Comparative Insights on Inpatient Outcomes in Diastolic Heart Failure with and Without Amyloidosis: A Nationwide Propensity-Matched Analysis

Cardiac amyloidosis (CA), an infiltrative restrictive cardiomyopathy, is a frequently underrecognized etiology of diastolic heart failure (HF). This study aimed to evaluate inpatient outcomes among patients hospitalized with decompensated diastolic HF with and without a secondary diagnosis of amyloidosis, utilizing data from the National Inpatient Sample (2018–2021). Among 2,444,699 patients hospitalized for decompensated diastolic HF, 9205 (0.3%) had a documented secondary diagnosis of amyloidosis. After 1:1 propensity-score matching, 1841 patients in each group were analyzed. Multivariate logistic regression revealed that the presence of amyloidosis was associated with significantly higher odds of in-hospital mortality (4.0% vs. 2.7%), cardiogenic shock (5.4% vs. 2.4%), acute kidney injury (28.3% vs. 22.0%), ventricular tachycardia (12.4% vs. 6.0%), and acute myocardial injury (9.5% vs. 6.0%) (all p < 0.05). Additionally, patients with amyloidosis had a longer mean length of stay (7.1 vs. 5.7 days) and higher mean hospitalization costs ($85,594 vs. $48,484, p < 0.05). Although the overall incidence of acute myocardial injury was elevated, subgroup analysis of ST-elevation and non–ST-elevation myocardial infarction revealed no significant differences. These findings underscore the considerable clinical and economic burden of amyloidosis in patients hospitalized with decompensated diastolic heart failure.