Effect of Serum C-Peptide Levels on the Development of Contrast-Induced Nephropathy in Diabetic Patients Undergoing Coronary Angiography

Contrast-induced nephropathy (CIN) is an important cause of morbidity and mortality, in patients with diabetes who undergo coronary angiography (CAG). It is known that serum C-peptide has renoprotective effects in diabetic nephropathy. Patients with diabetes (n = 552) who underwent CAG in our center between January 2020 and December 2021 were included, retrospectively. The patients were divided into 2 groups: not-developing CIN (group 1) and developing CIN (group 2). CIN developed in 128 (23.1%) of the patients with diabetes who underwent CAG. C-peptide, albumin, hemoglobin, hematocrit, initial creatinine, ejection fraction (EF), were significantly lower in the group that developed CIN compared with the group that did not (P < .05, for all). In correlation analysis, creatinine increase rate (Delta Cr) was negatively correlated with C-peptide, hematocrit, and ejection fraction (r = -.241, P < .001; r = -.135, P < .001; r = -.194, P = .001; respectively). In logistic regression analysis, C-peptide level (Odds Ratio: .404, 95% Confidence Interval: .286-.571, P < .001) was an independent predictor of CIN. In the present study, C-peptide level was an independent predictor of CIN in patients with diabetes. This study suggests that low levels of C-peptide are associated with a greater risk of CIN.