medwireNews: Older adults with type 1 diabetes spend more time in target glucose range when using the Cambridge hybrid closed-loop insulin delivery system than when using sensor-augmented pump delivery, shows a randomized trial.
All of the 37 trial participants were at least 60 years of age and had been using an insulin pump for 3 months or more. They were given a Dana Diabecare RS insulin pump and a Dexcom G6 continuous glucose monitor and undertook two 16-week periods of use in a random order. In one period these components were used as a sensor-augmented pump system and in another they were used as a hybrid closed-loop system, with basal insulin delivery managed by the CamAPS FX app from an unlocked Android smartphone.
Presenting the results at an online session hosted by the ATTD, Charlotte Boughton (Addenbrooke's Hospital, Cambridge, UK) noted that the prior use of pumps implies a degree of comfort with technology in this trial population, but stressed that they were not necessarily tech-savvy, with a few being new to smartphones.
The participants were a median age of 68 years at baseline, and had diabetes lasting a median of 38 years and relatively good glycemic control, with glycated hemoglobin levels averaging 7.4% (57 mmol/mol). Thirty-six people completed the study; one died of COVID-19.
During the closed-loop phase, the participants used the system for 96.7% of the time and had a time in range (TIR; 3.9–10.0 mmol/L; 70–180 mg/dL) averaging 79.9%, which was significantly greater than the 71.4% achieved during the sensor-augmented pump phase.
This was driven by a significant reduction in the time spent in hyperglycemia, at a median of 16.7% versus 21.4%, and did not come at the expense of more time in hypoglycemia, which was a median of 1.7% in both study phases.
The participants used significantly more basal insulin during the closed-loop phase than the sensor-augmented phase, but significantly less bolus insulin. Boughton suggested this was because of the closed-loop algorithm compensating for too-small boluses by the users, which reduced the need for corrective boluses.
She reported that the improved TIR was maintained across the full 16 weeks of closed-loop use, with the greatest benefits observed overnight and in people with the poorest glucose control at baseline.
The findings are published in The Lancet Healthy Longevity, with a linked commentary from Richard Pratley and Anna Casu, both from AdventHealth Diabetes Institute in Orlando, Florida, USA, who highlight that the study participants were “predominately White, technologically adept, older individuals with type 1 diabetes who were experienced pump users.”
They say: “In our experience, many older individuals with type 1 diabetes require extra education when initiating advanced insulin delivery devices such as the one employed in this study. Thus, more studies with larger groups of diverse patients, which use this and other approaches are required.”
Nonetheless, they conclude that “this study is an important step toward building the evidence base for optimal management of the growing population of older adults with type 1 diabetes.”
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Lancet Healthy Longev 2022; 3: e135–142
Lancet Healthy Longev 2022; 3: e120–121