Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Meta-Analysis
. 2020 Sep 17;15(9):e0239333.
doi: 10.1371/journal.pone.0239333. eCollection 2020.

Effect of smoking on tuberculosis treatment outcomes: A systematic review and meta-analysis

Abay Burusie  1 , Fikre Enquesilassie  2 , Adamu Addissie  2 , Berhe Dessalegn  3 , Tafesse Lamaro  4
Affiliations
Meta-Analysis

Effect of smoking on tuberculosis treatment outcomes: A systematic review and meta-analysis

Abay Burusie et al. PLoS One. .

Abstract

Introduction: Numerous studies have explored an effect of cigarette smoking on tuberculosis treatment outcomes but with dissimilar conclusions.

Objective: To determine the effect of cigarette smoking on tuberculosis treatment outcomes.

Methods: PubMed, Cochrane library and Google scholar databases were searched last on February 27, 2019. We applied the random-effects model for the analysis. Publication bias was assessed using funnel plot and Egger's regression. Furthermore, we performed Orwin's Fail-Safe N and cumulative meta-analysis to check for small studies' effect.

Results: Out of 22 studies we included in the qualitative synthesis, 12 studies reported p-values less than 0.05 where smoking significantly favored poor treatment outcomes. The remaining 10 studies reported p-values larger than 0.05 implying that smoking does not affect the treatment outcomes. Twenty studies met the criteria for inclusion in a meta-analysis. The meta-analysis found that smoking significantly increased the likelihood of poor tuberculosis treatment outcomes by 51% (OR = 1.51; 95% CI = 1.30 to 1.75 and I-square = 75.1%). In a sub-group analysis, the effect was higher for low- and middle-income countries (OR = 1.74; 95% CI = 1.31 to 2.30) and upper-middle-income economies (OR = 1.52; 95% CI = 1.16 to 1.98) than for high-income ones (OR = 1.34; 95% CI = 1.03 to 1.75) even though the differences in the effects among the strata were not statistically significant as demonstrated by overlapping of confidence intervals of the effects. Meta-regression analysis, adjusted for income economies, found the effect of smoking has not significantly improved over the years (p = 0.92) and thus implying neither of the covariates were source of the heterogeneity. Egger's regression test indicated that publication bias is unlikely (p = 0.403).

Conclusion: Cigarette smoking is significantly linked with poor tuberculosis treatment outcomes.

PubMed Disclaimer

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Flow chart for selecting studies for the systematic review and meta-analysis.
Fig 2
Fig 2. A forest plot displaying the effect of smoking on TB treatment outcomes.
Fig 3
Fig 3. Influential analysis for studies included in the meta-analysis.
Fig 4
Fig 4. Subgroup meta-analysis for the effect of smoking on TB treatment outcomes by income economies.
Fig 5
Fig 5. Sub-group analysis for the effect of smoking on TB treatment outcomes according to study timing.
Fig 6
Fig 6. Sub-group analysis according to the proportion of study participants living with HIV.
Fig 7
Fig 7. Funnel plot of the studies of the effect of smoking on TB treatment outcomes.
Fig 8
Fig 8. Contour enhanced funnel plot of studies of effect of smoking on TB treatment outcomes.
Fig 9
Fig 9. Cumulative meta-analysis of the effect of smoking on TB treatment outcomes.
See this image and copyright information in PMC

References

    1. World Health Organization; WHO report on the global tobacco epidemic, 2017: monitoring tobacco use and prevention policies: World Health Organization; 2017.
    1. World Health Organization. WHO global report on trends in prevalence of tobacco smoking 2015: World Health Organization; 2015.
    1. Öberg M, Jaakkola MS, Woodward A, Peruga A, Prüss-Ustün A. Worldwide burden of disease from exposure to second-hand smoke: a retrospective analysis of data from 192 countries. The Lancet 2011, 377(9760):139–146. - PubMed
    1. Qiu F, Liang C-L, Liu H, Zeng Y-Q, Hou S, Huang S, Lai X, et al. Impacts of cigarette smoking on immune responsiveness: Up and down or upside down? Oncotarget 2017, 8(1):268 10.18632/oncotarget.13613 - DOI - PMC - PubMed
    1. Maurya V, Vijayan VK, Shah A. Smoking and tuberculosis an association overlooked. The international journal of tuberculosis and lung disease: the official journal of the International Union against Tuberculosis and Lung Disease 2002, 6(11):942–951. - PubMed