Seasonal variation in the management and outcomes of cardiac arrest complicating acute myocardial infarction

Abstract

Summary Background There are limited data on the influence of seasons on the outcomes of acute myocardial infarction-cardiac arrest (AMI-CA). Aim To evaluate the outcomes of AMI-CA by seasons in the United States Design Retrospective cohort study Methods Using the National Inpatient Sample from 2000 to 2017, adult (>18 years) admissions with AMI-CA were identified. Seasons were defined by the month of admission as spring, summer, fall and winter. The outcomes of interest were prevalence of AMI-CA, in-hospital mortality, use of coronary angiography, percutaneous coronary intervention (PCI), hospital length of stay, hospitalization costs and discharge disposition. Results Of the 10 880 856 AMI admissions, 546 334 (5.0%) were complicated by CA, with a higher prevalence in fall and winter (5.1% each) compared to summer (5.0%) and spring (4.9%). Baseline characteristics of AMI-CA admissions admitted in various seasons were largely similar. Compared to AMI-CA admissions in spring, summer and fall, AMI-CA admissions in winter had slightly lower rates of coronary angiography (63.3–64.3% vs. 61.4%) and PCI (47.2–48.4% vs. 45.6%). Compared to those admitted in the spring, adjusted in-hospital mortality was higher for winter {46.8% vs. 44.2%; odds ratio (OR) 1.08 [95% confidence interval (CI) 1.06–1.10]; P < 0.001}, lower for summer [43% vs. 44.2%; OR 0.97 (95% CI 0.95–0.98); P < 0.001] and comparable for fall [44.4% vs. 44.2%; OR 1.01 (95% CI 0.99–1.03); P = 0.31] AMI-CA admissions. Length of hospital stay, total hospitalization charges and discharge dispositions for AMI-CA admissions were comparable across the seasons. Conclusions AMI-CA admissions in the winter were associated with lower rates of coronary angiography and PCI, and higher rates of in-hospital mortality compared to the other seasons.