Abstract
Hypertension is a major risk factor for strokes and myocardial infarction (MI). Given its effectiveness and safety profile, the calcium channel blocker amlodipine is among the most frequently prescribed antihypertensive drugs. This analysis was conducted to determine the costs and quality-adjusted life years (QALYs) associated with the use of amlodipine and valsartan, an angiotensin II receptor blocker, in preventing stroke and MI in Taiwanese hypertensive patients. A state transition (Markov) model was developed to compare the 5-year costs and QALYs for amlodipine and valsartan. Effectiveness data were based on the NAGOYA HEART Study, local studies, and a published meta-analysis. Utility data and costs of MI and stroke were retrieved from the published literature. Medical costs were based on the literature and inflated to 2011 prices; drug costs were based on National Health Insurance prices in 2014. A 3% discount rate was used for costs and QALYs and a third-party payer perspective adopted. One-way sensitivity and scenario analyses were conducted. Compared with valsartan, amlodipine was associated with cost savings of New Taiwan Dollars (NTD) 2,251 per patient per year: costs were NTD 4,296 and NTD 6,547 per patient per year for amlodipine and valsartan users, respectively. Fewer cardiovascular events were reported in patients receiving amlodipine versus valsartan (342 vs 413 per 10,000 patients over 5 years, respectively). Amlodipine had a net gain of 58 QALYs versus valsartan per 10,000 patients over 5 years. Sensitivity analyses showed that the discount rate and cohort age had a larger effect on total cost and cost difference than on QALYs. However, amlodipine results were more favorable than valsartan irrespective of discount rate or cohort age. When administered to Taiwanese patients for hypertension control, amlodipine was associated with lower cost and more QALYs compared with valsartan due to a lower risk of stroke and MI events.