High-protein meals require 30% additional insulin to prevent delayed postprandial hyperglycaemia.

Abstract

To determine the amount of additional insulin required for a high-protein meal to prevent postprandial hyperglycaemia in individuals with type 1 diabetes using insulin pump therapy. In this randomized cross-over study, 26 participants aged 8-40years, HbA1c <65mmol/mol (8.1%), received a 50g protein, 30g carbohydrate, low-fat (<1g) breakfast drink over five consecutive days at home. A standard insulin dose (100%) was compared with additional doses of 115, 130, 145 and 160% for the protein, in randomized order. Doses were commenced 15-min pre-drink and delivered over 3h using a combination bolus with 65% of the standard dose given up front. Postprandial glycaemia was assessed by 4h of continuous glucose monitoring. The 100% dosing resulted in postprandial hyperglycaemia. From 120min, ≥130% doses resulted in significantly lower postprandial glycaemic excursions compared with 100% (P<0.05). A 130% dose produced a mean (sd) glycaemic excursion that was 4.69(2.42)mmol/l lower than control, returning to baseline by 4h (P<0.001). From 120 min, there was a significant increase in the risk of hypoglycaemia compared with control for 145% [odds ratio (OR) 25.4, 95% confidence interval (CI) 5.5-206; P<0.001) and 160% (OR 103, 95% CI 19.2-993; P<0.001). Some 81% (n=21) of participants experienced hypoglycaemia following a 160% dose, whereas 58% (n=15) experienced hypoglycaemia following a 145% dose. There were no hypoglycaemic events reported with 130%. The addition of 30% more insulin to a standard dose for a high-protein meal, delivered using a combination bolus, improves postprandial glycaemia without increasing the risk of hypoglycaemia.