Administering a small rapid-acting insulin bolus 3 h after eating a mixed macronutrient meal improves postprandial glucose control, without hypoglycaemia, in people with Type 1 diabetes

Aims: To establish an optimal rapid-acting bolus insulin dose and administration timing strategy to improve postprandial glycaemia after mixed macronutrient meals in people with Type 1 diabetes treated with basal bolus insulin injections. Methods: Ten males [HbA1c 7.0±0.5% (52.5±5.9 mmol/ mol)] attended the laboratory at 07:30 h on four occasions and underwent (1) a low fat meal with bolus insulin dictated by carbohydrate counting (low-fat100%), (2) a high fat meal with bolus insulin dictated by carbohydrate counting (high fat100%), (3) a high fat meal with a bolus insulin dose increased by 30% (high-fat130%), (4) a high fat meal with bolus insulin dictated by carbohydrate counting, with an additional 30% administered at 3 h post-meal (high-fatsplit). Meals were matched for carbohydrate and protein content. Blood samples were collected periodically over a 6h postprandial period and were processed for glucose, insulin, triglycerides, TNF-a, fibrinogen and tissue factor pathway. Results: Blood glucose area under the curve was similar between low-fat100% and high-fatsplit; however, high-fat100% and high-fat130% were significantly higher, and lower, respectively. During the 6h postprandial period, 60% of patients under high fat130% experienced hypoglycaemia, with no incidences under the other conditions. There were no conditional differences in the lipaemic, inflammatory or pro-coagulant markers. Conclusions: When a carbohydrate meal with a large fat content is consumed, using the carbohydrate counting method for insulin dose adjustments at mealtime and administering a small insulin bolus 3h later provides similar postprandial glucose control to a meal containing negligible fat. This strategy is not associated with hypoglycaemia or metabolic disturbances.