Round-the-clock closed-loop glucose control leads to better outcomes

Last Updated: 2016-05-12

By Will Boggs MD

NEW YORK (Reuters Health) - Day/night closed-loop glucose control provides better outcomes in patients with type 1 diabetes, compared with evening/night closed-control or patient-controlled sensor augmented pump (SAP), according to results from a one-month extension of a randomized crossover study.

Earlier studies have shown that a closed-loop control system, or artificial pancreas (AP), provides better glycemic control in patients with type 1 diabetes than does patient-controlled SAP.

Dr. Eric Renard, from Montpellier University Hospital in France, and colleagues assessed the efficacy of glucose control achieved by day/night AP for one month under free-living circumstances in 20 patients who had completed their previous randomized crossover study comparing evening/night AP with SAP.

The percentage of time in target range over 24 hours was improved with day/night AP (64.7%) and evening/night AP (63.6%) compared with SAP (59.7%), according to the May 5 Diabetes Care online report.

Most of the improvements came from reduced percentages of time below the target range, whereas mean glucose was not significantly different among the three treatments.

Similarly, during the evening and night, both SAP regimens provided better percentages of time in target range.

Neither the percentage of time in target range nor mean blood glucose during the daytime differed among the three treatments.

Blood glucose variability over 24 hours was lowest with day/night AP, and mean insulin delivery over 24 hours was similar with day/night AP and SAP but lower with evening/night AP.

The mean number of hypoglycemic episodes was lower with both AP regimens than with the SAP regimen. There were no severe hypoglycemic episodes and no hospitalizations for ketoacidosis during the study.

"The reported present experience of day/night AP compared with evening/night AP points to the remaining improvements needed to achieve an AP system providing optimal nearly normal glucose control at all times," the researchers conclude. "Nevertheless, the sustainability of improved glucose control in the evening and overnight with AP supports its commercialization as a valuable additional feature of SAP therapy for patients with type 1 diabetes."

In a related report, Dr. Jennifer L. Sherr and colleagues from Yale School of Medicine, New Haven, Connecticut, assessed whether adjunctive therapy with pramlintide, an analog of the peptide amylin, or liraglutide, a GLP-1 agonist, would reduce prandial glycemic excursions compared with closed-loop control alone in two separate studies.

The addition of pramlintide to closed-loop control was associated with a 39% reduction in the peak increases in postprandial plasma glucose levels even in the face of a 13% reduction in prandial insulin delivery.

Liraglutide was less effective in altering peak postprandial glucose, but its treatment was associated with a 35% reduction in cumulative post-meal plasma glucose even with a 28% reduction in prandial insulin delivery.

Both treatments were well tolerated, and liraglutide-treated patients lost about 5% body weight and lowered total daily insulin doses by about 26%, changes that were greater than those observed with pramlintide.

Dr. Sherr told Reuters Health by email, "As closed-loop systems have moved to outpatient studies, and it is likely we will see regulatory approval and commercialization of the first iterations of a hybrid closed-loop system in the not-too-distant future, methods by which to further improve glycemic control need to continue to be explored. While we await fully closed-loop systems and dual-hormone systems using both glucagon and insulin, adjunctive agents have the potential to improve glycemic control while reducing insulin requirements and patient burden."

"Use of adjunctive therapy for those with type 1 diabetes is an area that deserves further exploration," she said. "These agents are likely to help improve glycemic control while having additional beneficial effects, such as weight loss, in those living with type 1 regardless of whether insulin is delivered in an open-loop or closed-loop manner."

Dr. Renard did not respond to a request for comments.

The European Commission funded the first study and seven coauthors reported disclosures. The National Institutes of Health and the Michael D. Ryan and Rosemary McNicholas Ryan Pediatric Diabetes Research Fund supported the second study, and two coauthors reported disclosures.

SOURCE: http://bit.ly/1WsyZ7O and http://bit.ly/221hP0h

Diabetes Care 2016.