Translating Glycated Hemoglobin A1c into Time Spent in Glucose Target Range: a Multicenter Study.

BACKGROUND: Approximately 90% of children and adolescents with type 1 diabetes in Sweden use continuous glucose monitoring (CGM), either as real-time CGM or intermittently scanned CGM to monitor their glucose levels. Time in target range (TIT) is an easily understandable metric for assessing glycemic control.

OBJECTIVE: The aim of this study was to examine the relation between TIT and HbA1c.

SUBJECTS AND METHODS: Subjects were recruited from 3 diabetes care centers in Sweden. Glucose data were collected for 133 children and adolescents with type 1 diabetes through CGM using Diasend®. Subjects with registration time over 80% were included in the analysis. HbA1c was collected from SWEDIABKIDS, the Swedish pediatric diabetes quality registry. TIT was defined as 3.9-7.8 mmol/L (70-140 mg/dL) and time in range (TIR) as 3.9-10 mmol/L (70-180 mg/dL).

RESULTS: During a period of 60 days, 105 subjects provided complete data for analysis. Mean age was 12.2 (± 3.3) years, mean HbA1c was 53.9 (± 8.2) mmol/mol or 7.1% (± 0.7%). Mean sensor glucose value was 8.6 (± 1.3) mmol/L, mean coefficient of variation was 42.2% (± 7.2%), mean TIT was 40.9% (± SD 12.2%), and mean TIR was 60.8% (± 13.1%). There was a significant nonlinear relation between TIT during 60 days and HbA1c, R2 = 0.69.

CONCLUSION: This study suggests a nonlinear relation between time spent in glucose target range and HbA1c. The finding implies that time spent in TIT could be a useful metric in addition to HbA1c to assess glycemic control. This article is protected by copyright. All rights reserved.