Switching from premixed human insulin to premixed insulin lispro: a prospective study comparing the effects on glucose control and quality of life.

AIM: To evaluate the clinical effects of switching from premixed human insulin to a premixed rapid-acting insulin analogue in type 2 diabetic patients. RESEARCH DESIGN AND METHODS: Thirty patients, who were treated with a twice-daily injection of premixed human insulin, were enrolled and randomized to (i) 50/50 premixed insulin lispro twice-daily at the same daily dose as premixed human insulin (analogue mix group), or (ii) continued premixed human insulin (control group). The doses of insulin were adjusted every month by registered diabetologists to achieve adequate blood glucose levels. At the beginning of the study, and again 4 months later, HbA1c and blood glucose levels were measured, and the amount of insulin required and BMI were recorded in both groups. Insulin therapy-related quality of life (ITR-QOL) and the diabetes treatment satisfaction questionnaire (DTSQ) were also assessed in the analogue mix group at the beginning of the study and again 4 months later. RESULTS: Although HbA1c levels did not change significantly over the duration of the study in the control group (7.33 +/- 0.58 vs 7.29 +/- 0.65%), HbA1c did improve significantly in the analogue mix group (7.59 +/- 0.44 vs 7.24 +/- 0.49%; p<0.05). The dose of insulin required in the analogue mix group did not change significantly (0.37 +/- 0.11 vs 0.38 +/- 0.14 U/kg/day), but increased in the control group from 0.34 +/- 0.15 to 0.37 +/- 0.16 U/kg/day (p<0.05). The switch to the premixed insulin analogue did not affect ITR-QOL and DTSQ scores. CONCLUSIONS: This study showed that switching from premixed human insulin to 50/50 premixed insulin lispro improved blood glucose control without compromising QOL. This finding suggests that a premixed rapid-acting insulin analogue is more effective than human insulin for Japanese type 2 diabetic patients.