Influence of primary payer status on non-ST-segment elevation myocardial infarction: 18-year retrospective cohort national temporal trends, management and outcomes

Background: The role of insurance on outcomes in non-ST-segment-elevation myocardial infarction (NSTEMI) patients is limited in the contemporary era. Methods: From the National Inpatient Sample, adult NSTEMI admissions were identified [2000-2017]. Expected primary payer was classified into Medicare, Medicaid, private, uninsured and others. Outcomes included in-hospital mortality, overall and early coronary angiography, percutaneous coronary intervention (PCI), resource utilization and discharge disposition. Results: Of the 7,290,565 NSTEMI admissions, Medicare, Medicaid, private, uninsured and other insurances were noted in 62.9%, 6.1%, 24.1%, 4.6% and 2.3%, respectively. Compared to others, those with Medicare insurance older (76 vs. 53-60 years), more likely to be female (48% vs. 25-44%), of white race, and with higher comorbidity (all P<0.001). Population from the Medicare cohort had higher in-hospital mortality (5.6%) compared to the others (1.9-3.4%), P<0.001. With Medicare as referent, in-hospital mortality was higher in other {adjusted odds ratio (aOR) 1.15 [95% confidence interval (CI), 1.11-1.19]; P<0.001}, and lower in Medicaid [aOR 0.95 (95% CI, 0.92-0.97); P<0.001], private [aOR 0.77 (95% CI, 0.75-0.78); P<0.001] and uninsured cohorts [aOR 0.97 (95% CI, 0.94-1.00); P=0.06] in a multivariable analysis. Coronary angiography (overall 52% vs. 65-74%; early 15% vs. 22-27%) and PCI (27% vs. 35-44%) were used lesser in the Medicare population. The Medicare population had longer lengths of stay, lowest hospitalization costs and fewer home discharges. Conclusions: Compared to other types of primary payers, NSTEMI admissions with Medicare insurance had lower use of coronary angiography and PCI, and higher in-hospital mortality.