Urinary C-peptide and urinary C-peptide creatinine ratio as markers for insulin resistance in obese children and adolescents.

BACKGROUND

Obesity is associated with insulin resistance (IR). Identifying high-risk obese children affected with IR is crucial to apply preventive management. We aimed to assess the diagnostic value of urinary C-peptide (UCP) and urinary C-peptide creatinine ratio (UCPCR) to diagnose IR in obese children.

METHODS

This prospective cross-sectional study was performed on 60 children with obesity as the study group. Sixty healthy children of matched age and sex with normal body mass index (BMI) served as the control group. Hemostasis model for the assessment of IR (HOMA-IR), glycated hemoglobin (HbA1c), fasting blood glucose and insulin, UCP, and UCPCR were assessed in all included children.

RESULTS

UCP and UCPCR were significantly higher in children with obesity (2.075 ± 0.783) ng/ml, (0.200 ± 0.021) nmol/mmol compared to the control group (1.012 ± 0.465) ng/ml, (0.148 ± 0.016) nmol/mmol, respectively. Both UCP and UCPCR were positively correlated with each other and with HOMA-IR, HbA1c, acanthosis nigricans, waist circumference, and BMI. At cutoff ≥2.45, the sensitivity of UCP to diagnose IR in obese children was 71.4%. At cutoff ≥0.20, the sensitivity of UCPCR to diagnose IR in obese children was 87.6%.

CONCLUSIONS

UCP and UCPCR are promising surrogate markers of IR in children and adolescents with obesity. However, UCPCR is a better marker than UCP.

IMPACT

Obesity is associated with IR. Identifying high-risk obese children affected with IR is crucial to apply preventive management. We aimed to assess the diagnostic value of UCP and UCPCR to detect IR in obese children. To the best of our knowledge, we are the first to use UCP and UCPCR to assess IR in obese children. We found that UCP and UCPCR are practical, easy, dependable noninvasive markers to assess IR in children with obesity and could potentially be useful in epidemiological studies and clinical practice.