A Cost-Utility Analysis of Losartan versus Atenolol in the Treatment of??Hypertension with Left Ventricular Hypertrophy

Abstract

The LIFE (Losartan Intervention For Endpoint reduction in hypertension) study demonstrated a 13% relative risk reduction in the primary composite endpoint (myocardial infarction, stroke or death) for patients with hypertension and electrocardiographically diagnosed left ventricular hypertrophy (LVH) treated with losartan compared with atenolol. Losartan recipients also had a 25% relative risk reduction for stroke compared with atenolol recipients. Incorporating the results found in the LIFE study into an economic model, an incremental cost-effectiveness analysis was performed comparing losartan with atenolol in the treatment of 67-year old patients with hypertension and LVH. A Markov state transition model, based on published results of the LIFE trial (mean follow-up of 4.8 years), was utilised to extrapolate the outcomes observed in this trial to the patients' lifetime. Utility estimates for the associated health states were obtained from various published sources. Lifetime treatment costs were calculated adopting a societal perspective. Both costs and benefits were discounted and incremental cost-effectiveness ratios (ICERs) were estimated. One-way and probabilistic sensitivity analyses were performed. The estimated ICER for losartan versus atenolol was 1337 Canadian dollars per QALY gained (1 Canadian dollar =0.75 US dollars, 2002 values). This ICER was robust to extensive sensitivity analysis, demonstrating a 95% probability that the ICER would be <20,000 Canadian dollars per QALY gained. From a Canadian societal perspective, losartan appears to be a cost-effective alternative to atenolol in patients with hypertension and LVH. The estimated ICERs, including the sensitivity analyses, were within the range of cost-effectiveness ratios for various currently funded interventions and drugs in developed countries.