Aims Both type 1 (T1D) and type 2 (T2D) diabetes are considered to be associated with different degrees of progressive beta cell damage. However, few long term studies have been made. Our aim was to study the clinical course of 20 years of diabetes disease, including diabetes progression, co-morbidity and mortality in a prospectively studied cohort of consecutively diagnosed diabetic patients.Methods Among all 233 patients diagnosed with diabetes during 1985-1987 in Malmö, Sweden, 50 of 118 surviving patients were followed-up after 20 years. The age at diagnose was 42.323.1 and 57.513.6 yrs for antibody positive and antibody negative patients, respectively. HbA1c and plasma lipids were analysed with regard to metabolic control.Results Islet antibody negative patients at diagnosis had highly preserved C-peptide levels after 20 years in contrast to antibody positive patients (antibody-negative: C-peptide 0yrs 0.780.47 and 20yrs 0.700.46 (nmol/l), p=0.51 and antibody-positive: C-peptide 0yrs 0.330.35 and 20yrs 0.100.18; p<0.001. Islet antibodies but not age, BMI or C-peptide at diagnosis were predictors of C-peptide levels at 20 years when analysed by logistic regression (p<0.05). HbA1c did not differ between the groups after 20 years. The 20-year mortality was higher among antibody-negative patients, dependent on the higher age at diagnosis in this group (number of deaths: antibody-positive: 18 of 56 vs. antibody-negative: 109 of 188, p<0.001). Of the deceased, 79 % had died from diseases or complications that may be associated to diabetes.
ConclusionWe found no progressive beta cell damage in autoantibody negative diabetes at a 20 year follow-up of the clinical course of diabetes.