Perioperative fully closed-loop insulin delivery in patients undergoing elective surgery: an open-label, randomised controlled trial

Introduction: Perioperative management of glucose levels remains challenging. We aimed to assess whether fully closed-loop subcutaneous insulin delivery would improve glycaemic control compared with standard insulin therapy in insulin-requiring patients undergoing elective surgery.

Research Design and Methods: We did a single-centre, open-label, randomised controlled trial. Patients with diabetes (other than type 1) undergoing elective surgery were recruited from different surgery units and randomized using a minimisation schedule (stratified by HbA1c and daily insulin dose) to fully closed-loop insulin delivery with faster-acting insulin aspart (closed-loop group) or standard insulin therapy according to local clinical practice (control group). Study treatment was administered from hospital admission to discharge (for a maximum of 20 days). The primary endpoint was the proportion of time with sensor glucose in the target range (5.6-10.0 mmol/L).

Results: Forty-five patients were enrolled and assigned to the closed-loop (n=23) or the control group (n=22). One patient (closed-loop group) withdrew from the study before surgery and was not analysed. Participants underwent abdominal (57%), vascular (23%), orthopaedic (9%), neuro- (9%) or thoracic (2%) surgery. The mean proportion of time that sensor glucose was in the target range was 76.7±10.1% in the closed-loop and 54.7±20.8% in the control group (mean difference 22.0 percentage points [95% CI: 11.9-32.0%; p<0.001]). No episodes of severe hypoglycaemia (<3.0 mmol/L) or hyperglycaemia with ketonaemia nor any study-related adverse events occurred in either group.

Conclusion: In the context of mixed elective surgery, the use of fully closed-loop subcutaneous insulin delivery improves glucose control, without a higher risk of hypoglycaemia.