The safety, effectiveness and cost-effectiveness of cytisine in achieving six-month continuous smoking abstinence in tuberculosis patients—protocol for a double-blind, placebo-controlled randomized trial

Background and aims: Tuberculosis (TB) patients who quit smoking have much better disease outcomes than those who continue to smoke. In general populations, behavioural support combined with pharmacotherapy is the most effective strategy in helping people to quit. However, there is no evidence for the effectiveness of this strategy in TB patients who smoke. We will assess the safety, effectiveness and cost-effectiveness of cytisine—a low-cost plant-derived nicotine substitute—for smoking cessation in TB patients compared with placebo, over and above brief behavioural support. Design: Two-arm, parallel, double-blind, placebo-controlled, multi-centre (30 sites in Bangladesh and Pakistan), individually randomized trial. Setting: TB treatment centres integrated into public health care systems in Bangladesh and Pakistan. Participants: Newly diagnosed (in the last 4 weeks) adult pulmonary TB patients who are daily smokers (with or without dual smokeless tobacco use) and are interested in quitting (n = 2388). Measurements: The primary outcome measure is biochemically verified continuous abstinence from smoking at 6 months post-randomization, assessed using Russell Standard criteria. The secondary outcome measures include continuous abstinence at 12 months, lapses and relapses; clinical TB outcomes; nicotine dependency and withdrawal; and adverse events. Comments: This is the first smoking cessation trial of cytisine in low- and middle-income countries evaluating both cessation and TB outcomes. If found effective, cytisine could become the most affordable cessation intervention to help TB patients who smoke.