Characteristics of Type 1 diabetes of over 50 years duration (the Golden Years Cohort)

Abstract

Background Type 1 diabetes mellitus is associated with high levels of premature morbidity and mortality. Prolonged survival is possible, however, and some patients appear to be protected from the long‐term complications of this condition. Methods Diabetes UK awards medals to patients who have had Type 1 diabetes for 50 years or more. By examining medal‐holders, we have established the clinical and biochemical features of a group of 400 subjects (54% male) with Type 1 diabetes of long duration. Results Mean age of the subjects was 68.9 years and mean age‐at‐onset of diabetes 13.7 years. Features of long duration diabetes in this cohort include normal body mass (mean BMI 25.0 kg m⁻²), low insulin dose (mean 0.52 units kg⁻²) and greatly elevated HDL‐cholesterol (mean 1.84 mmol/l). Mean HbA_1c was 7.6% (normal range 3.8–5.0%) and no patient had a normal HbA_1c at the time of venesection. As a group, they have long‐lived parents and consume moderate amounts of alcohol. Medical contact has often been sporadic. A significant proportion (29%) were taking anti‐hypertensive medication. Screening for micro‐ and macroalbuminuria was positive in 35.7%. Conclusions Patients with long‐duration (> 50 years) Type 1 diabetes are relatively protected from clinical diabetic nephropathy and large vessel disease; our data are consistent with protection possibly being genetically determined in part via elevated HDL‐cholesterol levels. An abnormal urinary albumin/creatinine ratio is common in these patients, despite their low risk of significant renal deterioration; this may have implications for microalbuminuria screening programmes.