4. Electronic Theses and Dissertations (ETDs) - Faculties submissions

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    Predicting in-hospital mortality in heart failure patients using machine learning
    (University of the Witwatersrand, Johannesburg, 2023-05) Mpanya, Dineo; Ntsinjana, Hopewell
    The age of onset and causes of heart failure differ between high-income and low-and-middle-income countries (LMIC). Heart failure patients in LMIC also experience a higher mortality rate. Innovative ways that can risk stratify heart failure patients in this region are needed. The aim of this study was to demonstrate the utility of machine learning in predicting all-cause mortality in heart failure patients hospitalised in a tertiary academic centre. Six supervised machine learning algorithms were trained to predict in-hospital all-cause mortality using data from 500 consecutive heart failure patients with a left ventricular ejection fraction (LVEF) less than 50%. The mean age was 55.2 ± 16.8 years. There were 271 (54.2%) males, and the mean LVEF was 29 ± 9.2%. The median duration of hospitalisation was 7 days (interquartile range: 4–11), and it did not differ between patients discharged alive and those who died. After a prediction window of 4 years (interquartile range: 2–6), 84 (16.8%) patients died before discharge from the hospital. The area under the receiver operating characteristic curve was 0.82, 0.78, 0.77, 0.76, 0.75, and 0.62 for random forest, logistic regression, support vector machines (SVM), extreme gradient boosting, multilayer perceptron (MLP), and decision trees, and the accuracy during the test phase was 88, 87, 86, 82, 78, and 76% for random forest, MLP, SVM, extreme gradient boosting, decision trees, and logistic regression. The support vector machines were the best performing algorithm, and furosemide, beta-blockers, spironolactone, early diastolic murmur, and a parasternal heave had a positive coefficient with the target feature, whereas coronary artery disease, potassium, oedema grade, ischaemic cardiomyopathy, and right bundle branch block on electrocardiogram had negative coefficients. Despite a small sample size, supervised machine learning algorithms successfully predicted all-cause mortality with modest accuracy. The SVM model will be externally validated using data from multiple cardiology centres in South Africa before developing a uniquely African risk prediction tool that can potentially transform heart failure management through precision medicine.
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    Governance quality and popular support for democracy in Africa
    (University of the Witwatersrand, Johannesburg, 2024) Mongae, Mmabatho; Alence, Rod
    The stability of democracy depends on citizens’ support for and satisfaction with democracy as a form of government. Yet the past decade has seen a public backlash against democracy worldwide, and Africa is no exception. This study aims to clarify the determinants of public perceptions of democracy, in particular how the quality of governance in African democracies affects public perceptions of democracy as a preferred system of government. Are citizens more likely to be supportive of and satisfied with democracy in countries that score higher on indicators of political and economic governance quality? This thesis addresses this question using a mixed methods approach. The study harnesses multi-level statistical analysis, incorporating national-level governance indicators from the Ibrahim Index of African Governance (IIAG), Varieties of Democracy (V-Dem), and Worldwide Governance Indicators (WGI), alongside individual-level survey data from Afrobarometer covering thirty-four African countries. The statistically selected case studies of Sudan, Botswana, South Africa, and Zimbabwe probe more deeply by capturing various experiences with democracy. The central finding is that public support for democracy in Africa depends significantly on the quality of governance. However, support for democracy is not based purely “instrumentally” on the receipt of material benefits, as citizens also value the practical provision of political freedoms and protections “intrinsic” to democracy. These findings challenge existing assumptions about the transactional nature of democratic support, highlighting the critical role of governance quality in fostering a deep-rooted commitment to democratic ideals. By foregrounding the lived experiences of African citizens within democratic systems, this thesis contributes to the discourse on democracy in Africa. It shifts the analytical lens from abstract institutional performance metrics to the tangible democratic encounters of individuals, providing a richer, more textured understanding of democratic resilience and support on the continent. Through this approach, the study not only responds to the existing gaps in literature but also offers fresh insights into the complex dynamics that underpin public attitudes towards democracy in Africa, thereby enhancing our understanding of the factors that promote or hinder democratic engagement and support
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    Ethical Foundations For International Investments In Developing Poor African Countries
    (University of the Witwatersrand, Johannesburg, 2024) Xate, Lulamile L.; Attoe, Aribiah David
    There is a moral and ethical obligation for the rich and developed nations and their business corporations to invest in and trade ethically with Africa. This moral obligation extends to African leaders and elites who facilitate the continued exploitation of Africa and corruption in the post-independence period. To reveal this obligation and its basis, I begin by reviewing and exploring the history of African colonialism in pursuit of capital profit maximization within the imperialist framework and its consequences, focusing on its immoral and unethical practices. I then show that the moral foundations of colonialism and post-independence African leadership have not been considered in understanding African underdevelopment in relation to the prosperity of other nations, and the role of African leaders. Finally, I argue there are morally right actions that can plausibly change this. I explicate this using three moral philosophical approaches – Kantian, Utilitarian and Ubuntu African relational ethics.
