medwireNews: A pilot randomized trial suggests that closed-loop insulin delivery is feasible for inpatients with insulin-dependent type 2 diabetes on the general ward.
Roman Hovorka (University of Cambridge, UK) and team chose an algorithm that did not account for the timing and content of meals, and patients did not receive a prandial insulin bolus, “reducing the risk of hypoglycaemia caused by delayed or reduced meal consumption and skipped meals, while also reducing staff workload.”
Despite this, the 20 patients assigned to closed-loop insulin delivery spent 59.8% of their time within the target blood glucose range (5.6–10.0 mmol/L), which was a significant improvement on the 38.1% recorded in the 20 patients whose blood glucose was managed according to local protocols.
This was largely due to a reduction in time spent above the target range in the closed-loop group, at 30.1% versus 49.1% in the control group. Time spent below target did not significantly differ between the groups (10.1 vs 12.9%).
Blood glucose variability was significantly less in the closed-loop than the control group, and closed-loop delivery improved glucose control during both the nighttime and daytime periods, the researchers report in The Lancet Diabetes & Endocrinology.
The team describes the study setting as “a real-world general ward environment”. However, the author of a linked commentary, Gerry Rayman (Diabetes and Endocrine Centre, Ipswich, Suffolk, UK), points out that 30 of the study participants were in hospital because of infected foot ulcers and a further four had ischemic diabetic foot.
While “understandable” for this pilot study, it contrasts with that fact that “85% of diabetes admissions are emergencies unrelated to diabetes,” he says. Patients in the current study, by contrast, would be under the care of a diabetes team and mostly lack the “additional complex comorbidities” common in diabetes patients that could influence treatment response.
Rayman describes the study as “a welcome advance,” given data showing that diabetic inpatients have good blood glucose control less than 40% of the time and one in 10 has a severe hypoglycemia event during their stay.
But he notes that “[i]f it is to be generalised, nurses on non-specialist wards will have to be trained to use the closed-loop system, including inserting and calibrating the sensor, which is not always straightforward and sensor failure is common even in the hands of diabetes specialists.”
Sensors used in the closed-loop group of the current study had to be replaced seven times during 72 hours of use, with five replacements being due to sensor failure. “[I]n the hands of non-technologists failure rates will be greater,” says Rayman.
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