Residual β-cell Function in Long-Duration Brazilian Type 1 Diabetes Is Associated with a Low Prevalence of Nephropathy

Abstract

Abstract Background: Persistence of β cell-function in Type 1 diabetes (T1D) is associated with glycaemia stability and lower prevalence of microvascular complications. We aimed to assess the prevalence of residual C- peptide secretion in long-term Brazilian childhood onset T1D receiving usual care and its association to clinical, metabolic variables and microvascular complications. Methods: A cross-sectional observational study with 138 T1D adults with >3 years of diagnosis receiving usual care. Clinical, metabolic variables and microvascular complications were compared between positive ultra-sensitive fasting serum C-peptide (FCP+) and negative (FCP-) participants. Results: T1D studied had > 5 yrs. of diagnosis and 60% had FCP >1.15pmol/L. FCP+ T1D were older at diagnosis (10 vs 8 yo; p=0.03) and had less duration of diabetes (11 vs 15 yo; p=0.002). There was no association between the FCP+ and other clinical and metabolic variable but was inversely associated with microalbuminuria (28.6% vs 13.4%, p=0.03), regardless of HbA1c. FCP> 47pmol/L were associated with nephropathy protection but were not related to others microvascular complications. Conclusion: Residual insulin secretion is present in 60% of T1D >3 years of diagnosis in usual care. FCP+ is positively associated with age of diagnosis and negatively with duration of disease and microalbuminuria regardless of HbA1c