Diabetes Dialogue: Time in Range, CGM Metrics for Predicting Outcomes in Diabetes

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Viral Shah, MD, joins Diabetes Dialogue to discuss a recent study examining associations between time in range and other advanced CGM metrics with diabetic retinopathy and the implications for use in predicting other microvascular outcomes.

New research is providing further evidence of the utility of time in range and other advanced continuous glucose monitoring (CGM) metrics in the prevention of negative microvascular outcomes in people with type 1 diabetes.

A retrospective analysis of CGM data from more than 160 adult patients, results of the study suggest time in range, time in tighter range, time above range, and mean glucose were associated with increased risk for incident diabetic retinopathy in adults with type 1 diabetes, which underline the importance of glycemic control and also call attention to the utility of time in range and advanced glucose metrics in disease management.

“It was very similar outcomes,” explained Viral Shah, MD, professor of medicine at Indiana University, in an episode of Diabetes Dialogue: Technology, Therapeutics, & Real-World Perspectives. “Whether you use the HbA1c or you use the time in range, what it suggests is that both metrics are providing us a very similar information about an individual's glycemic control as well as the long term in association with microvascular complications.”

For people with type 1 diabetes, the lifetime risk of developing diabetic retinopathy is approximately 90%. The most common ophthalmic disease in people with type 1 diabetes, identifying factors placing patients at risk of progression and avenues for mitigating risk have become a focal point of research efforts, including the current study by Shah and colleagues.1,2

In the study, investigators included 92 adults without diabetic retinopathy 71 adults with incident diabetic retinopathy who received care between June 2018 and March 2022. Leveraging CGM data collected retrospectively for up to 7 years before the date of eye examination defining incident diabetic retinopathy or control, investigators planned to aestivate associations between incident diabetic retinopathy and CGM metrics using logistic regression models.1

The cohort of adults with incident diabetic retinopathy had a mean age of 27 years, a mean diabetes duration of 15 years, and 52% were females. The cohort of controls had a mean age of 38 years, a mean diabetes duration of 20 years, and 48% were females.1

Upon adjustment, results of the investigators’ analyses revealed each 0.5% increase in HbA1c, 10 mg/dL increase in mean glucose, 5% decrease in time in target range of 70–180 mg/dL, 5% decrease in time in tight target range of 70–140 mg/dL, and 5% increase in time above 180 mg/dLwere associated with 24%, 22%, 18%, 28%, and 20% increase in odds of incident diabetic retinopathy, respectively. Investigators pointed out the Spearman correlations of time in range, time in tighter range, time above range, and mean glucose with each other were all equal to or greater than 0.97.1

This study, its results, and the utility of advanced CGM metrics in guiding careare the subject of this episode of Diabetes Dialogue, with Diana Isaacs, PharmD, an endocrine clinical pharmacist, director of Education and Training in Diabetes Technology, and codirector of Endocrine Disorders in Pregnancy at the Cleveland Clinic, and Natalie Bellini, DNP, program director of Diabetes Technology at University Hospitals Diabetes and Metabolic Care Center.

Relevant disclosures for Shah include Novo Nordisk, Dexcom Inc., Insulet Corporation, Tandem Diabetes Care, and others. Relevant disclosures for Isaacs include Eli Lilly and Company, Novo Nordisk, Sanofi, Abbott Diabetes Care, Dexcom, Medtronic, and others. Relevant disclosures for Bellini include Abbott Diabetes Care, MannKind, Provention Bio, and others.


  1. Shah VN, Kanapka LG, Akturk HK, et al. Time in Range Is Associated with Incident Diabetic Retinopathy in Adults with Type 1 Diabetes: A Longitudinal Study. Diabetes Technol Ther. Published online February 13, 2024. doi:10.1089/dia.2023.0486
  2. Stewart JM, Coassin M, Schwartz DM. Diabetic Retinopathy. [Updated 2021 Jan 3]. In: Feingold KR, Anawalt B, Blackman MR, et al., editors. Endotext [Internet]. South Dartmouth (MA):, Inc.; 2000-. Available from: