Basal rate tests (24-hour fasts) performed in type-1 diabetic subjects with either absolute fasting or snacks containing negligible carbohydrate amounts result in similar glucose profiles: A randomized controlled prospective trial.

AIMS: Basal rate tests (24-hour fasting periods) may be necessary to optimize basal insulin replacement in type 1 diabetes. It was the aim of this study to prospectively compare the allowance of negligible carbohydrate snacks vs absolute fasting.

METHODS: A total of 20 patients with type 1 diabetes (age, 48 ± 15 years (9 women, 11 men); BMI, 28.5 ± 4.5 kg/m2 ; HbA1c, 8.8% ± 2.0% (73.0 ± 21.9 mmol/mol); insulin dose, 0.69 ± 0.31 IU/kg body weight and per day) participated in 2 basal rate tests lasting 24 hours in random order with unchanged basal insulin replacement. On 1 occasion, negligible carbohydrate snacks (salads and vegetables, up to 5.1 g carbohydrate and 276.3 kJ per portion) were allowed; during the second test subjects were obliged to fast absolutely. Plasma glucose profiles were determined using an exact laboratory method. Hypoglycaemic episodes (plasma glucose < 70 mg/dL) were compared.

RESULTS: Plasma glucose concentrations during fasting periods, with and without negligible carbohydrate snacks, did not differ significantly ( P = .65) and differences were negligible (95% confidence intervals always included a difference of 0 mmol/L). Also, there was no difference in the number of hypoglycaemic plasma glucose values (P = .40) or in compensatory carbohydrate intake. Basal rate testing with negligible carbohydrate snacks was better tolerated (questionnaire, P = .046) and the desire to discontinue the fasting period was significantly reduced (P = .023).

CONCLUSIONS: Allowing negligible carbohydrate snacks results in unchanged plasma glucose profiles during basal rate testing and is better tolerated by patients with type 1 diabetes.