Cost-utility analysis of antihypertensive combination therapy in Japan by a Monte Carlo simulation model

The objective of the present study was to analyze the cost-effectiveness of lifetime antihypertensive therapy with angiotensin II receptor blocker (ARB) monotherapy, calcium channel blocker (CCB) monotherapy, or ARB plus CCB (ARB+CCB) combination therapy in Japan. Based on the results of large-scale clinical trials and epidemiological data, we constructed a Markov model for patients with essential hypertension. Our Markov model comprised coronary heart disease (CHD), stroke, and progression of diabetic nephropathy submodels. Based on this model, analysis of the prognosis of each patient was repeatedly conducted by Monte Carlo simulation. The three treatment strategies were compared in hypothetical 55-year-old patients with systolic blood pressure (SBP) of 160 mmHg in the absence and presence of comorbid diabetes. Olmesartan medoxomil 20 mg/d was the ARB and azelnidipine 16 mg/d the CCB in our model. On-treatment SBP was assumed to be 125, 140, and 140 mmHg in the ARB+CCB, ARB alone, and CCB alone groups, respectively. Costs and quality-adjusted life years (QALYs) were discounted by 3%/year. The ARB+CCB group was the most cost-effective both in male and female patients with or without diabetes. In conclusion, ARB plus CCB combination therapy may be a more cost-effective lifetime antihypertensive strategy than monotherapy with either agent alone.