Association of C-reactive protein-albumin-lymphocyte (CALLY) index with all-cause mortality in patients with type 2 diabetes: Results from the retrospective cohort study of NHANES 1999–2010

The C-reactive protein-albumin-lymphocyte (CALLY) index is a novel composite biomarker integrating nutritional, immune, and inflammatory statuses, which may offer significant prognostic value for chronic diseases. Given the multifactorial nature of diabetes mellitus, involving nutrition imbalance, immune suppression, and chronic inflammation, this study aimed to evaluate the prognostic significance of the CALLY index for all-cause mortality in diabetic patients. We analyzed data from 3988 diabetic patients aged ≥ 40 years from the National Health and Nutrition Examination Survey from 1999 to 2010. Weighted Cox proportional hazards models, Kaplan-Meier survival analyses, and smoothed curve fitting were conducted to examine associations between the CALLY index and mortality risk. The predictive performance was evaluated by the area under curve the receiver operating characteristic curve. During a median follow-up of 131 months, 1821 deaths occurred (weighted mortality: 41.7%). After full adjustments, each 1-unit increase in ln-transformed CALLY was associated with a 15% reduction in all-cause mortality risk (HR = 0.85, 95% CI: 0.81-0.90, P < .0001). Kaplan-Meier analysis demonstrated significantly greater survival with higher CALLY indices (P < .0001). Smooth curve fitting showed a nonlinear negative correlation between CALLY index and mortality. CALLY exhibited superior predictive accuracy (area under curve = 0.821) compared to traditional inflammatory indices (systemic immune-inflammatory index, platelet-to-lymphocyte ratio, neutrophil-to-lymphocyte ratio). Higher CALLY index is significantly associated with lower all-cause mortality among diabetic patients aged ≥ 40 years. As a simple, cost-effective biomarker, the CALLY index may enhance clinical prognostic assessment and facilitate individualized patient management in diabetes care.