Body roundness index as a predictor of 3-month readmission in elderly patients with first-episode acute heart failure.

AIMS: To determine whether admission body roundness index (BRI), a validated anthropometric metric of central adiposity, independently predicts 3-month all-cause readmission and rehospitalization for acute heart failure (AHF) in elderly patients hospitalized for a first AHF episode. METHODS: In this single-center retrospective cohort study, 317 patients aged >60 years with a first AHF hospitalization were enrolled and stratified by BRI tertiles. The endpoints were all-cause readmission and AHF rehospitalization within 3 months. Patients who died during follow-up were retained in the cohort and censored at the time of death, and associations were analyzed using the cause-specific Cox proportional hazards model. Associations were assessed using multivariable Cox regression, restricted cubic spline analysis, and pre-specified subgroup analyses. RESULTS: During follow-up, 3 patients (0.95%) died (1 in each tertile at 9, 22, and 45 days) and were censored at the time of death, and 128 patients (40.76%) experienced all-cause readmission and 68 (21.73%) were rehospitalized for AHF. After full adjustment, each 1-unit increment in BRI was associated with a 48% higher risk of all-cause readmission (HR 1.48, 95% CI 1.20-1.83) and a 2.15-fold risk of AHF rehospitalization (HR 2.15, 95% CI 1.55-2.98); risks in the highest tertile significantly exceeded those in the lowest tertile. Restricted cubic spline analysis unmasked striking nonlinear threshold effects: all-cause readmission risk escalated sharply when BRI surpassed 5.40 (HR 2.75, 95% CI 1.98-3.82), whereas AHF rehospitalization risk surged beyond a BRI of 7.05 (HR 2.93, 95% CI 1.34-6.40). Notably, the middle BRI tertile exhibited a markedly lower all-cause readmission risk relative to the lowest tertile (HR 0.38, 95% CI 0.17-0.87), whereas AHF rehospitalization risk did not differ. This divergent pattern mechanistically reconciles the "obesity paradox" by distinguishing a sarcopenic phenotype in the lowest-BRI group from a high-adiposity phenotype in the upper extreme. The direction of association remained consistent across all subgroups, with significant effect modification by smoking status, marital status, NYHA class, and diabetes. CONCLUSION: Admission BRI is an independent predictor of 3-month all-cause readmission and AHF rehospitalization in elderly patients with AHF, and may serve as a simple, low-cost tool for early post-discharge risk stratification in this population.