Real-life dosage and clinical efficacy of biphasic insulin preparations in patients with type 2 diabetes.

Introduction: This retrospective study used data from a primary care database to compare two insulin products in routine clinical practice for the treatment of type 2 diabetes in the UK.
Patients and Methods: Records were analyzed for patients with type 2 diabetes who had been initiated on biphasic insulin aspart 30 (BIAsp30) (n=632) or biphasic isophane human insulin 30 (BHI30) (n=762) and who had a glycated hemoglobin (HbA₁(c)) measurement at baseline (up to 6 months before the index date) and end of study (6-12 months after index date). Regression analyses were used to test for a statistically significant interaction between reduction in HbA₁(c) from baseline to end of study and the log-transformed average daily dose (logADD) of insulin.
Results: With BIAsp30 a significantly lower dose of insulin (47.74 insulin units [IU]/day vs. 66.63 IU/day, P<0.0001) was required to obtain a similar HbA₁(c) reduction (1.71%-point vs. 1.55%-point, P=0.24). To achieve an additional reduction of 0.1 percentage points in HbA₁(c) (eg, reduction from 9% to 7.9% HbA₁(c) instead of from 9% to 8%), the dose of BIAsp30 would need to be increased by a factor of 1.15. For BHI30, a greater increase in dose would be needed to achieve the same additional HbA₁(c) reduction (dose increase by a factor of 1.74).
Conclusion: Clinically meaningful reductions in HbA₁(c) can be achieved at lower insulin doses with BIAsp30 treatment than with BHI30. Lower insulin doses may have important implications for medication costs.