Effect of Residual Insulin Secretion on Glycaemic Control Among Young Cameroonian Individuals With Type 1 Diabetes

Objective The objective of the article is to determine the effect of residual insulin secretion on glycaemic control among young Cameroonian individuals diagnosed with type 1 diabetes (T1D). Methods We conducted a hospital-based cross-sectional study from April to August 2022. Forty-two children and adolescents diagnosed with T1D attending the paediatric diabetes clinic of the Yaoundé Central Hospital in Cameroon were enrolled in the study. Residual insulin secretion was assessed by measuring plasma C-peptide concentrations before and after a mixed meal tolerance test (MMTT) using an enzyme-linked immunosorbent assay (ELISA) method. Glycosylated haemoglobin (HbA1c) was measured by boronate affinity chromatography with the HemoCue® HbA1c 501 analyser. Residual insulin secretion was classified as absent (<0.033 nmol/L), low (0.033-0.2 nmol/L), or high (≥0.2 nmol/L) based on stimulated C-peptide levels. Clinical characteristics and HbA1c values were compared between participants with high residual insulin secretion and the rest of the cohort. Results The median age of participants was 18.5 (16-24) years, with a median diabetes duration of three (2-10) years and a median HbA1c of 8.4% (6.9-11.3). Stimulated C-peptide was detectable (≥0.033 nmol/L) in 25 (60%) participants and above 0.2 nmol/L in 12 (29%). Compared with those without or with low residual insulin secretion, participants with high secretion had a shorter median duration of diabetes (two (IQR: 1-4) vs six (IQR: 2-11) years; p=0.009), lower median daily insulin doses (0.7 (IQR: 0.4-0.8) vs 0.9 (IQR: 0.7-1.3) IU/kg; p=0.008), fewer median episodes of severe hypoglycaemia (zero (IQR: 0-2) vs four (IQR: 1-6); p=0.006), higher median BMI (26.1 (IQR: 25-29.3) vs 22.9 (IQR: 19.4-25.6) kg/m²; p=0.02), and lower median HbA1c levels (7.1 (IQR: 6.1-8.3) vs 9.1 (IQR: 8.1-12.2)%; p=0.01). Conclusion High residual insulin secretion was observed in nearly one-third of young Cameroonians with T1D and was strongly associated with better glycaemic control.