Efficacy of brief motivational interviewing on smoking cessation at tuberculosis clinics in T shwane, S outh A frica: a randomized controlled trial

Background and Aims Tuberculosis ( TB ) patients who smoke risk adverse TB outcomes and other long‐term health effects of smoking. This study aimed to determine the efficacy of brief motivational interviewing by lay health‐care workers ( LHCW s) in assisting TB patients to quit smoking. Design Multi‐centre two‐group parallel individual randomized controlled trial. Setting Six primary care tuberculosis clinics in a S outh A frican township. Participants Newly diagnosed adult TB patients identified as current smokers were randomized to brief motivational interviewing by a LHCW (intervention group, n  = 205) or brief smoking cessation advice from a TB nurse (control group, n  = 204). Measurements The primary outcome was self‐reported sustained 6‐month smoking abstinence. Exhaled carbon monoxide ( CO ) testing was offered to about half the participants. Secondary outcomes were sustained abstinence at 3 months; 7‐day point prevalence abstinence at 1, 3 and 6 months; and quit attempts. Allocation was concealed. Primary analysis relied on intention to treat. Multi‐level analysis accounted for site heterogeneity of effect. Findings Self‐reported 6‐month sustained abstinence was 21.5% for the intervention group versus 9.3% for the control group [relative risk ( RR ) = 2.29, 95% confidence interval ( CI ) = 1.34, 3.92]. Biochemically verified 6‐month sustained abstinence was also higher in the intervention group ( RR 2.21, 95% CI = 1.08, 4.51) for the 166 participants who were offered carbon monoxide testing. Self‐reported 3‐month sustained abstinence was 25.4% for the intervention group and 12.8% for the control group ( RR =  1.98, 95% CI =  1.24, 3.18). Conclusions Motivational interviewing by lay counsellors to promote smoking cessation in tuberculosis patients in S outh A frica approximately doubled sustained smoking abstinence for at least 6 months compared with brief advice alone.