Association of intensive care unit admission and mortality in patients with acute myocardial infarction

Abstract

BackgroundAn admission to the intensive care unit (ICU) after developing acute myocardial infarction (AMI) has been the standard of care and is recommended by professional societies. However, evidence that justifies its use, such as a reduction in mortality, has never been shown despite the associated financial burden. This study aimed to investigate the association between ICU admission and a reduction in 30-day mortality in patients who developed AMI. MethodsThe multicenter retrospective cohort study was conducted using data from an administrative database between 2014 and 2016 in Japan. Patients with AMI as the primary diagnosis in the Diagnosis Procedure Combination database were included. Exposure was ICU admission, which was defined by an ICU management code in the claims record. Comparison was those without an ICU management code. The primary outcome was 30-day mortality. An association between ICU admission and a 30-day mortality was tested using a logistic regression model with random effects. ResultsOf 18,745 patients [mean (standard deviation) age, 69 (13) years; 74% male] identified, 11,538 (62%) were admitted to ICUs and 7207 (38%) were admitted to non-ICUs. Among patients admitted to ICUs, 575 patients (5%) died within 30 days of admission, while 429 patients (6%) died in the non-ICU group. The association between ICU admission and mortality was confirmed both in unadjusted analysis [odds ratio (OR), 0.75; 95% confidence interval (CI), 0.64–0.89; p=0.001] and adjusted analysis (OR, 0.70; 95% CI, 0.54–0.90; p=0.01). ConclusionsICU admission was associated with lower 30-day mortality in patients who developed AMI.