Strong assumptions are required to generate a QALY value

Papers p 1165

Sildenafil is a true breakthrough drug in the sense that it provides a potential treatment for a condition for which there was no existing acceptable alternative. This complicates any attempt to describe the cost effectiveness of sildenafil in erectile dysfunction, such as that by Stolk et al in this week's BMJ (p 1165).1 They compare sildenafil with papaverine-phentolamine injections, which they argue are rationed on “medical grounds” and will not achieve the population benefits that might be achieved by sildenafil. More controversially, they argue that “the incremental cost-effectiveness of sildenafil lies at the favourable end of the scale when compared with interventions in health care for other diseases.”

The comparator therapy Stolk et al refer to, papaverine-phentolamine injections, seems not to have been rigorously evaluated and is not widely used. They used a cost utility approach in which a representative sample of the general population were asked to value the effects of treatment (for a condition that they did not have) to generate a cost per quality adjusted life year (QALY). Why might we question the validity of these findings?

Generating values for …