Association of estimated glomerular filtration rate from serum creatinine and cystatin C with new-onset diabetes: a nationwide cohort study in China

Aims The association between estimated glomerular filtration rate (eGFR) and the risk of diabetes remains uncertain. We aimed to examine the association between eGFR based on creatinine (eGFRcr), cystatin C (eGFRcys), or a combination of both (eGFRcr-cys) and new-onset diabetes, using data from the China Health and Retirement Longitudinal Study (CHARLS), a nationally representative cohort study. Methods A total of 4,775 participants with pertinent measurements and without diabetes at baseline from CHARLS were included in the final analysis. The eGFR was calculated by creatinine, cystatin C or a combination of both using the Chronic Kidney Disease Epidemiology Collaboration equations. The study outcome was new-onset diabetes, defined as physician-diagnosed diabetes or use of glucose-lowering drugs during follow-up, or fasting glucose >= 126 mg/dL, random glucose >= 200 mg/dL, or HbA1c >= 6.5% (48 mmol/mol) at the exit visit. Results The mean age of the study population was 59.6 years. The mean values for the eGFRcr, eGFRcys, and eGFRcr-cys were 92.4, 78.9 and 85.9 mL/min/1.73m(2), respectively. Over 4 years of follow-up, 612 (12.8%) participants experienced diabetes. Participants with lower eGFRcr-cys (< 60 mL/min/1.73m(2)) had a significantly higher risk of new-onset diabetes (adjusted OR, 1.46; 95%CI: 1.02, 2.09), compared to those with eGFRcr-cys >= 60 mL/min/1.73m(2). However, there was no significant association between eGFRcr (< 60 vs. >= 60 mL/min/1.73m(2); adjusted OR, 1.27; 95%CI: 0.75, 2.17) or eGFRcys (adjusted OR, 1.04; 95%CI: 0.80, 1.36) and new-onset diabetes. Conclusions Lower eGFRcr-cys (< 60 mL/min/1.73m(2)), but not eGFRcr or eGFRcys, was significantly associated with an increased risk of new-onset diabetes in Chinese adults.