Prognostic value of C-reactive protein to albumin ratio (CAR) for mortality in older adults with sepsis: Cohort study

STUDY OBJECTIVE: To evaluate the prognostic value of the C-reactive protein/albumin (CAR) for mortality in older adults with sepsis. DESIGN AND SETTING: Prospective observational cohort study conducted at General Hospital Zone No. 21, León, Guanajuato, Mexico (Nov 2023-Aug 2025). PARTICIPANTS: Consecutive patients aged >60 years with Sepsis-3-defined sepsis or septic shock, excluding those with prior ICU care, transfers, malignancies, cirrhosis, autoimmune disease, or non-septic shock. INTERVENTIONS: None. The CAR and Sequential Organ Failure Assessment (SOFA) scores were measured at diagnosis and 72 h. MAIN OUTCOME MEASURES: 28-day all-cause mortality, with predictive performance assessed via area under the ROC curve (AUC). RESULTS: CAR was higher in septic shock versus sepsis. In patients with sepsis, both initial (AUC = 0.867) and 72-h (AUC = 0.852) ratios predicted mortality better than SOFA (AUC = 0.786). In septic shock, SOFA was superior (AUC = 0.785 vs. 0.637). An initial ratio in the highest tertile independently predicted mortality (HR 2.88, 95% CI 1.15-5.19, p < 0.001). CONCLUSIONS: The CAR is a strong, independent mortality predictor in older adults with sepsis, outperforming SOFA in sepsis but not in septic shock. This simple biomarker can aid early identification of high-risk patients to guide timely intervention.