Changes in mortality patterns and associated socioeconomic differentials in a rural South African setting: findings from population surveillance in Agincourt, 1993-2013

A thesis submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy (by publications) 20th December 2017.Understanding a population’s mortality and disease patterns and their determinants is important for setting locally-relevant health and development priorities, identifying critical elements for strengthening of health systems, and determining the focus of health services and programmes. This thesis investigates changes in socioeconomic status (SES), cause composition of overall mortality and the socioeconomic patterning of mortality that occurred in a rural population in Agincourt, northeast South Africa over the period 1993-2013 using Health and Demographic Surveillance Systems (HDSS) data. It also assesses the feasibility of applying record linkage techniques to integrate data from HDSS and health facilities in order to enhance the utility of HDSS data for studying mortality and disease patterns and their determinants and implications in populations in resource-poor settings where vital registration systems are often weak. Results show a steady increase in the proportion of households that own assets associated with greater modern wealth and convergence towards the middle of the SES distribution over the period 2001-2013. However, improvements in SES were slower for poorer households and persistently varied by ethnicity with former Mozambican refugees being at a disadvantage. The population experienced steady and substantial increase in overall and communicable diseases related mortality from the mid-1990s to the mid-2000s, peaking around 2005-07 due to the HIV/AIDS epidemic. Overall mortality steadily declined afterwards following reduction in HIV/AIDS-related mortality due to the widespread introduction of free antiretroviral therapy (ART) available from public health facilities. By 2013, however, the cause of death distribution was yet to reach the levels it occupied in the early 1990s. Overall, the poorest individuals in the population experienced the highest mortality burden and HIV/AIDS and tuberculosis mortality persistently showed an inverse relation with SES throughout the period 2001-13. Although mortality from non-communicable diseases (NCDs) increased over time in both sexes and injuries were a prominent cause of death in males, neither of these causes of death showed consistent significant associations with household SES. A hybrid approach of deterministic followed by probabilistic record linkage, and the use of an extended set of conventional identifiers that included another household member’s first name yielded the best results for linking data from the Agincourt HDSS and health facilities with a sensitivity of 83.6% and a positive predictive value (PPV) of 95.1% for the best fully automated approach. In general, the findings highlight the need to identify the chronically poorest individuals and target them with interventions that can improve their SES and take them out of the vicious circle of poverty. The results also highlight the need for integrated health-care planning and programme delivery strategies to increase access to and uptake of HIV testing, linkage to care and ART, and prevention and treatment of NCDs especially among the poorest individuals to reduce the inequalities in cause-specific and overall mortality. The findings also contribute to the evidence base to inform further refinement and advancement of the health and epidemiological transition theory. Furthermore, the findings demonstrate the feasibility of linking HDSS data with data from health facilities which would facilitate population-based investigations on the e↵ect of socioeconomic disparities in the utilisation of healthcare services on mortality risk. Keywords Agincourt Cause of death composition Epidemiological Transition Health and Demographic Surveillance System (HDSS) Household assets HIV/AIDS Index of Inequality InterVA Mortality Non-communicable Diseases Population Surveillance Record linkage Rural Socioeconomic Status South Africa Verbal Autopsy Wealth IndexLG201

The impact of HIV/AIDS on under-five mortality in Malawi

Magister Scientiae - MScAlthough the under-five mortality rate in Malawi has been declining since 1960, it still remains one of the highest in the world. In order to appropriately target interventions to achieve substantial reductions in deaths among children under the age of five years in Malawi, there is an ongoing need for better knowledge of the proportion of cause-specific under-five mortality in the country. The aim of this study was to estimate the direct contribution of HIV/AIDS to the observed level of under-five mortality in Malawi during the period 2000 to 2004.South Afric