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    Essays on exchange rate movements and stock returns in emerging and frontier African economies
    (University of the Witwatersrand, Johannesburg, 2024) Atipaga, Umar-Farouk; Alagidede, Imhotep Paul; Tweneboah, George
    Global financial markets have recently undergone significant turmoil due to numerous factors, such as economic uncertainties, pandemics, geopolitical tensions, and extreme contagion. Unfortunately, African economies are not immune to these global developments and are often impacted by risk-off sentiment. As a result, these shocks have significant consequences for African exchange rates and capital markets. Due to the region's trade and investment dynamics, African economic policymakers rely heavily on exchange rate management as a policy tool. Additionally, capital flows in the form of equities are important for Africa’s growth agenda. The research explored four distinct, yet interconnected essays related to currency and equity movements in Africa, aiming to offer valuable insights into investment and policy considerations while enriching the existing literature. The first essay explored the connection between currency movements and equities in Africa. This approach departs from the usual VAR and GARCH models and employs a tool that accounts for time-frequency co-movements. This is critical for investment and policy decisions as it better explains which part of the sample period produces shocks. Given the recent market uncertainties, this study suggests that investors can determine the right investment horizon. The bivariate wavelet technique established a profound negative correlation at the upper end of the horizon, making room for diversification opportunities. With exchange rates playing a dominant leading role, it presents a case for policy considerations towards currency stability. The partial wavelet results revealed that investors should scale down to the short end of the investment horizon during crisis periods like COVID-19. In the second essay, the asymmetric linkages were modelled between stock returns of developed economies and African markets using quantile regressions along 0.05 quantile iii | P a g e intervals. The crux of this study is to determine the options available to holders of African stocks considering market integration. Having employed the U.S. and U.K. as proxy for advanced markets, we found diversification and hedging benefits from the two advanced markets for some African equities at different time scales. The quantile-on-quantile regression results revealed that both U.S. and U.K. stocks could offer safe-haven benefits for some African equities in extreme market conditions. The findings strongly project that investors making decisions to mitigate risks must appreciate the heterogeneity in the nexus between the advanced markets and African economies to arrive at optimal risk-adjusted returns The third essay applied transfer entropy techniques for the examination of information flows between advanced and African markets. Information content analysis is vital in the current investment and portfolio management dispensation. Findings from the information exchanges indicated that some African markets have led the market integration process ahead of their peers. This study compared significant periods of global interest, such as the Fed normalisation period and BREXIT. The results present important implications for risk management strategies and policy measures to anchor markets to withstand shocks. Due to the potential scales of investments from market integration with advanced markets, African policymakers are encouraged to champion this agenda. However, this requires the need to build economies to withstand shocks. Similarly, in the last essay, the information content was modelled between currencies of advanced markets and African economies. Exchange rate spillovers have significant implications for emerging and frontier economies due to the linkages between currency performance and other key variables. The essay examined information exchanges with the iv | P a g e world’s most liquid currencies over different crisis periods. The results possess essential implications for risk management strategies and policy frameworks, especially in this current period of heightened global uncertainties. Due to the spillovers in the currency market, African policymakers should be wary about the susceptibility of their currencies to global shocks.
