DIFFICULTIES IN CLASSIFYING DIABETES AT PRESENTATION IN THE YOUNG-ADULT

All newly diagnosed diabetic patients in Sweden aged 15-34 years have been registered since 1983. In this study the clinical characteristics initially and after 2.5-3 years were evaluated by a questionnaire to the patient's physician and by non-fasting C-peptide. The study comprised patients registered 1983-84, and for 281 patients (37 %), complete information was obtained. At diagnosis 75 % were classified as Type 1, 19 % as Type 2, and 6 % as secondary diabetes or as uncertain by their physician. Twenty patients (7.1 %) were reported to have ketoacidosis. Seventy-five percent were treated with insulin, 7 % with oral hypoglycaemic agents (OHG), and 18 % with diet alone. At follow-up 71 % were classified as Type 1, 21 % as Type 2, and 8 % as secondary or uncertain while treatment was 82 % insulin, 8 % OHG, and 9 % diet. During the follow-up period 42 % of the initially non-insulin-treated patients were put on insulin whereas only a few stopped insulin treatment. Patients treated with diet or OHG at follow-up were older, had higher percent desirable weight, and lower blood glucose at diagnosis than patients treated with insulin. All except one patient had measurable random C-peptide at follow-up and mean values were for patients treated with insulin 0.55, OHG 1.41 and diet alone 1.29 nmol l-1. Random blood glucose results were similar. In conclusion the majority of newly diagnosed patients in the age group 15-34 years have the characteristics of Type 1 diabetes and Type 2 diabetes is rare before 25-30 years of age. Patients with biochemically mild hyperglycaemia are difficult to classify and there is a need for new guidelines for classification of diabetes which include aetiopathogenetic aspects.