Closed-loop insulin delivery reduced nocturnal hypoglycemia compared to open-loop control (1 vs 6-8 events; P=0.04) and increased overnight time in target glucose range (P<0.0001).
RCT (n=12)
Random order
Does closed-loop insulin delivery reduce nocturnal hypoglycemia and improve time in target range in patients with type 1 diabetes on nights with or without antecedent afternoon exercise?
Closed-loop insulin delivery significantly reduces nocturnal hypoglycemia and increases time in target range compared to open-loop control in young patients with type 1 diabetes, regardless of afternoon exercise.
Absolute Event Rate: 8.3% vs 58.3%
p-value: p=0.04
OBJECTIVE: Afternoon exercise increases the risk of nocturnal hypoglycemia (NH) in subjects with type 1 diabetes. We hypothesized that automated feedback-controlled closed-loop (CL) insulin delivery would be superior to open-loop (OL) control in preventing NH and maintaining a higher proportion of blood glucose levels within the target blood glucose range on nights with and without antecedent afternoon exercise. RESEARCH DESIGN AND METHODS: Subjects completed two 48-h inpatient study periods in random order: usual OL control and CL control using a proportional-integrative-derivative plus insulin feedback algorithm. Each admission included a sedentary day and an exercise day, with a standardized protocol of 60 min of brisk treadmill walking to 65-70% maximum heart rate at 3:00 p.m. RESULTS: Among 12 subjects (age 12-26 years, A1C 7.4±0.6%), antecedent exercise increased the frequency of NH (reference blood glucose<60 mg/dL) during OL control from six to eight events. In contrast, there was only one NH event each on nights with and without antecedent exercise during CL control (P=0.04 vs. OL nights). Overnight, the percentage of glucose values in target range was increased with CL control (P<0.0001). Insulin delivery was lower between 10:00 p.m. and 2:00 a.m. on nights after exercise on CL versus OL, P=0.008. CONCLUSIONS: CL insulin delivery provides an effective means to reduce the risk of NH while increasing the percentage of time spent in target range, regardless of activity level in the mid-afternoon. These data suggest that CL control could be of benefit to patients with type 1 diabetes even if it is limited to the overnight period.
Sherr et al. (Wed,) conducted a rct in Type 1 diabetes (n=12). Closed-loop (CL) insulin delivery vs. Open-loop (OL) control was evaluated on Nocturnal hypoglycemia (NH) (p=0.04). Closed-loop insulin delivery reduced nocturnal hypoglycemia compared to open-loop control (1 vs 6-8 events; P=0.04) and increased overnight time in target glucose range (P<0.0001).