Table 1 Assumptions on engagement and their impact on the development of the initial framework

Engagement with initiation and maintenance of treatment are conceptually different behaviours [41]. We focused on maintenance of engagement with treatment (those already initiated on ART at any point)

Diagnosis and initiation of ART were not considered in this framework, and rather seen as a separate set of behaviours

Re-engagement was considered as part of the dynamic cycle of engagement with treatment once antiretrovirals have been initiated

We focused on adult engagement as adults make up the majority of people living with HIV globally [43]

Dimensions particular to engagement in childhood, such as caregiver relationships, were not explored

We focused on the individual’s contribution to engagement as measured from a health service-delivery perspective

Only dimensions that reflected a person’s engagement behaviour that could be observed by the health system were included

The health system’s position in the concept of ‘patient engagement with HIV care’ was not included, and engagement that could not be observed by the health system’s monitoring and evaluation machinery was also not included

The patient voice is not incorporated into this framework

Engagement was considered as a set of observable and measurable behaviours, distinct from individual, contextual and health system factors and the success or failure of treatment

Engagement behaviour was placed between the influential factors and the outcome of treatment success, as a separate concept

Engagement was considered with HIV care overall, and not just with healthcare services

Engagement behaviour was divided into ‘engagement with services’ and ‘engagement with treatment’ as separate components, with ‘engagement with treatment’ often taking place outside facility interactions

The working definition of engagement included retention, adherence and an ‘other’ component. The ‘other’ dimension was initially over-inclusively defined, encompassing participation and self-management

The ‘other’ dimension was subsequently refined through the stakeholder engagement and scoping study processes to a dimension labelled ‘active self-management’