Presence of adverse events in the first thirty days of treatment and other baseline demographic and smoking history characteristics did not significantly predict adherence in these trials (Hays et al., 2010). The distinction made between purposeful and unintentional adherence in one smoking cessation study (Toll, McKee, Martin, Jatlow, & seriously O��Malley, 2007) is important to note when considering potential predictors of adherence because the chronic disease adherence literature suggests that adherence-related motivation, beliefs, and attitudes that are amenable to change may be more likely to influence purposeful (also termed ��intentional��) adherence lapses and demographic factors such as age may be more likely to influence unintentional adherence lapses (e.g., forgetting; Clifford, Barber, & Horne, 2008; Wroe, 2002).

For example, a study to explore attitudes about bupropion found that greater self-efficacy beliefs for using bupropion as indicated were associated with higher levels of electronically monitored bupropion adherence, a greater number of treatment sessions attended, and an increased likelihood of completing treatment (Fucito, Toll, Salovey, & O��Malley, 2009). We report on adherence to a standard 12-week varenicline regimen that was mailed to all smokers who set quit dates in the COmprehensive Medication Program And Support Services (COMPASS) trial. This trial compared the effectiveness of three modalities of a behavioral smoking cessation program when combined with varenicline use among smokers seeking treatment at a large health care organization.

When varenicline treatment was integrated with either Web-based counseling, proactive phone-based counseling, or integrated phone and Web counseling, no significant differences in 6-month abstinence rates were found (Swan et al., 2010). Abstinence rates in this real-world effectiveness study were high (31%�C34%) and similar to rates seen in varenicline clinical trials when the medication was combined with in-person counseling (Swan et al., 2010). The goals of this secondary analysis are to describe rates and patterns of adherence to varenicline, investigate the extent to which varenicline adherence impacts smoking cessation outcomes, and to identify modifiable factors associated with varenicline adherence that can be addressed in future integrated behavioral and pharmacotherapy smoking cessation interventions.

Methods Setting and Participants Group Health is a consumer-governed nonprofit health care organization that serves approximately 600,000 residents of Washington and GSK-3 Idaho. Group Health enrollees were recruited from October 2006 to October 2007 through brochures placed in health plan�Cowned clinics, physician referrals, and through the Quit For Life Program administered by Free & Clear, Inc.