Defining Continuous Glucose Monitor Time in Range in a Large, Community-Based Cohort Without Diabetes

Continuous glucose monitor (CGM) companies are beginning to market these sensors to populations without diabetes, but the range of CGM values clinicians should expect to see for this population is unclear because there have been no large studies reporting these ranges.

This work aimed to report the physiological range of CGM time in range values observed across glycemic status, including individuals without diabetes, to serve as a reference for clinicians.

The Framingham Heart Study, a prospective cohort study, was conducted among community-dwelling adults with normoglycemia (n = 560), prediabetes (n = 463), and diabetes (n = 152). We conducted a cross-sectional investigation in participants who wore a Dexcom G6 Pro CGM (in blinded mode) for 7 or more complete days. Main outcome measures included CGM metrics including mean glucose and time spent in glucose ranges.

Normoglycemic participants (mean age 58.5 years, 64.5% women, 93.3% non-Hispanic White) spent 87.0% time in the 70 to 140 mg/dL CGM range, and, on average, more than 15 minutes/day (1.2% time) at more than 180 mg/dL. Furthermore, normoglycemic participants spent approximately 3 hours/day (12.1% time) with CGM glucose at more than 140 mg/dL. On average, participants with prediabetes and diabetes spent 77.1% and 46.2% of time in the 70 to 140 mg/dL range, respectively.

Our results contribute to the understanding of the physiological CGM range in more than 1000 participants without diabetes. These results are also important for clinicians to reference as CGM sensors become more widely accessible to people without known diabetes.