CGMs Help Diabetic Patients With Impaired Hypoglycemia Awareness

Miriam E Tucker

September 21, 2016

MUNICH — Continuous glucose monitoring (CGM) increased the time spent in glucose target range and cut the risk of severe hypoglycemia in patients with type 1 diabetes who have impaired hypoglycemia awareness, new research indicates.

The results were presented September 15 here at the European Association for the Study of Diabetes (EASD) 2016 Annual Meeting by Cornelis AJ van Beers, MD, of VU University Medical Center, Amsterdam, the Netherlands, and were simultaneously published in Lancet Diabetes & Endocrinology.

"In adult patients with type 1 diabetes and impaired awareness of hypoglycemia, continuous glucose monitoring improves time spent in target by decreasing both time spent below target and time spent above target and also diminishes severe hypoglycemia. These results support the use of CGM in this high-risk population," Dr van Beers said, noting that roughly a quarter of all adult patients with type 1 diabetes have diminished awareness of hypoglycemia.

Asked to comment, Steven J Russell, MD, of the Diabetes Research Center at Massachusetts General Hospital, Boston, said, "They showed a significant benefit, which doesn't surprise me very much."

He added, "If anything, it's surprising it's taken this long for someone to do a study to show there's benefit, because I think a lot of us have assumed that this was a good application of this technology and have anecdotal evidence that it's helpful in people with hypoglycemia unawareness….But as far as I know, this is the first randomized study to demonstrate it, which is a step forward. I don't think this result is surprising, but it's gratifying."

More Time in Target Range

The randomized, crossover study included 52 adults with type 1 diabetes aged 18 to 75, on either insulin-pump therapy or multiple daily injections and performing at least three finger-stick measurements a day. They all had impaired awareness of hypoglycemia, defined by a Gold score of 4 or greater.

The patients were randomized to one of two 16-week study period sequences of either CGM (Minimed Paradigm Veo, Medtronic) or self-monitored blood glucose (SMBG) while wearing blinded CGMs (iPro2, Medtronic), followed by the other intervention, with a 12-week washout in between, and with monthly follow-up visits during the active-treatment periods.

The low-glucose-suspend feature of the Medtronic system was not used for this study.

The 52 patients had a mean age 49 years, mean diabetes duration of 30.5 years, average HbA1c 7.5%, and Gold score 5.4. Forty-four percent were on insulin-pump therapy.

The primary end point, the mean difference in percentage of time spent in target glucose range, was achieved in 65% with CGM vs 55.4% using SMBG, with a mean difference of 9.6% (P < .0001).

The two study phases differed significantly in favor of the CGM group both in time spent above 10 mmol/L (180 mg/dL) (P < .0001) and at or below 3.9 mmol/L (70 mg/dL) (P < .0001).

There was an immediate effect of CGM on time spent in target in the first 4 weeks, but no considerable carryover effect was seen into the subsequent study phase, Dr van Beers noted.

Severe Hypoglycemia Reduced

Severe hypoglycemic episodes requiring third-party assistance occurred in 34 people during SMBG and 14 during CGM phases, a significant difference (P = .033). There were no differences in events resulting in coma, seizures, or hospital admissions.

The number of patients experiencing at least one severe hypoglycemic event was 10 with CGM (19%) vs 18 with SMBG (35%), a difference that lost significance after adjustment for a difference in study phase duration that arose because of a technical problem.

Average HbA1c values did not change significantly, remaining at 7.3% to 7.4% for the duration of both study periods.

There were no significant differences between treatment periods in self-reported hypoglycemia-awareness scores, but scores on the Hypoglycemia Fear Survey (HFS) Worry subscale were significantly lower after the CGM phase (P = .014).

The study was funded by Eli Lilly and Sanofi. Dr van Beers has no relevant financial relationships. Disclosures for the coauthors are listed in the article. Dr Russell has received honoraria from Tandem and Novo Nordisk; lecture and other fees from Tandem, Sanofi, Dexcom, and Eli Lilly; and nonfinancial support from Dexcom, Tandem Diabetes, SweetSpot Diabetes, International Biomedical, Abbott Diabetes Care, Insulet, and Medtronic. He owns stocks/shares in Companion Medical and has patents pending on the bionic pancreas.

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Lancet Diabetes Endocrinol. Published online September 15. Article

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