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Original Investigation
June 16, 2020

Effect of Continuous Glucose Monitoring on Glycemic Control in Adolescents and Young Adults With Type 1 Diabetes: A Randomized Clinical Trial

Author Affiliations
  • 1Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
  • 2Jaeb Center for Health Research, Tampa, Florida
  • 3University of North Carolina Diabetes Care Center, Chapel Hill
  • 4Children's Mercy Hospital, Kansas City, Missouri
  • 5Health Partners Institute, International Diabetes Center, St Louis Park, Minnesota
  • 6Baylor College of Medicine, Houston, Texas
  • 7Naomi Berrie Diabetes Center, Columbia University, New York, New York
  • 8Stanford University, Palo Alto, California
  • 9Rocky Mountain Diabetes & Osteoporosis Center, Idaho Falls, Idaho
  • 10Barbara Davis Center for Childhood Diabetes, Aurora, Colorado
  • 11Children's Hospital Los Angeles, Los Angeles, California
  • 12Yale Children’s Diabetes Program, New Haven, Connecticut
  • 13Vanderbilt University Medical Center, Nashville, Tennessee
  • 14SUNY Upstate Medical University, Syracuse, New York
  • 15Childrens Hospital of Philadelphia, Philadelphia, Pennsylvania
JAMA. 2020;323(23):2388-2396. doi:10.1001/jama.2020.6940
Visual Abstract. Continuous Glucose Monitoring and Glycemic Control in Youth With Type 1 Diabetes
Continuous Glucose Monitoring and Glycemic Control in Youth With Type 1 Diabetes
Key Points

Question  Is continuous glucose monitoring effective in improving glycemic control compared with standard blood glucose monitoring in adolescents and young adults with type 1 diabetes?

Findings  In this randomized clinical trial that included 153 participants aged 14 to 24 years with type 1 diabetes, treatment with continuous glucose monitoring compared with standard blood glucose monitoring resulted in a significantly lower hemoglobin A1c level after 26 weeks (adjusted difference, 0.37%).

Meaning  Among adolescents and young adults with type 1 diabetes, continuous glucose monitoring resulted in a small but statistically significant improvement in glycemic control over 26 weeks.

Abstract

Importance  Adolescents and young adults with type 1 diabetes exhibit the worst glycemic control among individuals with type 1 diabetes across the lifespan. Although continuous glucose monitoring (CGM) has been shown to improve glycemic control in adults, its benefit in adolescents and young adults has not been demonstrated.

Objective  To determine the effect of CGM on glycemic control in adolescents and young adults with type 1 diabetes.

Design, Setting, and Participants  Randomized clinical trial conducted between January 2018 and May 2019 at 14 endocrinology practices in the US including 153 individuals aged 14 to 24 years with type 1 diabetes and screening hemoglobin A1c (HbA1c) of 7.5% to 10.9%.

Interventions  Participants were randomized 1:1 to undergo CGM (CGM group; n = 74) or usual care using a blood glucose meter for glucose monitoring (blood glucose monitoring [BGM] group; n = 79).

Main Outcomes and Measures  The primary outcome was change in HbA1c from baseline to 26 weeks. There were 20 secondary outcomes, including additional HbA1c outcomes, CGM glucose metrics, and patient-reported outcomes with adjustment for multiple comparisons to control for the false discovery rate.

Results  Among the 153 participants (mean [SD] age, 17 [3] years; 76 [50%] were female; mean [SD] diabetes duration, 9 [5] years), 142 (93%) completed the study. In the CGM group, 68% of participants used CGM at least 5 days per week in month 6. Mean HbA1c was 8.9% at baseline and 8.5% at 26 weeks in the CGM group and 8.9% at both baseline and 26 weeks in the BGM group (adjusted between-group difference, −0.37% [95% CI, −0.66% to −0.08%]; P = .01). Of 20 prespecified secondary outcomes, there were statistically significant differences in 3 of 7 binary HbA1c outcomes, 8 of 9 CGM metrics, and 1 of 4 patient-reported outcomes. The most commonly reported adverse events in the CGM and BGM groups were severe hypoglycemia (3 participants with an event in the CGM group and 2 in the BGM group), hyperglycemia/ketosis (1 participant with an event in CGM group and 4 in the BGM group), and diabetic ketoacidosis (3 participants with an event in the CGM group and 1 in the BGM group).

Conclusions and Relevance  Among adolescents and young adults with type 1 diabetes, continuous glucose monitoring compared with standard blood glucose monitoring resulted in a small but statistically significant improvement in glycemic control over 26 weeks. Further research is needed to understand the clinical importance of the findings.

Trial Registration  ClinicalTrials.gov Identifier: NCT03263494

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