For cost analyses, we computed the costs of intervention per caller, selleck chem Lenalidomide the cost per quit based on the 6-month ITT 7-day PPA, and the incremental cost-effectiveness ratio (ICER; Drummond, Sculpher, Torrance, O��Brien, & Stoddart, 2005). Intervention costs included direct costs associated with registration, provision of NRT and counseling (standard and MAC), and mailing of a quit guide (all participants) and a MAC information sheet (MAC participants only). Facility space, supplies, and physician supervision time were included in the call costs; research-related costs were excluded. We also computed secondary analyses of potential moderators including gender and race in order to meet requirements for National Institutes of Health (NIH)-funded clinical trials (Dickerson, Leeman, Mazure, & O��Malley, 2009).
The evaluation of moderators was accomplished with moderated logistic regression (MLR; Jaccard, 2001), in which gender or racial subgroup served as moderators. These MLR models included the dummy-coded variables for NRT group (with 2 weeks of patch as the reference condition), the moderator (e.g., gender), and two-way interactions of each NRT group dummy variable and the moderator (Kraemer, Wilson, Fairburn, & Agras, 2002). We also tested smoking heaviness as a potential moderator given its robust association with abstinence (e.g., Hyland et al., 2004). Race was coded as White versus non-White; smoking heaviness was coded as light smoking (��15 cigarettes/day) versus heavy smoking (>15 cigarettes/day). The study was originally powered to detect at least a 6.
4% increase in the abstinence rate due to an enhanced intervention (e.g., using combination NRT); this effect size was based on prior quitline studies, and we predicted that 7-day PPA rates at 6 months would be approximately 12% in a standard intervention versus 18.4% in an enhanced intervention. Results Participant Characteristics, CONSORT Diagram, and Sample Representativeness Table 1 provides descriptive statistics for baseline variables by treatment group (main effects of NRT duration, NRT type, and MAC); groups did not differ on any of these variables. On average, participants smoked one pack of cigarettes per day; approximately 85% smoked their first cigarette within the first 30min after waking, indicating significant nicotine dependence (Baker et al., 2007). Table 1. Participant Characteristics by Treatment Conditiona The study CONSORT diagram is shown in Figure 1. Overall, 76% of study participants completed the 6-month follow-up assessment; the completion rate did not AV-951 differ by treatment groups. There were no serious adverse events (SAEs) or deaths during the study. Figure 1. CONSORT diagram.