Predictors of thirty-day readmission in nonagenarians presenting with acute heart failure with preserved ejection fraction: a nationwide analysis

BACKGROUD Acute heart failure with preserved ejection fraction (HFpEF) is a common but poorly studied cause of hospital admissions among nonagenarians. This study aimed to evaluate predictors of thirty-day readmission, in-hospital mortality, length of stay, and hospital charges in nonagenarians hospitalized with acute HFpEF. METHODS Patients hospitalized between January 2016 and December 2018 with a primary diagnosis of diastolic heart failure were identified using ICD-10 within the Nationwide Readmission Database. We excluded patients who died in index admission, and discharged in December each year to allow thirty-day follow-up. Univariate regression was performed on each variable. Variables with P-value < 0.2 were included in the multivariate regression model. RESULTS From a total of 45,393 index admissions, 43,646 patients (96.2%) survived to discharge. A total of 7,437 patients (15.6%) had a thirty-day readmission. Mean cost of readmission was 43,265 United States dollars (USD) per patient. Significant predictors of thirty-day readmission were chronic kidney disease stage III or higher [adjusted odds ratio (aOR) = 1.20, 95% CI: 1.07-1.34, P = 0.002] and diabetes mellitus (aOR = 1.18, 95% CI: 1.07-1.29, P = 0.001). Meanwhile, female (aOR = 0.90, 95% CI: 0.82-0.99, P = 0.028) and palliative care encounter (aOR = 0.27, 95% CI: 0.21-0.34, P < 0.001) were associated with lower odds of readmission. Cardiac arrhythmia (aOR = 1.46, 95% CI: 1.11-1.93, P = 0.007) and aortic stenosis (aOR = 1.36, 95% CI: 1.05-1.76, P = 0.020) were amongst predictors of in-hospital mortality. CONCLUSIONS In nonagenarians hospitalized with acute HFpEF, thirty-day readmission is common and costly. Chronic comorbidities predict poor outcomes. Further strategies need to be developed to improve the quality of care and prevent the poor outcome in nonagenarians.