Effect of Cessation Interventions on Hookah Smoking: Post-Hoc Analysis of a Cluster-Randomized Controlled Trial

We explored the differential effect of cessation interventions (behavioral support sessions with [BSS+] and without [BSS] bupropion) between hookah and cigarette smokers. We reanalyzed the data from a major cluster-randomized controlled trial, ASSIST (Action to Stop Smoking In Suspected Tuberculosis), which consisted of 3 conditions: (a) behavioral support sessions (BSS), (b) behavioral support sessions plus 7 weeks of bupropion therapy (BSS+), and (c) controls receiving usual care. The trial originally recruited 1,955 adult smokers with suspected tuberculosis from 33 health centers in the Jhang and Sargodha districts of Pakistan between 2010 and 2011. The primary endpoint was continuous 6-month smoking abstinence, which was determined by carbon monoxide levels. Subgroup-specific relative risks (RRs) of smoking abstinence were computed and tested for differential intervention effect using log binomial regression (generalized linear model) between 3 subgroups (cigarette-only: 1,255; mixed: 485; and hookah-only: 215). The test result for homogeneity of intervention effects between the smoking forms was statistically significant (p-value for BSS+: .04 and for BSS: .02). Compared to the control, both interventions appeared to be effective among hookah smokers (RR = 2.5; 95% CI = 1.3-4.7 and RR = 2.2; 95% CI = 1.3-3.8, respectively) but less effective among cigarette smokers (RR = 6.6; 95% CI = 4.6-9.6 and RR = 5.8; 95% CI = 4.0-8.5), respectively. The differential intervention effects on hookah and cigarette smokers were seen (a) because the behavioral support intervention was designed primarily for cigarette smokers; (b) because of differences in demographic characteristics, behavioral, and sociocultural determinants; or (c) because of differences in nicotine dependency levels between the 2 groups.