How to assess case-finding in chronic diseases: Comparison of different indices

TL;DR

This paper evaluates various indices for assessing case-finding in chronic diseases using a new illness-death model, finding that incidence-based indices are more reliable than prevalence-based ones.

Contribution

It introduces a new illness-death model for undiagnosed and diagnosed chronic disease states and compares the effectiveness of different indices in assessing case-finding performance.

Findings

Prevalence-based indices can lead to incorrect conclusions.

Some indices are insensitive to differences in case-finding quality.

Incidence-based indices perform well and are recommended for use.

Abstract

Recently, we have proposed a new illness-death model that comprises a state of undiagnosed chronic disease preceding the diagnosed disease. Based on this model, the question arises how case-finding can be assessed in the presence of mortality from all these states. We simulate two scenarios of different performance of case-finding and apply several indices to assess case-finding in both scenarios. One of the prevalence based indices leads to wrong conclusions. Some indices are partly insensitive to distinguish the quality of case-finding. The incidence based indices perform well. If possible, incidence based indices should be preferred.