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    Financial inclusion through WhatsApp banking in Johannesburg
    (University of the Witwatersrand, Johannesburg, 2022) Miller, Jade Rowan; Balabanoff,Garth
    Approximately three billion people will use mobile banking by 2024. Mobile devices and widespread Internet access are helping to boost mobile banking's popularity. Retail banks can now offer their customers even more convenience with mobile banking applications like WhatsApp. Consumers and financial institutions have embraced advanced technologies, including mobile banking, in recent years. Social media, mobile banking and new ideas like WhatsApp banking have made it easier for people to do business. Mobile banking is now possible thanks to high smartphone penetration and technological advancements. The fourth industrial revolution will continue to exponentially transform the modern economy. Globalisation has forced banks to open new channels to remain competitive in today's market. Banks have had to cut costs and improve their financial position by introducing new products and services. Mobile banking has grown rapidly globally due to the rapid development of information technology. Due to multi-channel distribution, most banks now have a global presence with cross-border customers. A quantitative approach was taken to examine factors that may influence behavioural intention to use WhatsApp banking in the context of financial inclusion. A questionnaire was used as the primary data collection instrument. The survey was conducted using an online questionnaire distributed to people living in Johannesburg, South Africa. The study adds to the body of knowledge by identifying factors that influence WhatsApp banking adoption, particularly in developing countries. The Technology Acceptance Model by Davis (1985) was used to investigate behavioural intention to use WhatsApp banking. My findings show that perceived trust, banking inclusion, perceived usefulness and awareness all play a significant role in WhatsApp banking adoption. Managers in financial institutions should focus on increasing consumer trust across all age groups to increase customer comfort with non-traditional banking platforms in general and thus increase financial inclusion. This is crucial because ix WhatsApp banking has the potential to bank the unbanked and underbanked while also increasing financial inclusion.
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    Different forms of government regimes and covid-19 outcomes in Africa
    (University of the Witwatersrand, Johannesburg, 2024) Masiya, Ulemu Vanessa; Olukoshi, Adebayo
    This study examines extent to which the government regime types contributed to explaining the low COVID 19 mortality and infection cases in Africa. The study analyses panel data from 54 countries in Africa across a 2-year period from January 2020 to December 2021. The following factors of demography, GDP per Capital, health expenditure, and government effectiveness were included as control variables in the models. The results of the panel regression analysis indicated that while authoritarian and partially democratic regimes were positively associated with a surge in COVID-19 cases and fatalities compared to fully democratic countries in Africa, the association lacked statistical significance. In contrast, government effectiveness and health expenditure were observed to be negatively associated with reduced COVID 19 mortality and infection rates at the 5 percent significance level. Hence, this result emphasized the role of good governance and increased health spending in managing the pandemic’s mortality and infection rates across the different types of government regimes in Africa.
