CST3 and diabetes mellitus: In another analysis of 3418 patients with measured GFR and cystatin C measurement, Stevens et al.47 found that diabetes was a non-GFR-related determinant of serum cystatin C. However, Delanaye et al.48 found, in a study involving 6158 patients with measured GFR and cystatin C measurement that eGFRcr and eGFRcys had the same performance in diabetic and nondiabetic patients.