Can incentives help smokers to quit in the medium to long term?

Cochrane: Incentives, usually as cash or as vouchers, are widely used to encourage smokers to try to quit, and to reward them if they succeed. Such schemes can be run in workplaces, in clinics, and sometimes as community programmes. For this third update of our review we now include studies in pregnant women. Another change is that we have separated out trials which use incentives from those which use competitions; we will now cover the competition trials in a separate update. The conclusions are: Incentives appear to boost cessation rates while they are in place.


Key results:

Mixed-population trials: Six months or more after the beginning of the trial, people receiving incentives were more likely to have quit than those in the control groups. Only three trials reported prolonged success beyond the close of the programme. One USA trial, paying quitters up to USD 750, found that nearly three times as many people stopped smoking in the experimental group compared to the controls. Another USA trial paying out up to USD 800 per quitter found that nearly twice as many people receiving payments stopped smoking compared to the control group. This trial also compared paying out rewards to returning the participant's own money to them if they managed to quit. Although more people in this trial took part in the rewards programmes than in the deposit programmes, the proportion of quitters in each group favoured the deposit-refund programme. The third trial was based in Thailand and rewarded quitters by returning their own money to them with bonuses. Although medium-term quit rates were encouraging, the deposit-return programmes generally struggled to match the rewards programmes for numbers willing to take part.
 
Pregnancy trials: Eight of the nine trials with usable data showed that women in the incentive groups were more likely to quit than those in the control groups, both at the end of the pregnancy and at the longest follow-up (up to 24 weeks after the birth). Four of the trials confirmed that payments made to reward a successful quit attempt ('contingent' payments), compared to fixed payments for attending the antenatal appointment ('non-contingent'), produced higher quit rates. The largest trial, based in the UK, used the NHS stop-smoking service to deliver support in quitting, and achieved a quit rate in the incentives group almost four times as high as in the control group. One trial which weighted the payments to meet the challenge of greater withdrawal symptoms in the first two weeks of quitting found that this made little difference to the women's chances of success.

Conclusions: 

Incentives appear to boost cessation rates while they are in place. The two trials recruiting from work sites that achieved sustained success rates beyond the reward schedule concentrated their resources into substantial cash payments for abstinence. Such an approach may only be feasible where independently-funded smoking cessation programmes are already available, and within a relatively affluent and educated population. Deposit-refund trials can suffer from relatively low rates of uptake, but those who do sign up and contribute their own money may achieve higher quit rates than reward-only participants. Incentive schemes conducted among pregnant smokers improved the cessation rates, both at the end-of-pregnancy and post-partum assessments. Current and future research might continue to explore the scale, loading and longevity of possible cash or voucher reward schedules, within a variety of smoking populations.