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    HbA1c Control in Type 2 Diabetic Patients with Coronary Artery Disease
    (University of the Witwatersrand, Johannesburg, 2023-10) Mhlaba, Lona; Tsabedze, Nqoba; Mpanya, Dineo
    Background: Type 2 diabetes mellitus (T2DM) patients with coronary artery disease (CAD) have an increased risk of recurrent cardiovascular events. These patients require optimal glucose control to prevent the progression of atherosclerotic cardiovascular disease (ASCVD). Current guideline recommendations target an HbA1c ≤7% to mitigate this risk. This study evaluated the level of HbA1c control in T2DM patients with CAD. Methods: This retrospective study assessed consecutive patients who presented with CAD to the Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) between April 2017 and December 2019. The study included T2DM patients on anti-diabetic medication with angiographically confirmed CAD. HbA1c control was assessed using the HbA1c level measured at the index presentation and during the most recent follow-up visit. Results: The study population comprised 262 T2DM patients with a mean age was 61.3 ±10.4 years. Among the T2DM patients, 188 (71.8%) were males. At index presentation, 110 (42.1%) T2DM patients presented with ST-segment elevation myocardial infarction, 69 (26.4%) had non-ST-segment elevation myocardial infarction, 43 (16.5%) had unstable angina, and 39 (14.9%) had stable angina. The baseline median systolic blood pressure was higher in patients with an HbA1c ≤7% [136 mmHg (Interquartile range (IQR): 117-151) vs 124 mmHg (IQR: 112-142), p= 0.0121], compared to those with an HbA1c level above 7%. Furthermore, T2DM with an HbA1c ≤7% also had a higher median diastolic blood pressure [85 mmHg (IQR: 75.5-97) vs 78 mmHg (IQR: 71-88), p=0.0205]. After a median follow-up of 16.5 months (IQR: 7-29), 28.7% of the study participants had an HbA1c ≤7%. On multivariable regression analysis, patients with ST-segment depression on the resting electrocardiogram and index presentation had optimal glycaemic control (Odds ratio: 0.27, CI: 0.12-0.59, p= 0.001). Conclusion: After a median follow-up duration of 16.5 months, only 28.7% of T2DM patients with CAD had optimal glycaemic control. This finding underscores the substantial unmet need for optimal diabetes control in this very high-risk group.
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    Institutional quality, capital structure and financial performance: the case of listed firms in Africa
    (University of the Witwatersrand, Johannesburg, 2024) Celliers, Jacqueline; Chipeta, C.; Moletsane, M.
    This research report examines the relationship between institutional quality, capital structure and the financial performance of firms listed on selected African stock markets. Panel data estimation techniques are carried out on a set of 347 firms from five African countries over the period 2003 to 2022 using the two-step system Generalised Method of Moments. The results show that only the Economic Freedom Index and the significance of the stock market have a significant negative effect on total leverage. The Economic Freedom Index also has a negative significant impact on short-term debt, while the legal rights index has a significant positive effect. The other measures of institutional quality included in this study, such as rule of law, control of corruption and significance of the banking sector, have insignificant effects on total- and short-term debt, while all institutional quality indicators have insignificant effects on long-term leverage. The results also indicate that all three measures of leverage have a significant negative impact on firm performance, and that institutional quality may moderate the negative effects of total- and long-term debt on the financial performance of firms but doesn’t appear to play a part in mitigating the effects of short-term leverage. This study adds value to the literature by investigating the link between institutional quality, capital structure and firm performance in Africa, as most previous studies focus on developed countries. Furthermore, it also explores the role of institutional quality in influencing the relationship between leverage and financial performance, specifically relating to firms in Africa.
