Browsing by Author "Zaba, Basia"

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    Age-Specific Mortality Patterns in HIV-Infected Individuals: A Comparative Analysis of African Community Study Data
    (Aids, 2007) Zaba, Basia; Marston, Milly; Crampin, Amelia C.; Isingo, Raphael; Biraro, Sam; Ba¨rnighausen, Till; Lopman, Ben; Lutalo, Tom; Glynn, Judith R.; Todd, Jim
    Describe age-specific mortality patterns of HIV-infected adults in African communities before introduction of HAART.Mortality data (deaths and person-years observed) for HIV-positive subjects aged 15–65 from six African community studies in five different countries were pooled, combining information from 1793 seroconverters and 8534 HIV positive when first tested. Age-specific mortality hazards were modelled using parametric regression based on the Weibull distribution, to investigate effects of sex, and site-specific measures of mean age at incidence, crude mortality rate of uninfected, and measures of epidemic maturity.The combined studies yielded a total of 31 777 person-years of observation for HIV-positive subjects, during which time 2602 deaths were recorded. Mortality rates rose almost linearly with age, from below 50/1000 at ages < 20 years, up to 150/1000 at 50 years +. There was no significant difference between men and women in level or age pattern of mortality. Weibull regression analysis suggested that intersite variation could be explained by HIV prevalence trend, and by the ratio of HIV proportional mortality to current HIV prevalence. A model representation was constructed with a common age pattern of mortality, but allowing the level to be adjusted by specifying HIV prevalence indicators.The linear age trend of mortality in HIV-infected populations was satisfactorily represented by a Weibull function providing a parametric model adaptable for representing different levels of HIV-related mortality. This model might be simpler to use in demographic projections of HIV-affected populations than models based on survival post-infection.
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    Data Resource Profile: Network for Analysing Longitudinal Population-based HIV/AIDS data on Africa (ALPHA Network)
    (International journal of epidemiology, 2016) Reniers, Georges; Lutalo, Tom; Wamukoya, Marylene; Urassa, Mark; Nakiyingi-Miiro, Jessica; Hosegood, Vicky; Wringe, Alison; Marston, Milly; Maquins, Sewe; Levira, Francis; Zaba, Basia
    The Network for Analysing Longitudinal Population-based HIV/AIDS data on Africa (ALPHA Network) was established in 2005 and aims to: (i) broaden the evidence base on HIV epidemiology for informing policy; (ii) strengthen analytical capacity for HIV research; and (iii) foster collaboration between study sites.1 All of the study sites participating in the ALPHA Network are independently managed and have their own scientific agendas and tailored research methodologies, but share a common interest in HIV epidemiology and its interactions with the socio-demographic characteristics of the populations they cover. The ALPHA Network study sites and their institutional affiliations are described in Table 1, and their geographical distribution is shown in Figure 1. Several of the ALPHA Network study sites have published site-specific profiles that contain more detail.2–10 Most of the ALPHA Network study sites are also members of the INDEPTH Network of demographic surveillance sites [http:// www.indepth-network.org/].
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    Effect of HIV infection on pregnancy-related mortality in sub-Saharan Africa: secondary analyses of pooled community based data from the network for Analysing Longitudinal Population-based HIV/AIDS data on Africa (ALPHA)
    (The Lancet, 2013) Zaba, Basia; Calvert, Clara; Marston, Milly; Isingo, Raphael; Nakiyingi-Miiro, Jessica; Lutalo, Tom; Crampin, Amelia; Robertson, Laura; Herbst, Kobus; Ronsmans, Carine
    Model-based estimates of the global proportions of maternal deaths that are in HIV-infected women range from 7% to 21%, and the eff ects of HIV on the risk of maternal death is highly uncertain. We used longitudinal data from the Analysing Longitudinal Population-based HIV/AIDS data on Africa (ALPHA) network to estimate the excess mortality associated with HIV during pregnancy and the post-partum period in sub-Saharan Africa. Methods The ALPHA network pooled data gathered between June, 1989 and April, 2012 in six community-based studies in eastern and southern Africa with HIV serological surveillance and verbal-autopsy reporting. Deaths occurring during pregnancy and up to 42 days post partum were defi ned as pregnancy related. Pregnant or postpartum person-years were calculated for HIV-infected and HIV-uninfected women, and HIV-infected to HIVuninfected mortality rate ratios and HIV-attributable rates were compared between pregnant or post-partum women and women who were not pregnant or post partum. Findings 138 074 women aged 15–49 years contributed 636 213 person-years of observation. 49 568 women had 86 963 pregnancies. 6760 of these women died, 235 of them during pregnancy or the post-partum period. Mean prevalence of HIV infection across all person-years in the pooled data was 17·2% (95% CI 17·0–17·3), but 60 of 118 (50·8%) of the women of known HIV status who died during pregnancy or post partum were HIV infected. The mortality rate ratio of HIV-infected to HIV-uninfected women was 20·5 (18·9–22·4) in women who were not pregnant or post partum and 8·2 (5·7–11·8) in pregnant or post-partum women. Excess mortality attributable to HIV was 51·8 (47·8–53·8) per 1000 person-years in women who were not pregnant or post partum and 11·8 (8·4–15·3) per 1000 person-years in pregnant or post-partum women. Interpretation HIV-infected pregnant or post-partum women had around eight times higher mortality than did their HIV-uninfected counterparts. On the basis of this estimate, we predict that roughly 24% of deaths in pregnant or post-partum women are attributable to HIV in sub-Saharan Africa, suggesting that safe motherhood programmes should pay special attention to the needs of HIV-infected pregnant or post-partum women.
