Objective: To investigate the temporal trend of metabolic control and potential predictors in German and Austrian children and adolescents with type 1 diabetes.
Research design and methods: This study is based on a large, multicenter database for prospective longitudinal documentation of diabetes care in Germany and Austria. Data from 30,708 patients documented in 305 diabetes centers between 1995 and 2009 were analyzed. Generalized linear mixed regression models were used to adjust trend analysis for relevant confounders.
Results: Unadjusted mean HbA(1c) decreased from 8.7 ± 1.8% in 1995 to 8.1 ± 1.5% in 2009. In multiple regression analysis, treatment year, age, sex, diabetes duration, migration background, BMI-SDS, and daily insulin dose were significant predictors of metabolic control (P < 0.001). After multiple adjustment, mean HbA(1c) decreased significantly by 0.038% per year (95% CI 0.032-0.043%), average odds ratio (OR) per year for HbA(1c) >7.5% (>9.0%) was 0.969 (95% CI 0.961-0.977) (0.948, 95% CI 0.941-0.956). Intensified insulin regimen was associated with lower frequency of poor metabolic control (HbA(1c) >9%; P = 0.005) but not with average HbA(1c) (P = 0.797). Rate of severe hypoglycemia and hypoglycemic coma decreased significantly (relative risk [RR] per year 0.948, 95% CI 0.918-0.979; RR 0.917, 95% CI 0.885-0.950) over the study period. Diabetic ketoacidosis rate showed no significant variation over time.
Conclusions: This study showed a significant improvement in metabolic control in children and adolescents with type 1 diabetes during the past decade and a simultaneous decrease in hypoglycemic events. The improvement was not completely explained by changes in the mode of insulin treatment. Other factors such as improved patient education may have accounted for the observed trend.