Association of the C-reactive protein-to-HDL cholesterol ratio with all-cause mortality in Chinese adults with impaired renal function: a prospective cohort study

Introduction Inflammation and dyslipidemia contribute to excess mortality in chronic kidney disease (CKD). The C-reactive protein-to-high-density lipoprotein cholesterol (CRP/HDL-C) ratio integrates these pathways, but its association with mortality among individuals with impaired renal function remains unclear. Methods This prospective cohort study included 2,202 participants from the China Health and Retirement Longitudinal Study with baseline eGFR < 60 mL/min/1.73 m² or self-reported CKD. The log-transformed CRP/HDL-C ratio was analyzed continuously and by tertiles. Cox proportional hazards models assessed associations with all-cause mortality, adjusting for demographic, lifestyle, and clinical factors. Restricted cubic splines, subgroup analyses, and sensitivity analyses were performed. Results During a median follow-up of 109.6 months, 671 deaths occurred. In the fully adjusted model, the highest versus lowest tertile was associated with higher all-cause mortality (HR = 1.74; 95% CI: 1.39–2.17; P < 0.001). Spline analysis indicated an overall association ( P < 0.001), without evidence of nonlinearity ( P = 0.735). No significant subgroup interactions were detected. However, excluding participants with CRP > 10 mg/L attenuated the association, which was no longer statistically significant (HR per one-unit increase in the log-transformed ratio = 1.09; 95% CI: 0.89–1.33). Conclusion Higher CRP/HDL-C was associated with increased all-cause mortality in this Chinese cohort. However, attenuation after excluding markedly elevated CRP suggests that high inflammatory burden may partly explain the association. External validation and evaluation of incremental predictive value are needed before clinical application.