Real-world impact of disease on functioning and activity: what is missed when using general instruments to estimate quality-adjusted life years.

Differences in rankings of disease severity by metric indicate that the results of cost-utility analyses might be biased against treatments for certain diseases. As patient preferences for clinical outcomes vary, the full burden of disease should be considered in evaluations. Restricting access to treatments based on an incomplete estimate of burden could lead to misallocation of resources and a withholding of therapies that patients find valuable.