Closing Age Disparities, Reducing Health Delays, and Bridging Treatment Gaps in TB Management

Between 2009 and 2018, SS+ TB and TB cases in mainland China (excluding Hong Kong, Macau, and Taiwan) demonstrated a consistent decline, with a strong positive correlation (R² = 0.97) pointing to effective diagnosis, treatment, and control measures. However, SS- TB continued to cause mortality, underlining the necessity for improved diagnosis and treatment strategies. Population size emerged as a primary factor influencing SS+ TB and TB cases, though other variables, such as economic conditions, healthcare infrastructure, and environmental factors, likely played a role in the prevalence of SS- TB cases.[1]

Analyzing age-related trends, TB cases were divided into three groups: <20 years, 20–50 years, and >50 years. The 20–50 and >50 age groups reported comparable numbers of cases, significantly exceeding those in the <20 group. Over the study period, SS+ TB and TB cases declined across all age groups, particularly among the younger populations (<20 and 20–50 years), reflecting effective disease control. Conversely, SS- TB cases in the >50 age group rose in 2018 compared to 2009, while younger groups showed stability, indicating effective control among youth but a growing concern for older individuals.[1]

Mortality trends revealed a decline in SS+ TB and TB-related deaths across all age groups, with the most significant reductions observed in younger populations. However, mortality for SS- TB cases in the >50 age group showed little change, remaining higher than in younger groups. Overall, the >50 age group exhibited the highest incidence and mortality rates across all TB categories, underscoring their increased vulnerability to infection and fatal outcomes. These findings highlight the importance of sustained efforts to control TB in younger populations and targeted interventions to address the heightened risks faced by the elderly.[1]

As countries progress toward TB elimination, addressing the increasing burden of TB among the elderly has become critical due to significant age-related disparities. Older individuals, particularly those with latent TB infections, face a higher risk of developing active TB due to immune senescence—the weakening of the immune system with age. This vulnerability is compounded by the fact that older generations were more likely exposed to TB during periods of higher transmission, despite the significant decline in TB spread in recent decades due to improved living conditions and healthcare.[2]

The interactions of the elderly predominantly occur within their age group, limiting the spread of TB to younger populations. However, this age-specific assortativity plays a less significant role in age-related TB disparities compared to immune senescence. Consequently, TB control strategies must prioritize preventing disease progression in the elderly, focusing on managing immune senescence and implementing targeted interventions to control transmission within this demographic.[2]

The dominant mechanism driving age-related TB disparities is immune senescence, highlighting the need for specialized, age-specific approaches. Strengthening healthcare measures for the elderly, such as early detection and prophylactic treatment of latent TB, will be essential for achieving sustained progress toward TB elimination goals.[2]

In Taiwan, TB diagnosis relies primarily on detecting symptomatic patients through contact tracing and active screening of high-risk groups. However, the disease's non-specific symptoms and declining incidence have made it harder for healthcare workers and clinicians to recognize TB promptly, leading to delayed diagnoses and potential transmission. Health System Delay (HSD), defined as the time from the first consultation for respiratory symptoms to the start of TB treatment, has potentially increased between 2003 and 2008 due to diagnostic complexities and changes in the healthcare system. Factors influencing HSD include the patient’s age, gender, the type of health facility visited, and the density of regional healthcare providers.[3]

Patients consulting primary care clinics or non-TB specialists, traveling long distances, or engaging in "doctor shopping" often face prolonged HSD. Conversely, regions like Eastern Taiwan benefit from shorter HSDs due to a higher concentration of TB-specialized providers. Medical centers tend to have longer delays because of the complexity of diagnosing TB in patients with multiple comorbidities. Notably, regional variations in HSD reflect disparities in medical infrastructure and provider availability, emphasizing the need for improved healthcare accessibility and targeted interventions to reduce delays and enhance TB control efforts across Taiwan.[3]

Tuberculosis (TB) is a significant and enduring risk factor for developing chronic obstructive pulmonary disease (COPD), with its impact persisting for at least six years post-diagnosis. Delays in initiating anti-TB treatment are associated with a dose-response increase in COPD risk, as untreated TB can worsen airway damage and accelerate COPD development. Early diagnosis and timely treatment of pulmonary TB are crucial to mitigating this risk, and improving the quality of TB care could help prevent some COPD cases. Clinicians should remain vigilant for COPD in patients with a history of TB, while recognizing that conditions like diabetes mellitus may indirectly reduce COPD risk, potentially due to lifestyle changes such as smoking cessation following a diabetes diagnosis.[4]

References:

1. Huang, F. and Bello, S.T., 2024. Spatiotemporal analysis of regional and age differences in tuberculosis prevalence in mainland China. Tropical Medicine & International Health, 29(9), pp.833-841.

2. Fu, H., Lin, HH., Hallett, T.B. et al. Explaining age disparities in tuberculosis burden in Taiwan: a modelling study. BMC Infect Dis 20, 191 (2020). 

3. Chen, C.C., Chiang, C.Y., Pan, S.C., Wang, J.Y. and Lin, H.H., 2015. Health system delay among patients with tuberculosis in Taiwan: 2003–2010. BMC infectious diseases, 15, pp.1-9.

4. Lee C-H, Lee M-C, Lin H-H, Shu C-C, Wang J-Y, et al. (2012) Pulmonary Tuberculosis and Delay in Anti-Tuberculous Treatment Are Important Risk Factors for Chronic Obstructive Pulmonary Disease. PLoS ONE 7(5): e37978.