease mortality and hormone therapy before and after the Women's Health Initiative.

Abstract

To assess whether coronary heart disease mortality in Finnish hormone therapy (HT) users differed before and after 2002 when the Women's Health Initiative study was published. The risks of coronary heart disease death in HT users in relation to the age-matched background population were compared between the pre- (1995-2001) and post- (2002-2009) Women's Health Initiative eras. We used a nationwide register on HT (ie, estradiol with or without progestin) reimbursement and linked them to causes of death in 290,272 women aged 40 years or older. Exposure to HT for 1 year or less was accompanied by a 29% reduction (0.71; 0.63-0.80; three per 10,000 fewer deaths) and an exposure of 1-8 years with a 43% reduction (0.57; 0.48-0.66; three per 10,000 fewer deaths) in the risk of coronary heart disease death in the pre-Women's Health Initiative era. In the post-Women's Health Initiative era, HT use of 1 year or less was associated with an 18% reduction (0.82; 0.76-1.00; one per 10,000 fewer deaths) and an exposure of 1-8 years with a 54% reduction (0.46; 0.32-0.64; two per 10,000 fewer deaths) in coronary heart disease mortality. Discontinuation of HT was associated with an increased risk of cardiac death of 42% (1.42; 1.17-1.71; seven per 10,000 extra deaths) in the pre-Women's Health Initiative era and 31% (1.31; 0.92-1.82; two per 10,000 extra deaths) in the post-Women's Health Initiative era during the first posttreatment year. This risk increase vanished in further follow-up during both eras. Changes in HT use after the Women's Health Initiative failed to affect coronary heart disease mortality of HT users in this nationwide study.