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

Abstract

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.