Trajectories of HbA1c levels in children and youth with type 1 diabetes.

Orit Pinhas-Hamiel,Valentina Boyko,Liat Lerner-Geva,Uri Hamiel,Brian Reichman,Chana Graph-Barel,Francesca D'Addio

doi:10.1371/journal.pone.0109109

Abstract

PurposeTo illustrate the distribution of Hemoglobin A1c (HbA1c) levels according to age and gender among children, adolescents and youth with type 1 diabetes (T1DM).MethodsConsecutive HbA1c measurements of 349 patients, aged 2 to 30 years with T1DM were obtained from 1995 through 2010. Measurement from patients diagnosed with celiac disease (n = 20), eating disorders (n = 41) and hemoglobinopathy (n = 1) were excluded. The study sample comprised 4815 measurements of HbA1c from 287 patients. Regression percentiles of HbA1c were calculated as a function of age and gender by the quantile regression method using the SAS procedure QUANTREG.ResultsCrude percentiles of HbA1c as a function of age and gender, and the modeled curves produced using quantile regression showed good concordance. The curves show a decline in HbA1c levels from age 2 to 4 years at each percentile. Thereafter, there is a gradual increase during the prepubertal years with a peak at ages 12 to 14 years. HbA1c levels subsequently decline to the lowest values in the third decade. Curves of females and males followed closely, with females having HbA1c levels about 0.1% (1.1 mmol/mol) higher in the 25th 50th and 75th percentiles.ConclusionWe constructed age-specific distribution curves for HbA1c levels for patients with T1DM. These percentiles may be used to demonstrate the individual patient's measurements longitudinally compared with age-matched patients.

Highlights

Type 1 diabetes (T1DM) is a lifelong disease affecting children and adolescents that can lead to significant morbidity
The aim of the present study was to describe the distribution of hemoglobin A1c (HbA1c) levels among patients with T1DM, and to develop age dependent percentile curves for HbA1c levels visual representation of the of HbA1c levels according to age in individual patients compared with a reference patient population
We previously found no differences in HbA1c levels, between normal weight, overweight and obese subjects with T1DM [14], data were not stratified according to weight groups

Summary

Introduction

Type 1 diabetes (T1DM) is a lifelong disease affecting children and adolescents that can lead to significant morbidity. Lowering HbA1c levels to below or around 7% (53 mmol/mol) has been shown to reduce microvascular and macrovascular complications of diabetes [1], HbA1c measurement provides a treatment goal. According to the guidelines of the International Society of Pediatrics and Adolescents (ISPAD) treatment of T1DM should target HbA1c level of ,7.5% (,58 mmol/mol), if achieved without severe episodes of hypoglycemia [2]. HbA1c levels above 9.5% (,80 mmol/mol), reflecting poor glycemic control, were found in 17% of youth in the SEARCH for diabetes in Youth Study conducted in the United States among 3,947 individuals with T1DM [5]. Results from the Type 1 Diabetes Exchange Clinic Network, including 13,316 participants revealed that overall, only 32% met the ADA targets for their age group and 25% met the ISPAD goals. The proportions meeting the ADA goals were 64% for the under-6-year age group, 43% for 6- to 12-year-olds, and 21% for the 13- to 19-year-olds [7]

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