The HIV care cascade in sub‐Saharan Africa: systematic review of published criteria and definitions

Abstract

Introduction:The HIV care cascade examines the attrition of people living with HIV from diagnosis to the use of antiretroviral therapy (ART) and suppression of viral replication. We reviewed the literature from sub-Saharan Africa to assess the definitions used for the different steps in the HIV care cascade. Methods: We searched PubMed, Embase and CINAHL for articles published from January 2004 to December 2020. Longitudinal and cross-sectional studies were included if they reported on at least one step of the UNAIDS 90-90-90 cascade or two steps of an extended 7-step cascade. A step was clearly defined if authors reported definitions for numerator and denominator, including the description of the eligible population and methods of assessment or measurement. The review protocol has been published and registered in Prospero. Results and discussion: Overall, 3364 articles were screened, and 82 studies from 19 countries met the inclusion criteria. Most studies were from Southern (38 studies, 34 from South Africa) and East Africa (29 studies). Fifty-eight studies (71.6%) were longitudinal, with a median follow-up of three years. The medium number of steps covered out of 7 steps was 3 (interquartile range [IQR] 2 to 4); the median year of publication was 2015 (IQR 2013(IQR to 2019. The number of different definitions for the numerators ranged from four definitions (for step "People living with HIV") to 21 (step "Viral suppression"). For the denominators, it ranged from three definitions ("Diagnosed and aware of HIV status") to 14 ("Viral suppression"). Only 12 studies assessed all three of the 90-90-90 steps. Most studies used longitudinal data, but denominator-denominator or denominator-numerator linkages over several steps were rare. Also, cascade data are lacking for many countries. Our review covers the academic literature but did not consider other data, such as government reports on the HIV care cascade. Also, it did not examine disengagement and reengagement in care. Conclusions: The proportions of patients retained at each step of the HIV care cascade cannot be compared between studies, countries and time periods, nor meta-analysed, due to the many different definitions used for numerators and denominators. There is a need for standardization of methods and definitions.

Cervical Cancer Screening Cascade for women living with HIV: A cohort study from Zimbabwe

“…When a fixed-denominator is used, there is internal consistency, and the continuum of care across the cascade relates to the single most important denominator, women in care [14]. In contrast, when a changing-denominator is used [1,9,13], problems with retention (retention gaps) at different stages of the cascade are highlighted [20,21]. We used guideline-indicated time-frames in these analyses (S1 Table ).…”

“…Cervical cancer incidence and mortality decrease when screening programs engage and retain women from screening to treatment to follow-up along a care continuum [9,10]. The HIV care cascade has been successfully used to scale-up of antiretroviral therapy (ART) [11][12][13][14][15]. We believe the cascade approach could be similarly used to scale-up cervical cancer screening, supporing the WHO goal to eliminate cervical cancer.…”

Implementation Science for the Prevention and Treatment of HIV among Adolescents and Young Adults in Sub-Saharan Africa: A Scoping Review

“…There appeared to be a stronger focus on HIV prevention compared to the HIV care and treatment components in the HIV prevention, care, and treatment continuum of care. In contrast, a recent all age-inclusive systematic review of the HIV care cascade in SSA found that viral suppression was the most frequently studied component, followed by diagnosis and linkage to care [61]. This systematic review also included articles from as far back as 2004 and was not limited to implementation science studies, which may, along with the all age-inclusive focus, account for the contrasting findings.…”

Future directions for HIV service delivery research: Research gaps identified through WHO guideline development

“…A recent systematic review of published criteria and definitions across the HIV care cascade in sub-Saharan Africa found that proportions of individuals retained in care at each step of the HIV care cascade cannot be compared between studies due to the highly variable definitions used for numerators and denominators; this review concluding that there is a need for standardized methods and definitions [ 29 ]. In general, the review process of reengagement also revealed an urgent need to standardize conceptualization and representation of the reengagement cascade and how to harmonize quantification of effects.…”