Use of CD4 Count in Defining Late Presentation to HIV Care
Several different models have been developed to highlight stages in the continuum of HIV/AIDS care. Recently, Gardner and colleagues presented the 'spectrum of engagement in HIV care' (hereafter referred to as the 'cascade') to highlight the range of barriers to achieving optimal treatment outcomes. This model has subsequently been referenced in several high-impact peer-reviewed journals and has been highlighted for clarifying the range of services that should be considered to improve the uptake of HIV testing and subsequent linkage to care. Although this model was developed in a high-income context, the range of services highlighted is relevant in other economic settings, although the provision of these services may differ based on the existing infrastructure of the health system. This model therefore highlights important considerations with respect to individual health and how the provision of services can best improve the health outcomes of HIV-infected patients.
The cascade provides a useful framework to determine how the ELPG measure will work in practice and highlights important concerns with respect to individual health and the role of health services. The cascade highlights two types of information as being important. First, CD4 count is important because it describes the level of disease progression. This, however, is not sufficient to characterize the nature of delays in testing and treatment services more generally, because CD4 thresholds represent immune system assessments of a particular individual at one specific point in time, and do not contain information on health-seeking history or other relevant information. The second key piece of information is the time lag between each service being accessed along the cascade. The timing of events is not only important from a clinical perspective, but also critically affects the individual's knowledge about the disease, as well as the risk of transmission to their partners, especially as individuals are highly infectious in the early and late stages of disease. Therefore, the following analysis will use the cascade to consider the limitations of using the consensus definition and propose suggestions to improve its application going forward.
The Spectrum of Engagement in HIV Care
Several different models have been developed to highlight stages in the continuum of HIV/AIDS care. Recently, Gardner and colleagues presented the 'spectrum of engagement in HIV care' (hereafter referred to as the 'cascade') to highlight the range of barriers to achieving optimal treatment outcomes. This model has subsequently been referenced in several high-impact peer-reviewed journals and has been highlighted for clarifying the range of services that should be considered to improve the uptake of HIV testing and subsequent linkage to care. Although this model was developed in a high-income context, the range of services highlighted is relevant in other economic settings, although the provision of these services may differ based on the existing infrastructure of the health system. This model therefore highlights important considerations with respect to individual health and how the provision of services can best improve the health outcomes of HIV-infected patients.
The cascade provides a useful framework to determine how the ELPG measure will work in practice and highlights important concerns with respect to individual health and the role of health services. The cascade highlights two types of information as being important. First, CD4 count is important because it describes the level of disease progression. This, however, is not sufficient to characterize the nature of delays in testing and treatment services more generally, because CD4 thresholds represent immune system assessments of a particular individual at one specific point in time, and do not contain information on health-seeking history or other relevant information. The second key piece of information is the time lag between each service being accessed along the cascade. The timing of events is not only important from a clinical perspective, but also critically affects the individual's knowledge about the disease, as well as the risk of transmission to their partners, especially as individuals are highly infectious in the early and late stages of disease. Therefore, the following analysis will use the cascade to consider the limitations of using the consensus definition and propose suggestions to improve its application going forward.
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