Evaluating the relationship between C-peptide levels and insulin resistance in patients with and without diabetic complications.

Urinary C Peptide/ Creatinine Ratio Is Related to Insulin Resistance but Not Vascular Complications In Type 2 Diabetes

BACKGROUND.  Insulin resistance (IR) is considered the main mechanism of type 2 diabetes (T2DM). Diabetic vascular complications (DVC) are main causes of morbidity and mortality. Urinary c-peptide to creatinine ratio (UCPCR) is a novel promising biomarker that may be of value in assessment of IR and DVC. AIM.  The present work aimed at studying the relation between UCPCR, IR and DVC in subjects with T2DM. MATERIALS AND METHODS.  This was a cross-sectional study performed on a group of subjects with T2DM. Insulin resistance was assessed by measuring homeostasis model assessment for insulin resistance (HOMA-IR). Laboratory investigations included glycemic parameters and renal functions. Human C-peptide ELISA kit was used to asses c-peptide level in a spot urine sample after processing. RESULTS.  The study included 90 subjects with T2DM. There was highly statistically significant positive correlations between UCPCR and HOMA-IR, FPG and HbA1c with P values of <0.001, 0.006 and 0.005 respectively. FPG, HbA1c, and UCPCR were the independent risk factors for IR in the univariate regression analysis. However, UCPCR was the only independent risk factor for IR in multivariate analysis (OR 16.431(1.401–192.706). UCPCR cut-off value (>0.19) nmol/mmol was able to differentiate significantly (p<0.001) between patients with IR and those without IR with good sensitivity, specificity and AUC (85.11%, 60.47% and 0.716 respectively). CONCLUSION.  In patients with T2DM, UCPCR could be used as a simple, noninvasive and available biomarker for IR. It also could be used as a marker of glycemic control. However, UCPCR is not related to DVC.

Comparing C-peptide and HbA1c levels in obese patients with and without type 2 diabetes

Background: Diabetes mellitus (DM) is a chronic metabolic disorder characterized by either insufficient insulin production by the pancreas or the body's inability to utilize it. HbA1c level of 6.5% was recommended for diagnosing diabetes. C-peptide is a byproduct of insulin synthesis has been widely studied as a diagnostic biomarker for DM. Obesity is a major risk factor for the development of type 2 DM (T2DM) and is associated with insulin resistance. With the increasing global burden of obesity and diabetes, our study investigates the relationship between HbA1c and C-peptide levels in obese individuals with and without diabetes. Objectives were to assess and compare HbA1c and C-peptide levels among obese individuals with diabetes and without diabetes and to evaluate the correlation between these parameters within each group. Methods: This study was included 30 obese diabetic and 30 obese non-diabetic participants recruited over 3 months. Blood samples were collected for estimating HbA1c and C-peptide. Ethical approval was obtained prior to the study. Data were analyzed using Jamovi software. Results: HbA1c and C-peptide levels were significantly higher in obese individuals with diabetes compared to non-diabetic obese controls (p<0.001). A strong positive correlation was observed between HbA1c and C-peptide levels in both groups, with a stronger association in diabetics (r=0.94) compared to non-diabetics (r=0.88); both correlations were statistically significant. Conclusions: Higher levels and strong positive correlation between HbA1c and C-peptide-especially in diabetics-suggests increased insulin secretion in response to poor glycemic control and insulin resistance.  

Evaluation of Serum C-peptide levels, Insulin Resistance and Lipid profile in Obese Patients with Type 2 Diabetes Mellitus: A Hospital-Based Study from Uttarakhand

Background: Obesity and insulin resistance play a central role in the onset and progression of Type 2 Diabetes Mellitus (T2DM). Serum C-peptide, which serves as a marker of endogenous insulin secretion, has been recognized as a valuable indicator of β-cell function and metabolic condition. Increasing evidence suggests that elevated C-peptide levels may be associated with insulin resistance and metabolic abnormalities. The present study was conducted to assess the Serum C-peptide levels, insulin resistance and lipid profile in obese patients diagnosed with Type 2 Diabetes Mellitus. A total of 75 obese patients with type 2 diabetes Mellitus and 50 obese healthy controls were enrolled in this study. C-peptide showed a statistically significant positive correlation with HOMA-IR, total cholesterol, body mass index and waist circumference, while HDL-Cholesterol showed a significant negative correlation. The study demonstrated a significant association between serum C-peptide levels and insulin resistance among obese patients with Type 2 Diabetes Mellitus. Serum C-peptide levels, HOMA-IR, total cholesterol, triglyceride levels were significantly higher in obese diabetic patients compare to heathy controls. HDL cholesterol levels were low in obese diabetic patients compare to healthy controls. Elevated serum C-peptide levels may reflect compensatory endogenous insulin secretion secondary to insulin resistance. Estimation of serum C-peptide may therefore serve as a useful biochemical marker for assessing metabolic dysfunction and insulin resistance in obese diabetic patients.

