CGM Cuts Hypoglycemia in At-Risk Type 1 Diabetes Patients

Miriam E Tucker

March 05, 2018

Use of real-time continuous glucose monitoring (CGM) reduces hypoglycemia in people with type 1 diabetes who have impaired hypoglycemia awareness or severe hypoglycemia and use multiple daily insulin injections, new research shows.

Findings from the HypoDE study were published online February 16 in the Lancet by Lutz Heinemann, PhD, of Science-Consulting in Diabetes GmbH, Düsseldorf, Germany, and colleagues and also presented at the recent Advanced Technologies & Treatments for Diabetes conference in Vienna.

"Individuals with type 1 diabetes treated by multiple daily insulin injections and with impaired hypoglycemia awareness or severe hypoglycemia can minimize both biochemical and clinical hypoglycemia through use of real-time CGM without compromising overall glycemic control," Heinemann and colleagues write.

They add that because the majority of people with type 1 diabetes are treated with multiple daily insulin injections rather than insulin pumps, "this finding has high clinical relevance."

In an accompanying editorial, Richard M Bergenstal, MD, of the International Diabetes Center at Park Nicollet, Minneapolis, points out that initial CGM and hybrid closed-loop trials had excluded patients with impaired hypoglycemia awareness, while early CGM studies didn't include patients on multiple daily insulin injections.   

"The HypoDE study convincingly shows that people with impaired awareness of hypoglycemia using multiple daily insulin injections therapy can benefit from use of real-time CGM," Bergenstal writes.

He also points out that this study further supports the idea that some measure of hypoglycemia should be reported in addition to HbA1c for complete assessment of overall glycemic control, with the emerging concept of "time in range" as a more personalized management approach for type 1 diabetes.

"CGM might be the best example of diabetes precision medicine widely available today, since an individual's daily glucose patterns are revealed at a glance and can effectively guide a clinician's and a patient's shared decision-making session," he writes.

Hypoglycemia Rates Significantly Reduced

HypoDE was a 6-month, open-label, multicenter randomized controlled trial in 149 patients with type 1 diabetes who had a history of impaired hypoglycemia awareness or severe hypoglycemia during the previous year.

The participants were 40% women, a mean age of 47 years, had a diabetes duration of 21 years, and baseline HbA1c of 7.5%. After wearing a masked CGM for 28 days, they were randomized to unmasked real-time CGM (Dexcom G5) or a control group (who continued to wear masked CGMs) for 26 weeks. 

The primary outcome was baseline-adjusted number of hypoglycemic events (defined as glucose ≤ 3.0 mmol/L / 54 mg/dL for at least 20 minutes) during the follow-up phase.

The mean number of hypoglycemic events defined by real-time CGM was reduced from 10.8 to 3.5 per 28 days in the real-time CGM group, compared with no significant change (14.4 to 13.7 per 28 days) in controls. The incidence of hypoglycemic events decreased by 72% with real-time CGM (P < .0001).

The proportion of patients who experienced no hypoglycemic events were 33.3% (25) with real-time CGM vs 7.6% (5) of controls, corresponding to an odds ratio of 6.1 for avoiding hypoglycemia (P = .0006), Heinemann and colleagues report.

Time in range (3.9–10.0 mmol/L / 70–180 mg/dL) increased by 0.7 percentage points with real-time CGM, while it dropped by 2.6 percentage points in controls (P = .0513).

Hyperglycemic glucose values increased slightly in both groups but didn't differ between them.  

Glycemic variability significantly decreased with real-time CGM from 39.3% at baseline to 34.1% at follow-up. Glycemic variability less than 36% is considered stable, the authors note.

In total there were 63 severe hypoglycemia events, 24 with real-time CGM and 39 in controls, which translates to nearly double the incidence for controls (1.18 vs 0.64 events/patient-year).

Similarly, 19 events required third-party assistance with real-time CGM vs 36 events for controls, or 0.51 vs 1.09 events/patient-year (P = .0071).

Real-Time CGM Allows Physician and Patient to Agree on Action Plan

The fact that severe hypoglycemia still occurred with real-time CGM "indicates that, despite use of real-time CGM, a subgroup of participants had a persistently elevated hypoglycemia risk," Heinemann and colleagues say.

Regarding the use of real-time CGM overall, Bergenstal comments, "the aim is to have a simple standard display of a glucose profile, available to both clinician and patient, during a clinic visit or during a more cost-effective telehealth encounter."

"Clinician and patient can both agree on an individualized action plan aimed at adjusting therapy to minimize any clearly visible low or high glucose patterns, which should result in more glucose values that are in the target range."

HypoDE was funded by Dexcom. Heinemann reports receiving grants from Dexcom and personal fees from Roche Diagnostics, Integrity, Medtronic, and Sanofi. He also owns shares of the Profil Institute for Metabolic Research and ProSciento. Bergenstal has received research support, consulted, or been on the scientific advisory board for Abbott Diabetes Care, Dexcom, Johnson & Johnson, Medtronic, Onduo, Roche, Sanofi, and United Healthcare. His technology research is partly funded by the National Institute of Diabetes and Digestive and Kidney Diseases.

Lancet. Published online February 16, 2018. Abstract, Editorial

For more diabetes and endocrinology news, follow us on Twitter and on Facebook.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.