Valutazione economica dello studio IDEAL

Abstract

Introduction: the IDEAL (“High-dose atorvastatin vs usual-dose simvastatin for secondary prevention after myocardial infarction”) study was carried out to compare intensive lowering of low-density lipoprotein (LDL)-cholesterol using the highest recommended dose of atorvastatin 80 mg with simvastatin 40 mg. Aim: our aim was to investigate the economic consequence of high dose of atorvastatin vs usual-dose of simvastatin in reducing major coronary events in patients with a history of acute myocardial infarction (AMI). Methods: the analysis is based on clinical outcome data from the IDEAL study. We conducted a cost-effectiveness analysis, comparing high dose of atorvastatin (80 mg/die) versus usual-dose of simvastatin (20 mg/die) in the perspective of the Italian National Health Service. We identified and quantified medical costs: drug costs according to the Italian National Therapeutic Formulary and hospitalizations were quantified based on the Italian National Health Service tariffs (2006). Effects were measured in terms of mortality and morbidity reduction (number of deaths, life years gained and frequency of hospitalizations). We considered an observation period of 4.8 years. The costs borne after the first 12 months were discounted using an annual rate of 3%. We conducted one and multi-way sensitivity analyses on unit cost and effectiveness. We also conducted a threshold analysis. Results: the cost of simvastatin or atorvastatin therapy over the 4.8 years period amounted to approximately 2.3 millions euro and 2.6 millions euro per 1,000 patients respectively. Atorvastatin was more efficacious compared to simvastatin and the overall cost of care per 1,000 patients over 4.8 years of follow-up was estimated at 4.3 millions euro in the simvastatin and 4,18 millions euro in the atorvastatin group, resulting into a cost saving of 121,518 euro that is 2.8% of total costs occurred in the simvastatin group. Discussion: this study is the first economic evaluation of IDEAL study based on the Italian context. Atorvastatin therapy is dominant since it is both less costly and more effective than simvastatin. Results of sensitivity analysis showed that atorvastatin therapy remains dominant even in the most unfavourable hypotheses.