medwireNews: Individuals with type 1 diabetes and residual β-cell function have better nocturnal and postprandial glycemic control than those with no β-cell function, UK study findings indicate.
This suggests that “[t]he amount of support needed to manage these time periods may be divergent between those with detectable and undetectable levels of C-peptide,” write Daniel West (Newcastle University, Newcastle upon Tyne, UK) and co-authors in Diabetic Medicine.
Furthermore, they suggest that “the assistance of residual β-cell function in managing blood glucose may allow tighter more ambitious glucose targets for C-peptide positive type 1 diabetes individuals.”
For the study, 66 people with established type 1 diabetes wore a blinded continuous glucose monitor, kept a food and insulin diary, and continued with standard care for 7 to 8 days. During this time, they also completed a 2-hour postprandial urine C-peptide to creatinine ratio test.
Overall, 34 participants, with a mean disease duration of 25 years, had an undetectable level of C-peptide, 13 participants (mean disease duration 28 years) had a low C-peptide level (3–200 pmol/L), and 19 (mean disease duration 11 years) had a high C-peptide level (>200 pmol/L).
The researchers report that, over 24 hours of measurement, the group with greater β-cell function, as indicated by a high C-peptide level, spent a significantly higher proportion of time in normoglycemia than the group with undetectable C-peptide levels, at an average of 71.8% versus 60.5%, and had significantly lower glycemic variability (standard deviation [SD] 2.8 vs 3.4 mmol/L; 50.5 vs 61.3 mg/dL).
A similar pattern occurred for nocturnal measurements, with normoglycemia recorded in 76.4% of the high C-peptide group and 57.7% of the undetectable C-peptide group between midnight and 06:00, and nocturnal variability at SDs of 1.1 versus 1.5 mmol/L (20.3 vs 27.5 mg/dL), both of which outcomes were significantly different.
An analysis of individual event outcomes adjusted for potential confounders corroborated these findings and additionally showed that people with undetectable C-peptide had significantly higher nocturnal hyperglycemia versus those with low C-peptide, and significantly more postprandial hypoglycemic events relative to those with high C-peptide.
The team also looked at postprandial differences and found that the high C-peptide group spent significantly more time in normoglycemia during the 5 hours after a meal than those with undetectable C-peptide at a mean of 68.1% versus 51.4%.
West et al conclude that their research “builds upon previous work demonstrating that individuals with residual β-cell function spend less overall free-living time in hyperglycaemia or hypoglycaemia compared with those with undetectable β-cell function.”
They add that the study “further demonstrates the importance of interventions aiming to preserve β-cell function in the recently diagnosed.”
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