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 1-year risk of death between readmitted vs. non-readmitted 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 non-AHF) and cause of the first readmission (cardiovascular [CV] or non-CV). 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 non-readmitted patients (211 [32%] vs. 71 [10%], respectively, p<0.001). All-cause 6-month readmission was associated with an increased 1-year risk of death in a multivariate analysis in both the derivation cohort (adjusted hazard ratio (aHR) 3 [95% confidence interval (CI) 2.2–4], p<0.001) and the validation cohort (aHR 1.8 [95% CI 1.4–2.2], p<0.001). Moreover, deleterious effect of readmission on 1-year survival was equally observed in AHF and non-AHF patients, independent of whether the reason of first readmission was cardiovascular or non-CV, in both study cohorts. The results are displayed in Figure 1.
Figure 1. Main results of the study
Conclusions
Our data demonstrates that readmission is associated with a markedly increased risk of death within 1 year in patients presenting to the emergency department with acute dyspnoea. Furthermore, the detrimental relationship between outcomes is similar in non-cardiac and cardiac causes.
Acknowledgement/Funding
The work was supported by the Research Council of Lithuania, grant Nr. MIP-049/2015 and approved by Lithuanian Bioethics Committee, Nr. L-15-01.