C-peptide levels were significantly associated with insulin resistance, beta cell function, and microvascular complications in T2DM patients, illustrating 'the clinical utility of C-peptide in microvascular complications such as diabetic nephropathy and diabetic retinopathy.'
Fasting insulin, HOMA-IR, HOMA-beta cell function, C-peptide index, and TNF-α all increased significantly across tertiles of C-peptide levels.
Patients with diabetic retinopathy and diabetic nephropathy had significantly higher C-peptide levels compared to those without these complications.
After adjustment for multiple confounding factors, C-peptide levels remained significantly associated with fasting insulin, HOMA-beta cell function, C-peptide index, HOMA-IR, and resistin in T2DM patients with complications.
The study used a Randox Evidence biochip analyzer to measure fasting insulin, C-peptide, resistin, and TNF-α in 91 T2DM participants after overnight fasting.
C-peptide can serve as an appropriate index for identifying insulin resistance in T2DM patients with complications.
This research suggests that C-peptide, a byproduct released when the pancreas produces insulin, is closely linked to insulin resistance and beta cell dysfunction in people with type 2 diabetes. The study examined 91 type 2 diabetes patients and found that as C-peptide levels rose across three groups (tertiles), so did measures of insulin resistance, beta cell activity, and inflammation markers like TNF-α. Patients with diabetic eye disease (retinopathy) and kidney disease (nephropathy) had notably higher C-peptide levels, and C-peptide levels rose as the number of diabetic complications increased. Even after accounting for factors like age, body weight, blood pressure, cholesterol, blood sugar control, and diabetes medications, C-peptide remained significantly tied to insulin resistance and other metabolic markers in patients who had diabetic complications. This suggests that C-peptide is not just a passive byproduct but may reflect the underlying biological processes driving both insulin resistance and the development of diabetes-related complications. This research suggests that measuring C-peptide levels in clinical practice could help doctors identify insulin resistance and monitor the risk of complications such as kidney or eye disease in people with type 2 diabetes. Because C-peptide is easier to measure in some settings than insulin itself and is not affected by insulin treatments, it may offer a practical tool for assessing metabolic health in diabetic patients.
Siddiqui K, Joy S, Nawaz S, George T, David S, Mujammami M, et al.. (2026). Evaluating the relationship between C-peptide levels and insulin resistance in patients with and without diabetic complications.. Medicine. https://doi.org/10.1097/MD.0000000000050326