Efficacy of a premixed semisynthetic human insulin regimen

Sixty-one insulin-requiring non-insulin-dependent (type II) diabetic patients who had been transferred from a regimen of mixed intermediate and short-acting insulin to a fixed regimen of premixed insulin (70% neutral protamine Hagedorn and 30% regular, human semisynthetic insulin) given twice daily were studied retrospectively. The average age was 65 years (range, 35 to 84) and the average duration of their diabetes was 13.8 years (range, 1.5 to 33 years). Thirty-one percent were men, 69% women. Hemoglobin A1c (HbA1c) dropped significantly after transfer from a mean of 12.3% to a mean of 9.2% (P less than 0.001). After an average of 14.1 months, 40 patients still had a lower HbA1c (P less than 0.01), showing sustained improvement. The mean HbA1c at the last visit was 10.2% (normal range, 5.5% to 8.5%) with the average reduction in HbA1c being 2.1%. This sustained improvement occurred without a significant gain in weight (P = 0.63) or a significant increase in total insulin doses (median, 2 units), and was independent of the type of insulin used previously. Hypoglycemic episodes actually declined from an average of 1.0 to 0.6 per month. Of those patients who had previously not reported hypoglycemia, only 28% reported hypoglycemic events, and of those reporting previous hypoglycemia, 57% experienced a reduction. This surprising improvement in glycemic control was not due to compliance with insulin injections or remote premixing of insulin but possibly due to the increased accuracy of measuring the premixed insulin dose. The convenience and stability of a premixed insulin regimen results in better glycemic control in the insulin-requiring non-insulin-dependent diabetic population.