Abstract
We report the cases of a diagnosis changed from type 2 to type 1 diabetes mellitus. In checking GAD antibody and C-peptide levels in those over 65 years old at diabetes diagnosis treated with insulin, we found GAD antibody in 3 subjects with antibody titers of 30377.9±46570.8 (U/ml) (titer range: 53.8-84,000) . Subjects were aged 80.3±11.2 years 72.3±5.0 years at onset, for a mean 8.0±8.2 years (mean±SD) disease duration. HbA1c was 8.0±1.9 (%) , serum C-peptide 0.38±0.48 (ng/ml) (not detected in one subject) , and daily insulin dose 0.44±0.17 (U/kg/day) . One subject had brittle diabetes and very difficult plasma glucose control despite insulin treatment. Two patients are currently alive, and one died of pneumonia. These findings suggest that type 1 diabetes prevalence among the insulin-treated elderly may be higher than currently thought.