Pension exposure and health:Evidence from a longitudinal study in South Africa

Social protection schemes have been expanding around the world with the objective of protecting older persons during retirement. While theoretically they have been seen as tools to improve individual wellbeing, there are few studies that evaluate whether social pensions can improve health. In this study, we exploit the change in eligibility criteria for the South African Old Age grant to estimate the association between pension exposure eligibility and health of older persons. For this, we use data from the Health and Aging in Africa: A longitudinal Study of an INDEPTH Community in South Africa (HAALSI) and model pension exposure in terms of its cumulative effect. Our results show that pension exposure is associated with better health as measured by a set of health indices. Disentangling these effects, we find that pension exposure is most likely to improve health through the delayed onset of physical disabilities in the elderly population. Our study highlights the relevance of social protection schemes as a mechanism to protect older persons physical health.</p

Social patterns and differentials in the fertility transition in the context of HIV/AIDS: evidence from population surveillance, rural South Africa, 1993 - 2013.

BACKGROUND: Literature is limited on the effects of high prevalence HIV on fertility in the absence of treatment, and the effects of the introduction of sustained access to antiretroviral therapy (ART) on fertility. We summarize fertility patterns in rural northeast South Africa over 21 years during dynamic social and epidemiological change. METHODS: We use data for females aged 15-49 from the Agincourt health and socio-demographic surveillance system (1993-2013). We use discrete time event history analysis to summarize patterns in the probability of any birth. RESULTS: Overall fertility declined in 2001-2003, increased in 2004-2011, and then declined in 2012-2013. South Africans showed a similar pattern. Mozambicans showed a different pattern, with strong declines prior to 2003 before stalling during 2004-2007, and then continued fertility decline afterwards. There was an inverse gradient between fertility levels and household socioeconomic status. The gradient did not vary by time or nationality. CONCLUSIONS: The fertility transition in rural South Africa shows a pattern of decline until the height of the HIV/AIDS pandemic, with a resulting stall until further decline in the context of ART rollout. Fertility patterns are not homogenous among groups

Task shifting to improve the provision of integrated chronic care: realist evaluation of a lay health worker intervention in rural South Africa

Introduction Task shifting is a potential solution to the shortage of healthcare personnel in low/middle-income countries, but contextual factors often dilute its effectiveness. We report on a task shifting intervention using lay health workers to support clinic staff in providing chronic disease care in rural South Africa, where the HIV epidemic and an ageing population have increased demand for care. Methods We conducted a realist evaluation in a cluster randomised controlled trial. We conducted observations in clinics, focus group discussions, in-depth interviews and patient exit interviews, and wrote weekly diaries to collect data. Results All clinic managers had to cope with an increasing but variable patient load and unplanned staff shortages, insufficient space, poorly functioning equipment and erratic supply of drugs. These conditions inevitably generated tension among staff. Lay health workers relieved the staff of some of their tasks and improved care for patients, but in some cases the presence of the lay health worker generated conflict with other staff. Where managers were able to respond to the changing circumstances, and to contain tension among staff, facilities were better able to meet patient needs. This required facility managers to be flexible, consultative and willing to act on suggestions, sometimes from junior staff and patients. While all facilities experienced an erratic supply of drugs and poorly maintained equipment, facilities where there was effective management, teamwork and sufficient space had better chronic care processes and a higher proportion of patients attending on their appointed day. Conclusion Lay health workers can be valuable members of a clinic team, and an important resource for managing increasing patient demand in primary healthcare. Task shifting will only be effective if clinic managers respond to the constantly changing system and contain conflict between staff. Strengthening facility-level management and leadership skills is a priority. Trial registration number ISRCTN12128227

Clustering South African households based on their asset status using latent variable models

