Is Tobacco Use Associated With Risk of Recurrence and Mortality Among People With TB?: A Systematic Review and Meta-Analysis

Abstract

Background: Associations between tobacco use and poor TB treatment outcomes are well documented. However, for important outcomes such as TB recurrence or relapse and mortality during treatment, as well as for associations with smokeless tobacco (ST), the evidence is not summarized systematically.

Research question: Is tobacco use associated with risk of poor treatment outcomes among people with TB?

Study design and methods: The MEDLINE, Embase, and Cumulative Index of Nursing and Allied Health Literature databases were searched on November 22, 2021. Epidemiologic studies reporting associations between tobacco use and at least one TB treatment outcome were eligible. Independent double-screening, extractions, and quality assessments were undertaken. Random effects meta-analyses were conducted for the two primary review outcomes (TB recurrence or relapse and mortality during treatment), and heterogeneity was explored using subgroups. Other outcomes were synthesized narratively.

Results: Our searches identified 1,249 records, of which 28 were included in the meta-analyses. Based on 15 studies, higher risk of TB recurrence or relapse was found with ever using tobacco vs never using tobacco (risk ratio [RR], 1.78; 95% CI, 1.31-2.43; I² = 85%), current tobacco use vs no tobacco use (RR, 1.95; 95% CI, 1.59-2.40; I² = 72%), and former tobacco use vs never using tobacco (RR, 1.84; 95% CI, 1.21-2.80; I² = 4%); heterogeneity arose from differences in study quality, design, and participant characteristics. Thirty-eight studies were identified for mortality, of which 13 reported mortality during treatment. Ever tobacco use (RR, 1.55; 95% CI, 1.32-1.81; I² = 0%) and current tobacco use (RR, 1.51; 95% CI, 1.09-2.10; I² = 87%) significantly increased the likelihood of mortality during treatment among people with TB compared with never using tobacco and not currently using tobacco, respectively; heterogeneity was explained largely by differences in study design. Almost all studies in the meta-analyses scored high or moderate on quality assessments. Narrative synthesis showed that tobacco use was a risk factor for other unfavorable TB treatment outcomes, as previously documented. Evidence on ST was limited, but identified studies suggested an increased risk for poor outcomes with its use compared with not using it.

Interpretation: Tobacco use significantly increases the risk of TB recurrence or relapse and mortality during treatment among people with TB, highlighting the need to address tobacco use to improve TB outcomes.

Trial registry: PROSPERO; No.: CRD42017060821; URL: https://www.crd.york.ac.uk/prospero/.

Keywords: TB; meta-analysis; risk of mortality; risk of recurrence; smoking; systematic review; tobacco.