Use of antiretroviral therapy in households and risk of HIV acquisition in rural KwaZulu-Natal, South Africa, 2004–12: a prospective cohort study

Vandormael, Alain; Newell, Marie‐Louise; Bärnighausen, Till; Tanser, Frank

doi:10.1016/s2214-109x(14)70018-x

Cited by 50 publications

(67 citation statements)

References 27 publications

(43 reference statements)

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“…This community is characterized by frequent migration (38% of men and 32% of women were nonresident in 2008) [31], low marital rates (only 23% of men and 31% of women have ever been married) [32], late marriage especially for men, polygamous marriages (about 14% of all marriages for men and 12% of all marriages for women) [32] and multiple sexual partnerships, as well as by poor knowledge and disclosure of HIV status [33]. …”

Section: Methodsmentioning

confidence: 99%

Space-time migration patterns and risk of HIV acquisition in rural South Africa

Dobra

Bärnighausen

Vandormael

et al. 2017

Aids

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Objective:To quantify the space-time dimensions of human mobility in relationship to the risk of HIV acquisition.Methods:We used data from the population cohort located in a high HIV prevalence, rural population in KwaZulu-Natal, South Africa (2000–2014). We geolocated 8006 migration events (representing 1 028 782 km traveled) for 17 743 individuals (≥15 years of age) who were HIV negative at baseline and followed up these individuals for HIV acquisition (70 395 person-years). Based on the complete geolocated residential history of every individual in this cohort, we constructed two detailed time-varying migration indices. We then used interval-censored Cox proportional hazards models to quantify the relationship between the migration indices and the risk of HIV acquisition.Results:In total, 17.4% of participants migrated at least once outside the rural study community during the period of observation (median migration distance = 107.1 km, interquartile range 18.9–387.5). The two migration indices were highly predictive of hazard of HIV acquisition (P < 0.01) in both men and women. Holding other factors equal, the risk of acquiring HIV infection increased by 50% for migration distances of 40 km (men) and 109 km (women). HIV acquisition risk also increased by 50% when participants spent 44% (men) and 90% (women) of their respective time outside the rural study community.Conclusion:This in-depth analysis of a population cohort in a rural sub-Saharan African population has revealed a clear nonlinear relationship between distance migrated and HIV acquisition. Our findings show that even relatively short-distance migration events confer substantial additional risk of acquisition.

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Section: Methodsmentioning

confidence: 99%

Space-time migration patterns and risk of HIV acquisition in rural South Africa

Dobra

Bärnighausen

Vandormael

et al. 2017

Aids

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“…For simplicity, we do not simulate this phased approach and instead assume concurrent enrollment and follow-up. 12 ) Per trial protocol, we simulated 2 treatment strategies: (1) delayed ART initiation (control, at CD4 <350/µL) and (2) immediate ART initiation (intervention, at HIV diagnosis). Under both strategies, simulated individuals were offered home-based HIV screening at 6-month intervals.…”

Section: Analytic Overviewmentioning

confidence: 99%

“…Controlling for behavioral, demographic, economic, and environmental risk factors, individual HIV acquisition risk declined signifi cantly with increasing ART coverage both in the surrounding community 11 and among household members of the opposite sex. 12 To quantify the preventive benefi ts of expanded ART access more conclusively and to assess the feasibility of intensive treatment expansion programs, several trials of treatment-as-prevention are ongoing [13][14][15] or planned. 16,17 In general, these trials aim to randomize geographic clusters of a population to initiate ART based on national guidelines (control, typically CD4 <350/µL vs immediately upon diagnosis [intervention]); most also incorporate frequent routine HIV screening into the intervention.…”

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confidence: 99%

The Impact of the 2013 WHO Antiretroviral Therapy Guidelines on the Feasibility of HIV Population Prevention Trials

