Association between intensive care unit usage and long-term medication adherence, mortality, and readmission among initially stable patients with non–st-segment–elevation myocardial infarction

BACKGROUND: Hospitals in the United States vary in their use of intensive care units (ICUs) for hemodynamically stable patients with non–ST-segment–elevation myocardial infarction (NSTEMI). The association between ICU use and long-term outcomes after NSTEMI is unknown. METHODS AND RESULTS: Using data from the National Cardiovascular Data Registry linked to Medicare claims, we identified 65 256 NSTEMI patients aged ≥ 65 years without cardiogenic shock or cardiac arrest on presentation between 2011 and 2014. We compared 1-year medication non-adherence, cardiovascular readmission, and mortality across hospitals by ICU use using multivariable regression models. Among 520 hospitals, 154 (29.6%) were high ICU users (>70% of stable NSTEMI patients admitted to ICU), 270 (51.9%) were intermediate (30%–70%), and 196 (37.7%) were low (<30%). Compared with low ICU usage hospitals, no differences were observed in the risks of 1-year medication non-adherence (adjusted odds ratio 1.08, 95% CI, 0.97–1.21), mortality (adjusted hazard ratio 1.06, 95% CI, 0.98–1.15), and cardiovascular readmission (adjusted hazard ratio 0.99, 95% CI, 0.95–1.04) at high usage hospitals. Patients hospitalized at intermediate ICU usage hospitals had lower rates of evidence-based therapy and diagnostic catheterization within 24 hours of hospital arrival, and higher risks of 1-year mortality (adjusted hazard ratio 1.07, 95% CI, 1.02–1.12) and medication non-adherence (adjusted odds ratio 1.09, 95% CI, 1.02–1.15) compared with low ICU usage hospitals. CONCLUSIONS: Routine ICU use is unlikely to be beneficial for hemodynamically stable NSTEMI patients; medication adher-ence, long-term mortality, and cardiovascular readmission did not differ for high ICU usage hospitals compared with hospitals with low ICU usage rates.