Immediate versus delayed quitting and rates of relapse among smokers treated successfully with varenicline, bupropion SR or placebo

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.

Trial registration: ClinicalTrials.gov NCT00141206 NCT00143364.

Figure 1

Participant disposition

Figure 2

Cumulative contributions of immediate quitters (IQs) and delayed quitters (DQs) to continuous abstinence rates, week X to week 12. Varenicline versus bupropion SR IQs (24.0%, 18.0%; P= 0.007); DQs (20.0%, 11.6%; P< 0.001). Varenicline versus placebo IQs (24.0%, 10.2%; P< 0.001); DQs (20.0%, 7.5%; P < 0.001). Bupropion SR versus placebo IQs (18.0%, 10.2%; P< 0.001) and DQs (11.6%, 7.5%; P= 0.009)

Figure 3

Continuous abstinence rates, weeks 9–12, by quit pattern, immediate or delayed. Differences between treatment groups were not significant

Figure 4

Weekly abstinence status of delayed quitters (DQs) following the day 8 TQD weeks 2–12. Most DQs remained continuously abstinent from the point of the first week of abstinence and did not lapse. DQs who lapsed generally re-established abstinence in the week following the lapse

Figure 5

Post-treatment relapse (rate of decline in continuous abstinence) by quit pattern (weeks)