Tuberculosis mortality rate refers to the proportion of individuals diagnosed with tuberculosis (TB) who ultimately die from the disease. Despite being a preventable and curable illness, tuberculosis remains a leading infectious cause of death worldwide. Its continued impact underscores the complex challenges in its control and elimination.
The Nature of Tuberculosis Lethality
Tuberculosis is a bacterial infection caused by Mycobacterium tuberculosis, primarily targeting the lungs. When inhaled, these bacteria can establish an infection within the lung tissue, forming granulomas. If the immune system cannot contain the infection, the bacteria multiply, leading to progressive destruction of lung tissue. This damage can severely impair lung function, resulting in respiratory failure, a common cause of death.
The infection can also spread from the lungs through the bloodstream or lymphatic system to other parts of the body, a condition known as extrapulmonary TB. This dissemination can affect organs such as the brain, leading to tuberculous meningitis, or the spine, causing Pott’s disease. Without effective treatment, the systemic spread and organ damage become overwhelming, leading to multi-organ dysfunction and ultimately, death.
Global and Regional Mortality Patterns
Globally, tuberculosis remains a significant cause of death, with an estimated 1.3 million people dying from the disease in 2022. This figure includes 167,000 individuals co-infected with HIV. The global mortality rate, excluding those with HIV, was around 11 per 100,000 population in 2022.
Mortality rates vary considerably across different regions and countries. The highest burden of TB deaths is concentrated in the World Health Organization (WHO) regions of Africa and South-East Asia. India, Indonesia, and the Philippines accounted for a substantial portion of the global TB burden in 2022.
Historically, TB mortality declined until the COVID-19 pandemic, which disrupted services and led to increased deaths in 2020 and 2021. While rates decreased slightly in 2022, they remained higher than pre-pandemic levels. Demographic groups disproportionately affected include adult males, who accounted for about 55% of all TB deaths in 2022, and individuals aged 25-44 years.
Key Factors Contributing to Deaths
Co-infection with Human Immunodeficiency Virus (HIV) increases the risk of death from tuberculosis. HIV weakens the immune system, making individuals more susceptible to developing active TB and more severe, rapidly progressing forms of the illness. TB is a leading cause of death among people living with HIV.
Drug resistance poses a challenge to effective TB treatment and elevates mortality rates. Multidrug-resistant TB (MDR-TB) refers to strains resistant to the two potent first-line anti-TB drugs, isoniazid and rifampicin. Extensively drug-resistant TB (XDR-TB) is a more severe form, resistant to isoniazid, rifampicin, any fluoroquinolone, and at least one of three injectable second-line drugs. Treating drug-resistant TB requires longer, more complex, and less effective regimens, leading to poorer outcomes and higher fatality rates.
Socio-economic determinants play a role in contributing to TB deaths. Poverty, malnutrition, and overcrowded living conditions can weaken immunity and facilitate bacterial transmission. These factors often lead to delayed diagnosis, as individuals may lack resources or awareness to seek timely medical attention. Inadequate adherence to prolonged treatment regimens, due to financial constraints or lack of support, can result in treatment failure and increased mortality.
Limited healthcare access and delays in diagnosis and treatment are contributors to TB deaths. Many individuals in high-burden settings face geographical or financial barriers to accessing diagnostic services and appropriate healthcare facilities. Long waiting times for diagnostic test results can further delay effective treatment. Such delays allow the disease to progress, increasing severity and the likelihood of a fatal outcome.
Progress and Initiatives to Reduce Mortality
Progress in TB diagnosis is a foundational step in reducing mortality. Advancements include rapid molecular tests that detect Mycobacterium tuberculosis and drug resistance quickly. These tests allow for earlier and more accurate identification of the disease, enabling prompt treatment.
Effective treatment regimens are an important part of TB control. Directly Observed Treatment, Short-course (DOTS) historically improved adherence and cure rates. Newer, shorter, and more effective drug regimens have been developed for both drug-sensitive and drug-resistant TB, including all-oral regimens that improve patient outcomes. These advancements reduce treatment duration and improve the chances of successful cure.
Preventive therapy reduces the risk of individuals developing active TB disease. For those at high risk, such as close contacts of TB patients or people living with HIV, short-course regimens are effective in preventing progression to active disease. This proactive approach reduces the number of individuals who could succumb to the illness.
Vaccination efforts involve the Bacille Calmette-Guérin (BCG) vaccine, which offers protection against severe forms of TB in children. While BCG does not prevent pulmonary TB in adults, research continues into new, more effective TB vaccines for broader protection. These efforts aim to develop tools that can prevent infection or disease progression on a larger scale.
Global strategies, such as the WHO End TB Strategy, outline targets to reduce TB incidence and mortality. These initiatives advocate for strengthening health systems, ensuring universal access to diagnosis and treatment, and addressing social determinants of health. Collaborative efforts among international organizations, governments, and civil society aim to scale up interventions and ensure quality TB care reaches all who need it. Sustained funding and continued research are essential for developing new diagnostics, drugs, and vaccines to eliminate TB as a public health threat.
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References
World Health Organization. Global Tuberculosis Report 2023. Geneva: World Health Organization; 2023. Licence: CC BY-NC-SA 3.0 IGO.