GAD autoantibodies in a selection-free population of insulin-treated diabetic patients: indicator of a high prevalence of LADA?

Up to the present only few data have been available concerning the prevalence of diabetes-specific autoantibodies (anti-GAD, ICA, IAA, IA-2) in unselected populations, in particular in type 2 diabetic patients. Hence, the aim of the present study was to determine the prevalence of anti-GAD in a selection-free population of insulin-treated diabetic patients. Accordingly, 90% of all the insulin-treated diabetic patients (type 1, n=127, type 2, n=117) aged 16–60 years and living in the city of Jena (100 242 inhabitants) were examined. In order to test sera for anti-GAD, serum samples were taken in 75% of type 1 ( n=95) and in 80% of insulin-treated type 2 diabetic ( n=94) patients. Results: In the group of type 1 diabetic patients 55% of the patients tested were positive for anti-GAD. But, interestingly, in the type 2 group, a total of 21% patients were positive. With respect to this high percentage of anti-GAD positive type 2 diabetic patients it must be suggested that the frequency of patients with latent autoimmune diabetes mellitus in adults (LADA) was underestimated in the past.