Gap between glycemic, patient-reported outcomes in HypoDE study
medwireNews: Continuous glucose monitoring (CGM) has a less impressive effect on patient-reported outcomes than on glycemic control among patients with type 1 diabetes, reveal the HypoDE investigators.
However, self-reported endpoints did improve significantly among patients using CGM, who reported improvements in fear of hypoglycemia and distress caused by hypoglycemia, as well as satisfaction with their method of glucose monitoring.
Glycemic control cannot and will not aid understanding of the potential burden of living with real-time continuous glucose monitoring in terms of carrying the device, additional visibility of disease state, nor intrusion of alarms.
The 75 patients in the CGM group had an average 13.5% improvement in satisfaction with their glucose-monitoring device, which was significantly greater than the 4.7% improvement seen in the control group of 66 patients who continued with usual care. This encompassed significant improvements for the openness, emotional burden, and behavioral burden subscales, but not the trust subscale.
The CGM group also had a 26.0% improvement in total score on the Hypoglycemia Fear Survey, versus a 14.1% improvement in the control group, which was again a significant difference. And they also had a significantly greater improvement in the hypoglycemia subscale of the Diabetes Distress Scale for type 1 diabetes, at 24.6% versus 13.6%.
“The effect on hypoglycemia-related distress is especially important since all recruited participants had problems with hypoglycemia,” comment Dominic Ehrmann (Otto-Friedrich-University of Bamberg, Germany) and study co-authors.
They note that this recruitment criterion is a possible explanation for the small effect sizes on patient-reported outcomes in HypoDE and other trials, because patients were enrolled on the basis of factors such as high hypoglycemia risk or low time in normal glucose range, rather than because of high levels of illness-related distress.
“Thus, a definite answer as to whether continuous glucose monitoring impacts patient-reported outcomes is still lacking,” writes the team in Diabetes Technology & Therapeutics.
All these effect sizes were medium, whereas the previously reported effect size for the primary endpoint of low-glucose events was large. Patients who used unmasked CGM for 26 weeks had a 67.6% reduction in this endpoint, compared with a 4.9% reduction in the control group, who continued with their usual care but had masked CGM during the first and last 4 weeks of the 30-week trial.
An unexpected finding was that despite the significant effect of CGM on the primary endpoint both the CGM and control groups had a large improvement in hypoglycemia unawareness, of almost 41%.
The researchers suggest that the improvement in the control group could be explained by “heightened vigilance to symptoms of hypoglycemia due to inclusion in a hypoglycemia-specific study,” but point out that this could also contribute to the improvement in the CGM group, making it impossible to ascertain the effects of CGM per se on hypoglycemia unawareness.
Of note, a previous study in patients selected for hypoglycemia unawareness found that neither continuous nor flash glucose monitoring improved this outcome, despite the former reducing the time spent in hypoglycemia.
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