Persistent differences among centers over 3 years in glycemic control and hypoglycemia in a study of 3,805 children and adolescents with type 1 diabetes from the Hvidore Study Group

OBJECTIVE - Twenty-one international pediatric diabetes centers from 17 cou ntries investigated the effect of simple feedback about the grand mean HbA( 1c) level of all centers and the average value of each center on changes in metabolic control, rate of severe hypoglycemia, and insulin therapy over a 3-year period. RESEARCH DESIGN AND METHODS - Clinical data collection and determination of HbA(1c) levels were conducted at a central location in 1995 (n = 2,780, ag e 0-18 years) and 1998 (n = 2, 101, age 11-18 years). RESULTS- Striking differences in average HbA(1c) concentrations were found among centers; these differences remained after adjustment for the signific ant confounders of sex, age, and diabetes duration. They were apparent even in patients with short diabetes duration and remained stable 3 years later (mean adjusted HbA(1c) level: 8.62 +/- 0.03 vs. 8.67 +/- 0.04 [1995 vs. 19 98, respectively]). Three centers had improved significantly, four centers had deteriorated significantly in their overall adjusted HbA(1c) levels, an d 14 centers had not changed in glycemiccontrol. During the observation per iod, there were increases in the adjusted insulin close by 0.076 U/kg, the adjusted number of injections by 0.23 injections per day, and the adjusted BMI by 0.95 kg/m(2). The 1995 versus 1998 difference in glycerine control f or the seven centers could not be explained by prevailing insulin regimens or rates of hypoglycemia. CONCLUSIONS - This study reveals significant outcome differences among larg e international pediatric diabetes centers. Feedback and comparison of HbA( 1c) levels led to an intensification Of insulin therapy in most centers, bu t improved glycerine control in only a few.