Metabolic control and prevalence of microvascular complications in young Danish patients with Type 1 diabetes mellitus

Aims: After Danish nationwide investigations (1987, 1989) demonstrated unacceptable blood glucose control in unselected young diabetic patients, we set out to estimate the present glycaemic control and the prevalence of microvascular complications in a cohort of children and adolescents participating in the two previous studies. Methods: This follow-up represents 339 patients (47% of the inception cohort), median age 21.1 years (range 12.0-26.9), median diabetes duration 13.2 years (range 8.9-24.5). A standardized questionnaire, fundus photographs (with central reading) and a physical examination were performed. HbA(IC) and overnight albumin excretion rate (AER) were analysed centrally. Results: Although 88% (n = 309) of the young persons were treated with three or more daily insulin injections, HbA(IC) (nondiabetic range 4.3-5.8, mean 5.3%) was 9.7 ± 1.7% (mean ± SD). Males had higher HbA(IC) values than females (P < 0.015). Mean daily insulin dose was 0.92 ± 0.25 IU.kg^-1.24h^-1. Microalbuminuria (AER > 20-150 μg/min) and macroalbuminuria (AER > 150 μg/min) were found in 9.0% and 3.7% of the patients, respectively, and was associated with increased diastolic blood pressure (P < 0.01) and presence of retinopathy (P < 0.01). Retinopathy was present in ≃ 60% of the patients and was associated with age, diabetes duration, HbA(IC), diastolic blood pressure and AER (all P < 0.01). Subclinical neuropathy (vibration perception threshold by biothesiometry > 6.5 v) was found in 62% and showed a significant association with age, linear height, diastolic blood pressure (all P < 0.01) and diabetic retinopathy (P = 0.1). Conclusions: In spite of the majority of the patients being on multiple insulin injections, only 11% had HbA(IC) values below 8% and the prevalence of diabetic microvascular complications in kidneys, eyes and nerves was unacceptable high.