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Original Investigation
June 16, 2020

Effect of Continuous Glucose Monitoring on Hypoglycemia in Older Adults With Type 1 Diabetes: A Randomized Clinical Trial

Author Affiliations
  • 1AdventHealth Translational Research Institute, Orlando, Florida
  • 2Jaeb Center for Health Research, Tampa, Florida
  • 3Rodebaugh Diabetes Center, University of Pennsylvania Perelman School of Medicine, Philadelphia
  • 4Oregon Health and Science University, Portland
  • 5Feinberg School of Medicine, Northwestern University, Chicago, Illinois
  • 6Iowa Diabetes and Endocrinology Research Center, Des Moines
  • 7Atlanta Diabetes Associates, Atlanta, Georgia
  • 8Park Nicollet International Diabetes Center, Minneapolis, Minnesota
  • 9Elson S. Floyd College of Medicine, Washington State University, Spokane
  • 10University of South California, School of Pharmacy, Los Angeles
  • 11Naomi Berri Diabetes Center, Columbia University, New York, New York
  • 12University of Washington, Seattle
  • 13Henry Ford Health System, Detroit, Michigan
  • 14Mayo Clinic, Rochester, Minnesota
  • 15Icahn School of Medicine at Mount Sinai, New York, New York
  • 16Washington University School of Medicine in St Louis, St Louis, Missouri
  • 17Keck School of Medicine, University of Southern California, Los Angeles
  • 18University of Chicago, Chicago, Illinois
  • 19Scripps Whittier Diabetes Institute, La Jolla, California
  • 20University of Michigan, Ann Arbor
  • 21Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora
  • 22University of Massachusetts Medical School, Worcester
  • 23University of Miami, Miami, Florida
  • 24SUNY Upstate Medical University, Syracuse, New York
  • 25University of North Carolina at Chapel Hill, Chapel Hill
JAMA. 2020;323(23):2397-2406. doi:10.1001/jama.2020.6928
Visual Abstract. Continuous Glucose Monitoring and Hypoglycemia in Older Adults With Type 1 Diabetes
Continuous Glucose Monitoring and Hypoglycemia in Older Adults With Type 1 Diabetes
Key Points

Question  Is continuous glucose monitoring effective in reducing hypoglycemia compared with standard blood glucose monitoring in older adults with type 1 diabetes?

Findings  In this randomized clinical trial that included 203 adults aged 60 years or older with type 1 diabetes, treatment for 6 months with continuous glucose monitoring compared with standard blood glucose monitoring resulted in a significantly lower percentage of glucose values less than 70 mg/dL (adjusted difference, 1.9%).

Meaning  Among older adults with type 1 diabetes, continuous glucose monitoring resulted in a small but statistically significant improvement in hypoglycemia over 6 months.

Abstract

Importance  Continuous glucose monitoring (CGM) provides real-time assessment of glucose levels and may be beneficial in reducing hypoglycemia in older adults with type 1 diabetes.

Objective  To determine whether CGM is effective in reducing hypoglycemia compared with standard blood glucose monitoring (BGM) in older adults with type 1 diabetes.

Design, Setting, and Participants  Randomized clinical trial conducted at 22 endocrinology practices in the United States among 203 adults at least 60 years of age with type 1 diabetes.

Interventions  Participants were randomly assigned in a 1:1 ratio to use CGM (n = 103) or standard BGM (n = 100).

Main Outcomes and Measures  The primary outcome was CGM-measured percentage of time that sensor glucose values were less than 70 mg/dL during 6 months of follow-up. There were 31 prespecified secondary outcomes, including additional CGM metrics for hypoglycemia, hyperglycemia, and glucose control; hemoglobin A1c (HbA1c); and cognition and patient-reported outcomes, with adjustment for multiple comparisons to control for false-discovery rate.

Results  Of the 203 participants (median age, 68 [interquartile range {IQR}, 65-71] years; median type 1 diabetes duration, 36 [IQR, 25-48] years; 52% female; 53% insulin pump use; mean HbA1c, 7.5% [SD, 0.9%]), 83% used CGM at least 6 days per week during month 6. Median time with glucose levels less than 70 mg/dL was 5.1% (73 minutes per day) at baseline and 2.7% (39 minutes per day) during follow-up in the CGM group vs 4.7% (68 minutes per day) and 4.9% (70 minutes per day), respectively, in the standard BGM group (adjusted treatment difference, −1.9% (−27 minutes per day); 95% CI, −2.8% to −1.1% [−40 to −16 minutes per day]; P <.001). Of the 31 prespecified secondary end points, there were statistically significant differences for all 9 CGM metrics, 6 of 7 HbA1c outcomes, and none of the 15 cognitive and patient-reported outcomes. Mean HbA1c decreased in the CGM group compared with the standard BGM group (adjusted group difference, −0.3%; 95% CI, −0.4% to −0.1%; P <.001). The most commonly reported adverse events using CGM and standard BGM, respectively, were severe hypoglycemia (1 and 10), fractures (5 and 1), falls (4 and 3), and emergency department visits (6 and 8).

Conclusions and Relevance  Among adults aged 60 years or older with type 1 diabetes, continuous glucose monitoring compared with standard blood glucose monitoring resulted in a small but statistically significant improvement in hypoglycemia over 6 months. Further research is needed to understand the long-term clinical benefit.

Trial Registration  ClinicalTrials.gov Identifier: NCT03240432

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