Alpha cell dysfunction in type 2 diabetes: associations with insulin resistance and reduced insulin secretion

Abstract Introduction This study examined how insulin resistance and impaired insulin secretion are associated with hyperglucagonemia during oral glucose tolerance tests (OGTT) in type 2 diabetes mellitus (T2DM). Research design and methods A retrospective analysis included 247 patients with T2DM treated at Tianjin Medical University General Hospital from October 2022 to March 2025. All underwent a 75 g OGTT, with blood samples collected at 0, 0.5, 1, 2, and 3 hours for glucose, insulin, C-peptide, and glucagon measurement. Insulin resistance was assessed via homeostasis model assessment of insulin resistance (HomaIR) and C-peptide immunoreactivity insulin resistance (CPRIR), while insulin secretion was evaluated using C-peptide area under the curve (AUCcp), homeostasis model assessment of beta cell function (HomaB), first-phase and second-phase insulin secretion during OGTT (first PH and second PH). Generalized linear models and mediation analyses examined associations between glucagon levels and above indices. Model fitness and robustness were evaluated via residual diagnostics, Cook’s distance, and bootstrapped CIs. Results Glucagon levels during the OGTT were significantly elevated in patients with severe insulin resistance (HomaIR Q3 and CPRIR Q1), even after adjusting for confounders. In contrast, groups with the poorest insulin secretion (AUCcp Q1, HomaB Q1, first PH Q1, and second PH Q1) did not show elevated glucagon levels compared with those with better secretion. Mediation analysis confirmed that neither AUCcp nor HomaB mediated the relationship between insulin resistance and glucagon levels. Residual diagnostics demonstrated a satisfactory model fit. Furthermore, sensitivity analyses, both by excluding influential points identified via Cook’s distance and by applying bootstrapped CIs, yielded consistent results, thereby affirming the robustness of the model. Conclusions In T2DM, impaired glucagon suppression during OGTT is associated with insulin resistance closely, highlighting insulin resistance as a key factor in alpha-cell dysfunction.

Association of Serum Lithium Levels with Insulin Resistance in Type-2 Diabetes Patients.

EVALUATION OF THE ASSOCIATION BETWEEN C-PEPTIDE AND HBA1C IN PAEDIATRIC TYPE 1 DIABETES MELLITUS

Introduction: Type 1 diabetes mellitus is a chronic autoimmune disorder characterized by progressive destruction of pancreatic β-cells, resulting in reduced endogenous insulin secretion. Serum C-peptide is a reliable biomarker of residual β-cell function, while HbA1c reflects long-term glycaemic control. This study was conducted to evaluate the association between serum C-peptide and HbA1c among paediatric patients with type 1 diabetes mellitus. Methods: This hospital-based cross-sectional study was conducted in the Department of Paediatrics, Government Cuddalore Medical College and Hospital, over a period of 18 months. A total of 45 children and adolescents aged 1–18 years with type 1 diabetes mellitus receiving regular insulin therapy were included by consecutive sampling. Demographic details, disease duration, BMI, daily insulin requirement, serum C-peptide, and HbA1c levels were recorded. Data were analyzed using descriptive statistics, comparison of means, and correlation analysis. Results: The majority of participants belonged to the 6–10 years age group (37.8%), and males constituted 53.3% of the study population. Serum C-peptide levels ≤0.6 ng/mL were observed in 64.4% of children, while 35.6% had levels >0.6 ng/mL. The mean HbA1c was 8.94 ± 1.42%. Mean HbA1c declined progressively with increasing C-peptide categories, from 10.5 ± 1.0% among children with C-peptide <0.2 ng/mL to 7.8 ± 1.0% among those with C-peptide >0.6 ng/mL, and this difference was statistically significant (p < 0.001). Serum C-peptide showed significant negative correlations with HbA1c, duration of diabetes, and daily insulin dose, and significant positive correlations with age at diagnosis and BMI. Conclusion: Serum C-peptide was significantly associated with HbA1c among paediatric patients with type 1 diabetes mellitus. Lower C-peptide levels were associated with poorer glycaemic control and higher insulin requirement. C-peptide estimation may be useful as a supportive biomarker for individualized diabetes management.