METABOLIC EVOLUTION OF TYPE-2 DIABETES - A 10-YEAR FOLLOW-UP FROM THETIME OF DIAGNOSIS

Objectives. To investigate fasting and post-load plasma glucose, insul in and C-peptide levels during oral glucose tolerance tests in patient s with type 2 diabetes and in control subjects, and the metabolic evol ution of the diabetes. Design, setting and subjects. A 10-year prospec tive study consisting of a representative group of 133 (70 men, 63 wom en) newly diagnosed type 2 diabetic patients diagnosed at health centr es between 1979 and 1981 and 144 (62 men, 82 women) nondiabetic contro l subjects recruited from the population register. At baseline, diabet ic subjects were treated with diet only. The subjects were studied at baseline and after 5 and 10 years. Main outcome measures. The changes in plasma glucose, insulin and C-peptide levels in diabetic and contro l subjects at baseline and after 5 and 10 years follow-up. Factors ass ociated with the decline in insulin and C-peptide levels in diabetic p atients (e.g. metabolic control, islet cell antibodies). Results. A sl ight increase in glucose levels was seen during the follow-up in both diabetic with diet and/or oral drug treated patients, but post-glucose insulin (and C-peptide and 5- and 10-year examination) levels decline d in diabetic patients; this was opposite to the controls, in whom the levels tended to increase. The decline in insulin levels (area under the curve) during the follow-up was greatest in those diabetic patient s with poor metabolic control during the follow-up. The cumulative inc idence of requirement for insulin based on various cut-off levels for postglucagon C-peptide nearly doubled between the 5- and 10-year exami nations. Islet cell antibodies were predictive of insulin deficiency. Conclusions. Type 2 diabetes was characterized by progressive impairme nt of insulin response to glucose and this decline was associated with poor metabolic control of diabetes.