Post-tuberculosis lung diseases: Beyond treatment outcome.

Dear Editor,

I read the article[1] published “Treatment outcome among post-TB obstructive airways diseases and COPD: A prospective cohort study” with great interest. The authors in the study observed more frequency of exacerbations, hospitalization rate, and rate of fall of forced expiratory volume in one second (FEV1) per year among post-TB Obstructive airways diseases (OAD) cohort than COPD cohort. Also, the mortality rate was more among post-TB OAD compared to classical COPD.

Increasing evidence suggests that post-TB lung disease causes significant morbidity and mortality in high-burden countries. It is an important but less recognized chronic respiratory disease in high TB burden countries such as India. In recent years, post-TB lung disease has attracted large interest from medical community.

Several studies indicate that prevalence estimates for lung impairment after pulmonary TB vary from 18% to 87% depending on the population studied.[2] Mortality rates for TB survivors may be up to three times higher than the general population.[3] Post-TB morbidity is one of the important causes of chronic lung disease in high burden countries, where clinical services remain inadequate.

Delayed diagnosis and inappropriate regimens during tuberculosis treatment may play a role in causing post-TB lung disease. Pulmonary TB directly contributes to poor lung function due to parenchymal destruction, loss of alveolar surfaces, and primary vascular processes. Additional insults, such as tobacco smoking, household and outdoor air pollution, and exposure to dust, gases, or fumes independently, cause chronic respiratory disease.[4]

The substantial proportion of TB cases after completion of treatment show lung function impairment (more cases with obstructive than restrictive), impaired quality of life, and low-performance status. Pharmacological treatment has limited role in managing such cases.

Burden of post-TB lung disease can be mitigated with other intervention like smoking cessation, pulmonary rehabilitation, and vaccination. Psychological and nutritional support may be of greater importance for long-term positive impact.[5] The burden of post-lung disease highlights the need for improving the basic provision of need-based timely care in resource-limited countries.

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Conflict of interest

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