The analysis was based on the published Center for Outcomes Research (CORE) Diabetes Model. This was a Markov model that projected the risk of complications due to diabetes over time. A 30-year time horizon was considered and the authors stated that the analysis took the perspective of the third-party payer.
The clinical evidence on the treatment efficacy and baseline characteristics of the patient population came from a 52-week, double-dummy, placebo, randomised controlled trial (RCT); the Liraglutide Effect and Action in Diabetes (LEAD)-3 trial. This included 746 eligible patients, with 251 in the liraglutide 1.2mg group, 247 in the liraglutide 1.8mg group, and 248 in the glimepiride group. Other clinical data on diabetes complications were already incorporated in the decision model and were derived from the most relevant published epidemiological and clinical sources, such as the UK Prospective Diabetes Study. The primary endpoint was the reduction in haemoglobin A1c
with the two treatments. Assumptions were needed for the long-term effects of the treatments because only 52 weeks of data were available.
Monetary benefit and utility valuations:
Measure of benefit:
Survival was the key outcome of the model; it was not combined with the costs. Event rates were also reported.
The economic analysis included the costs of drugs, management of disease (medications and monitoring), and diabetes-related complications. The costs were presented as macro-categories and were derived from published sources, but the details of these were not given. All costs were in US dollars ($) and were discounted at an annual rate of 3%. The price year was 2007.
Analysis of uncertainty:
Deterministic sensitivity analyses were undertaken on the change in haemoglobin A1c
(using a published 95% confidence interval), the decay curve for glimepiride, and the discount rate.