Abstract
AIMS: We assessed to what degree smokers who fail to quit on the target quit date (TQD) or lapse following TQD eventually achieve success with continued treatment. DESIGN: A secondary analysis of pooled data of successful quitters treated with varenicline (306 of 696), bupropion (199 of 671) and placebo (121 of 685) from two identically-designed clinical trials of varenicline versus bupropion sustained-release and placebo. SETTING: Multiple research centers in the US. PARTICIPANTS: Adult smokers (n==2052) randomized to 12 weeks drug treatment plus 40 weeks follow-up. MEASUREMENT: The primary end-point for the trials was continuous abstinence for weeks 9-12. TQD was day 8. Two patterns of successful quitting were identified. Immediate quitters (IQs) were continuously abstinent for weeks 2-12. Delayed quitters (DQs) smoked during 1 or more weeks for weeks 2-8. FINDINGS: Cumulative continuous abstinence (IQs + DQs) increased for all treatments during weeks 3-8. Overall IQs and DQs for varenicline were (24%; 20%) versus bupropion (18.0%, P=0.007; 11.6%, P<0.001) or placebo (10.2%, P<0.001; 7.5%, P<0.001). However, DQs as a proportion of successful quitters was similar for all treatments (varenicline 45%; bupropion 39%; placebo 42%) and accounted for approximately one-third of those remaining continuously abstinent for weeks 9-52. No gender differences were observed by quit pattern. Post-treatment relapse was similar across groups. CONCLUSIONS: Our data support continuing cessation treatments without interruption for smokers motivated to remain in the quitting process despite lack of success early in the treatment.