Development and description of a theory-driven, evidence-based, complex intervention to improve adherence to treatment for tuberculosis in the UK: the IMPACT study

Figures & data

Figure 1. Conceptual map of formative research and intervention development.Note: HCP = healthcare provider, LMIC = low or middle-income countries, PaPA = Perceptions and Practicalities Approach, IDG = Intervention Development Group.

This figure graphically summarises the development process for the IMPACT intervention, from the formative research elements to the resulting intervention components. The top boxes summarise the pieces of formative research conducted (reviews, interventions, observations), the next row of boxes summarise key findings from each of these pieces of research, the next row of boxes describe how findings were analysed utilising the underpinning theoretical frameworks, and the final row of three boxes summarise key aspects of each main intervention component (the TNA, videos and patient booklet).

Figure 2. Logic model for the IMPACT intervention. Note: TNA = TB needs assessment. HCP = Health care professional. Dotted lines demonstrate where anticipated effects are repeated across mechanisms.

Read the detailed description of this figure

This diagram shows the logic model for the IMPACT intervention. Each main intervention component (TNA, videos and patient booklet) is listed on the left-hand side column. The intervention channel used to deliver each intervention component is then described in the next column of boxes to the right. The next column of boxes along describes the theorised mechanisms through which these components operate based on evidence and theory. The fourth column of boxes then describes each anticipated effect resulting from the mechanisms and the final column on the far right shows the primary outcome being used to measure intervention effects. Arrows are used to show the relationships between the components, channels, mechanisms, anticipated effects and outcome. Dotted lines demonstrate where anticipated effects are repeated across mechanisms. The bottom box describes how the intervention context influences the intervention content, channel, mechanisms, anticipated effects and outcome, including the influence of demographic, clinical, health-systems and psychosocial determines of non-adherence to TB treatment.

Figure 3. IMPACT intervention component delivery across patient treatment pathway.Note: TNA = TB Needs Assessment, ISQ = Information and Support Questionnaire. *Point of touch occurs outside of standard care treatment pathway. **Month 6 is treatment completion for standard treatment. If treatment continues monthly, the TNA follow-up is completed at each session.

This diagram shows how the IMPACT intervention components are delivered across the patients’ treatment pathway. The two rows of boxes show what intervention components are delivered in sessions in the initiation (Baseline to Week 6) versus continuation (Months 2+) phases of treatment. Each individual box summarises what is delivered at each treatment timepoint in relation to each intervention component.