Older adults with type 1 diabetes initiating continuous glucose monitoring for the first time had a reduction in time spent in hypoglycemia, improved time in range and a lower HbA1c, according to findings from a randomized clinical trial.
In the Wireless Innovation for Seniors with Diabetes Mellitus (WISDM) study, adults aged 60 years and older with type 1 diabetes randomly assigned to CGM had improvements in time in range and reductions in HbA1c at 26 weeks. These improvements were also observed in a group of adults who were randomly assigned to blood glucose monitoring for 26 weeks, followed by a switch to CGM for an additional 26 weeks during an extension phase of the study.
“This extension study has further demonstrated that CGM can be used to effectively reduce hypoglycemia without increasing hyperglycemia among older adults with type 1 diabetes over a prolonged period of time,” Kellee M. Miller, PhD, MPH, senior director of research services and business development for T1D Exchange in Boston, and colleagues wrote in a study published in Diabetes Technology & Therapeutics. “The benefits of CGM observed in this study combined with recently improved Medicare coverage for therapeutic CGM should serve to increase adoption of CGM as standard of care in all adult populations, particularly the vulnerable population of older adults with type 1 diabetes at an increased risk of hypoglycemia.”
Researchers enrolled 203 adults aged 60 years or older with type 1 diabetes who had not previously used CGM. Participants were randomly assigned 1:1 to use the Dexcom G5 CGM or a control group using blood glucose monitoring for 26 weeks. At 26 weeks, the 198 participants who completed the randomized clinical trial entered an extension phase in which the blood glucose monitoring group began using CGM and the CGM group continued to use CGM for an additional 26 weeks. Clinic visits took place at 4, 8, 16 and 26 weeks during the randomized trial phase, and at 39 and 52 weeks during the extension phase. Percent of time in hypoglycemia, time in range and time in hyperglycemia were collected from CGM. A masked CGM was used to collect data from the blood glucose monitoring group during the randomized phase. HbA1c was calculated at a central laboratory. Participant-reported measures such as quality of life, hypoglycemia awareness and fear, and diabetes distress were collected at baseline, 26 weeks and 52 weeks.
CGM improves time in range, HbA1c
The CGM group had time in hypoglycemia decline from 5% at baseline to 2.6% at 26 weeks (P < .001). Time in range improved from 56% at baseline to 64% at 26 weeks (P < .001). Both improvements were sustained at 52 weeks. Mean HbA1c declined from 7.6% at baseline to 7.4% at 52 weeks (P = .01).
The blood glucose monitoring group has time spent in hypoglycemia decline from 3.9% at 26 weeks to 1.9% at 52 weeks (P < .001). Time in range improved from 56% at 26 weeks to 60% at 52 weeks (P = .006). Mean HbA1c declined from 7.5% at 26 weeks to 7.3% at 52 weeks (P = .03).
No differences in person-reported outcomes were observed in the blood glucose monitoring group. The CGM cohort had a small improvement in hypoglycemia fear and glucose monitoring satisfaction from baseline to 52 weeks.
At 52 weeks, 37% in the CGM group and 34% in the blood glucose monitoring group were using the Dexcom mobile app to view glucose values. Most participants were using CGM to dose insulin without blood glucose monitoring finger sticks by the end of the study, but only 12% in the CGM group and 10% in the blood glucose monitoring group were sharing glucose values with another person.
Fewer severe hypoglycemia events with CGM
The blood glucose monitoring group had a reduction in the number of participants having a severe hypoglycemic event from nine in the randomized phase to two in the extension phase (P = .02). The CGM group has one severe hypoglycemic event in the randomized phase and four in the extension phase.
The researchers said the study showed CGM can provide benefits for older adults with type 1 diabetes, but several barriers still exist for expanding CGM access.
“Medicare historically now covers nonadjunctive CGM for therapeutic use, but there have been several restrictions, including requirement of blood glucose monitoring testing at least four times per day before coverage approval and requirement of office visit every 6 months,” the researchers wrote. “Of note, these restrictions were revised effectively on July 18, 2021, to remove the four blood glucose monitoring per day testing minimum.”