Admission Red Cell Distribution Width-to-Albumin Ratio Predicts In-Hospital Mortality in Implantable Cardioverter-Defibrillator Recipients Hospitalized with Acute Decompensated Heart Failure

Background Early risk stratification remains a major challenge in implantable cardioverter-defibrillator (ICD) recipients hospitalized with acute decompensated heart failure with reduced ejection fraction (ADHF-HFrEF). The red cell distribution width-to-albumin ratio (RAR), a composite biomarker integrating inflammatory and nutritional status, has emerged as a promising prognostic marker in cardiovascular disease. However, its prognostic significance in ICD recipients hospitalized with ADHF-HFrEF remains unknown. This study aimed to evaluate the association between admission RAR and in-hospital mortality in this high-risk population. Methods This retrospective observational cohort study included 514 consecutive ICD recipients hospitalized with ADHF-HFrEF between January 2022 and March 2025. Admission RAR was calculated by dividing red cell distribution width (%) by serum albumin (g/dL). The primary outcome was all-cause in-hospital mortality. Independent predictors of mortality were identified using multivariable logistic regression analysis, and the discriminative performance of RAR was assessed using receiver operating characteristic (ROC) curve analysis. Results Among the 514 patients, 78 (15.2%) died during hospitalization. Admission RAR was significantly higher in non-survivors than in survivors (4.58 ± 1.56 vs. 3.42 ± 0.80, p < 0.001). After multivariable adjustment, age (OR 1.060, 95% CI 1.029–1.091; p < 0.001), serum creatinine (OR 1.570, 95% CI 1.205–2.045; p = 0.001), serum sodium (OR 0.773, 95% CI 0.718–0.832; p < 0.001), C-reactive protein (OR 1.013, 95% CI 1.004–1.021; p = 0.003), and RAR > 4.05 (OR 5.812, 95% CI 2.980–11.335; p < 0.001) were independently associated with in-hospital mortality. RAR demonstrated good discriminatory performance for predicting in-hospital mortality (AUC 0.813, 95% CI 0.773–0.848; p < 0.001). Conclusion Admission RAR was independently associated with in-hospital mortality in ICD recipients hospitalized with ADHF-HFrEF. As a simple, inexpensive, and routinely available biomarker, RAR may complement early admission risk stratification in this particularly vulnerable patient population. Prospective multicenter studies are warranted to externally validate these findings.