Analytical approach:
The economic analysis was based on a Markov model, with a 10-year time horizon. The authors stated that the analysis was carried out from the perspective of the UK NHS.
Effectiveness data:
The clinical data were identified by a systematic review of the literature in MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL), which contained the Hypertension and Heart Group’s specialist register. The reference lists of retrieved articles were handsearched. Two searches were carried out; one for hypertension and one for heart failure. Head-to-head randomised, double-blind, active-controlled trials of adult patients were included. The key endpoint was the mean change from baseline to 24 hours after the dose, in diastolic blood pressure and systolic blood pressure, for the hypertension trials, and a composite of cardiovascular death and hospital admission for the management of heart failure, for the heart failure trials. A random-effects model was used to calculate the weighted mean differences. Heterogeneity between the pooled studies was investigated. Framingham equations were used to estimate the long-term impact of short-term changes in blood pressure. All-cause mortality was based on UK life tables.
Monetary benefit and utility valuations:
The utility values were derived from a National Institute for Health and Clinical Excellence (NICE) guideline. A similar utility loss, due to adverse treatment effects, was assumed for both treatment arms.
Measure of benefit:
Quality-adjusted life-years (QALYs) were used as the summary benefit measure and were discounted at an annual rate of 3.5%.
Cost data:
The economic analysis included the costs of drug acquisition and of managing initial non-fatal stroke and coronary heart disease events, as well as those for ongoing management. The drug costs were based on their official prices (except for generic losartan, which was based on expert opinion), while other costs were from a NICE guideline. All costs were in UK pounds sterling (£). The price year was 2009 and a 3.5% annual discount rate was applied.
Analysis of uncertainty:
Four alternative scenarios were considered, as one-way sensitivity analyses, by changing the baseline risk (increasing the cohort pre-treatment systolic blood pressure to a range of 140 to 180 mmHg), varying the hypertensive effectiveness, reducing the price of generic losartan, and varying the cohort starting age.