Cost-effectiveness of adding ezetimibe to atorvastatin vs switching to rosuvastatin therapy in Portugal

Background: Statin monotherapy is the mainstay of low-density lipoprotein cholesterol (LDL-C) management for high cardiovascular risk patients in Portugal; however, several therapeutic options are available and predicted to have different clinical and economic impacts. The aim of this study was to evaluate the cost-effectiveness of adding ezetimibe 10 mg (EZ10) to atorvastatin 10 or 20 mg (A10/20) vs switching to rosuvastatin 10 or 20 mg (R10/20) in Portuguese patients with coronary heart disease (CHD) and/or diabetes who are currently above the LDL-C goal. Methods: A Markov model was used to describe CHD disease progression and the lifetime costs and utilities associated with each disease state were used to estimate the gains in life-years and quality-adjusted life-years (QALYs), as well as the incremental cost-effectiveness ratio (ICER), of the two treatment regimens. Model inputs, such as age, gender, and prevalence of cardiovascular risk factors of the dyslipidemic Portuguese patients were obtained from the Portuguese cohort of the Dyslipidemia International Study (DYSIS). The efficacy of each treatment regimen, the cost of drugs and of treating CHD events, and the utilities for each disease state were derived from published sources. Results: The estimated lifetime discounted number of QALYs gained by patients treated with A10/20 was 8.70, while in those switching to R10/20 it was 8.81 and in those adding EZ10 it was 8.93. Discounted total health costs were estimated to be (sic)11,131 for A10/20, but (sic)14,511 and (sic)16,571 for R10/20 and A10/20 + EZ10, respectively. The ICER of adding ezetimibe vs switching to rosuvastatin was (sic)16,465/QALY. Based on the Portuguese cost-effectiveness willingness-to-pay threshold of (sic)30,000/QALY, adding ezetimibe vs switching to rosuvastatin would be a cost-effective use of resources in Portugal. Sensitivity analyses in patients with differing clinical histories (CHD or diabetes or both) yielded similar values, with no ICER over E30,000/QALY. Conclusions: From the perspective of the National Health Service, prescribing ezetimibe to high cardiovascular risk patients being treated with atorvastatin vs switching them to rosuvastatin is projected to be a cost-effective use of resources in Portugal.