Commentary on Wu et al. (2017): Do very brief reduction interventions increase quitting among smokers not ready to quit?

Abstract

Some smokers unready to quit will quit in response to a brief smoking reduction intervention. Whether this is due to their being more likely to try to quit, more likely to succeed, or both, and whether the intervention's effectiveness is due to reduction, advice to quit, or both is unclear. Most smokers are not ready to quit in the near future, but reducing cigarettes per day (CPD) is common in such smokers 1. Interventions to reduce CPD aided by nicotine replacement therapy (NRT) increase quitting among smokers not ready to quit 2, but most smokers do not want to use medications 3. Although greater self-selected reduction in CPD appears to predict quitting 4, only one 5 of three prior randomized controlled trials (RCT) found that a reduction intervention without medication increased abstinence among smokers not ready to quit 5-7. Wu and colleagues’ recent pragmatic RCT contributes to the existing literature with evidence that a very brief reduction intervention (approximately 5 minutes in total) with physician's advice to quit but without medication increases point-prevalence abstinence in comparison to no treatment at a 12-month follow-up (13 versus 7%) 8. We commend the authors for a rigorous test of this important topic in a generalizable setting. One concern is that this study's comparison condition did not include clinician advice to quit smoking, which increases cessation more than no treatment 9. Thus, it is unclear whether the effectiveness of Wu and colleagues’ intervention is due to the reduction intervention, advice to quit, or a combination of the two. This is important, because both prior trials that compared a reduction intervention without medication to advice to quit did not find that reduction increased abstinence 5, 6. It is also unclear if the effectiveness of Wu and colleagues’ reduction intervention was due to an increased number of quit attempts (QA) or the increased success of QA. This is important, because the processes that prompt making a QA differ from those that engender the success of a QA 10. The only prior RCT of a reduction intervention without medication that measured QAs found that a reduction intervention did not predict making a QA 6 but self-selected magnitude of reduction did 11. We know of no trials that have tested the effect of a non-pharmacological reduction intervention on quit success (i.e. abstinence among those who made a QA). An intervention that increases QAs (i.e. initiates behavior) could be useful for those with low motivation to quit or low self-efficacy for quitting. In contrast, an intervention that increases quit success (i.e. maintains behavior) could be useful to overcome barriers to staying quit, such as high dependence, among those already motivated. Knowing which of these was the active ingredient in successful reduction studies is important for knowing who would benefit most from reduction interventions. Importantly, this trial is consistent with the finding that reducing CPD increases abstinence among smokers not ready to quit 2 but does not appear to be effective among those who intend to quit now 12. One explanation for this difference is that reducing CPD could be effective by increasing motivation to quit 11 and thus less impactful for those already motivated to quit. Another explanation is that, among smokers who intend to quit now, reducing CPD delays quitting which could decrease motivation to quit 13. In summary, including Wu and colleagues’ recent finding, two of three trials found reduction interventions without medication for smokers not ready to quit increases cessation in comparison to no treatment 5, 7, 8. Whether this is due to the reduction intervention, advice to quit, or both, and whether this is due to increasing QAs or quit success remains unclear. Nonetheless, Wu and colleagues’ findings suggest that a very brief and feasible reduction intervention can increase substantially the odds of future cessation for smokers not ready to quit now. E.M.K. has nothing to disclose. J.R.H. has received consulting and speaking fees from several companies that develop or market pharmacological and behavioral treatments for smoking cessation or harm reduction and from several non-profit organizations that promote tobacco control. He also consults for Swedish Match.