Differential time trends of outcomes and costs of care for acute myocardial infarction hospitalizations by ST elevation and type of intervention in the United States, 2001-2011

Abstract

Background: Little is known whether time trends of in-hospital mortality and costs of care for acute myocardial infarction (AMI) differ by type of AMI (ST-elevation myocardial infarction [STEMI] vs. non-ST-elevation [NSTEMI]) and by the intervention received (percutaneous coronary intervention [PCI], coronary artery bypass grafting [CABG], or no intervention) in the United States.

Methods and results: We conducted a serial cross-sectional study of all hospitalizations for AMI aged 30 years or older using the Nationwide Inpatient Sample, 2001-2011 (1,456,154 discharges; a weighted estimate of 7,135,592 discharges). Hospitalizations were stratified by type of AMI and intervention, and the time trends of in-hospital mortality and hospital costs were examined for each combination of the AMI type and intervention, after adjusting for both patient- and hospital-level characteristics. Compared with 2001, adjusted in-hospital mortality improved significantly for NSTEMI patients in 2011, regardless of the intervention received (PCI odds ratio [OR] 0.68, 95% CI 0.56 to 0.83; CABG OR 0.57, 0.45 to 0.72; without intervention OR 0.61, 0.57 to 0.65). As for STEMI, a decline in adjusted in-hospital mortality was significant for those who underwent PCI (OR 0.83; 0.73 to 0.94); however, no significant improvement was observed for those who received CABG or without intervention. Hospital costs per hospitalization increased significantly for patients who underwent intervention, but not for those without intervention.

Conclusions: In the United States, the decrease in in-hospital mortality and the increase in costs differed by the AMI type and the intervention received. These non-uniform trends may be informative for designing effective health policies to reduce the health and economic burdens of AMI.

Keywords: acute myocardial infarction; hospital costs; in‐hospital mortality; time trend.

Figure 1.

Temporal trends of in‐hospital mortality for acute myocardial infarction hospitalizations in the United States by ST‐elevation/non‐ST‐elevation and percutaneous coronary intervention/cardiac bypass graft stenting use. Year 2001 was used as the reference. CABG indicates coronary artery bypass grafting; PCI, percutaneous coronary intervention; STEMI, non‐ST‐elevation myocardial infarction.

Figure 2.

Temporal trends of percent change of hospital costs for acute myocardial infarction hospitalizations in the United States by ST‐elevation/non‐ST‐elevation and percutaneous coronary intervention/cardiac bypass graft stenting use. Year 2001 was used as the reference. CABG indicates coronary artery bypass grafting; PCI, percutaneous coronary intervention; STEMI, non‐ST‐elevation myocardial infarction.