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    Financial inclusion, institutional quality, and poverty reduction in Africa
    (University of the Witwatersrand, Johannesburg, 2023) Nsiah, Anthony Yaw; Tweneboah, George
    Financial inclusion is seen as an enabler to growth in an economy, as such enhance poverty reduction, especially in developing regions like Africa. Poverty levels in Africa are still very high, especially with the advent of the Covid-19 pandemic, despite efforts of governments and development partners to address it. The extant literature has provided some information regarding the financial inclusion and poverty reduction nexus in the continent and elsewhere. However, the exact threshold level of inclusion at which poverty could be altered has not been thoroughly explored. Also, the critical role institutions play in transferring the benefits of financial services to households and firms towards poverty reduction has not been extensively interrogated. This thesis therefore consists of three separate empirical studies which all intend to fill the knowledge gap, using advanced econometric methodologies. For the first essay, we examined the determinants of financial inclusion in Africa, considering demand, supply as well as infrastructure side factors. Despite the importance of financial inclusion, many factors play a role in one’s decision to get involved in the financial sector. Using the GMM technique, the study revealed that GNI per capita (demand-side factor), Domestic credit to private sector (Supply-side factor) and institution quality (infrastructure-side factor) were significantly identified to be determinants of financial inclusion in Africa. It was further revealed that GNI per capita, Money supply and Institutional quality contribute to the minimization of barriers to financial inclusion. The second essay sought to estimate the threshold level at which financial inclusion, aided by strong institutions, will lead to poverty reduction in Africa. Financial inclusion has been identified as an important concept in fighting poverty due to its ability to increase income level of households. Using the Hansen’s threshold estimation method, the study found double threshold values at which financial inclusion would increase household consumption expenditure, leading to poverty reduction. The study also established a certain threshold level beyond which, financial barriers will have a negative iv impact on consumption which has the tendency to scare households from participating in the financial sector. The results further indicated that dependency ratio, gross national income, interest rate, inflation, education, and government expenditure contribute significantly to reducing barriers to reduce poverty. Institutional quality was also found to significantly moderate the financial inclusion and poverty reduction relationship. The last but not the least essay investigated the nature of the relationship between financial inclusion, financial stability, and poverty reduction in Africa. Financial inclusion plays an important role in enhancing stability of the financial system. It has however been argued that some level of financial inclusion has the tendency to destabilize the financial system, thwarting poverty reduction efforts. Using the panel Autoregressive Distributive Lag (ARDL) model, the study found that financial inclusion is positively related to financial stability in both short and long-run, with education, GNI per capita and domestic credit to private sector positively related to financial stability and trade openness negatively related to same, in the long-run. The study further established that financial stability is positively related to consumption as such leads to poverty reduction with trade openness, government expenditure, GNI per capita, education, domestic credit to private sector and institutional quality been positively related to household consumption, as such its effects lead to poverty reduction. This indicates that financial stability plays a complementary role in the financial inclusion drive to fight poverty in Africa. It is recommended that development partners, central banks and governments in the region should consciously implement policies that are aimed at promoting financial inclusion through the strengthening of institution, due to its ability to end poverty as well as take pragmatic measures to minimize barriers to financial inclusion. Despite the financial inclusion drive, regulations must not be taking for granted in order not to compromise stability of the financial system for the joint benefit in the fight against poverty as well as ensure financial stability
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    Attitudes and perceptions of caregivers regarding their presence at induction of anaesthesia
    (University of the Witwatersrand, Johannesburg, 2021) Le Roux, Johannes Jacobus; Redelinghuys, Cara
    Background Caregiver presence at their children’s induction of anaesthesia is practiced daily around the world. International studies demonstrated conflicting emotions in caregivers present at induction of anesthesia of their children. These positive and negative emotions ranged from comforting and reassuring, to traumatising and disturbing. Research exploring the attitudes and perceptions of caregivers regarding this practice is limited within the African context. Aims The aim of this study was to describe caregivers’ attitudes and perceptions regarding their presence at induction of their children’s anaesthesia. Methods This descriptive, phenomenological, qualitative study was conducted in 2020 at Chris Hani Baragwanath Academic Hospital, a 3200-bed facility in South Africa. Twenty caregivers of children (aged 2 to 8 years) undergoing elective surgery were recruited. Data was collected through face-to-face, in-depth, semi-structured individual interviews using purposive sampling. Interviews ranged between 11 and 55 minutes in duration and were conducted within 24 hours of induction of anaesthesia. The audio recorded interviews were transcribed and subjected to inductive reflexive thematic analysis. Results Six themes were developed: Fulfilment of caregiver role, A positive experience, A traumatic experience, Not prepared for the experience, My world is my reality, and Your world is a place different to mine. Conclusion A caregiver’s perception of the induction process is influenced by multiple factors. A finding specific to our cohort is the interplay between complex multifaceted cultural beliefs and anaesthesia of their children. By acknowledging and addressing these beliefs, a caregiver’s presence can be tailored to ensure a positive experience for all involved at induction