Post-Discharge Beta-Blockers And Early Mortality And Readmission In Older Patients With Heart Failure: An Instrumental Variable Analysis

Introduction: The rate of growth of the older heart failure population has outpaced that of any other age group. Importantly, these older patients were underrepresented in the early beta-blocker trials and there are several reasons, including a decreased potential for mortality benefit and an increased risk of side effects, why the risk/benefit trade-off may be different in this older population. Hypothesis: The association between receipt of a beta-blocker at the time of hospital discharge and early mortality and readmissions in heart failure with reduced ejection fraction (HFrEF) patients aged ≥75 is not significantly different than among HFrEF patients <75 years old. Methods: We used 100% Medicare Parts A and B and a random 40% sample of Part D to create a cohort of beneficiaries with ≥1 hospitalization for HFrEF between 2008 and 2016 and determined beta-blocker use at hospital discharge. The primary outcome was 90-day, all-cause mortality; the secondary outcome was 90-day, all-cause readmission. To address both measured and unmeasured confounding, we used the two-stage least squared instrumental variable analysis method. Results: Among all HFrEF patients, receipt of a beta-blocker at the time of discharge was associated with a -4.34% (95% CI -6.26% to -2.42%, p<0.001) decrease in 90-day mortality and a -4.67% (95% CI -7.41% to -1.91%, p=0.001) decrease in 90-day readmission rates. Among patients >75 years old, receipt of a beta-blocker was also associated with a significant -4.74% decrease (95% CI -7.13% to -2.34%, p<0.001) in 90-day mortality and a -4.67% (95% CI -8.96% to -2.93%, p<0.00) decrease in 90-day readmissions. Conclusions: We find that patients aged ≥75 years who receive a beta-blocker at HFrEF discharge have significantly lower 90-day mortality and readmission rates. The magnitude of benefit from beta-blocker therapy after HFrEF discharge does not appear to wane with age.