Doctoral Degrees (Paediatrics and Child Health)

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Browsing Doctoral Degrees (Paediatrics and Child Health) by Author "Osman, Muhammad"

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    Tuberculosis-associated mortality in South Africa: longitudinal trends and the impact of health system interventions
    (Stellenbosch : Stellenbosch University, 2021-03) Osman, Muhammad; Hesseling, Anneke Catharina; Naidoo, Prenavum; Welte, Alex; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Paediatrics and Child Health.
    ENGLISH ABSTRACT: Tuberculosis (TB) is estimated to have infected a quarter of the world’s population. In 2019, it was estimated that 10 million people developed TB globally and that the treatment coverage was 71%. In South Africa, approximately 360,000 people developed TB in 2019 with an estimated treatment coverage of 58%. Human immunodeficiency virus (HIV) is one of the most important drivers of TB, especially in sub-Saharan Africa. Of the estimated 38 million people living with HIV globally, 7.5 million (20%) were in South Africa. People living with HIV are more likely to develop TB disease and TB is one of the leading causes of death among people living with HIV. Among the estimated 1.4 million TB deaths in 2019; 59,000 occurred in South Africa. This estimate of mortality includes any death, regardless of the cause, occurring before or during antituberculosis treatment, and does not include TB-related deaths that occurred after the successful completion of treatment. TB reporting in South Africa is based on data captured in TB treatment registers and there are no routine estimates for TB-associated mortality before or after TB treatment. I used the onion model and the TB care cascade frameworks, to evaluate TB-associated mortality during, before and after TB treatment. Through a series of four interlinked studies, I investigated TB-associated mortality during TB treatment for adults and in children. I showed that mortality in South Africa decreased from 11% in 2009 to 8% in 2016 in adults, and from 3.3% in 2007 to 1.9% in 2016 in children and adolescents. I demonstrated that young children, older adolescents, the oldest adults, males, and people living with HIV (especially those with the lowest CD4 counts) were at highest risk of mortality during TB treatment whilst antiretroviral therapy (ART) had a protective effect. I also showed how this differs by HIV status and demonstrated that in people living with HIV, younger adult females have the greatest risk of mortality. I collected data for two studies to evaluate mortality before TB treatment. In the first, I reported a TB prevalence of 8% in people who died suddenly and unexpectedly; more than 90% had undiagnosed TB. I demonstrated multiple missed opportunities for TB screening and testing in these individuals. Sentinel surveillance for TB in this group could be an important indicator of TB control efforts. In the second study, I reported initial loss to follow up (ILTFU) of 20% in TB patients in 2 sub-districts of Cape Town among whom 17% had died. Although hospitals accounted for 25% of TB diagnoses, they contributed to 55% of patients with ILTFU and to 85% of the mortality in this group. This study demonstrates the need for earlier case-finding to reduce mortality and the value of including hospitals in routine TB reporting. Given the exclusion of mortality after TB treatment from the current definition of TB- deaths and the recognition of the burden of post-TB lung health, I conducted a study in Cape Town to assess TB patients who had successfully completed TB treatment. I showed the complexity of tracing these individuals. In the sample of adults located, I reported a high burden of respiratory symptoms and 6% had recurrent TB. The mortality rate following the successful completion of TB treatment was 2.5 deaths per 100 person years with a standardised mortality ratio of 4 compared to the general population. This highlights the need for ongoing care, post TB treatment completion. In this dissertation I documented the key health system changes in the public sector in South Africa and the changes in TB-associated mortality over time. Finally, I attempted to collate the findings of TB-associated mortality during, before and after TB treatment in the context of losses along the TB care cascade. This dissertation provides novel insights into TB-associated mortality in South Africa. I propose additional strategies to improve mortality estimates and to reduce TB-associated mortality in South Africa.