2014

HIV Clinical Trials

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Background: Several cluster-randomized HIV prevention trials aim to demonstrate the population-level preventive impact of antiretroviral therapy (ART). 2013 World Health Organization (WHO) guidelines raising the ART initiation threshold to CD4 <500/µL could attenuate these trials' effect size by increasing ART usage in control clusters. Methods: We used a computational model to simulate strategies from a hypothetical cluster-randomized HIV prevention trial. The primary model outcome was the relative reduction in 24-month HIV incidence between control (ART offered with CD4 below threshold) and intervention (ART offered to all) strategies. We assessed this incidence reduction using the revised (CD4 <500/µL) and prior (CD4 <350/µL) control ART initiation thresholds. Additionally, we evaluated changes to trial characteristics that could bolster the incidence reduction. Results: With a control ART initiation threshold of CD4 <350/µL, 24-month HIV incidence under control and intervention strategies was 2.46/100 person-years (PY) and 1.96/100 PY, a 21% reduction. Raising the threshold to CD4 <500/µL decreased the incidence reduction by more than one-third, to 12%. Using this higher threshold, moving to a 36-month horizon (vs 24-month), yearly control-strategy HIV screening (vs biannual), and intervention-strategy screening every 2 months (vs biannual), resulted in a 31% incidence reduction that was similar to effect size projections for ongoing trials. Alternate assumptions regarding cross-cluster contamination had the greatest infl uence on the incidence reduction. Conclusions: Implementing the 2013 WHO HIV treatment threshold could substantially diminish the incidence reduction in HIV population prevention trials. Alternative HIV testing frequencies and trial horizons can bolster this incidence reduction, but they could be logistically and ethically challenging. The feasibility of HIV population prevention trials should be reassessed as the implementation of treatment guidelines evolves.

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Section: Introductionmentioning

confidence: 99%

“…For simplicity, we do not simulate this phased approach, and instead assume concurrent enrollment and follow-up. 12 …”

mentioning

confidence: 99%

The Impact of the 2013 WHO Antiretroviral Therapy Guidelines on the Feasibility of HIV Population Prevention Trials

Ross

Tanser

Pei

et al. 2014

HIV Clinical Trials

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Introduction Several cluster-randomized HIV prevention trials aim to demonstrate the population-level preventive impact of antiretroviral therapy (ART). 2013 World Health Organization guidelines raising the ART initiation threshold to CD4<500/µL could attenuate these trials’ effect size by increasing ART usage in control clusters. Methods We used a computational model to simulate strategies from a hypothetical cluster-randomized HIV prevention trial. The primary model outcome was the relative reduction in 24-month HIV incidence between control (ART offered with CD4 below threshold) and intervention (ART offered to all) strategies. We assessed this incidence reduction using the revised (CD4<500/µL) and prior (CD4<350/µL) control ART initiation thresholds. Additionally, we evaluated changes to trial characteristics that could bolster the incidence reduction. Results With a control ART initiation threshold of CD4<350/µL, 24-month HIV incidence under control and intervention strategies was 2.46/100PY and 1.96/100PY, a 21% reduction. Raising the threshold to CD4<500/µL decreased the incidence reduction by more than one-third, to 12%. Using this higher threshold, moving to a 36-month horizon (vs. 24-month), yearly control-strategy HIV screening (vs. biannual), and 2-monthly intervention-strategy screening (vs. biannual), resulted in a 31% incidence reduction, similar to effect size projections for ongoing trials. Alternate assumptions regarding cross-cluster contamination had the greatest influence on the incidence reduction. Conclusions Implementing the 2013 WHO HIV treatment threshold could substantially diminish the incidence reduction in HIV population prevention trials. Alternative HIV testing frequencies and trial horizons can bolster this incidence reduction, but could be logistically and ethically challenging. The feasibility of HIV population prevention trials should be reassessed as implementation of treatment guidelines evolves.

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Use of antiretroviral therapy in households and risk of HIV acquisition in rural KwaZulu-Natal, South Africa, 2004–12: a prospective cohort study

Cited by 50 publications

References 27 publications

Space-time migration patterns and risk of HIV acquisition in rural South Africa

Space-time migration patterns and risk of HIV acquisition in rural South Africa

The Impact of the 2013 WHO Antiretroviral Therapy Guidelines on the Feasibility of HIV Population Prevention Trials

The Impact of the 2013 WHO Antiretroviral Therapy Guidelines on the Feasibility of HIV Population Prevention Trials

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