Cost utility analysis of sildenafil compared with papaverine-phentolamine injections.

Objective: To compare the cost effectiveness of sildenafil and papaverine-phentolamine injections for treating erectile dysfunction.
Design: Cost utility analysis comparing treatment with sildenafil (allowing a switch to injection therapy) and treatment with papaverine-phentolamine (no switch allowed). Costs and effects were estimated from the societal perspective. Using time trade-off, a sample of the general public (n=169) valued health states relating to erectile dysfunction. These values were used to estimated health related quality of life by converting the clinical outcomes of a trial into quality adjusted life years (QALYs).
Participants: 169 residents of Rotterdam.
Main Outcome Measures: Cost per quality adjusted life year.
Results: Participants thought that erectile dysfunction limits quality of life considerably: the mean utility gain attributable to sildenafil is 0.11. Overall, treatment with sildenafil gained more QALYs, but the total costs were higher. The incremental cost effectiveness ratio for the introduction of sildenafil was pound sterling 3639 in the first year and fell in following years. Doubling the frequency of use of sildenafil almost doubled the cost per additional QALY.
Conclusions: Treatment with sildenafil is cost effective. When considering funding sildenafil, healthcare systems should take into account that the frequency of use affects cost effectiveness.