Search strategy

We used the PICO acronym (Participants; Interventions/exposures; Comparators and Outcomes) as a guide to develop search terms for electronic database search. In this specific review;

Participants in the studies were tuberculosis patients who were receiving anti-TB treatment

The intervention was smoking cessation or no history of smoking by the participant

The controls are tuberculosis patients who are smokers or have exposure to second-hand smoke

Outcomes included any of the tuberculosis treatment outcomes defined above

First, we searched PubMed, the Cochrane library and google scholar databases using free-text and Medical Subject-Heading (MeSH) terms for tuberculosis, treatment outcome and smoking without restrictions as to study period. Thereafter, we undertook advanced searching by combining the search terms using Boolean operators. We concluded any electronic database search on February 27, 2019 (S1 Annex). However, we screened reference lists of studies extracted through the electronic search to identify additional studies.