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.

AIMS: Multiple studies have addressed the association between detectable levels of C-peptide and glycemic control, as well as the development of chronic complications of type 1 diabetes mellitus (T1DM), including both macrovascular and microvascular diseases. We aimed to summarize the available evidence on the clinical significance of detectable levels of C-peptide in T1DM.

METHOD: A systematic search was performed on online databases using the following key terms: T1DM, C-peptide, diabetes mellitus complications, and glycemic parameters. We pooled standardized mean difference (SMD) and odds ratios (OR).

RESULTS

Of the 1519 articles retrieved from the initial search, 38 (12 cohort and 26 cross-sectional studies) met our eligibility criteria. Individuals with T1DM in the detectable C-peptide group, compared with the undetectable C-peptide group, had lower mean HbA1c [pooled SMD (95 % confidence interval (95 % CI)): -0.08 (-0.13 to -0.02), I2 = 0 %, p.

VALUE: 0.005] and daily insulin dose [-0.41 (-0.65 to -0.18), I2 = 83 %, p.value < 0.001]. They also showed lower odds for retinopathy [pooled crude OR (95 % CI): 0.53 (0.41 to 0.69), I2 = 65 %, p.value < 0.001] and nephropathy complications [0.62 (0.55 to 0.70), I2 = 19 %, p.value < 0.001]; however, the two groups were similar regarding neuropathy [0.92 (0.65 to 1.31), I2 = 0 %, p.

VALUE: 0.31].

CONCLUSIONS

The available evidence suggests that individuals with T1DM in the detectable C-peptide group may experience better clinical outcomes.