Changes in mortality patterns and associated socioeconomic differentials in a rural South African setting: findings from population surveillance in Agincourt, 1993-2013
Date
2018
Authors
Kabudula, Chodziwadziwa Whiteson
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Abstract
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 Index
Description
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.