Refining the Cardiovascular-Kidney-Metabolic Staging System for Improved Risk Stratification of Chronic Kidney...

The original cardiovascular-kidney-metabolic (CKM) staging system uniformly categorized all individuals with type 2 diabetes (T2D) as Stage 2. We aimed to improve the prognostic accuracy for chronic kidney disease (CKD) progression by incorporating the Kidney Disease: Improving Global Outcomes risk categories - based on estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR) - into CKM Stage 2.

This study included 600 individuals with T2D from Kure Medical Center and Chugoku Cancer Center. The primary outcome was CKD progression, defined as a ≥30% decline in eGFR. The refined system significantly improved risk stratification for CKD progression compared with the original system, showing a higher area under the receiver operating characteristic curve and greater integrated discrimination improvement. The risk of CKD progression, reflected by hazard ratios derived from the Fine-Gray subdistribution hazard models, increased progressively across the refined CKM stages after adjustment for potential confounders, including baseline eGFR. However, the independent prognostic value of the refined system was attenuated when baseline UACR was additionally included in the model.

Integrating eGFR and UACR into the original CKM staging system enhances the prognostic performance for CKD progression in individuals with T2D. This refined system, incorporating these renal biomarkers, provides superior risk stratification compared with the original system, and serves as a more robust tool for clinical prognostic assessment.