Fulminant type 1 diabetes as a high risk group for diabetic microangiopathy - a nationwide 5-year-study in Japan

Aims/hypothesis The aim of the present study was to assess the development of microangiopathy in patients with fulminant type 1 diabetes, a novel subtype of type 1B diabetes. Materials and methods In a nationwide survey, we followed 41 patients with fulminant type 1 diabetes and 76 age- and sex-matched patients with type 1A diabetes for 5 years. The following data were recorded every 12 months after the onset of diabetes: seven-point blood glucose concentrations, HbA(1c) level, urinary albumin excretion, serum C-peptide level, blood pressure, daily dosages of insulin, frequency of severe hypoglycaemic episodes, and neurological and fundoscopic examination. Results The 5-year cumulative incidence of microangiopathy was 24.4% in fulminant type 1 diabetes and 2.6% in type 1A diabetes. In longitudinal studies using the Kaplan-Meier method, the cumulative incidence of each form of microangiopathy was significantly higher in fulminant type 1 diabetes than in type 1A diabetes; retinopathy was 9.8% vs 0% (p = 0.014), nephropathy 12.2% vs 2.6% (p = 0.015) and neuropathy 12.2% vs 1.3% (p = 0.010), respectively. Mean HbA(1c) levels were similar in the fulminant and type 1A diabetes groups during the follow-up periods. However, the mean M-value, mean insulin dosages and the frequency of severe hypoglycaemic episodes were significantly higher, and the mean postprandial C-peptide level was significantly lower in the fulminant type 1 diabetes group. Conclusions/interpretation These data suggest that patients with fulminant type 1 diabetes are a high-risk subgroup for diabetic microangiopathy associated with the lack of endogenous insulin secretion from the onset of diabetes.