C-peptide predicts all-cause and cardiovascular death in a cohort of individuals with newly diagnosed type 2 diabetes: The Skaraborg diabetes register

Aims: To study the association between baseline level of C-peptide and all-cause death, cardiovascular death and cardiovascular complications among persons with newly diagnosed type 2 diabetes. Methods: The Skaraborg Diabetes Register contains data on baseline C-peptide concentrations among 398 persons <65 years with newly diagnosed type 2 diabetes 1996–1998. National registries were used to determine all-cause death, cardiovascular death and incidence of myocardial infarction and ischemic stroke until 31 December 2014. The association between baseline C-peptide and outcomes were evaluated with adjustment for multiple confounders by Cox regression analysis. Missing data were handled by multiple imputation. Results: In the imputed and fully adjusted model there was a significant association between 1 nmol/l increase in C-peptide concentration and all-cause death (HR 2.20, 95% CI 1.49–3.25, p < 0.001, number of events = 104), underlying cardiovascular death (HR 2.69, 1.49–4.85, p = 0.001, n = 35) and the composite outcome of underlying cardiovascular death, myocardial infarction or ischemic stroke (HR 1.61, 1.06–2.45, p = 0.027, n = 90). Conclusions: Elevated C-peptide levels at baseline in persons with newly diagnosed type 2 diabetes are associated with increased risk of all-cause and cardiovascular mortality. C-peptide might be used to identify persons at high risk of cardiovascular complications and premature death.