Pulmonary Function Outcomes after Tuberculosis treatment in Children: A Systematic Review and Meta-analysis
Authors: Lew Yao Long , Tan Angelica F , Yerkovich Stephanie T , Yeo Tsin Wen , Chang Anne B , Lowbridge Chris 
Published: October 2023

Background

Despite tuberculosis (TB) being a curable disease, current guidelines fail to account for long-term outcomes of post-tuberculosis lung disease (PTLD) – a cause of global morbidity despite successful completion of effective treatment. Our systematic review aimed to synthesise the available evidence on the lung function outcomes of childhood pulmonary tuberculosis (PTB).

Methods

PubMed, ISI Web of Science, the Cochrane Library, and ProQuest databases were searched for English-only studies without time restriction (latest search date 22 March 2023). Inclusion criteria were (1) patients who had TB with pulmonary involvement at age ≤18 years; (2) pulmonary function tests (PFTs) performed on patients after treatment completion; and (3) observational studies, including cohort and cross-sectional studies. We adhered to the recommendations of the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

Results

From 8040 records, five studies were included (involving n=567 children) with spirometry measures from four studies included into meta-analyses. The effect size of childhood TB on forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC) z-scores were estimated to be -1.53 (95% CI: -2.65, -0.41; p=0.007) and -1.93 (95% CI: -3.35, -0.50; p=0.008) respectively.

Discussion

The small number of included studies reflects this under-researched area, relative to the global burden of TB. Nevertheless, as childhood PTB impacts future lung function, pulmonary function tests (such as spirometry) should be considered a routine test when evaluating the long-term lung health of children beyond their completion of TB treatment.

What is already known on this topic?

Tuberculosis (TB) is a treatable disease, but despite resolution of the infection, lung function deficits associated with post-tuberculosis lung disease (PTLD) can persist. While this is well-appreciated in adults, the extent and severity of PTLD in children is not well characterised. This area of work is important because of the potential long-term impacts of PTLD on children’s lung health and development.

What this study adds

Our meta-analyses showed that childhood TB causes significant decline in at least two spirometry parameters despite high levels of between-study heterogeneity. The effect size of childhood TB on forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC) z-scores were estimated to be -1.53 (95% CI: -2.65, -0.41; p=0.007) and -1.93 (95% CI: -3.35, -0.50; p=0.008). A previous meta-analysis of spirometric data from adult populations with drug-susceptible TB gave combined estimated mean of 76.6% (95% CI: 71.6, 81.6) and 81.8% (95% CI: 77.4, 86.2) of predicted FEV1and FVC respectively. While direct comparison with this current study was not possible, it suggests that childhood TB results in lung function decline just as much as adult TB, if not more so.

How this study might affect research, practice, or policy

This study supports incorporation of routine pulmonary function tests into the follow-ups of children with prior history of TB, allowing for early detection and management of PTLD.