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

The Wireless Innovation for Seniors With Diabetes Mellitus (WISDM) study, published in the Journal of American Medical Association in 2020,¹ was one of the first randomized control trials to assess whether Dexcom CGM use was more effective in reducing hypoglycemia than self-monitoring of blood glucose (SMBG) in older adults with type 1 diabetes (n=203, >60 years of age). Compared with the SMBG control group, the Dexcom CGM group achieved the following results: 

• Median percent time <70 mg/dL decreased from 5.1% (73 minutes per day) at baseline to 2.7% (39 minutes per day) at the 6-month follow-up for the CGM group. By contrast, hypoglycemia exposure remained relatively unchanged for the SMBG group—from 4.7% (68 minutes per day) at baseline to 4.9% (70 minutes per day) during follow-up—for an adjusted treatment group difference of −1.9% (95% CI, −2.8% to −1.1%; P <0.001).
  • This corresponds to a significant reduction in hypoglycemia of 27 minutes per day (P <.001).
• Reduction in hypoglycemia observed in the CGM group was independent of baseline characteristics, including age (<70 vs ≥70 years), socioeconomic status, presence of cognitive impairment, or A1C.
• Mean time spent in the target range of 70 to 180 mg/dL was 8.8 percentage points (2.1 hours per day) higher in the CGM group compared with the SMBG group (P <0.001).
• Baseline A1C was relatively low. However, the CGM group observed a small but statistically significant decrease in mean A1C (adjusted group difference, −0.3%; P <0.001).
• Adherence to CGM was high; 83% of users wore their Dexcom CGM >6 days per week.

Percent of time spent in hypoglycemia (<3.9 mmol/L) by study visit

View the article