Detection of decline in estimated glomerular filtration rate in patients with type 2 diabetes by cystatin C-based equations.

Background: Aging population is a significant issue in Viet Nam and across the globe. Elderly individuals are at higher risk of chronic kidney disease (CKD), especially those with diabetes. Several studies found that the estimated glomerular filtration rate (eGFR) determined using creatinine-based equations was not as accurate as that determined using cystatin C-based equations. Cystatin C-based equations may be beneficial in elderly patients with an age-associated decline in kidney function. Early determination of eGFR decline and associated factors would aid in appropriate interventions to improve kidney function in elderly patients with diabetes.

Aim: To determine the utility of cystatin C-based equations in early detection of eGFR decline and to explore factors associated with eGFR decline in elderly patients with diabetes.

Methods: This cross-sectional study included 93 participants aged ≥ 60 years evaluated in Can Tho University of Medicine and Pharmacy Hospital between October 2022 and July 2023, including 47 and 46 participants with and without diabetes respectively, according to the American Diabetes Association criteria for diabetes. The kappa coefficient, Student's t, Mann-Whitney, χ ², Pearson's correlation, multivariate logistic regression, and multiple linear regression analyses were employed.

Results: The eGFRs were lower with the cystatin C-based equations than with the creatinine-based equations. Good agreement was found between the Modification of Diet in Renal Disease (MDRD) and CKD Epidemiology Collaboration (CKD-EPI) 2021 creatinine-cystatin C equations (kappa = 0.66). In the diabetes group, 30% of the participants had low eGFR. Both plasma glucose and glycated hemoglobin were associated with an increased risk of eGFR decline (P < 0.05) and negatively correlated with eGFR (P = 0.001). By multivariate logistic regression, total cholesterol, and exercise were independently associated with low eGFR. By multiple linear regression, higher plasma glucose levels were correlated with lower eGFR (P = 0.026, r = -0.366).

Conclusion: Cystatin C-based equations were superior in the early detection of a decline in eGFR, and the MDRD equation may be considered as an alternative to the CKD-EPI 2021 creatinine-cystatin C equation. Exercise, plasma glucose, and total cholesterol were independently associated with eGFR in patients with diabetes.