The Agincourt Health and Demographic Surveillance System has since 2001 conducted a biannual household asset survey in order to quantify household socio-economic status (SES) in a rural population living in northeast South Africa. The survey contains binary, ordinal and nominal items. In the absence of income or expenditure data, the SES landscape in the study population is explored and described by clustering the households into homogeneous groups based on their asset status. A model-based approach to clustering the Agincourt households, based on latent variable models, is proposed. In the case of modeling binary or ordinal items, item response theory models are employed. For nominal survey items, a factor analysis model, similar in nature to a multinomial probit model, is used. Both model types have an underlying latent variable structure - this similarity is exploited and the models are combined to produce a hybrid model capable of handling mixed data types. Further, a mixture of the hybrid models is considered to provide clustering capabilities within the context of mixed binary, ordinal and nominal response data. The proposed model is termed a mixture of factor analyzers for mixed data (MFA-MD). The MFA-MD model is applied to the survey data to cluster the Agincourt households into homogeneous groups. The model is estimated within the Bayesian paradigm, using a Markov chain Monte Carlo algorithm. Intuitive groupings result, providing insight to the different socio-economic strata within the Agincourt region.Comment: Published in at http://dx.doi.org/10.1214/14-AOAS726 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Social patterns and differentials in the fertility transition in the context of HIV/AIDS: evidence from population surveillance, rural South Africa, 1993 – 2013

BACKGROUND: Literature is limited on the effects of high prevalence HIV on fertility in the absence of treatment, and the effects of the introduction of sustained access to antiretroviral therapy (ART) on fertility. We summarize fertility patterns in rural northeast South Africa over 21 years during dynamic social and epidemiological change. METHODS: We use data for females aged 15–49 from the Agincourt health and socio-demographic surveillance system (1993–2013). We use discrete time event history analysis to summarize patterns in the probability of any birth. RESULTS: Overall fertility declined in 2001–2003, increased in 2004–2011, and then declined in 2012–2013. South Africans showed a similar pattern. Mozambicans showed a different pattern, with strong declines prior to 2003 before stalling during 2004–2007, and then continued fertility decline afterwards. There was an inverse gradient between fertility levels and household socioeconomic status. The gradient did not vary by time or nationality. CONCLUSIONS: The fertility transition in rural South Africa shows a pattern of decline until the height of the HIV/AIDS pandemic, with a resulting stall until further decline in the context of ART rollout. Fertility patterns are not homogenous among groups.Thanks are due to key funding partners of the MRC/Wits Rural Public Health and Health Transitions Research Unit who have enabled the ongoing Agincourt Health and Socio-demographic Surveillance System: the Wellcome Trust, UK (grants 058893/Z/99/A, 069683/Z/02/Z, and 085477/Z/08/Z); the Medical Research Council, University of the Witwatersrand, and Anglo-American Chairman’s Fund, South Africa; the William and Flora Hewlett Foundation (grant 2008–1840), the Andrew W. Mellon Foundation, and the National Institute on Aging (NIA) of the National Institutes of Health (NIH), USA (grants 1R24AG032112-01 and 5R24AG032112- 03)

Comparing verbal autopsy cause of death findings as determined by physician coding and probabilistic modelling: a public health analysis of 54 000 deaths in Africa and Asia.

BACKGROUND: Coverage of civil registration and vital statistics varies globally, with most deaths in Africa and Asia remaining either unregistered or registered without cause of death. One important constraint has been a lack of fit-for-purpose tools for registering deaths and assigning causes in situations where no doctor is involved. Verbal autopsy (interviewing care-givers and witnesses to deaths and interpreting their information into causes of death) is the only available solution. Automated interpretation of verbal autopsy data into cause of death information is essential for rapid, consistent and affordable processing. METHODS: Verbal autopsy archives covering 54 182 deaths from five African and Asian countries were sourced on the basis of their geographical, epidemiological and methodological diversity, with existing physician-coded causes of death attributed. These data were unified into the WHO 2012 verbal autopsy standard format, and processed using the InterVA-4 model. Cause-specific mortality fractions from InterVA-4 and physician codes were calculated for each of 60 WHO 2012 cause categories, by age group, sex and source. Results from the two approaches were assessed for concordance and ratios of fractions by cause category. As an alternative metric, the Wilcoxon matched-pairs signed ranks test with two one-sided tests for stochastic equivalence was used. FINDINGS: The overall concordance correlation coefficient between InterVA-4 and physician codes was 0.83 (95% CI 0.75 to 0.91) and this increased to 0.97 (95% CI 0.96 to 0.99) when HIV/AIDS and pulmonary TB deaths were combined into a single category. Over half (53%) of the cause category ratios between InterVA-4 and physician codes by source were not significantly different from unity at the 99% level, increasing to 62% by age group. Wilcoxon tests for stochastic equivalence also demonstrated equivalence. CONCLUSIONS: These findings show strong concordance between InterVA-4 and physician-coded findings over this large and diverse data set. Although these analyses cannot prove that either approach constitutes absolute truth, there was high public health equivalence between the findings. Given the urgent need for adequate cause of death data from settings where deaths currently pass unregistered, and since the WHO 2012 verbal autopsy standard and InterVA-4 tools represent relatively simple, cheap and available methods for determining cause of death on a large scale, they should be used as current tools of choice to fill gaps in cause of death data

