A prospective evaluation of insulin dosing recommendations in patients with type 1 diabetes at near normal glucose control: Basal dosing

Abstract

Background: Current basal insulin dosing recommendations are based on retrospective studies of Type 1 patients with diabetes in whom the glucose control was not intensely established. Using continuous glucose monitoring (CGM) we prospectively studied these recommendations in patients treated with continuous subcutaneous insulin infusion.

Methods: With CGM 30 subjects were titrated with daily insulin adjustments to achieve a basal glucose targets of <5% of values <70 mg/dl and <20%, >170 mg/dl. The basal rate during meal time was studied by a sequential daily single meal omission until the glucose goals were achieved.

Results: Glucose targets were achieved in all subjects. The observed ratios of total basal dose (TBD) to total daily dose and TBD to weight, in kilograms, were 0.384 and 0.185, respectively. Previously reported formulas for estimating the TBD resulted in significantly higher values than we observed. The difference between the maximum to the minimum hourly basal insulin infusion rate was more than 100% and the peak rate was reached by 0200 hours in 73% of subjects. During the post study observation period in which there was no further study intervention and in those subjects with baseline A1C >6.9%, the A1C decreased 0.45 % (p = 0.0110) in a mean of 12.8 weeks.

Conclusions: Current literature overestimates TBD dose and underestimates the degree and the time of onset of the dawn phenomenon. Maintaining near normal glycemia in the ambulatory setting may be achieved in selected Type 1 patients for at least two weeks and maybe longer.

Keywords: basal; diabetes; glucose; insulin; pump.

Figures

Figure 1.

The mean and standard deviation of the hourly basal glucose in 30 subjects with Type 1 diabetes treated with continuous subcutaneous insulin infusion with daily insulin dosage adjustments guided by continuous glucose monitoring. The basal glucose data from the meal period of that day in which the meal was omitted was transposed to the meal period of the 24 hour basal glucose report.

Figure 2.

The relationship of total basal dose (units/day) to total daily dose (units/day) in 30 subjects with Type 1 diabetes with near normal glucose control treated with continuous subcutaneous insulin infusion with daily insulin dosage adjustments guided by continuous glucose monitoring and on a 50% carbohydrate diet.

Figure 3.

Relationship of total basal dose (units/day) to body weight (kg) in 30 subjects with Type 1 diabetes with near normal glucose control treated with continuous subcutaneous insulin infusion with daily insulin dosage adjustments guided by continuous glucose monitoring.

Figure 4.

The distribution of ranges of % differences between the minimum to maximum basal rate insulin infusion during a 24 hours period in 30 subjects with Type 1 diabetes treated with continuous subcutaneous insulin infusion with daily insulin dosage adjustments guided by continuous glucose monitoring.

Figure 5.

The distribution of hourly range in which the subjects reached peak insulin infusion rate. The subjects were treated with continuous subcutaneous insulin infusion with daily insulin dosage adjustments guided by continuous glucose monitoring.