The analysis was based on a Markov model, with a lifetime horizon. The authors stated that the analysis was carried out from the payer perspective.
The clinical inputs for the treatment effect, measured by a reduction in blood pressure, were identified by a systematic search of the MEDLINE database up to 2008. Only double-blind, randomised controlled trials (RCTs) that evaluated an angiotensin II inhibitor in combination with hydrochlorothiazide, compared with either placebo or another active treatment were considered. Where required, an indirect comparison was performed, considering the comparability of interventions and patient populations. Multiple results were pooled using the inverse variance method. Epidemiological data and other Greek population data were from large country-specific databases. The reduction in blood pressure and its relationship with the risk of developing cardiovascular disease were key inputs for the model. The association was based on published risk equations.
Monetary benefit and utility valuations:
The health utilities were from three published studies and authors’ assumptions.
Measure of benefit:
Quality-adjusted life-years (QALYs) were the summary benefit measure and they were discounted at an annual rate of 3%.
The economic analysis included the annual costs of antihypertensive medication, the management and treatment of cardiovascular events, and the maintenance of patients following hospital discharge. The drug costs were from the latest price list from the Ministry of Commerce, while other costs were from a sample of 362 patients from the database of the National Insurance Fund. The price year was 2008. All costs were in Euros (EUR) and were discounted at an annual rate of 3%.
Analysis of uncertainty:
Various one-way sensitivity analyses were carried out on the model inputs, using ranges reported in the literature or based on authors’ opinions. Several subgroup analyses were conducted.