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

Abstract

Background Hospitals in the United States vary in their use of intensive care units ( ICU s) 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 adherence, long‐term mortality, and cardiovascular readmission did not differ for high ICU usage hospitals compared with hospitals with low ICU usage rates.