Preserved C-peptide secretion is associated with fewer low-glucose events and lower glucose variability on flash glucose monitoring in adults with type 1 diabetes

Abstract

Aims/hypothesis We aimed to assess whether persistence of C-peptide secretion is associated with less glucose variability and fewer low-glucose events in adults with type 1 diabetes who use flash monitoring. Methods We performed a cross-sectional study of 290 adults attending a university teaching hospital diabetes clinic, with type 1 diabetes, who use flash monitoring and in whom a random plasma C-peptide was available in the past 2 years. Variables relating to flash monitoring were compared between individuals with low C-peptide (<10 pmol/l) and those with persistent C-peptide (either 10-200 pmol/l or 10-50 pmol/l). In addition, the relationship between self-reported hypoglycaemia and C-peptide was assessed (n = 167). Data are median (interquartile range). Results Individuals with preserved C-peptide secretion (10-200 pmol/l) had shorter duration of diabetes (15 [9-24] vs 25 [15-34] years, p < 0.001) and older age at diagnosis (23 [14-28] vs 15 [9-25] years, p < 0.001), although current age did not differ in this cohort. Preserved C-peptide was associated with lower time with glucose <3.9 mmol/l (3% [2-6%] vs 5% [3-9%], p < 0.001), fewer low-glucose events per 2 week period (7 [4-10] vs 10 [5-16], p < 0.001), lower SD of glucose (3.8 [3.4-4.2] vs 4.1 [3.5-4.7] mmol/l, p = 0.017) and lower CV of glucose (38.0 [35.0-41.6] vs 41.8 [36.5-45.8], p < 0.001). These differences were also present in those with C-peptide 10-50 pmol/l and associations were independent of diabetes duration and estimated HbA 1c in logistic regression analysis. Preserved C-peptide was also associated with lower rates of self-reported asymptomatic hypoglycaemia (8.0% vs 22.8% in the past month, p = 0.028). Conclusions/interpretation Preserved C-peptide secretion is associated with fewer low-glucose events and lower glucose variability on flash monitoring. This suggests that individuals with preserved C-peptide may more safely achieve intensive glycaemic targets.

Socioeconomic deprivation, technology use, C‐peptide, smoking and other predictors of glycaemic control in adults with type 1 diabetes

“…Individuals with higher C‐peptide concentration were more likely to have lower HbA 1c and this association remained strongly significant in multivariate analysis. Previous studies have reported mixed results, with two smaller cohorts showing no difference in HbA 1c based on C‐peptide status 12,16 . However, a larger cross‐sectional study ( n = 1272) showed significantly lower HbA 1c in those with C‐peptide concentration 50–100 pM (compared to <50 pM), 11 in line with our findings in a similarly sized cohort.…”

“…Some factors, such as flash monitoring use, 8,14 CSII use 6,7 and lower socioeconomic deprivation, 15 would be fully expected based on previously published data. Other factors, such as persistent C‐peptide secretion, 11,12,16 male gender, 17 lower BMI 18,19 and non‐ smoking status, 18 have been reported but their relationship to HbA 1c in type 1 diabetes has not been consistently demonstrated, particularly independently of potential confounders. Participation in DAFNE was not independently associated with meeting glycaemic targets, although our centre has previously demonstrated that completing DAFNE is prospectively associated with substantial improvement in HbA 1c 6 …”

“…Access to these interventions, however, remains limited and skewed towards individuals with lower levels of socioeconomic deprivation 8‐10 . Glycaemic targets may be achieved with a lower risk of hypoglycaemia in individuals with retained C‐peptide secretion 11,12 . We sought to assess the association of these factors, as well as a range of additional clinical and demographic features, upon the likelihood of achieving glycaemic targets in a large cohort of individuals with type 1 diabetes.…”

Invincible β‐cells in type 1 diabetes

“…As HbA1c is an indirect measure of average glycemia and does not provide a measure of glycemic variability, a tailored approach should be implemented to increase time in range while reducing hypoglycemia, or time below range. Every 10% increase in time in range is associated with a 0.5–0.8% reduction in HbA1c, and is associated with clinically significant benefits; that is, reduction of the risk of microvascular complication 4 . Rickels et al 3 .…”

Log-linear relationship between endogenous insulin secretion and glycemic variability in patients with type 2 diabetes on continuous glucose monitoring

“…To achieve this target, it is necessary to clarify the patient factors that influence GV. In type 1 diabetes, low endogenous insulin secretion is associated with GV instability 9 . In addition, we have previously shown that impaired endogenous insulin secretion affects GV stability in type 2 diabetes 10 .…”