Center differences in diabetes treatment outcomes among children with type 1 diabetes: a nationwide study of 3,866 Danish children.

OBJECTIVES Mean differences in HbA1c across centers are well established, but less well understood. The aim was to assess whether differences in patient case-mix can explain the variation in mean HbA1c between pediatric diabetes centers in Denmark. The association between HbA1c , frequency of blood glucose monitoring (BGM), treatment modality, and center visits was investigated. RESEARCH DESIGN AND METHODS This longitudinal nationwide study included 3,866 Danish children with type 1 diabetes from 2013-2017 (n= 12,708 child-year observations) from 16 different pediatric diabetes centers. Mean HbA1c , proportion of children reaching HbA1c treatment target (HbA1c ≤58mmol/mol (7.5%)) were compared across centers using linear regression models. This was done with and without adjustment for socioeconomic characteristics (patient case-mix). RESULTS The mean difference in HbA1c during follow-up was 11.6mmol/mol [95% CI 7.9, 15.3] (1.1% [95% CI 0.7, 1.4]) when comparing the centers with the lowest vs. highest mean HbA1c . The difference was attenuated and remained significant after adjustment for the patient case-mix (difference: 10.5mmol/mol [95% CI 6.8, 14.2] (1.0% [95% CI 0.6, 1.3])). Overall, 6.8% of the differences in mean HbA1c across centers were explained by differences in the patient case-mix. Across centers, more frequent BGM was associated with lower HbA1c . The proportion of insulin pump users and number of visits was not associated with HbA1c . CONCLUSION In a setting of universal health care, large differences in HbA1c across centers were found, and could not be explained by patient background, number of visits or use of technology. Only BGM was associated with center HbA1c . This article is protected by copyright. All rights reserved.