The HIV care cascade: models, measures and moving forward

Abstract

IntroductionThis article seeks to identify where delays occur along the adult HIV care cascade (“the cascade”), to improve understanding of what constitutes “delay” at each stage of the cascade and how this can be measured across a range of settings and to inform service delivery efforts. Current metrics are reviewed, measures informed by global guidelines are suggested and areas for further clarification are underscored.DiscussionQuestions remain on how best to evaluate late entry into each stage of the cascade. The delayed uptake of HIV testing may be more consistently measured once rapid CD4 testing is administered at the time of HIV testing. For late enrolment, preliminary research has begun to determine how different time intervals for linking to HIV care affect individual health. Regarding treatment, since 2013, the World Health Organization (WHO) and UNAIDS recommend treatment initiation when CD4 <500 cells/mm3; these guidelines provide a useful albeit evolving threshold to define late treatment initiation. Finally, WHO guidelines for high-, low- and middle-income countries also could be used to standardize measures for achieving viral suppression.ConclusionsThere is no “one size fits all” model as the provision of services may differ based on a range of factors. Nonetheless, measures informed by global guidelines are needed to more consistently evaluate the scope of and factors associated with delays to each stage of the cascade. Doing so will help identify how practitioners can best deliver services and facilitate access to and continued engagement in care.

Constructing the cascade of HIV care

“…Given the same cascade breadth, a cascade is 'deeper' if it contains data on more stages than another 'shallower' cascade. [28]. In the absence of a clear set of guidelines, analysts must make substantive decisions on how to address issues such as cycling in and out of care in their choice of staging depth.…”

The biopolitics of engagement and the HIV cascade of care: a synthesis of the literature on patient citizenship and antiretroviral therapy

“…The cascade creates a framework for generating step-wise estimates of intervention access, coverage, adherence, retention, and outcome at national and regional level (Kozak, Zinski, Leeper, Willig and Mugavero, 2013;MacCarthy et al, 2015). Such a framework provides an overview of key indicators (diagnosed and undiagnosed infections; numbers on or off treatment) and their public health implications, and offers a surveillance grid for monitoring patient dis/engagement through the pathways of care.…”

The social life of HIV care: On the making of ‘care beyond the virus’

“…With our primary interest being access to ART, a key threshold in the cascade of HIV care (Mugavero et al 2013;MacCarthy et al 2015), we treat HIV care engagements as effects of their practices of implementation. Rather than assuming a single, prior and stable knowledge of HIV care, we assume care objects and effects to be emergent, contingent and multiple expressions of material practices (Latimer 2018;Buse et al 2018).…”

“…The cascade of care is a clinically informed surveillance framework for generating stepwise epidemiological estimates regarding the process of engaging people into HIV care, including measures of intervention access, adherence and outcome (Mugavero et al 2013;MacCarthy et al 2015;UNAIDS 2014). It promotes key metrics in relation to the numbers or proportions of people diagnosed and undiagnosed, as well as in and out of treatment, and their public health implications.…”