Cost effectiveness of angiotensin receptor blocker monotherapy in patients with hypertension in the Netherlands: a comparative analysis using clinical trial and drug utilization data

Abstract

Background and objective: Health gains and related cost savings achieved by optimizing treatment in hypertensive patients is highly important. The aim of this study was to evaluate the costs and cost effectiveness of treatment with angiotensin II receptor antagonists (angiotensin II receptor blockers [ARBs]) in patients with essential hypertension and to compare within-trial with real-life dosing of ARBs.

Methods: Cost effectiveness was estimated based on a published clinical trial comparing the BP-lowering effects of olmesartan, losartan, valsartan, and irbesartan. BP lowering after 8 weeks of treatment was entered into the Framingham risk functions to estimate cardiovascular complications after 1 and 5 years, using an international health economics model that was adapted to the Netherlands. Dutch costs (2006 values) and complications derived from the model were discounted at 4% and 1.5%, respectively, and cost effectiveness was expressed in net costs per cardiovascular complication averted. In a drug-utilization study, pharmacy dispensing records were used to evaluate differences between within-trial and daily-practice dosing and related costs for treatment in the Netherlands.

Results: After 8 weeks, the trial-based analysis showed that treatment with olmesartan versus losartan, valsartan, and irbesartan resulted in a significantly larger decrease in BP (11.5 vs 8.2, 7.9 and 9.9 mmHg [p < 0.05], respectively) and consequently more complications averted. Cost effectiveness for olmesartan, losartan, valsartan, and irbesartan was estimated at euro39,100, euro77,100, euro70,700, and euro50,900 per cardiovascular complication averted, respectively. The incremental cost-effectiveness analysis indicated the most favorable cost-effectiveness outcome for olmesartan, with lower costs and less cardiovascular complications for olmesartan compared with the other three ARBs. The drug-utilization analysis showed that the dosing followed within clinical trials was not found in daily practice. On average, losartan, valsartan, and irbesartan were administered at doses above those used in clinical trials, whereas olmesartan was dosed lower than in clinical trials, resulting in relatively lower costs.

Conclusion: Based on the exact trial data, olmesartan was estimated to be the most favorable option of the four ARBs based on within-trial decreases in BP levels after 8 weeks and in terms of cost-effectiveness for this particular Dutch setting. However, for definite conclusions to be drawn, this hypothesis-generating study requires confirmation from further prospective studies comparing ARBs based on comparable BP control and including hard endpoints.