Incidence rate estimation, periodic testing and the limitations of the mid-point imputation approach

Vandormael, Alain; Dobra, Adrian; Bärnighausen, Till; Oliveira, Túlio de; Tanser, Frank

doi:10.1093/ije/dyx134

Cited by 61 publications

(80 citation statements)

References 59 publications

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“…The findings were robust to different model specifications, different age-eligibility criteria, differing methods of constructing "communities," and the inclusion of differing control variables (including being robust to changes in sexual behaviour, for example). Further, methods to impute the date of HIV seroconversion were systematically investigated and the results were found to be robust to participant selfselection associated with missed test dates and drop-out [54,55]. It is thus unlikely that any collection of systematic biases could consistently and simultaneously explain the findings across the different studies conducted within households, couples, communities, population sub-groups, genders, and using differing outcome metrics (and in one case, the outcome of a different disease-i.e., newly diagnosed TB infection).…”

Section: Studymentioning

confidence: 99%

Opportunities and Challenges in HIV Treatment as Prevention Research: Results from the ANRS 12249 Cluster-Randomized Trial and Associated Population Cohort

et al. 2020

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Purpose of Review The ANRS 12249 treatment as prevention (TasP) trial investigated the impact of a universal test and treat (UTT) approach on reducing HIV incidence in one of the regions of the world most severely affected by the HIV epidemic-KwaZulu-Natal, South Africa. We summarize key findings from this trial as well as recent findings from controlled studies conducted in the linked population cohort quantifying the long-term effects of expanding ART on directly measured HIV incidence (2004-2017). Recent Findings The ANRS TasP trial did not-and could not-demonstrate a reduction in HIV incidence, because the offer of UTT in the intervention communities did not increase ART coverage and population viral suppression compared to the standard of care in the control communities. Ten controlled studies from the linked population cohort-including several quasiexperimental study designs-exploit heterogeneity in ART exposure to show a consistent and substantial impact of expanding provision of ART and population viral suppression on reduction in HIV incidence at the couple, household, community, and population levels. Summary In this setting, all of the evidence from large, population-based studies (inclusive of the ANRS TasP trial) is remarkably coherent and consistent-i.e., higher ART coverage and population viral suppression were repeatedly associated with clear, measurable decreases in HIV incidence. Thus, the expanded provision of ART has plausibly contributed in a major way toward the dramatic 43% decline in population-level HIV incidence in this typical rural African population. The outcome of the ANRS TasP trial constitutes a powerful null finding with important insights for overcoming implementation challenges in the population delivery of ART. This finding does not imply lack of ART effectiveness in blocking onward transmission of HIV nor its inability to reduce HIV incidence. Rather, it demonstrates that large increases in ART coverage over current levels will require health systems innovations to attract people living with HIV in early stages of the disease to participate in HIV treatment. Such innovations and new approaches are required for the true potential of UTT to be realized.

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Section: Studymentioning

confidence: 99%

Opportunities and Challenges in HIV Treatment as Prevention Research: Results from the ANRS 12249 Cluster-Randomized Trial and Associated Population Cohort

et al. 2020

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“…Partner's HIV status was considered as unknown if the partner's HIV test result was unavailable or unknown at the time of the partnership formation. We performed a sensitivity analysis where we imputed a random date of seroconversion from a uniform distribution bounded by the latest‐negative and earliest‐positive test dates (Table and Figure ).…”

Section: Methodsmentioning

confidence: 99%

HIV seroconcordance among heterosexual couples in rural KwaZulu‐Natal, South Africa: a population‐based analysis

