The creatinine-to-cystatin C ratio as a prognostic risk-stratification biomarker in chronic kidney disease

Background The creatinine-to-cystatin C ratio (Cr/CysC) is a promising surrogate marker for muscle mass. While associated with adverse outcomes in various diseases, its prognostic utility for cardiorenal risks in the Chinese non-dialysis chronic kidney disease (CKD) population remains inadequately explored. This study aimed to investigate the association between the Cr/CysC ratio and the risks of cardiovascular disease (CVD) and CKD progression in a large Chinese CKD cohort. Methods We conducted a retrospective cohort study of 16,031 non-dialysis CKD patients from the China Renal Data System (CRDS). Cox proportional hazards models were used to assess the relationship between the serum Cr/CysC ratio and the incidence of CVD and CKD progression over 28,189.68 person-years of follow-up. Results In CKD patients, a higher serum Cr/CysC ratio was significantly associated with lower risks of both CVD events and CKD progression. Compared to the lowest quartile (Q1), patients in the highest quartile (Q4) had a 21% lower risk of CVD (HR: 0.79, 95% CI: 0.67–0.92) and a 49% lower risk of CKD progression (HR: 0.51, 95% CI: 0.46–0.58). When analyzed as a continuous variable, each unit increase in the log-transformed ratio was associated with a significantly reduced risk for both outcomes ( p 0.001). Conclusion A higher serum Cr/CysC ratio is independently associated with reduced risks of CVD and CKD progression in Chinese patients with non-dialysis CKD. This ratio may serves as a useful prognostic marker for risk stratification in this population.