Post-tuberculosis airway disease: A population-based cohort study of people immigrating to British Columbia, Canada, 1985–2015

Abstract

Background: Current epidemiological evidence of post-TB airway disease is largely cross-sectional and derived from high-TB-incidence settings. We present the first cohort study of post-TB airway disease in a low-TB-incidence setting. ( 1) analyze the risk of airway disease by respiratory TB, (2) assess potential unmeasured confounding between TB and airway disease, and (3) investigate TB effect measure modification. Methods: A population-based cohort study using healthcare claims data for immigrants to British Columbia (BC), Canada, 1985À2015. Airway disease included chronic airway obstruction, asthma, bronchitis, bronchiolitis, and emphysema. Respiratory TB was defined from TB registry data. Cox proportional hazards (PH) regressions were used to analyze time-to-airway disease by respiratory TB. Sensitivity analyses included varying definitions of TB and airway disease. Potential unmeasured confounding by smoking was evaluated by E-value and hybrid least absolute shrinkage and selection operator (LASSO)-high-dimensional propensity score (hdPS). Findings: In our cohort (N = 1 005 328; n TB =1141) there were 116 840 incident cases of airway disease during our 30-year study period (10.43 per 1,000 person-years of follow-up), with cumulative incidence of 42¢5% among respiratory TB patients compared with 11¢6% among non-TB controls. The covariate-adjusted hazard ratio (aHR) for airway disease by respiratory TB was 2¢08 (95% CI: 1¢91À2¢28) with E-value=3¢58. The LASSO-hdPS analysis produced aHR=2¢26 (95% CI: 2¢07À2¢47). Interpretation: A twofold higher risk of airway disease was observed among immigrants diagnosed with respiratory TB, compared with non-TB controls, in a low-TB-incidence setting. Unmeasured confounding is unlikely to explain this relationship. Models of post-TB care are needed.

Pulmonary functional assessment: longitudinal study after treatment of pulmonary tuberculosis

“…The most prevalent ventilatory disorder found in our study was of mild OVD, which is consistent with findings reported in most studies 7,34,35 . The pathophysiological mechanism that leads to obstructive functional changes after PTB is not well established.…”

“…In a systematic review, after the evaluation of 156 articles, obstruction was mentioned in 52 (33%) 6 , and even in countries with low incidences of PTB, respiratory diseases are frequent after treatment of PTB 7 . The proportion of obstruction is variable and was related to the extent of radiological changes 8,9 .…”

Is It Feasible to Conduct Post-Tuberculosis Assessments at the End of Tuberculosis Treatment under Routine Programmatic Conditions in China?

“…The proportion of our study patients with respiratory symptoms were also in line with findings from Benin and Malawi [ 12 , 15 ]. We did not have the resources to undertake pulmonary spirometry or other more sophisticated tests of lung function to understand the reasons for these continuing symptoms, but it is likely from the published literature that post-TB patients with respiratory symptoms have restrictive pulmonary disease, obstructive pulmonary disease or both [ 18 , 19 ].…”

Asthma Therapies on Pulmonary Tuberculosis Pneumonia in Predominant Bronchiectasis–Asthma Combination

“…As mentioned before, we excluded PTB or pneumonia before the entry study. However, post-PTB or post-pneumonia was a predisposing factor of airway disease ( Bashir et al, 2016 ; Basham et al, 2021 ). Thus, we used the terms such as “BCAS cohort is associated with PTB or pneumonia” and “bronchodilators and steroids are associated with PTB or pneumonia in BCAS cohort” in this study.…”