Background Associations between smoking and poor tuberculosis (TB) treatment outcomes are well documented. However, for important outcomes such as TB recurrence/relapse and mortality-during-treatment, as well as for associations with smokeless tobacco (ST), the evidence is not systematically summarised. Research Question Is tobacco use associated with risk of poor treatment outcomes among people with TB. Study Design and Methods MEDLINE, EMBASE and CINAHL were searched on November 22, 2021. Epidemiological 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/relapse and mortality-during-treatment), and heterogeneity was explored using subgroups. Other outcomes were narratively synthesised. PROSPERO registration: CRD42017060821. 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/relapse was found with ever-smoking vs. never-smoking (RR=1·78, 95%CI=1·31-2·43, I2=85%), current-smoking vs. non-smoking (RR=1·95, 95%CI=1·59-2·40, I2=72%), and past-smoking vs. never-smoking (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-smoking (RR=1·55, 95%CI=1·32-1·81, I2=0%), and current-smoking (RR=1·51, 95%CI=1·09-2·10, I2=87%) significantly increased the likelihood of mortality-during-treatment among people with TB compared to never and non-current smoking, respectively; heterogeneity was largely explained by differences in study design. Almost all studies in the meta-analyses scored ‘high’ or ‘moderate’ on quality assessments. Narrative synthesis showed that smoking was a risk factor for other unfavourable TB treatment outcomes, as previously documented. Evidence on ST was limited, but identified studies suggested an increased risk for poor outcomes with their use compared to non-use. Interpretation Smoking significantly increases the risk of TB recurrence/relapse and mortality-during-treatment among people with TB, highlighting the need to address smoking to improve TB outcomes.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)