Unplanned readmissions after discharge increases risk of death in acute dyspnoea patients: non-cardiac is as severe as cardiac causes

Abstract

Introduction: Acute dyspnoea is a major reason for admission to the emergency department and has been associated with high rates of readmission and mortality. However, the association of readmission with mortality risk has not been widely studied in patients with acute dyspnoea. Purpose: To determine whether unplanned readmission during first 6 months after discharge is associated with greater risk of death within 1 year in patients with acute dyspnoea. Methods: Derivation cohort consisted of 1371 patients from the prospective observational study, which enrolled acute dyspnoea patients admitted to emergency departments of two university centres from 2015 to 2017 and discharged alive from the hospital. Cox regression analysis compared 1year risk of death between readmitted vs. nonreadmitted patients in the first 6 months after discharge. In addition, we studied this association in 1986 patients from a multicentre validation cohort, which included acute dyspnoea patients from 2006 to 2014. Sensitivity analysis was done in the subgroups divided by cause of index admission (acute heart failure [AHF] and nonAHF) and cause of the first readmission (cardiovascular [CV] or nonCV). The statistical analyses were performed using R statistical software. P value of <0.05 was considered statistically significant. Results: In the derivation cohort 666 (49%) of patients were readmitted at 6 months and 282 (21%) died in 1 year. Readmitted patients died more frequently than nonreadmitted patients (211 [32%] vs. 71 [10%], respectively, p<0.001). Allcause 6month readmission was associated with an increased 1year risk of death in a multivariate analysis in both the derivation cohort (adjusted hazard ratio (aHR) 3 [95% confidence interval (CI) 2.24], p<0.001) and the validation cohort (aHR 1.8 [95% CI 1.42.2], p<0.001). Moreover, deleterious effect of readmission on 1year survival was equally observed in AHF and nonAHF patients, independent of whether the reason of first readmiss