Rate, causes, and predictors of 90‐day readmissions and the association with index hospitalization coronary revascularization following non‐ST elevation myocardial infarction in the United States

OBJECTIVES: To assess the causes and predictors of readmission after NSTEMI. BACKGROUND: Studies on readmissions following non-ST elevation myocardial infarction (NSTEMI) are limited. We investigated the rate and causes for readmission and the impact of coronary revascularization on 90-day readmissions following a hospitalization for NSTEMI in a large, nationally representative United States database. METHODS: We queried the National Readmission Database for the year 2016 using appropriate ICD-10-CM/PCS codes to identify all adult admissions for NSTEMI. We determined the 90-day readmissions for major adverse cardiac events (MACE). All-cause readmission was a secondary endpoint. The association between coronary revascularization and the likelihood of readmission was analyzed using multivariate Cox regression analysis. RESULTS: A total of 296,965 adult discharges following an admission for NSTEMI were included in this study. The rate of readmissions for MACE was 5.2% (n = 15,637) and for any cause was 18.0% (n = 53,316). 38% of MACE readmissions and 40% of all-cause readmissions occurred between 30- and 90-days following the index hospitalization. During index hospitalization, 51.0% underwent coronary revascularization (40.8% with PCI and 10.2% with CABG). This was independently predictive of a lower risk of 90-day readmission for MACE (adjusted HR 0.59, 95% confidence interval (CI) 0.56-0.63, p < .001) and for any cause (adjusted HR 0.65, 95% CI 0.63-0.67, p < .001). In-hospital mortality for MACE readmissions was significantly higher compared to that of index hospitalization (3.8% vs. 2.6%, p < .001). CONCLUSION: Readmissions following NSTEMI carry higher mortality than the index hospitalization. Coronary revascularization for NSTEMI is associated with a lower readmission rate at 90 days.