February 25, 2019
4 min read

Insulin dosing system associated with 1% HbA1c reduction in type 2 diabetes

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Adults with type 2 diabetes prescribed insulin therapy who were assigned to an automated dosing support system for 6 months saw an average 1% decrease in HbA1c and a 0.7% greater benefit than similar adults assigned to health care professional support, according to findings from a randomized controlled trial published in The Lancet.

Richard M. Bergenstal

The d-Nav insulin guidance service (Hygieia) is a hand-held device designed to automatically titrate a dose of insulin based on glucose readings, according to Richard M. Bergenstal, MD, executive director of the International Diabetes Center Park Nicollet in Minneapolis. Patients use the device to check their blood glucose before each injection and obtain a recommended insulin dose, he said.

“You start measuring your blood sugar, and you put into the system your insulin regimen,” Bergenstal told Endocrine Today. “You could be on a 70/30 regimen, a once-a-day basal regimen or a basal/bolus regimen. Once the system sees a pattern, which usually takes about 1 week, it will start predicting how much insulin to take. It’s the same thing we teach every diabetes educator to do with a log book that can take 20 minutes to sort out, and this just does it all for us. The nice part about it is, it not only predicts up, but it also predicts down. About one-fifth of the insulin changes were down.”

Study design

In an open-label study, Bergenstal and colleagues analyzed data from 181 patients with type 2 diabetes recruited from three specialty diabetes centers in the United States between February 2015 and March 2017: the International Diabetes Center in Minneapolis, the Henry Ford Medical Center Endocrinology in Detroit and the Iowa Diabetes and Endocrinology Research Center in Des Moines. Patients had an HbA1c of at least 7.5% and had been using the same insulin regimen for at least 3 months (mean age, 60 years; mean diabetes duration, 15.7 years; mean HbA1c, 8.6%; initial total daily insulin dose, 0.7 U/kg per day). Patients assigned to the intervention group (n = 93) were provided with and trained on the d-Nav device, which was then set up with each patient’s current insulin regimen and dose. The remaining patients (n = 88) were assigned to usual care. Patients in both groups received seven interactions with health care professionals (three face-to-face visits at baseline, 3 and 6 months, and four phone calls). Researchers assessed HbA1c at each visit. Primary objective was to assess whether d-Nav users who also had health professional support experienced a different average change in HbA1c between baseline and 6 months vs. controls.


“The health care support part is more of a confidence builder,” said Bergenstal, speaking before he presented the findings at the International Conference on Advanced Technologies and Treatment for Diabetes in Berlin. “We check in and ask the patient if everything is working. Many patients fear that, the more insulin they need, the worse they are doing. We have to get them over that fear. More insulin isn’t the enemy — high glucose is.”

Bergenstal said health care providers also made recommendations for patients in the usual care group, who performed recommended daily self-monitored blood glucose.

“We called them the same amount, and we made [dosing] changes with them too, but about one-tenth of the time, because you just don’t have the data,” Bergenstal said.

Glycemic control, weight gain

At 6 months, the mean decrease in HbA1c was 1% for the intervention group and 0.3% for the control group, for an effect size of 0.7% (P < .0001).

At baseline, 23% of participants in the intervention group and 32% of participants in the control group had an HbA1c of less than 8%, according to researchers. By 6 months, 62% of participants in the intervention group and 33% in the control group had an HbA1c of 8% or less (effect size, 29.4%; P = .0001).

On average, insulin dose adjustments were done 1.1 times per week for participants in the intervention group, with an average of 0.2 adjustments per week resulting in a decrease in dose.

“In other words, 1 (15.4%) of every 6.5 dose adjustments decreased the insulin dose,” the researchers wrote.

Researchers observed small weight gain in both groups during the study. The average proportional increase in weight from baseline was 2.3% in the intervention group and 0.7% in the control group (P = .0001). In the intervention group, the total daily dose of insulin increased from 0.77 U/kg per day at baseline to 1.24 U/kg per day at 6 months. Total daily insulin dose for controls increased from 0.71 U/kg per day at baseline to 0.76 U/kg per day.

“The final total daily dose was 63.8% higher in the intervention group than in the control group,” the researchers wrote.

Average frequency of confirmed hypoglycemia was similar in both groups, according to researchers.

Approach looks appealing’

In commentary accompanying the study, Mark L. Evans, MD, FRCP, and Rajna Golubic, MD, PhD, both of the MRC Institute of Metabolic Science at the University of Cambridge, United Kingdom, wrote that “at face value, the approach looks appealing,” but noted that the study authors highlighted frequent contact with providers throughout the 6-month intervention.


“In the real world, if such frequency of contact was an essential requirement for success of the system, it would be challenging for many services,” Evans and Golubic wrote. “Finally, and importantly, how comfortable would patients and clinical teams be in allowing an algorithm to manage insulin dose titration? Generally, participants in this study were comfortable with receiving dose advice from the device.”

On Feb. 20, the FDA granted 501(k) clearance for the d-Nav mobile app to be used as an aid in optimizing insulin management among patients with type 2 diabetes, according to a press release from Hygieia. In addition to delivering insulin recommendations directly to the patient, it is also the first insulin-titration app that can connect to any blood glucose meter that shares data with the cloud. It is available for both iOS and Android mobile phones.

The d-Nav service has been in use for more than 6 years in Northern Ireland and is currently being offered in the United States by Blue Cross Blue Shield of Michigan, according to the company. – by Regina Schaffer

For more information:

Richard M. Bergenstal, MD, can be reached at the International Diabetes Center, 3800 Park Nicollet Blvd., Minneapolis, MN 55416; email: richard.bergenstal@parknicollet.com.

Disclosures: The National Institute of Diabetes and Digestive and Kidney Diseases at the NIH funded this study. Bergenstal reports no relevant financial disclosures. Please see the study for the other authors’ relevant financial disclosures.