New Analysis Links Detectable C-Peptide Levels to Improved Health Outcomes in Type 1 Diabetes

"People with T1DM who had detectable C-peptide levels used less insulin daily and had lower average HbA1c levels than those with undetectable C-peptide. They also had a lower chance of developing retinopathy and nephropathy, with odds ratios of 0.53 and 0.62, respectively," the researchers reported.

C-peptide, a byproduct of insulin production, is a crucial indicator of endogenous insulin secretion. In individuals with T1DM, the pancreas typically produces little to no insulin, leading to a reliance on exogenous insulin therapy. However, detectable C-peptide levels suggest some residual beta-cell function, which could significantly impact glycemic management and overall health.

Several studies have explored the relationship between detectable levels of C-peptide and glycemic control and the onset of chronic complications in Type 1 Diabetes, encompassing macrovascular and microvascular diseases. In light of this, Parham Samimisedeh, Cardiovascular Research Center, Alborz University of Medical Sciences, Karaj, Iran, and colleagues sought to synthesize the existing evidence regarding the clinical significance of detectable C-peptide levels in individuals with T1DM.

For this purpose, the researchers conducted a systematic search of online databases using key terms such as T1DM, C-peptide, diabetes mellitus complications, and glycemic parameters. They aggregated the data to calculate pooled standardized mean differences (SMD) and odds ratios (OR).

The researchers analyzed 1,519 articles from the initial search, identifying 38 studies that met their eligibility criteria—comprising 12 cohort studies and 26 cross-sectional studies. The following were the findings from the review:

• Individuals with detectable C-peptide levels had significantly lower mean HbA1c than those with undetectable levels, with a pooled standardized mean difference of −0.08.
• The detectable C-peptide group required lower daily insulin doses, with a difference of −0.41.
• The group exhibited reduced odds of developing retinopathy (pooled crude odds ratio (OR): 0.53) and nephropathy complications (OR: 0.62).
• No significant differences were found between the two groups for neuropathy (OR: 0.92).

According to the authors, the study is the first systematic review to investigate the relationship between C-peptide levels and key parameters in individuals with T1DM.

"Those with detectable C-peptide levels may achieve better glycemic control, characterized by lower HbA1c levels, reduced daily insulin requirements, and a decreased likelihood of diabetic ketoacidosis (DKA). Additionally, detectable C-peptide levels are likely associated with a reduced risk of hypoglycemic events," the researchers wrote.

Reference:

Alan, M. S., Tayebi, A., Afshar, E. J., Alan, S. S., Alan, M. S., Fazeli, R., Sohbatzade, T., Samimisedeh, P., & Rastad, H. (2024). Association of detectable C-peptide levels with glycemic control and chronic complications in individuals with type 1 diabetes mellitus: A systematic review and meta-analysis. Journal of Diabetes and its Complications, 108867. https://doi.org/10.1016/j.jdiacomp.2024.108867