The novel CKD-INF score for distinguishing infectious from non-infectious inflammation in patients with non-dialysis chronic kidney disease

Our study analyzed 831 non-dialysis chronic kidney disease (CKD) patients admitted from January 2007 to January 2023, using 665 for creating and 166 for validating the CKD-Infectious Inflammation (CKD-INF) score. This score distinguishes inflammation types using logistic regression outcomes and aligns with the International Sepsis Definition Conference criteria. The study’s participants had an average age of 76.2 ± 11.2 years, with 37% female and over half diagnosed with diabetes. The resulting score was as follows: $${gathered} {CKD} - {INF} = 1.8*{CRP}( {{mg}/{L}} ) + 3.3*{NLR} + 7.9*{WBC}( {{K}/{{ L}}} ) \\ \;\;\; + 172.1*{Fever} ≥ 38\,{^∘ }{C}( {{no} = 0,{yes} = 1} ), \\ {gathered}$$ where NLR refers to the neutrophil-to-lymphocyte ratio, CRP to C-reactive protein, and WBC indicates white blood cell count. CKD-INF exhibited a higher AUC of 0.85 (with a 95% CI of 0.82–0.87), higher sensitivity (75.3%) and specificity (82%) compared to its components including CRP. The CKD-INF score showed higher weighted κ values (0.57) for infection prediction at hospital admission than its individual components. In both training and validation groups, the CKD-INF score outperformed CRP as a predictor of infection in univariate and multivariate analyses. The CKD-INF score, derived from routine laboratory tests, can be an effective tool for predicting infections in CKD patients, potentially aiding in their early management.