From HIV infection to therapeutic response: a population-based longitudinal HIV cascade-of-care study in KwaZulu-Natal, South Africa

Abstract

Summary Background Standard approaches to estimation of losses in the HIV cascade of care are typically cross-sectional and do not include the population stages before linkage to clinical care. We used indiviual-level longitudinal cascade data, transition by transition, including population stages, both to identify the health-system losses in the cascade and to show the differences in inference between standard methods and the longitudinal approach. Methods We used non-parametric survival analysis to estimate a longitudinal HIV care cascade for a large population of people with HIV residing in rural KwaZulu-Natal, South Africa. We linked data from a longitudinal population health surveillance (which is maintained by the Africa Health Research Institute) with patient records from the local public-sector HIV treatment programme (contained in an electronic clinical HIV treatment and care database, ARTemis). We followed up all people who had been newly detected as having HIV between Jan 1, 2006, and Dec 31, 2011, across six cascade stages: three population stages (first positive HIV test, HIV status knowledge, and linkage to care) and three clinical stages (eligibility for antiretroviral therapy [ART], initiation of ART, and therapeutic response). We compared our estimates to cross-sectional cascades in the same population. We estimated the cumulative incidence of reaching a particular cascade stage at a specific time with Kaplan-Meier survival analysis. Findings Our population consisted of 5205 individuals with HIV who were followed up for 24 031 person-years. We recorded 598 deaths. 4539 individuals gained knowledge of their positive HIV status, 2818 were linked to care, 2151 became eligible for ART, 1839 began ART, and 1456 had successful responses to therapy. We used Kaplan-Meier survival analysis to adjust for censorship due to the end of data collection, and found that 8 years after testing positive in the population health surveillance, 16% had died. Among living patients, 82% knew their HIV status, 45% were linked to care, 39% were eligible for ART, 35% initiated ART, and 33% had reached therapeutic response. Median times to transition for these cascade stages were 52 months, 52 months, 20 months, 3 months, and 9 months, respectively. Compared with the population stages in the cascade, the transitions across the clinical stages were fast. Over calendar time, rates of linkage to care have decreased and patients presenting for the first time for care were, on average, healthier. Interpretation HIV programmes should focus on linkage to care as the most important bottleneck in the cascade. Cascade estimation should be longitudinal rather than cross-sectional and start with the population stages preceding clinical care. Funding Wellcome Trust, PEPFAR.

Improvements in the South African HIV care cascade: findings on 90‐90‐90 targets from successive population‐representative surveys in North West Province

“…Other discrepancies and the wide range of estimates of the first 90 might be due to large regional differences in testing uptake; although national and regional data in this case are similar. Nonetheless, our findings contribute to growing evidence that diagnosis remains a major barrier to achieving 90-90-90 [32] and to the increasing consensus that given the large disparity in knowledge of status among men, who test less frequently and who have poorer HIV outcomes over the lifecourse as compared to women [33]; new programming must creatively target men [9,34,35]. Our findings regarding the second 90 target, "on ART, " that 88.6% of men and 92.4% of women with known status are on treatment, are higher than similar surveys [27,28] and national estimates [5].…”

‘I told her this is your life’: relationship dynamics, partner support and adherence to antiretroviral therapy among South African couples

“…A recent longitudinal study found that only 45% of HIV-positive individuals are linked into care (Haber et al 2017), and our study recruited those who made this critical link, in which positive relationship dynamics may have played a role. In addition, because we did not recruit participants based on couple HIV status, our sample consisted primarily of seroconcordant HIV-positive couples who were more likely to self-select to enrol in the study (e.g., couples who are discordant may be more likely to be broken up or less stable).…”

A longitudinal, HIV care continuum

“…Haber et al used a similar approach, summarizing the distribution of the population 2 years after enrollment [29]. A strength McNairy's and our approach is that both consider outcomes of patients who do not initiate ART.…”