PURPOSE: Cost-effectiveness modelling of diagnostic and screening strategies enables the comparison of multiple test- and treat strategies well beyond the number of comparators in a clinical study.

The flipside is that often hundreds, thousands, or a googolplex of strategies can be formulated. Comparing them all may be infeasible, inefficient, and the results difficult to interpret and communicate.

As cost-effectiveness modelling is increasingly used to evaluate diagnostic/screening tests, inform guidelines and national policy, addressing this challenge is essential.

We will present approaches to the cost-effectiveness analysis of many diagnostic strategies and discuss with the audience how best to handle their complexity.

DESCRIPTION: Martin Henriksson will introduce the challenges and policy implications, followed by case studies providing food for thought:

• Cascade screening for familial hypercholesterolemia, where strategies were selected according to their probability of being cost-effective (Rita Faria).
• From two billion to seven strategies in screening for atrial fibrillation, modelling outcomes for all potential strategies, systematically narrowing down to a few potentially cost-effective ones (Mattias Aronsson).
• Metamodeling using an existing simulation model, to exhaustively evaluate all potential screening strategies for colorectal cancer (Erik Koffijberg).

We will discuss:

• How to present the results of 100s of strategies?
• Can we determine beforehand or during evaluation which (further) strategies might be interesting to evaluate (and ignore the rest)?
• How can metamodeling support evaluation of many strategies?

We will demonstrate the challenges in selecting and comparing multiple testing strategies with live polls (e.g. guessing the number candidate strategies for evaluation, the strategies which are unlikely to be cost-effective); and encourage the audience to take part in the discussion by asking for their views and questions throughout.

This interactive workshop will be relevant for analysts performing and decision makers considering cost-effectiveness analyses of diagnostics, as well as anyone interested in cost-effectiveness modelling of many complex pathways.