Toward precision smoking cessation treatment I: Moderator results from a factorial experiment

Abstract

Background: The development of tobacco use treatments that are effective for all smokers is critical to improving clinical and public health. The Multiphase Optimization Strategy (MOST) uses highly efficient factorial experiments to evaluate multiple intervention components for possible inclusion in an optimized tobacco use treatment. Factorial experiments permit analyses of the influence of patient characteristics on main and interaction effects of multiple, relatively discrete, intervention components. This study examined whether person-factor and smoking characteristics moderated the main or interactive effects of intervention components on 26-week self-reported abstinence rates.

Methods: This fractional factorial experiment evaluated six smoking cessation intervention components among primary care patients (N=637): Prequit Nicotine Patch vs. None, Prequit Nicotine Gum vs. None, Preparation Counseling vs. None, Intensive Cessation In-Person Counseling vs. Minimal, Intensive Cessation Telephone Counseling vs. Minimal, and 16 vs. 8 Weeks of Combination Nicotine Replacement Therapy (NRT; nicotine patch+nicotine gum).

Results: Both psychiatric history and smoking heaviness moderated intervention component effects. In comparison with participants with no self-reported history of a psychiatric disorder, those with a positive history showed better response to 16- vs. 8-weeks of combination NRT, but a poorer response to counseling interventions. Also, in contrast to light smokers, heavier smokers showed a poorer response to counseling interventions.

Conclusions: Heavy smokers and those with psychiatric histories demonstrated a differential response to intervention components. This research illustrates the use of factorial designs to examine the interactions between person characteristics and relatively discrete intervention components. Future research is needed to replicate these findings.

Keywords: Factorial design; Moderators; Psychiatric comorbidity; Smoking cessation; Treatment.

Figure 1. Treatment main effects on Week 26 abstinence rates moderated by psychiatric history. These graphs depict the mean Week 26 abstinence rates and 95% confidence intervals for each treatment group by the presence (n=264; 41%) or absence (n=372; 59%) of a psychiatric history

Figure 1a. Week 26 abstinence rates for the psychiatric history x Preparation Counseling interaction Figure 1b. Week 26 abstinence rates for the psychiatric history x In-Person Counseling interaction Figure 1c. Week 26 abstinence rates for the psychiatric history x Medication Duration interaction

Figure 2. Treatment interaction effects on Week 26 abstinence rates moderated by psychiatric history. These graphs depict the mean Week 26 abstinence rates and 95% confidence intervals for each combination of treatments by the presence (n=264; 41%) or absence (n=372; 59%) of a psychiatric history

Figure 2a. Week 26 abstinence rates for the psychiatric history x Phone Counseling x In-Person Counseling interaction Figure 2b. Week 26 abstinence rates for the psychiatric history x Prequit Patch x In-Person Counseling interaction

Figure 3

Week 26 abstinence rates for the interaction of heavy smoking (smoking >20 cigs/day) x Phone Counseling x In-Person Counseling. This graph depicts the mean Week 26 abstinence rates and 95% confidence intervals for each treatment combination by the amount of cigarettes smoked.