Residual β-cell function in Brazilian Type 1 diabetes after 3 years of diagnosis: prevalence and association with low presence of nephropathy

Relationship Between C-Peptide Levels, Clinical Features, and Serum Data in a Brazilian Type 1 Diabetes Population with Large Variations in Genomic Ancestry

Type 1 diabetes (T1D) is a chronic disease characterized by the immune-mediated destruction of the pancreatic beta cells responsible for insulin production. The secreted insulin and C-peptide are equimolar. Due to its longer half-life, C-peptide has become a safer means of assessing the pancreatic reserve. C-peptide levels were evaluated in a population of patients with T1D, focusing on the relationship between this variable and other factors. In addition, the influence of C-peptide on metabolic control and microvascular complications was investigated. This cross-sectional study included 95 patients who had been diagnosed with T1D at least five years earlier. These patients were evaluated using a clinical demographic survey, anthropometric data, laboratory tests, and fundoscopy. This study showed that 29.5% of patients had residual insulin secretion, which correlated directly with their age at diagnosis. No statistically significant differences in metabolic control or microvascular complications were observed between the C-peptide level groups. In addition, our results indicate that ancestry does not influence the persistence of residual C-peptide function in our highly mixed population. It is recommended that future research consider incorporating new variables, such as HLA and pancreatic autoimmunity, as factors that may influence residual β-cell function.

Preserved C-peptide is common and associated with higher time in range in Chinese type 1 diabetes

Objective

The aim of this study is to determine the residual C-peptide level and to explore the clinical significance of preserved C-peptide secretion in glycemic control in Chinese individuals with type 1 diabetes (T1D).

Research design and methods

A total of 534 participants with T1D were enrolled and divided into two groups, low-C-peptide group (fasting C-peptide ≤10 pmol/L) and preserved-C-peptide group (fasting C-peptide >10 pmol/L), and clinical factors were compared between the two groups. In 174 participants who were followed, factors associated with C-peptide loss were also identified by Cox regression. In addition, glucose metrics derived from intermittently scanned continuous glucose monitoring were compared between individuals with low C-peptide and those with preserved C-peptide in 178 participants.

Results

The lack of preserved C-peptide was associated with longer diabetes duration, glutamic acid decarboxylase autoantibody, and higher daily insulin doses, after adjustment {OR, 1.10 [interquartile range (IQR), 1.06-1.14]; OR, 0.46 (IQR, 0.27-0.77); OR, 1.04 (IQR, 1.02-1.06)}. In the longitudinal analysis, the percentages of individuals with preserved C-peptide were 71.4%, 56.8%, 71.7%, 62.5%, and 22.2% over 5 years of follow-up. Preserved C-peptide was also associated with higher time in range after adjustment of diabetes duration [62.4 (IQR, 47.3-76.6) vs. 50.3 (IQR, 36.2-63.0) %, adjusted P = 0.003].

Conclusions

Our results indicate that a high proportion of Chinese patients with T1D had preserved C-peptide secretion. Meanwhile, residual C-peptide was associated with favorable glycemic control, suggesting the importance of research on adjunctive therapy to maintain β-cell function in T1D.

Changes in C-Peptide Values in Children with Type 1 Diabetes - a Three-Year Study

Background: C-peptide is used as an important indicator of residual insulin secretion in patients diagnosed with type 1 diabetes mellitus (T1DM) and treated with insulin. Aim:We have aimed to monitor the serum C-peptide (CP) levels during the first three years after diagnosis of T1DM in a cohort of children admitted to the Diabetes Department of "M. S. Curie" Emergency Clinical Hospital for Children, Bucharest, Romania, and to investigate the factors that could influence the rate of decline in its secretion. Method:We conducted a longitudinal, retrospective cohort study on a group of 215 children and adolescents who met the inclusion criteria and were monitored in our clinic over the course of a long period of time. We analyzed several parameters, including fasting serum CP values at diagnosis and yearly throughout T1DM evolution, the severity of diabetic ketoacidosis (DKA) at onset, HbA1c at diagnosis, family history of T1DM/T2DM, patient gender and presence of concurrent acute infectious disease at diagnosis, with the purpose of evaluating their influence on the preservation of endogenous insulin secretion. Based on serum CP value measured three years after T1DM onset, patients were divided into two groups: group 1, with low insulin residual secretion (CP < 0.6 ng/mL), and group 2, with preserved insulin residual secretion (CP ≥0.6 ng/mL) Results:At the moment of diagnosis, patients in group 1 were younger than those in group 2 (6.03 ± 3.54 years and 9.76 ± 2.75 years, respectively). The proportion of children with diabetic ketoacidosis (DKA) at onset was greater in group 1 (68% of patients) than group 2, in which the majority of subjects (60%) did not have DKA. The C-peptide value at diagnosis was significantly lower (0.55 ± 0.36 ng/mL) among patients in group 1 than those in group 2 (1.11 ± 0.59 ng/mL). In group 1 there was a higher proportion of patients (65%) with acute infectious disease at onset. Family history of T1DM/T2DM was associated with a more rapid decline in CP values. Our data showed no correlation between CP levels monitored for three years and HbA1c at diagnosis and no association with the gender of each patient. Conclusion:Patients with higher CP concentrations at diagnosis maintained increased values (> 0.6 ng/mL) three years after disease onset. Younger children had a faster decline of CP secretion during the first three years following diabetes diagnosis. In patients with severe symptoms (DKA) and associated infectious disease at onset, a risk of rapid CP decline was found.