Metabolic and immunologic features of Chinese patients with atypical diabetes mellitus

To determine whether atypical diabetes mellitus (ADM) is present in the Chinese population in Hong Kong.

The records of Chinese patients who attended the Diabetes Clinic at Queen Mary Hospital were reviewed. We identified 11 patients who initially presented with acute diabetic ketoacidosis but subsequently displayed clinical features more typical of type 2 diabetes. Metabolic studies and HLA typing were performed to characterize this group of Chinese patients with ADM.

C-peptide response of the patients with ADM 1 h after a standard meal was intermediate between that of type 1 diabetic patients (matched for age and duration of diabetes) and that of nondiabetic control subjects (matched for age and BMI) (analysis of variance, P = 0.02). Insulin sensitivity measured by a short insulin tolerance test was not significantly different between patients with ADM and their matched nondiabetic control subjects. HLA typing showed that none of the patients with ADM had the DR3 allele and that the frequency of DR9 was not increased. Only one patient had significantly increased levels of antibodies to GAD and islet cell antigen 512.

ADM, which was first described in African-Americans, is seen also in Chinese subjects. These patients have significant residual C-peptide secretory capacity and should not be misdiagnosed and treated as patients with type 1 diabetes with life-long insulin therapy.