Perioperative glycaemic control in insulin-treated type 2 diabetes patients undergoing gastric bypass surgery

Roux-and-Y gastric bypass (RYGB) rapidly reduces insulin requirements in patients with insulin-dependent type 2 diabetes mellitus (T₂DMi). A too modest reduction in insulin dose may lead to hypoglycaemia in the early postoperative period.

To evaluate a regimen designed to maintain blood glucose levels between 5-15 mmol/l and to prevent hypoglycaemic events (blood glucose <3.5 mmol/l) after RYGB surgery.

The effect of a 75% reduction in insulin dose was studied in 85 T₂DMi patients during the first ten days after RYGB. Patients with severe b-cell failure (fasting C-peptide <0.3 nmol/l) were excluded.

percentage of patients exceeding the upper or lower blood glucose limits, and the number of hypoglycaemic events.

The mean blood glucose level was 12.4±0.3 mmol/l (mean ± SE) on the day of surgery (day 0), 10.7±0.3 mmol/l on day 1, 10.0±0.5 mmol/l on day 2, and 8.3±0.3 on day 10. Of all measurements performed during this ten-day period, 12.4% were above the target range, and 2.6% were <5 mmol/l. There were no hypoglycaemic events during the stay in hospital. During the first week at home 2% of the measurements were <3.5 mmol/l.

A 75% reduction in insulin dose is safe in T₂DMi patients without severe b-cell failure, and prevents hypoglycaemia in the early postoperative period of RYGB in most cases.