Severity as a Criterion for Prioritizing Diagnostic Measures.

The extent to which a condition is severe constitutes an important part of several approaches to healthcare priority setting. For example, the Netherlands, Norway, Sweden, and the UK are all countries with explicit criteria for priority setting that apply severity as one of their considerations. However, these criteria are mainly applied to treatments rather than diagnostic measures. When the criterion of severity is applied to treatments, it is often applied as follows: the more severe the condition targeted by a treatment, the higher the cost that can be accepted per health improvement. However, applying this approach to diagnostic measures gives rise to at least three challenges. First, the issue of heterogeneity, while treatments may often be indicated for a specific patient population, diagnostic measures often target larger segments of patients. Second, the issue of secondary findings, the fact that diagnostic measures may generate secondary findings. Third, the issue of (non)-treatability, the fact that there are conditions for which there are diagnostic measures but not (yet) any treatment options. The aim of this paper is to explore these challenges. This exploration involves making sense of them from a decision-making perspective which, in turn, reveals a number of characteristic features about the notion of severity.