Long-term clinical and cost outcomes of treatment with biphasic insulin aspart 30/70 versus insulin glargine in insulin naïve type 2 diabetes patients: cost-effectiveness analysis in the UK setting

Abstract

To evaluate the long-term clinical and cost outcomes associated with biphasic insulin aspart 30/70 (BIAsp 30/70, premixed 30% soluble and 70% protaminated insulin aspart in one injection) compared to insulin glargine treatment in insulin-naïve type 2 diabetes patients failing oral antidiabetic agents in the UK, based on findings recently reported from the INITIATE clinical trial. The CORE Diabetes Model, a published, peer-reviewed and validated model of diabetes, was used to evaluate life expectancy, quality-adjusted life expectancy, cumulative incidence of complications and direct medical costs over patient lifetimes. The model simulates the range of diabetic complications and disease progression within a series of sub-models (cardiovascular disease, neuropathy, renal and eye disease) based on published data. Baseline cohort characteristics (54.5% male, mean age 52.45 years, mean diabetes duration 9 years, mean HbA(1c) 9.77%) and treatment effects were based on INITIATE. Costs were derived from published UK sources. The analysis was run over a 35-year time horizon (patient lifetime) from a third party payer perspective. Costs and clinical benefits were discounted at 3.5% per annum. Sensitivity analyses were performed. BIAsp 30/70 was associated with projected improvements in discounted life expectancy (0.19 +/- 0.20 years) and quality-adjusted life expectancy (0.19 +/- 0.14 quality-adjusted life years [QALYs]), as well as a reduced incidence of retinopathy and nephropathy complications, versus glargine. Total lifetime direct costs were 1319 pounds higher with BIAsp 30/70 than with glargine leading to an incremental cost-effectiveness ratio of 6951 pounds per QALY gained. This study is the first to address the long-term health economic implications of treating type 2 diabetes patients failing oral anti-diabetics with a biphasic insulin mix versus long-acting insulin. Our projections indicate that improved HbA1c levels with BIAsp 30/70 treatment are associated with improvements in life expectancy and quality-adjusted life expectancy, and that BIAsp 30/70 represents excellent value for money compared to insulin glargine in the UK.