Post-meal Urinary C-peptide creatinine ratio is a moderate measure of insulin secretion in diabetes patients in Cameroon: results from a cross-sectional study

Abstract

Introduction: Urinary C-peptide creatinine ratio (UCPCR) measured in urine collected at home after a meal has been shown to correlate strongly with stimulated blood C-peptide in European populations. This association and the clinical utility of UCPCR in a sub-Saharan African clinical setting has not been described before. We aimed to assess the performance of UCPCR as a measure of endogenous insulin secretion in Cameroon.Methods: UCPCR was measured on two separate days before and after a standard mixed-meal tolerance test (MMTT), after lunch and after supper in 14 patients with diabetes and 14 healthy control individuals. Blood C-peptide was measured serially during a standard 75g oral glucose tolerance test (OGTT) every 30 minutes, on a separate day. The primary outcome was the correlation between stimulated blood C-peptide levels and post-meal UCPCR values.Results: stimulated blood C-peptide was significantly lower in participants with diabetes vs controls; median (IQR) 719 (110-999) pmol/l vs 1080 (934-1820) pmol/l, p=0.04. Fasting and post-MMTT UCPCR correlated strongly with stimulated blood C-peptide measurement in participants with diabetes (r= 0.71, p= 0.005) and (r=0.71, p=0.004) respectively. Post-meal UCPCR showed a moderate or poor correlation with stimulated blood C-peptide levels (supper r=0.56, p=0.04, lunch r=0.31, p=0.29). In participants without diabetes, UCPCR showed no relationship with stimulated blood C-peptide (supper r= -0.03, p=0.92, lunch r= -0.06, p=0.83). Conclusion: these results suggest that post-meal UCPCR performs less well in this population compared to European populations and may not be useful to assess endogenous insulin secretion in participants without diabetes in Cameroon.

Keywords

• ucpcr
• insulin secretion
• diabetes patients
• cameroon