Invisible in the Evidence: Representation Information Gaps in Drug-Resistant Tuberculosis Clinical Trials and the Development of a Trial Representation Equity Index

This study develops and applies the Trial Representation Equity Index (TREI), a structured framework for evaluating representation characteristics in published clinical trial evidence from a humanitarian applicability perspective. Applied to three landmark drug-resistant tuberculosis trials, TB-PRACTECAL, ZeNix, and STREAM Stage 2, the TREI assessed five domains: geographic diversity, sex representation, age representation, comorbidity inclusion, and health-system diversity. STREAM Stage 2 achieved the highest composite score (16/25; High Representation), while TB-PRACTECAL scored 14/25 and ZeNix scored 12/25 (both Moderate Representation). Across all three trials, no humanitarianly relevant population characteristic, including refugee status, displacement history, migration status, housing status, or socioeconomic indicators, was reported in any published source, constituting a systematic Representation-Information Gap. The paper introduces Humanitarian External Validity as a conceptual extension of conventional external validity, focusing on the applicability of trial evidence to populations and health-system contexts characteristic of humanitarian settings. Policy recommendations address trial reporting standards, regulatory authorities, WHO guideline development, trial sponsors, and humanitarian organisations.