Persistent chronic respiratory symptoms despite TB cure is poorly correlated with lung function

Abstract

BACKGROUND: Persistent respiratory symptoms and lung function deficits are common after patients with TB. We aimed to define the burden of post-TB lung disease (PTLD) and assess associations between symptoms and impairment in two high TB incidence communities.METHODS: This was a cross-sectional survey of adults in Cape Town, South Africa who completed TB treatment 1–5 years previously. Questionnaires, spirometry and 6-minute walking distance (6MWD) were used to assess relationships between outcome measures and associated factors.RESULTS: Of the 145 participants recruited (mean age: 42 years, range: 18–75; 55 [38%] women), 55 (38%) had airflow obstruction and 84 (58%) had low forced vital capacity (FVC); the mean 6MWD was 463 m (range: 240–723). Respiratory symptoms were common: chronic cough (n = 27, 19%), wheeze (n = 61, 42%) and dyspnoea (modified MRC dyspnoea score 3 or 4: n = 36, 25%). There was poor correlation between FVC or obstruction and 6MWD. Only low body mass index showed consistent association with outcomes on multivariable analyses. Only 19 (13%) participants had a diagnosis of respiratory disease, and 16 (11%) currently received inhalers.CONCLUSION: There was substantial burden of symptoms and physiological impairment in this “cured” population, but poor correlation between objective outcome measures, highlighting deficits in our understanding of PTLD.

Post-tuberculosis lung disease: Exposing the elephant in the room

“…But even where this has been done, frequently the associations with symptoms and spirometry can be disappointing. [11] Nonetheless, this study by Ozoh et al . [10] provides us with a snapshot of the more severe end of the spectrum of PTLD – those patients that we as pulmonologists are likely to encounter.…”

“…Although this variable has not been consistently associated with post-TB outcomes, logic suggests that recurrent episodes should compound the lung damage. [11 , 12] Indeed, what is described here is a group with physiologically severe, symptomatic chronic lung disease. The symptom burden was high, with over 90% of patients reporting cough and sputum production, half of whom had haemoptysis.…”

“…Interestingly, there were some significant associations between the SGRQ and spirometry parameters on bivariate analysis, unlike in other prospective studies. [11] …”

“…But even where this has been done, frequently the associations with symptoms and spirometry can be disappointing. [11] Nonetheless, this study by Ozoh et al [10] provides us with a snapshot of the more severe end of the spectrum of PTLD -those patients that we as pulmonologists are likely to encounter. Taken together with existing community data, this shows us that the overall burden of PTLD is high, and a small but significant proportion of these patients will have severe life-and activity-limiting disease.…”

“…Interestingly, there were some significant associations between the SGRQ and spirometry parameters on bivariate analysis, unlike in other prospective studies. [11] Ozoh et al [10] presents in this issue a small sample of highly selected patients that were recruited on the basis of self-presentation and are likely not to represent the global population of individuals post-TB. Certainly in other studies performed in the sub-Saharan community, the estimates of symptoms and burden of disease was lower than these estimates.…”