title: Hemoglobin A1c (HbA1c) changes over time among adolescent and young adult participants in the T1D exchange clinic registry.
abstract: Hemoglobin A1c (HbA1c) levels among individuals with type 1 diabetes (T1D) influence the longitudinal risk for diabetes-related complications. Few studies have examined HbA1c trends across time in children, adolescents, and young adults with T1D. This study examines changes in glycemic control across the specific transition periods of pre-adolescence-to-adolescence and adolescence-to-young adulthood, and the demographic and clinical factors associated with these changes.
  
  
  
  Available HbA1c lab results for up to 10 yr were collected from medical records at 67 T1D Exchange clinics. Two retrospective cohorts were evaluated: the pre-adolescent-to-adolescent cohort consisting of 85 016 HbA1c measurements from 6574 participants collected when the participants were 8-18 yr old and the adolescent-to-young adult cohort, 2200 participants who were 16-26 yr old at the time of 17 279 HbA1c measurements.
  
  
  
  HbA1c in the 8-18 cohort increased over time after age 10 yr until ages 16-17; followed by a plateau. HbA1c levels in the 16-26 cohort remained steady from 16-18, and then gradually declined. For both cohorts, race/ethnicity, income, health insurance, and pump use were all significant in explaining individual variations in age-centered HbA1c (p < 0.001). For the 8-18 cohort, insulin pump use, age of onset, and health insurance were significant in predicting individual HbA1c trajectory.
  
  
  
  Glycemic control among patients 8-18 yr old worsens over time, through age 16. Elevated HbA1c levels observed in 18 yr-olds begin a steady improvement into early adulthood. Focused interventions to prevent deterioration in glucose control in pre-adolescence, adolescence, and early adulthood are needed.
authors.affiliation: Pediatrics (Endocrinology), Children's Mercy Hospitals and Clinics, Kansas City, MO, 64018, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Clements
authors.affiliation: Jaeb Center for Health Research, T1D Exchange, Tampa, FL, 33647, USA.
authors.forename: Nicole C
authors.initials: NC
authors.lastname: Foster
authors.affiliation: Barbara Davis Center for Childhood Diabetes, University of Colorado Denver, Aurora, CO, 80045, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Maahs
authors.affiliation: University of Florida College of Medicine, Division of Endocrinology, Gainesville, FL, 32610, USA.
authors.forename: Desmond A
authors.initials: DA
authors.lastname: Schatz
authors.affiliation: Park Nicollet International Diabetes Center, Minneapolis, MN, 55416, USA.
authors.forename: Beth A
authors.initials: BA
authors.lastname: Olson
authors.affiliation: University of Iowa Children's Hospital, Department of Pediatrics, Iowa City, IA, 52242, USA.
authors.forename: Eva
authors.initials: E
authors.lastname: Tsalikian
authors.affiliation: Pediatric Endocrinology, University of Michigan, Department of Pediatrics and Communicable Diseases, Ann Arbor, MI, 48109, USA.
authors.forename: Joyce M
authors.initials: JM
authors.lastname: Lee
authors.affiliation: University of Virginia Health System, Department of Pediatrics, Charlottesville, VA, 22908, USA.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Burt-Solorzano
authors.affiliation: Yale University School of Medicine, New Haven, CT, 06520, USA.
authors.forename: William V
authors.initials: WV
authors.lastname: Tamborlane
authors.affiliation: Jaeb Center for Health Research, T1D Exchange, Tampa, FL, 33647, USA.
authors.forename: Vincent
authors.initials: V
authors.lastname: Chen
authors.affiliation: Jaeb Center for Health Research, T1D Exchange, Tampa, FL, 33647, USA.
authors.forename: Kellee M
authors.initials: KM
authors.lastname: Miller
authors.affiliation: Jaeb Center for Health Research, T1D Exchange, Tampa, FL, 33647, USA.
authors.forename: Roy W
authors.initials: RW
authors.lastname: Beck
mesh_terms: D017668:Age of Onset; D001786:Blood Glucose; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000188:drug therapy; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage; D007328:Insulin / Q000008:administration & dosage; D019458:Insurance Coverage; D008137:Longitudinal Studies; D008297:Male; D012042:Registries; D012189:Retrospective Studies; D012737:Sex Factors; D012959:Socioeconomic Factors
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin; C517652:hemoglobin A1c protein, human
keywords: HbA1c; diabetes mellitus type 1; insulin; pediatric transition to adult care; retrospective studies