Hospitalisations during the 30-day period preceding admissions with cardiac arrest

Background Cardiac arrest (CA) is common but deadly. Prior hospitalisation represents a missed opportunity for prevention and identification of high-risk groups before CA. This study aims to determine the extent of and underlying reasons for hospitalisations during the 30-day period preceding an admission with CA.Methods We conducted a retrospective cohort study using the United States National Readmission Database (NRD) during 2018–2020. We evaluated hospitalisations with a diagnosis of CA and admissions in the 30-day period before hospitalisation with CA. Multiple logistic regressions were used to identify factors associated with prior hospitalisation and mortality on admission with CA.Results Among 1,637,240 hospital episodes with CA, 255,500 (15.6%) had an admission to hospital in the 30-day period prior to hospitalisation with a diagnosis with CA. The categories for causes of previous admissions were disorders of the circulatory system (27%), infectious and parasite disease (13%), and disorders of the respiratory system (12%). The most common diagnoses were sepsis, hypertensive heart and renal disease, acute myocardial infarction, and respiratory failure. Cancer (OR 2.09 95%CI 2.04–2.15, p < 0.001), chronic kidney disease (OR 1.45 95%CI 1.42–1.48, p < 0.001), and chronic lung disease (OR 1.25 95%CI 1.22–1.27, p < 0.001) were the most significant factors associated with prior admission. Previous hospital admission was associated with increased odds of mortality (OR 1.58 95%CI 1.55–1.62, p < 0.001).Conclusions Hospitalisations within the 30-day period preceding an admission with CA are common and occur in about 1 out 6 patients. The most common primary diagnoses for prior hospitalisation were sepsis, renal and cardiovascular disease.