Nocturnal Hypoglycemia Halved With Insulin Degludec vs Glargine, Confirms Study in Type 1 Diabetes

Mitchel L. Zoler, PhD

July 06, 2021

Patients with type 1 diabetes who used insulin degludec as their basal insulin had fewer than half the number of nocturnal hypoglycemia events, compared with patients who used insulin glargine U100, in a head-to-head crossover study with 51 patients who had a history of nighttime hypoglycemia episodes.

Patients with type 1 diabetes who are "struggling with nocturnal hypoglycemia would benefit from insulin degludec treatment," said Julie M. Brøsen, MD, at the annual scientific sessions of the American Diabetes Association.

Accumulating Evidence for Less Hypoglycemia With Insulin Degludec

Results from several studies comparing insulin degludec (Tresiba), a second-generation, longer-acting insulin with more stable steady-state performance, with the first-generation basal insulin analogue glargine (Lantus), have built the case that degludec produces fewer hypoglycemia events.

The landmark SWITCH 1 crossover study published in 2017 showed in about 500 patients with type 1 diabetes and a risk factor for hypoglycemia that treatment with insulin degludec led to significantly few total hypoglycemia episodes and significantly fewer nocturnal episodes, compared with insulin glargine.

Next came similar findings from ReFLeCT, a multicenter observational study that followed 556 unselected patients with type 1 diabetes in routine practice settings who switched to insulin degludec following treatment with a different basal insulin. The results showed a significant drop-off in total, nonsevere, severe, and nocturnal hypoglycemia events.

Homing in on Higher-Risk Patients

The current study, HypoDeg (Insulin Degludec and Symptomatic Nocturnal Hypoglycaemia), ran at 10 Danish centers and enrolled 149 adults with type 1 diabetes who had at least one episode of severe nocturnal hypoglycemia within the prior 2 years, focusing on patients most at risk for future nocturnal hypoglycemia events. In an unusual study design, researchers identified nocturnal hypoglycemic episodes with hourly venous blood samples drawn from a subcutaneous line.

They randomized the patients to basal insulin treatment with either insulin degludec or to insulin glargine U100, allowed their treatment to stabilize for 3 months, and then tallied nocturnal hypoglycemia events for 9 months. They then crossed patients to the alternative basal insulin and repeated the process.

Results from the full study have not yet appeared in published form but were in a pair of reports at the 2020 scientific sessions of the ADA.

One report included findings based on 136 episodes of severe hypoglycemia identified clinically and showed these events occurred 35% less often during treatment with insulin degludec, a significant difference. The overall finding was primarily driven by 48% fewer episodes of severe nocturnal hypoglycemia, but this difference was not significant.

The second report identified hypoglycemia events with continuous glucose monitoring in 74 of the study participants, which identified 193 episodes of nonsevere nocturnal hypoglycemia and found that treatment with insulin degludec cut the rate by 47%, primarily by reducing asymptomatic episodes.

Hourly Blood Draws Track Overnight Hypoglycemia

The current study included 51 of the 149 HypoDeg patients who agreed to undergo overnight blood sampling and had this done at least once while treated with each of the two study insulins. (The study design called for two blood sampling nights for each willing patient during each of the two treatment periods.) The 51 patients had type 1 diabetes for an average of 28 years and an average age of 58 years. Two-thirds were men, their baseline A1c was 7.8%, and on average had 2.6 episodes of severe nocturnal hypoglycemia during the prior 2 years.

The researchers drew hourly blood specimens on a total of 196 nights from the 51 participating patients and identified 57 nights when blood glucose levels reached hypoglycemia thresholds in 33 patients. One-third of the events occurred when patients were on insulin degludec treatment, and two-thirds when they were on insulin glargine, reported Brøsen.

She presented three separate analyses of the data. One analysis focused on level 1 hypoglycemia events, when blood glucose dips to 70 mg/dL or less, which occurred 54% less often when patients were on insulin degludec. A second analysis looked at level 2 events, when blood glucose falls below 54 mg/dL, and treatment with insulin degludec cut this by 64% compared with insulin glargine. The third analysis focused on symptomatic events when blood glucose was 70 mg/dL or less, and treatment with insulin degludec linked with a 62% cut in this metric. All three between-group differences were significant.

Evidence Supports Already-Changed Practice

This new evidence "supports recommending" insulin degludec over insulin glargine, commented Bastiaan E. de Galan, MD, PhD, an endocrinologist and professor at Maastrict (the Netherlands) University Medical Center. The new results "extend those from previous trials in populations with type 1 diabetes that were unselected for the risk of hypoglycemia. In clinical practice, insulin degludec is already considered for patients who reported nocturnal hypoglycemia while on insulin glargine U100, but it's great this study provides the scientific evidence," said de Galan in an interview.

"The lower rate of nocturnal hypoglycemia with degludec, compared with glargine U100 is well established. Inpatient assessment of hypoglycemia with measurement of hourly plasma glucose allowed HypoDeg to provide stronger evidence than prior studies. The benefit of delgudec versus glargine U100 was significant and clinically meaningful, in hypo-prone patients who would benefit the most" by using insulin degludec, commented Gian Paolo Fadini, MD, an endocrinologist at the University of Padova (Italy), and a lead investigator on the ReFLeCT study.

But insulin degludec is not a completely silver bullet. Its prolonged duration of action and stability that may in part explain why it limits hypoglycemia events can also be a drawback: "It probably offers fewer options for flexibility. Any change in dose takes at least a day or 2 to settle, which may be unfavorable in certain circumstances," noted de Galan.

"I wouldn't recommend insulin degludec for all patients with type 1 diabetes. It's an individual evaluation in each patient," said Brøsen. "We will be looking into whether some patients are better off on insulin glargine."

Cost Makes a Difference

Another, potentially more consequential flaw is insulin degludec's relative expense.

"To date, use of degludec in routine practice has been limited by its cost, compared with older basal insulins," observed Fadini in an interview. "In several countries, including the United States, degludec is substantially more expensive than glargine."

The ADA's Standards of Medical Care in Diabetes–2021 includes table 9.3 that lists the costs of various insulins and shows the median average wholesale price of insulin glargine U100 follow-on products as $190/vial, compared with a $407 price for a similar vial of insulin degludec.

Insulin degludec "is clearly superior from a hypoglycemia standpoint. Patients with type 1 diabetes like the reduction because hypoglycemia is scary, and dangerous. The main issue is cost, and the extent to which it may be covered by insurance," commented Lisa Chow, MD, an endocrinologist at the University of Minnesota, Minneapolis. "We generally won't prescribe degludec unless it is at a price affordable to the patient. We try to use patient assistance programs sponsored by the company [that markets insulin degludec: Novo Nordisk] to try to make it more affordable."

Chow also highlighted that a new wrinkle has been introduction of a more concentrated formulation of insulin glargine, U300, which appears to cause less hypoglycemia than insulin glargine U100. Recent study results indicated that no significant difference exists in the incidence of hypoglycemia among patients treated with insulin glargine U300 and those treated with insulin degludec, such as findings from the BRIGHT trial, which included just over 900 patients, and in the CONCLUDE trial, which randomized more than 1,600 patients.

The HypoDeg study was sponsored by Novo Nordisk, the company that markets insulin degludec. Brøsen had no personal disclosures, but several of her coauthors were either Novo Nordisk employees or had financial relationships with the company. de Galan has received research funding from Novo Nordisk. Fadini has received lecture fees and research funding from Novo Nordisk, from Sanofi, the company that markets insulin glargine, and from several other companies. Chow has received research funding from Dexcom.

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