Severe tuberculosis in London: Investigation of factors contributing to tuberculosis severity and deaths in London between 2010 and 2021
File(s)
Author(s)
Barrett, Jessica
Type
Thesis
Abstract
Tuberculosis continues to cause significant morbidity and mortality, even in countries considered to have low-tuberculosis incidence globally. The true case:fatality ratio for tuberculosis is not known for a number of reasons including unidentified infections, late sequelae, and misattribution of deaths on national registers and vital registration. As a result studies of risk factors for all-cause mortality on tuberculosis treatment may incorrectly emphasise the contribution of comorbidities and age as the study population include non-TB deaths. The situation has been further complicated by the COVID-19 pandemic which has introduced many barriers to accessing healthcare for an already vulnerable patient group.
To address the issue of misattribution all TB deaths from Public Health England records and the London TB register for two high-incidence areas of London were reviewed to establish cause of death, and where tuberculosis contributed, were included in an age-matched case-control study to identify risk factors for death. In addition, morbidity and mortality risk factors for two further groups were explored: people admitted to intensive care with tuberculosis, and TB-COVID-19 coinfected patients in 2020. Impact of COVID-19 on local tuberculosis services was also reviewed.
Of 313 deaths, 242 were either directly or indirectly caused by tuberculosis, and 29 of these had tuberculosis diagnosed post-mortem. Significant adjusted risk factors for TB-caused deaths included thrombocytopenia, hypoalbuminaemia and pulmonary tuberculosis. Hypoalbuminaemia and either severe pulmonary TB, or secondary respiratory infection or failure were consistent risk factors across other groups including TB-contributed deaths, pulmonary TB deaths and deaths in-hospital following intensive care. While TB-COVID-19 coinfection was not associated with increased mortality, there was a sharp increase in diagnosis of disseminated TB following early pandemic lockdown measures with consequent morbidity.
Correct attribution and detailed understanding of the factors contributing to TB-deaths will help services support the most vulnerable patients and strengthen response to future crises.
To address the issue of misattribution all TB deaths from Public Health England records and the London TB register for two high-incidence areas of London were reviewed to establish cause of death, and where tuberculosis contributed, were included in an age-matched case-control study to identify risk factors for death. In addition, morbidity and mortality risk factors for two further groups were explored: people admitted to intensive care with tuberculosis, and TB-COVID-19 coinfected patients in 2020. Impact of COVID-19 on local tuberculosis services was also reviewed.
Of 313 deaths, 242 were either directly or indirectly caused by tuberculosis, and 29 of these had tuberculosis diagnosed post-mortem. Significant adjusted risk factors for TB-caused deaths included thrombocytopenia, hypoalbuminaemia and pulmonary tuberculosis. Hypoalbuminaemia and either severe pulmonary TB, or secondary respiratory infection or failure were consistent risk factors across other groups including TB-contributed deaths, pulmonary TB deaths and deaths in-hospital following intensive care. While TB-COVID-19 coinfection was not associated with increased mortality, there was a sharp increase in diagnosis of disseminated TB following early pandemic lockdown measures with consequent morbidity.
Correct attribution and detailed understanding of the factors contributing to TB-deaths will help services support the most vulnerable patients and strengthen response to future crises.
Version
Open Access
Date Issued
2024-07-14
Date Awarded
01/08/2025
License URL
Advisor
Kon, Onn Min
Whittington, Ashley
Publisher Department
National Heart & Lung Institute
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Medicine (Research) MD (Res)