Predictors of Varenicline Adherence Among Cancer Patients Treated for Tobacco Dependence and its Association With Smoking Cessation.

INTRODUCTION: The degree to which smokers adhere to pharmacotherapy predicts treatment success. The development of interventions to increase adherence requires identification of predictors of treatment adherence, particularly among specific clinical populations.

METHODS: Using data from a 12-week open-label phase of a clinical trial of varenicline for tobacco dependence among cancer patients (N = 207), we examined: (1) the relationship between self-reported varenicline adherence and verified smoking cessation and (2) demographic and disease-related variables, and early changes in cognition, affect, withdrawal, the reinforcing effects of smoking, and medication side effects, as correlates of varenicline adherence.

RESULTS: At the end of 12 weeks, 35% of the sample had quit smoking and 52% reported taking ≥80% of varenicline. Varenicline adherence was associated with cessation (p < .001): 58% of participants who were adherent had quit smoking versus 11% of those who were not. Participants who experienced early reductions in depressed mood and satisfaction from smoking and experienced an increase in the toxic effects of smoking, showed greater varenicline adherence (p < .05); the relationship between greater adherence and improved cognition, reduced craving, and reduced sleep problems and vomiting approached significance (p < .10).

CONCLUSIONS: Among cancer patients treated for tobacco dependence with varenicline, adherence is associated with smoking cessation. Initial changes in depressed mood and the reinforcing effects of smoking are predictive of adherence.

IMPLICATIONS: The benefits of varenicline for treating tobacco dependence among cancer patients may depend upon boosting adherence by addressing early signs of depression and reducing the reinforcing dimensions of cigarettes.