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    Estimating Incidence from Prevalence in Generalised HIV Epidemics: Methods and Validation
    (PLoS medicine, 2008) Hallett, Timothy B.; Zaba, Basia; Todd, Jim; Lopman, Ben; Mwita, Wambura; Biraro, Sam; Gregson, Simon
    HIV surveillance of generalised epidemics in Africa primarily relies on prevalence at antenatal clinics, but estimates of incidence in the general population would be more useful. Repeated cross-sectional measures of HIV prevalence are now becoming available for general populations in many countries, and we aim to develop and validate methods that use these data to estimate HIV incidence.Two methods were developed that decompose observed changes in prevalence between two serosurveys into the contributions of new infections and mortality. Method 1 uses cohort mortality rates, and method 2 uses information on survival after infection. The performance of these two methods was assessed using simulated data from a mathematical model and actual data from three community-based cohort studies in Africa. Comparison with simulated data indicated that these methods can accurately estimates incidence rates and changes in incidence in a variety of epidemic conditions. Method 1 is simple to implement but relies on locally appropriate mortality data, whilst method 2 can make use of the same survival distribution in a wide range of scenarios. The estimates from both methods are within the 95% confidence intervals of almost all actual measurements of HIV incidence in adults and young people, and the patterns of incidence over age are correctly captured.It is possible to estimate incidence from cross-sectional prevalence data with sufficient accuracy to monitor the HIV epidemic. Although these methods will theoretically work in any context, we have able to test them only in southern and eastern Africa, where HIV epidemics are mature and generalised. The choice of method will depend on the local availability of HIV mortality data.
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    “He was no longer listening to me”: A qualitative study in six Sub-Saharan African countries exploring next-of-kin perspectives on caring following the death of a relative from AIDS
    (AIDS Care, 2019) Ssekubugu, Robert; Renju, Jenny; Zaba, Basia; Seeley, Janet; Bukenya, Dominic; Ddaaki, William; Moshabela, Mosa; Wamoyi, Joyce; McLean, Estelle; Ondenge, Kenneth; Skovdal, Morten; Wringe, Alison
    In the era of widespread antiretroviral therapy, few studies have explored the perspectives of the relatives involved in caring for people living with HIV (PLHIV) during periods of ill-health leading up to their demise. In this analysis, we explore the process of care for PLHIV as their death approached, from their relatives’ perspective. We apply Tronto’s care ethics framework that distinguishes between care-receiving among PLHIV on the one hand, and caring about, caring for and care-giving by their relatives on the other. We draw on 44 in-depth interviews conducted with caregivers following the death of their relatives, in seven rural settings in Eastern and Southern Africa. Relatives suggested that prior to the onset of poor health, few of the deceased had disclosed their HIV status and fewer still were relying on anyone for help. This lack of disclosure meant that some caregivers spoke of enduring a long period of worry, and feelings of helplessness as they were unable to translate their concern and “caring about” into “caring for”. This transition often occurred when the deceased became in need of physical, emotional or financial care. The responsibility was often culturally prescribed, rarely questioned and usually fell to women. The move to “care-giving” was characterised by physical acts of providing care for their relative, which lasted until death. Tronto’s conceptualisation of caring relationships highlights how the burden of caring often intensifies as family members’ caring evolves from “caring about”, to “caring for”, and eventually to “giving care” to their relatives. This progression can lead to caregivers experiencing frustration, provoking tensions with their relatives and highlighting the need for interventions to support family members caring for PLHIV. Interventions should also encourage PLHIV to disclose their HIV status and seek early access to HIV care and treatment services.
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    InterVA-4 as a public health tool for measuring HIV/AIDS mortality: a validation study from five African countries
    (Global Health Action, 2013) Byass, Peter; Calvert, Clara; Nakiyingi-Miiro, Jessica; Lutalo, Tom; Michael, Denna; Crampin, Amelia; Gregson, Simon; Takaruza, Albert; Robertson, Laura; Herbst, Kobus; Todd, Jim; Zaba, Basia
    Reliable population-based data on HIV infection and AIDS mortality in sub-Saharan Africa are scanty, even though that is the region where most of the world’s AIDS deaths occur. There is therefore a great need for reliable and valid public health tools for assessing AIDS mortality. Objective: The aim of this article is to validate the InterVA-4 verbal autopsy (VA) interpretative model within African populations where HIV sero-status is recorded on a prospective basis, and examine the distribution of cause-specific mortality among HIV-positive and HIV-negative people. Design: Data from six sites of the Alpha Network, including HIV sero-status and VA interviews, were pooled. VA data according to the 2012 WHO format were extracted, and processed using the InterVA-4 model into likely causes of death. The model was blinded to the sero-status data. Cases with known pre-mortem HIV infection status were used to determine the specificity with which InterVA-4 could attribute HIV/AIDS as a cause of death. Cause-specific mortality fractions by HIV infection status were calculated, and a person-time model was built to analyse adjusted cause-specific mortality rate ratios. Results: The InterVA-4 model identified HIV/AIDS-related deaths with a specificity of 90.1% (95% CI 88.7 91.4%). Overall sensitivity could not be calculated, because HIV-positive people die from a range of causes. In a person-time model including 1,739 deaths in 1,161,688 HIV-negative person-years observed and 2,890 deaths in 75,110 HIV-positive person-years observed, the mortality ratio HIV-positive:negative was 29.0 (95% CI 27.1 31.0), after adjustment for age, sex, and study site. Cause-specific HIV-positive:negative mortality ratios for acute respiratory infections, HIV/AIDS-related deaths, meningitis, tuberculosis, and malnutrition were higher than the all-cause ratio; all causes had HIV-positive:negative mortality ratios significantly higher than unity.