Intraperitoneal insulin delivery provides superior glycaemic regulation to subcutaneous insulin delivery in model predictive control‐based fully‐automated artificial pancreas in patients with type 1 diabetes: a pilot study

Aims To compare intraperitoneal ( IP ) to subcutaneous ( SC ) insulin delivery in an artificial pancreas ( AP ). Research design and methods Ten adults with type 1 diabetes participated in a non‐randomized, non‐blinded sequential AP study using the same SC glucose sensing and Zone Model Predictive Control ( ZMPC ) algorithm adjusted for insulin clearance. On first admission, subjects underwent closed‐loop control with SC delivery of a fast‐acting insulin analogue for 24 hours. Following implantation of a DiaPort IP insulin delivery system, the identical 24‐hour trial was performed with IP regular insulin delivery. The clinical protocol included 3 unannounced meals with 70, 40 and 70 g carbohydrate, respectively. Primary endpoint was time spent with blood glucose ( BG ) in the range of 80 to 140 mg/ dL (4.4‐7.7 mmol/L). Results Percent of time spent within the 80 to 140 mg/ dL range was significantly higher for IP delivery than for SC delivery: 39.8 ± 7.6 vs 25.6 ± 13.1 ( P = .03). Mean BG (mg/ dL ) and percent of time spent within the broader 70 to 180 mg/ dL range were also significantly better for IP insulin: 151.0 ± 11.0 vs 190.0 ± 31.0 ( P = .004) and 65.7 ± 9.2 vs 43.9 ± 14.7 ( P = .001), respectively. Superiority of glucose control with IP insulin came from the reduced time spent in hyperglycaemia (>180 mg/ dL : 32.4 ± 8.9 vs 53.5 ± 17.4, P = .014; >250 mg/ dL : 5.9 ± 5.6 vs 23.0 ± 11.3, P = .0004). Higher daily doses of insulin ( IU ) were delivered with the IP route (43.7 ± 0.1 vs 32.3 ± 0.1, P < .001) with no increased percent time spent <70 mg/ dL ( IP : 2.5 ± 2.9 vs SC : 4.1 ± 5.3, P = .42). Conclusions Glycaemic regulation with fully‐automated AP delivering IP insulin was superior to that with SC insulin delivery. This pilot study provides proof‐of‐concept for an AP system combining a ZMPC algorithm with IP insulin delivery.