Increased cardiac and stroke death risk in the first year after discontinuation of postmenopausal hormone therapy

Objective: The aim of the study was to evaluate the risk of cardiac and stroke deaths in women who discontinue postmenopausal hormone therapy (HT). Methods: We analyzed the risk of death due to cardiac (n = 5,204) and cerebrovascular (n = 3,434) causes in Finnish women who discontinued systemic HT during 1994 to 2013 (n = 432,775). The risks were compared with those in the age-matched female background population and with those in age-matched HT users. Women diagnosed with cardiac or cerebrovascular events within 1 year before discontinuation of HT were excluded (n = 8,711). Results: Women younger than 60 years at discontinuation of HT showed a significantly increased risk of cardiac death (after ≤5 y of HT exposure, standardized mortality ratio [SMR] 1.52, 95% CI 1.13-2.00; after >5 y of exposure, SMR 2.08, 95% CI 1.44-2.90) and stroke death (after ≤5 y of exposure, SMR 2.62, 95% CI 2.07-3.28; after >5 y of exposure, SMR 3.22, 95% CI 2.29-4.40) during the first year after treatment as compared with age-matched female background population. When compared with HT users, elevations in risks of cardiac and stroke deaths were even higher. Increased mortality risks were limited to the first post-HT year because increases in risks vanished or markedly decreased when the follow-up time was extended over more than 1 year. Conclusions: Discontinuation of postmenopausal HT may be associated with increased risk of cardiac and stroke death in the first posttreatment year. Further investigation is required to evaluate causality of the observed associations.