et al. 2020

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Introduction High levels of HIV seroconcordance at the population level reduce the potential for effective HIV transmission. However, the level of HIV seroconcordance is largely unknown among heterosexual couples in sub‐Saharan Africa. We aimed to quantify the population level HIV seroconcordance in stable heterosexual couples in rural South Africa. Methods We followed adults (≥15 years old) using a population‐based, longitudinal and open surveillance system in KwaZulu‐Natal, South Africa, from 2003 to 2016. Sexual partnerships and HIV status were confirmed via household surveys and annual HIV surveillance. We calculated the proportions of HIV seroconcordance and serodiscordance in stable sexual partnerships and compared them to the expected proportions under the assumption of random mixing using individual‐based microsimulation models. Among unpartnered individuals, we estimated the incidence rates and hazard of sexual partnership formation with HIV‐positive or HIV‐negative partners by participants' own time‐varying HIV status. Competing risks survival regressions were fitted adjusting for sociodemographic and clinical factors. We also calculated Newman's assortativity coefficients. Results A total of 18,341 HIV‐negative and 11,361 HIV‐positive individuals contributed 154,469 person‐years (PY) of follow‐up. Overall, 28% of the participants were in stable sexual partnerships. Of the 677 newly formed stable sexual partnerships, 7.7% (95% CI: 5.8 to 10.0) were HIV‐positive seroconcordant (i.e. both individuals in the partnership were HIV‐positive), which was three times higher than the expected proportion (2.3%) in microsimulation models based on random mixing. The incidence rates of sexual partnership formation were 0.54/1000PY with HIV‐positive, 1.12/1000PY with HIV‐negative and 2.65/1000PY with unknown serostatus partners. HIV‐positive individuals had 2.39 (95% CI: 1.43 to 3.99) times higher hazard of forming a sexual partnership with an HIV‐positive partner than did HIV‐negative individuals after adjusting for age, opposite‐sex HIV prevalence (by 5‐years age groups), HIV prevalence in the surrounding community, ART coverage and other sociodemographic factors. Similarly, forming a sexual partnership with an HIV‐negative partner was 1.47 (95% CI: 1.01 to 2.14) times higher in HIV‐negative individuals in the adjusted model. Newman's coefficient also showed that assortativity by participant and partner HIV status was moderate (r = 0.35). Conclusions A high degree of population level HIV seroconcordance (both positive and negative) was observed at the time of forming new sexual partnerships. Understanding factors driving these patterns may help the development of strategies to bring the HIV epidemic under control.

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“…However, we assigned the timing of seroconversion as a random date rather than the commonly used midpoint to reduce on the potential for overestimation of HIV risk during episodes with MSVs. 25,26 Also, the number of events per predictor variable (EPV) in the multivariable model was relatively low (8.5) compared with the recommended minimum EPV of 10. 50 Although this low EPV can affect model-based inferences, the strong evidence for the association between MSV and HIV incidence in both the simple and multivariable models suggests that our conclusions could be valid.…”

Section: Biomedical Factorsmentioning

confidence: 97%

“…Furthermore, instead of assigning the date of seroconversion as midpoint between the last-negative and firstpositive test dates, we assigned a random date in this interval, thereby reducing on the artifactual clustering of seroconversion times in the middle of observation periods with missed scheduled testing. 25,26 Therefore, the aim of this study was to examine the association between the number of missed study visits (MSVs) within episodes of 2 consecutively attended visits and subsequent HIV risk in a predominantly FSW cohort attending a dedicated clinic in Kampala, Uganda.…”

Section: Introductionmentioning

confidence: 99%

Missed Study Visits and Subsequent HIV Incidence Among Women in a Predominantly Sex Worker Cohort Attending a Dedicated Clinic Service in Kampala, Uganda

Kasamba

Nash

Shahmanesh

et al. 2019

JAIDS Journal of Acquired Immune Deficiency Syndromes

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Background: There is limited evidence on the relationship between sustained exposure of female sex workers (FSWs) to targeted HIV programmes and HIV incidence. We investigate the relationship between the number of missed study visits (MSVs) within each episode of 2 consecutively attended visits (MSVs) and subsequent HIV risk in a predominantly FSW cohort. Methods: Women at high risk of HIV are invited to attend an ongoing dedicated clinic offering a combination HIV prevention intervention in Kampala, Uganda. Study visits are scheduled once every 3 months. The analysis included HIV-seronegative women with $1 follow-up visit from enrollment (between April 2008 and May 2017) to August 2017. Cox regression models were fitted adjusted for characteristics on sociodemographic, reproductive, behavioral, and sexually transmitted infections (through clinical examination and serological testing for syphilis).

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Incidence rate estimation, periodic testing and the limitations of the mid-point imputation approach

Cited by 61 publications

References 59 publications

Opportunities and Challenges in HIV Treatment as Prevention Research: Results from the ANRS 12249 Cluster-Randomized Trial and Associated Population Cohort

Opportunities and Challenges in HIV Treatment as Prevention Research: Results from the ANRS 12249 Cluster-Randomized Trial and Associated Population Cohort

HIV seroconcordance among heterosexual couples in rural KwaZulu‐Natal, South Africa: a population‐based analysis

Missed Study Visits and Subsequent HIV Incidence Among Women in a Predominantly Sex Worker Cohort Attending a Dedicated Clinic Service in Kampala, Uganda

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