Care pathways during a child's final illness in rural South Africa: Findings from a social autopsy study.

BACKGROUND: Half of under-5 deaths in South Africa occur at home, however the reasons remain poorly described and data on the care pathways during fatal childhood illness is limited. This study aimed to better describe care-seeking behavior in fatal childhood illness and to assess barriers to healthcare and modifiable factors that contribute to under-5 deaths in rural South Africa. METHODS: We conducted a social autopsy study on all under-5 deaths in two rural South African health and demographic surveillance system sites. Descriptive analyses based on the Pathways to Survival Framework were used to characterise how caregivers move through the stages of seeking and providing care for children during their final illness and to identify modifiable factors that contributed to death. FINDINGS: Of 53 deaths, 40% occurred outside health facilities. Rates of antenatal and perinatal preventative care-seeking were high: over 70% of mothers had tested for HIV, 93% received professional assistance during delivery and 79% of children were reportedly immunised appropriately for age. Of the 48 deaths tracked through the stages of the Pathways to Survival Framework, 10% died suddenly without any care, 23% received home care of whom 80% had signs of severe or possibly severe illness, and 85% sought or attempted to seek formal care outside the home. Although half of all children left the first facility alive, only 27% were referred for further care. CONCLUSIONS: Modifiable factors for preventing deaths during a child's final illness occur both inside and outside the home. The most important modifiable factors occurring inside the home relate to caregivers' recognition of illness and appreciation of urgency in response to the severity of the child's symptoms and signs. Outside the home, modifiable factors relate to inadequate referral and follow-up by health professionals. Further research should focus on identifying and overcoming barriers to referral

Time to review policy on screening for, and managing, hypertension in South Africa : evidence from primary care

Background Current policy in South Africa requires measurement of blood pressure at every visit in primary care. The number of patients regularly visiting primary care clinics for routine care is increasing rapidly, causing long queues, and unmanageable workloads. Methods We used data collected during a randomised control trial in primary care clinics in South Africa to estimate how changes in policy might affect workloads and improve identification of undiagnosed hypertension. Results The prevalence of raised blood pressure increased with age; 65% of individuals aged over 60 years had a raised blood pressure, and 49% of them were not on any treatment. Over three months, eight health facilities saw 8,947 individual chronic disease patients, receiving 22,323 visits from them. Of these visits, 60% were related to hypertension, with or without HIV, and a further 35% were related to HIV alone. Long waits for blood pressure checks caused friction at all levels of the clinics. Blood pressure machines frequently broke down due to heavy use, and high blood pressures readings were often ignored. If chronic disease patients without a diagnosis of hypertension had their blood pressure checked only once a year, the number of checks would be reduced by more than 80%. Individuals with hypertension had a blood pressure check on average once every 7 weeks, but South African guidelines recommend that this should be done every 3 months at most. Conclusions The numbers of chronic disease patients in primary care clinics in South Africa is rising rapidly. New policies for measuring blood pressure in these patients attending clinics are urgently needed