Predicting insulin requirements for a portable insulin pump using the Biostator. Evidence for reversible insulin resistance in poorly controlled type I diabetics.

Glycemic control was achieved in 14 patients with insulin-dependent diabetes mellitus (IDDM) by 36-48-h treatment with a recently marketed clinical model, Biostator glucose controller (Life Science Instruments, Miles Laboratories, Elkhart, Indiana). Control was maintained by continuous subcutaneous insulin infusion with a portable pump, programmed using infusion profiles from the Biostator. Control of glycemic excursion with the Biostator was variable among patients. This control, reflected by the M-value or a blood glucose index (mean of pre-, peak, and 2-h postmeal levels for four meals) of each patient, correlated directly with their prior glycemic control, as assessed by hemoglobin A1c (HbA1c) level (r = 0.66, P less than 0.01 and r = 0.82, P less than 0.005, for M-value and blood glucose index, respectively). Total insulin infused by the Biostator/24 h overpredicted the subcutaneous infusion dose required on day 2 of pump treatment (183 +/- 11%, P less 0.001). Therefore, these data were not used to program the portable pump. Instead, total insulin dose was estimated using a dietary glucose/insulin (G/I) ratio. This ratio, derived from dietary total available glucose, urine glucose, and insulin dose/24 h during depot insulin treatment, accurately estimated total insulin for pump infusion (97 +/- 4%). The basal infusion rate of the Biostator between 2400 and 0600 h also exceeded the subcutaneous infusion requirement and was reduced to 40% for the initial pump basal rate. The remainder of the insulin (total minus basal) was distributed as premeal boluses according to the Biostator infusion profile for meals.(ABSTRACT TRUNCATED AT 250 WORDS)