Tuberculosis patients learning about second-hand smoke (TBLASS): results of a pilot randomised controlled trial

Passive smoking is associated with tuberculosis (TB). Measures are required to protect non-smoking TB patients from second-hand smoke (SHS).

We developed a behavioural intervention to encourage TB patients to implement smoking restrictions at home in Pakistan.

To assess the likelihood of such an intervention being successful and to inform a definitive trial in future.

This was a pilot randomised controlled trial in which non-smoking TB patients were randomised to receive either individual-based support or individual-based support combined with family reminders. We recruited patients living with at least one smoker in their homes. Our primary outcome was urinary cotinine level as a measure of SHS exposure 2 months post-randomisation.

Of 273 patients assessed for eligibility, 150 (56%) patients were recruited and all but one were retained throughout the trial. A statistically significant absolute reduction was observed in non-smoking participants' exposure to SHS based on urinary cotinine levels in both Arm 1 (71%, 95%CI 61-79) and Arm 2 (76%, 95%CI 67-83) between baseline and follow-up at 2 months.

The recruitment and retention rates for trial participants make it feasible to conduct a definitive trial in future. The observed effect size makes it worthwhile to conduct such a trial.