Epidemiology of tuberculosis and multidrug-resistant tuberculosis in Ethiopia and China

Abstract

Tuberculosis (TB) is the leading cause of death from an infectious disease worldwide, killing more than one million people every year. Recently, the emergence of multidrug-resistant tuberculosis (MDR-TB), defined as TB that is resistant to at least isoniazid and rifampicin, has become a major public health problem. However, there is limited information on the epidemiology of TB in high-incidence countries, particularly regarding the treatment outcomes and the spatial patterns of MDR-TB. The identification of areas where TB and MDR-TB are concentrated and factors that are associated with poor MDR-TB treatment outcomes could allow policy-makers to implement targeted interventions aimed at prevention and management. This might be particularly important in resource-constrained settings and in high TB and MDR-TB burden countries such as Ethiopia and China.

This PhD has been undertaken during the period when the Sustainable Development Goals (SDGs) target is to end the global TB epidemic by 2030. The overall aim of the research in this thesis is, therefore, to better understand the epidemiology of TB and MDR-TB in Ethiopia and China. The specific objectives of this thesis were: 1) to investigate the spatial epidemiology and ecological-level factors associated with TB and MDR-TB in Ethiopia; 2) to estimate the psycho-social burden of MDR-TB; 3) to assess the treatment outcomes of patients with MDR-TB in Ethiopia and China; and 4) to develop a clinical risk score for the prediction of MDR-TB treatment outcomes.

The results of this research showed spatial clustering of TB and MDR-TB in the border area of northwest Ethiopia. TB clustering was associated with several socio-climatic factors, including lower educational status, a high percentage of migration, urbanization, high temperatures and high rainfall. MDR-TB clustering was associated with high population density, high economic inactivity rate, a high proportion of the population being urban, and a high percentage of males. Results from our systematic review and meta-analysis indicated a high burden of mental health disorders (such as depression (25%), anxiety (24%), and psychosis (10%)), social stressors (such as stigma, discrimination, and isolation), and poor health-related quality of life among MDR-TB patients. The MDR-TB treatment success rate was 80% in northwest Ethiopia; and being a farmer and having anaemia were identified as independent predictors of a poor treatment outcome. The treatment success rate was 58% for MDR-TB and 30% for extensively drug-resistant tuberculosis (XDR-TB) in Hunan Province, China; and resistance to ofloxacin was an independent predictor of a poor MDR-TB treatment outcome. Based on these studies, a simple risk score was developed to estimate the absolute risk of poor treatment outcomes in patients with MDR-TB.

In summary, this thesis provided setting-specific information about the epidemiology of MDR-TB in Ethiopia and China, and estimated the psycho-social burden of MDR-TB. The thesis identified the areas where TB and MDR-TB are clustered in northwest Ethiopia. The treatment outcomes of MDR-TB were assessed in Ethiopia and China, and a clinical risk score was developed for the prediction of poor treatment outcomes. The thesis provided some policy recommendations that could assist to achieve the End-TB targets. Show more