Negotiating clinical practice guidelines: Doctors' experiences with implementing and rationing high-cost cystic fibrosis treatment.

In all societies, demand for healthcare exceeds available resources. When resources for healthcare are limited, clinicians inevitably engage in distributive decisions that affect the care of individual patients: so-called bedside rationing. Clinical practice guidelines intend to steer bedside rationing through transparent eligibility criteria. Still, the distributive challenge is exacerbated by increasingly available high-cost treatments for rare diseases, treatments entrenched in a great deal of uncertainty due to limited evidence of therapeutic effect. In this qualitative study, we investigated the real-life implementation of a clinical practice guideline for a costly cystic fibrosis treatment, elexacaftor/tezacaftor/ivacaftor (Kaftrio), reimbursed in Norway since 2022. Thereby, we provide empirical and theoretical contributions to the health economics literature on priority setting by drawing on policy enactment theory and the clinical decision-making literature. Using data from 18 in-depth interviews analysed by reflexive thematic analysis, we found that clinicians perceived Kaftrio to be exceptionally effective, making it very difficult to withdraw treatment in cases of uncertain or inadequate effect as suggested by the start-stop criteria intended to steer initiation and discontinuation of treatment. Clinicians enacted the guideline to deliver, not withhold treatment in cases of uncertain eligibility by shaping the guideline's meaning. Building on the empirical findings, we propose a model that theorises how clinicians negotiated the treatment's therapeutic effect across various axes of medical knowledge from observed to justified effects. In the era of high-cost genetic therapeutics, our study provides an important contribution to the understanding of tools and mechanisms to ensure fair and open priority setting.