The lifetime cost effectiveness of amlodipine-based therapy plus atorvastatin compared with atenolol plus atorvastatin, amlodipine-based therapy alone and atenolol-based therapy alone: results from ASCOT1.
BACKGROUND: ASCOT (Anglo-Scandinavian Cardiac Outcomes Trial) showed in hypertensive patients that blood pressure-lowering treatment with an amlodipine-based regimen reduces events compared with an atenolol-based regimen and that atorvastatin was more effective than placebo. OBJECTIVE: To assess the cost effectiveness of four alternative treatment strategies in patients with hypertension and three or more cardiovascular risk factors in the UK (from the UK NHS perspective) or Sweden (from the societal perspective): amlodipine-based plus atorvastatin, atenolol-based plus atorvastatin, amlodipine-based alone and atenolol-based alone. METHODS: Based on the trial data, a Markov model was constructed where the risk of myocardial infarction, revascularization procedures and stroke and the long-term costs, quality of life and mortality associated with these events were estimated. Transition probabilities and costs (euro, 2007 values) were based on the patient-level trial data. Outcomes were reported as life-years gained and QALYs. In the latter case, utility reduction from events was based on a substudy in ASCOT patients. Treatment was applied for the duration of the lipid-lowering arm of the trial (3 years) and patients were then followed to the end of their life. RESULTS: Amlodipine-based therapy plus atorvastatin was the most expensive but also most effective treatment. Compared with amlodipine-based therapy alone, the cost to gain one QALY was euro 11,965 in the UK and euro 8,591 in Sweden. The incremental cost effectiveness of amlodipine-based therapy compared with atenolol-based therapy was euro 9,548 and euro 3,965 per QALY gained in the UK and Sweden, respectively. Atenolol-based therapy plus atorvastatin was eliminated through extended dominance. Applying the threshold values used by the National Institute for Health and Clinical Excellence (NICE) and the Swedish National Board of Health and Welfare, a combination of amlodipine-based therapy and atorvastatin appears to be cost effective in patients with hypertension and three or more additional risk factors.