To investigate the predictive value of peripheral blood C-reactive protein-to-albumin ratio (CAR) for in-hospital mortality in elderly patients with return of spontaneous circulation (ROSC) after cardiopulmonary resuscitation (CPR).

A total of 130 elderly CPR patients with ROSC admitted to the Second Affiliated Hospital of Xi'an Jiaotong University from May 2023 to April 2025 were enrolled as the study subjects, and based on the survival status at discharge, they were divided into a survival group (n=22) and a death group (n=108). Indicators including age, gender, underlying diseases, etiology, time and location of cardiac arrest (CA), defibrillation or not, time to initiation and duration of CPR, doses of vasopressor drugs, chest compression fraction and CAR level were collected. SPSS 27.0 statistics was used for data analysis, and independent-samples t test or Chi-square test was performed for comparison between groups depending on data type. Binary logistic regression analysis was applied to analyze the influencing factors for in-hospital death of elderly CPR patients with ROSC. Receiver operativecharacteristic (ROC) curve was drawn to assess the predictive value of CAR for in-hospital death in these patients.

Among the 130 elderly CPR patients with ROSC, 22 (16.92%) survived to discharge and 108 (83.08%) died in hospital. Taking whether in-hospital death occurred as the dependent variable, binary logistic regression analysis revealed that CPR duration ≥30 min (OR=2.061, 95%CI 1.116-3.806; P=0.021), time from CPR to ROSC ≥10 min (OR=3.108, 95%CI 1.197-8.073; P=0.020) and CAR (OR=1.740, 95%CI 1.351-2.241; P<0.001) were risk factors for in-hospital death in elderly CPR patients with ROSC, and whereas in-hospital occurrence of CA (OR=0.515, 95%CI 0.345-0.770; P=0.001) and shockable rhythm (OR=0.658, 95%CI 0.523-0.827; P<0.001) were protective factors. ROC curve analysis showed that the area under the curve (AUC) of CAR for predicting the in-hospital death of elderly CPR patients with ROSC was 0.845 (95%CI 0.754-0.935), with an optimal cutoff value of 1.44, a corresponding sensitivity of 0.769 and a specificity of 0.864.

Elderly CPR patients with ROSC have a high mortality rate, and CAR level demonstrates high predictive value for in-hospital death, which may provide a reference for clinical treatment.