Diabetic Subjects Diagnosed Through the Diabetes Prevention Trial–Type 1 (DPT-1) Are Often Asymptomatic With Normal A1C at Diabetes Onset

OBJECTIVE: Upon diagnosis of type 1 diabetes, patients are usually symptomatic, and many have ketoacidosis. Screening for islet autoantibodies (IAs) has been shown to decrease A1C level and rate of hospitalization at diabetes onset. Metabolic tests and the presence of symptoms were described at diabetes onset during the Diabetes Prevention Trial–Type 1 (DPT-1). RESEARCH DESIGN AND METHODS: The DPT-1 screened relatives of patients with type 1 diabetes for islet cell autoantiobodies (ICAs). Those with positive ICAs had intravenous and oral glucose tolerance tests (IVGTTs and OGTTs) and were randomized into one of two prevention trials. Throughout the DPT-1 parenteral and oral insulin study, 246 people were diagnosed with type 1 diabetes. RESULTS: Of the 246 subjects diagnosed with diabetes, 218 had data regarding the presence of symptoms, and 138 (63.3%) reported no symptoms suggestive of diabetes. Eight subjects (3.67%) presented with ketosis. Subjects presented with a mean ± SD A1C of 6.41 ± 1.15%. At diagnosis, 90 subjects (50.8%) had A1C in the normal range (<6.2%). OGTT data at the time of diagnosis indicate that 35.4% had a glucose result of <100 mg/dl at 0 min. CONCLUSIONS: The majority of subjects diagnosed with type 1 diabetes through the DPT-1 were asymptomatic at onset and had normal fasting glucose and A1C levels. This suggests that intermittent screening (IA followed by OGTT) may allow diagnosis of diabetes before severe metabolic decompensation. Screening with A1C will miss identifying many of the subjects with newly diagnosed type 1 diabetes in this cohort.