Neutrophil-Percentage-to-Albumin Ratio and Monocyte-to-Albumin Ratio: Utility of the Combined Biomarkers in the Prediction of 30-Day Mortality in Male Diabetes Patients Over 80 Years Old with Bloodstream Infections

Background: Elderly patients with diabetes mellitus (DM) are highly vulnerable to bloodstream infections (BSI), which lead to a significantly high risk of mortality. Novel inflammatory markers that attach to albumin, such as Neutrophil-percentage-to-albumin ratio (NPAR), C-reactive protein-to-albumin ratio (CAR), Monocyte-to-albumin ratio (MAR), Red blood cell distribution width-to-albumin ratio (RAR), Prognostic Nutritional Index (PNI) and C-reactive protein-albumin-lymphocyte index (CALLY index), have proven to be effective in predicting infections. However, the association between these factors and BSI in diabetes patients over 80 years old still remains to be fully elucidated. Purpose: To investigate the predictive value of the novel inflammatory markers NPAR, CAR, MAR, RAR, PNI and CALLY index for the prognosis in male diabetes patients over 80 years old with bloodstream Infections of 30-day mortality. Patients and Methods: Male diabetes patients over 80 years old who diagnosed with BSI were recruited between January 2012 and January 2025. Receiver operating characteristic (ROC) curves, Kaplan-Meier curves (K-M curves) and Cox regression analysis were used to investigate the association between these factors and 30-day mortality. Results: A total of 350 diabetes patients with BSI were recruited in the study, with an average age of 89.77± 8.62 years. There are 55 deaths within 30 days, with an all-cause mortality rate of 15.71%. After adjusting for multiple factors, the NPAR2 and MAR2 groups still correlated with 30 days mortality. (NPAR2 HR, 95% CI: 2.738, 1.058– 7.084, P = 0.038; MAR2 HR, 95% CI: 1.871, 1.012– 3.458, P =0.046). The CAR, RAR, PNI and the CALLY index showed no significant differences in COX regression. Conclusion: NPAR and MAR are more sensitive markers in male diabetes patients over 80 years old with BSI and can provide a reference for predicting 30-day mortality in patients with BSI. Keywords: inflammatory markers, neutrophil percentage-to-albumin ratio, monocyte-to-albumin ratio, bloodstream infections, elder, mortality