The association of in-hospital guideline adherence and longitudinal postdischarge mortality in older patients with non-ST-segment elevation myocardial infarction

Background Prior work has demonstrated that adherence to American College of Cardiology/American Heart Association guideline recommendations is associated with decreased in-hospital mortality in non-ST-segment elevation myocardial infarction (NSTEMI) patients; however, it is unknown whether this association persists after hospital discharge in older, real-world populations. Methods We evaluated 32,646 NSTEMI patients >65 years treated at 243 US hospitals participating in CRUSADE from 2003 to 2006, linked to Medicare longitudinal claims data (followed to January 1, 2010). Hospital composite adherence examined the use of 13 individual American College of Cardiology/American Heart Association Class IA guideline-recommended interventions. Among patients who survived to hospital discharge, we used Cox proportional hazards modeling to examine the association between hospital composite adherence and 1- and 3-year mortality conditional on surviving initial hospitalization and adjusting for patient baseline clinical factors and hospital characteristics. Results The overall median composite guideline adherence to all 13 interventions was 77.4% with median (25th, 75th percentiles) hospital adherence ranging from 66.7% (61.9%, 70.1%) in the lowest adherence quartile to 85.8% (83.7%, 88.7%) in the highest adherence quartiles. Overall survival at 1 and 3 years was 80.0% and 62.8%, respectively. Relative to patients treated at the lowest adherence hospitals, those treated at the highest had similar adjusted mortality risk at 1 year but significantly lower 3-year mortality risk (adjusted hazard ratio [95% CI] 0.90 [0.82-0.99]). For every 10% increase in adherence to all 13 hospital composite therapies, there was a 5% reduction in 3-year mortality risk (0.95 [0.91-0.98]). Conclusions Use of guideline-based therapies during acute hospitalization for NSTEMI was associated with significant decreases in mortality up to 3 years post-hospital discharge.