Manualised package intervention to achieve treatment adherence in people with tuberculosis: the IMPACT pilot cluster-RCT.

Abstract

Background and objectives: Tuberculosis remains a United Kingdom health concern. It occurs predominantly in people who have lived in tuberculosis endemic countries or have links there. Adherence to anti-tuberculosis treatment can be challenging, especially for people who experience severe side effects or social marginalisation. Poor adherence can lead to treatment failure. Current adherence support interventions make little difference to outcome. We identified the need for a 'manualised' approach to (1) improve case-managers' ability to detect people likely to non-adhere and (2) guide targeted adherence support. Objective(s): 1. Synthesise knowledge on drivers and interventions to support anti-tuberculosis treatment adherence 2. Apply the Perceptions and Practicalities framework to understand poor adherence 3. Develop a manualised intervention to identify adherence-related risks, modifiable barriers and support mechanisms 4. Pilot the intervention and assess feasibility of data collection 5. Evaluate implementation through fidelity and reach, and assess impact on adherence 6. Assess intervention delivery costs to guide a full trial plus economic evaluation Methods: The study ran April 2018-September 2022. Formative work included scoping reviews of adherence literature; National Health Service patients, caregivers, and health worker interviews; and clinic observations. A multidisciplinary group, including people with lived experience of tuberculosis, healthcare professionals, and researchers, coproduced the intervention package. We performed a (1:a...1) pilot cluster-randomised trial (Na...=a...79 participants evaluated), randomising four London tuberculosis clinics, in preparation for a definitive cluster-randomised trial. Participants in control clinics received standard care. The primary outcome was adherence, doses taken of a possible 168 measured using evriMED boxes and other sources. We recorded treatment outcomes and changes in participants' needs, health-related beliefs and perceptions, costs, and health status. We conducted a mixed-methods process evaluation, using questionnaires, interviews, case-report forms, checklists and clinic observations. At intervention sites, additional resources were: Electronic tuberculosis needs assessment completed at all visits. Two animated videos to increase motivation and ability to take treatment. Interactive treatment guide designed around the Perceptions and Practicalities framework. Detailed manual for case managers. Result(s): We developed a tuberculosis needs assessment for tuberculosis services. This appeared better than standard care at identifying people requiring adherence support [e.g. at baseline 21/36 (58.3%) intervention vs. 4/43 (9.3%) control] and social support (over 24 weeks, on 29 vs. 6 occasions respectively). Cumulative dose-taking was high across the study population at 24 weeks [84% (95% confidence interval 78-91%) overall; 81% (68-93%) intervention; 88% (67-100%) control]. Dose-taking patterns were similar between arms. The videos and booklet produced short-term improvements in beliefs, necessity, concerns and practical barriers. Collecting health economic data using self-completed questionnaires was feasible; retrieving data from records more challenging. The intervention was acceptable to patients and staff though took longer than control to perform. Limitation(s): Study sample contained few people more likely to non-adhere. Assessments may have altered intervention's effects. Use of medication monitor in both arms may have affected results. Copyright © 2026 Lipman et al.