Economic evaluation of the use of irbesartan and amlodipine in the treatment of diabetic nephropathy in patients with hypertension in Canada

BACKGROUND:Irbesartan has been shown to reduce the doubling of serum creatinine (a strong predictor of progression to end-stage renal disease), the onset of end-stage renal disease and all-cause mortality in patients with type 2 diabetes when compared with standard care and amlodipine. OBJECTIVE: The present study assessed the cost effectiveness of irbesartan, an angiotensin II receptor antagonist, and amlodipine, a calcium channel blocker, in the treatment of Canadian patients with diabetic nephropathy and hypertension. METHODS: The analysis was conducted based on a Markov model using Monte Carlo simulation analysis to estimate the expected values for outcomes of interest. Transition probabilities were obtained from a comparative trial of amlodipine, irbesartan and standard care (antihypertensive treatment excluding other angiotensin II receptor antagonists or calcium channel blockers) in patients with overt diabetic nephropathy and hypertension. Canadian costs for the health states studied were obtained from published data. RESULTS: Based on the results of the Monte Carlo simulation, irbesartan was dominant over standard care and amlodipine because it both reduces costs and leads to greater life expectancy. The incremental cost-effectiveness ratio for amlodipine in comparison with standard care was $102,000. Estimates of net benefit were correlated with transition probabilities relating to progression from the initial health state. The results were insensitive to univariate sensitivity analysis. CONCLUSIONS: Irbesartan use would lead to a reduction in medical costs and an increase in life expectancy when compared with amlodipine or standard care.