Hypoglycemic events were reduced by real-time continuous glucose monitoring (rtCGM), according to an industry-funded study that compared the technology to self-monitoring of blood glucose for 26 weeks. The trial included 141 German patients with type 1 diabetes and a history of impaired hypoglycemia awareness or severe hypoglycemia during the previous year taking multiple daily insulin injections (MDI).
The study was published online Feb. 16 and in the April 7 issue of The Lancet. The following commentary by Hertzel Gerstein, MD, MSc, FRCPC, was published in the ACP Journal Club section of the May 15 Annals of Internal Medicine.
RtCGM is a reliable, convenient way for people with diabetes to monitor glucose levels. In addition to alerting patients with type 1 diabetes to hypoglycemia, it can potentially reduce glycemic excursions related to diet, activity, and comorbid illness and automate insulin provision through linked continuous subcutaneous insulin infusion pumps. The elegant, well-conducted clinical trial by Heinemann and colleagues has now shown that rtCGM also reduces the frequency of hypoglycemic episodes in patients treated with MDI. The 72% reduction in episodes lasting ≥20 minutes was accompanied by a 64% reduction in severe hypoglycemia—a serious event that could lead to coma or death. Whereas the HypoDE trial enrolled patients who had MDI-treated type 1 diabetes and a personal history that put them at high risk for severe hypoglycemia, its findings are consistent with trials in lower-risk patients with type 1 diabetes and may also be relevant to insulin-treated patients with type 2 diabetes who have had episodes of severe hypoglycemia. However, a similar study in the latter population has not yet been reported and needs to be done.
The large effect size in the HypoDE trial, combined with the reduction in severe hypoglycemia, is compelling evidence for clinicians to recommend this intervention to their patients at high-risk for severe hypoglycemia. Although economic analyses were not provided, the reduced need for capillary glucose testing (and its eventual elimination with future rtCGM systems), improved clinical outcomes, and the expected reduction in rtCGM cost with time may render this technology cost-saving. In the meantime, rtCGM clearly has a place in the management of motivated patients with type 1 diabetes and risk factors for severe hypoglycemia. Its place in the typical, well-controlled patient with type 1 diabetes and in patients with varying aptitudes, education, and socioeconomic status needs to be characterized.