The impact of frailty on initiation, continuation and discontinuation of secondary prevention medications following myocardial infarction

Abstract

AimTo evaluate the association between frailty and initiating, continuing, or discontinuing secondary prevention medications following myocardial infarction (MI). MethodsWe conducted a cohort study using linked health data, including all adults aged ≥65 years who discharged from hospital following MI from January 2013 to April 2018 in Victoria, Australia (N = 29,771). The Hospital Frailty Risk Score (HFRS) was used to assess frailty. Logistic regression was used to investigate associations of frailty with initiation, continuation, and discontinuation of secondary prevention medications (P2Y12 inhibitor antiplatelets, beta-blockers, renin-angiotensin-aldosterone system (RAAS) inhibitors, and lipid-lowering therapies) in the 90 days from discharge post-MI, by HFRS, adjusted for age, sex, and Charlson Comorbidity Index. ResultsIncreasing frailty was associated with lower probability of initiating and continuing P2Y12 inhibitors, RAAS inhibitors, and lipid-lowering therapies, but not beta-blockers. At at an HFRS of 0, the predicted probabiliy of having all four medications initiated or continued was 0.59 (95 %CI 0.57–0.62) for STEMI and 0.35 (0.34–0.36) for non-STEMI, compared to 0.38 (0.33–0.42) and 0.16 (0.14–0.18) at an HFRS of 15. Increasing frailty was associated with higher probability of discontinuing these medications post-MI. The predicted probability of discontinuing at least one secondary prevention medication post-MI at an HFRS of 0 was 0.10 (0.08–0.11) for STEMI and 0.14 (0.13–0.15) for non-STEMI, compared to 0.27 (0.22–0.32) and 0.34 (0.32–0.36) at an HFRS of 15. ConclusionPeople with higher levels of frailty were managed more conservatively following MI than people with lower levels of frailty. Whether this conservative treatment is justified warrants further study.