Objectives To determine if comparable older women and men received different durations of P2Y 12 inhibitor therapy following acute myocardial infarction (AMI) and if therapy duration differences were justified by differences in ischaemic benefits and/or bleeding risks. Design Retrospective cohort. Setting 20% sample of 2007-2015 US Medicare fee-for-service administrative claims data. Participants ≥66-year-old P2Y 12 inhibitor new users following 2008-2013 AMI hospitalisation (N=30 613). Older women compared to older men with similar predicted risks of study outcomes. Primary and secondary outcome measures Primary outcome: P2Y 12 inhibitor duration (modelled as risk of therapy discontinuation). Secondary outcomes: clinical events while on P2Y 12 inhibitor therapy, including (1) death/hospice admission, (2) composite of ischaemic events (AMI/stroke/revascularisation) and (3) hospitalised bleeds. Cause-specific risks and relative risks (RRs) estimated using Aalen-Johansen cumulative incidence curves and bootstrapped 95% CIs. Results 10 486 women matched to 10 486 men with comparable predicted risks of all 4 study outcomes. No difference in treatment discontinuation was observed at 12 months (women 31.2% risk; men 30.9% risk; RR 1.01; 95% CI 0.97 to 1.05), but women were more likely than men to discontinue therapy at 24 months (54.4% and 52.9% risk, respectively; RR 1.03; 95% CI 1.00 to 1.05). Among patients who did not discontinue P2Y 12 inhibitor therapy, women had lower 24-month risks of ischaemic outcomes than men (13.1% and 14.7%, respectively; RR 0.90; 95% CI 0.84 to 0.96), potentially lower 24-month risks of death/hospice admission (5.0% and 5.5%, respectively; RR 0.91; 95% CI 0.82 to 1.02), but women and men both had 2.5% 24-month bleeding risks (RR 0.98; 95% CI 0.82 to 1.14). Conclusions Risks for death/hospice and ischaemic events were lower among women still taking a P2Y 12 inhibitor than comparable men, with no difference in bleeding risks. Shorter P2Y 12 inhibitor durations in older women than comparable men observed between 12 and 24 months post-AMI may reflect a disparity that is not justified by differences in clinical need.
|State||Published - Dec 1 2021|
Bibliographical noteFunding Information:
Funding The database infrastructure used for this project was funded by the Pharmacoepidemiology Gillings Innovation Lab (PEGIL) for the Population-Based Evaluation of Drug Benefits and Harms in Older US Adults (GIL200811.0010); the Center for Pharmacoepidemiology, Department of Epidemiology, UNC Gillings School of Global Public Health; the CER Strategic Initiative of UNC’s Clinical and Translational Science Award (UL1TR001111); the Cecil G. Sheps Center for Health Services Research, UNC; and the UNC School of Medicine. RPH received support while conducting this research from the NIH National Heart, Lung and Blood Institute (NHLBI) (National Research Service Award Training Grant No. 4T32HL007055-43) as a post-doctoral research fellow with the Cardiovascular Disease Epidemiology Program at The University of North Carolina at Chapel Hill and from the American Foundation for Pharmaceutical Education (AFPE) PreDoctoral Fellowship in Health Outcome Disparities. At the time of submission, RPH was supported as a Postdoctoral Fellow in Advanced Geriatrics with the Geriatric Research, Education, and Clinical Center at the Veterans Affairs Healthcare System, Pittsburgh, PA.
- clinical pharmacology
- geriatric medicine
- myocardial infarction
- statistics & research methods
ASJC Scopus subject areas
- Medicine (all)