Tappin et al investigated the efficacy of financial incentives (£400 of shopping vouchers) for smoking cessation in deprived pregnant women (n=612) and evidenced a 43% quit rate at 4 weeks vs 21% in the control group. The validity and usefulness of the findings are questionable as this apparent ‘success’ contrasts with: (a) a relative risk of premature birth of 1.52 (95% CI 0.95 to 2.39) (p=0.09) in the incentive group (13.4% vs 8.6% in control group); and (b) a non-significant difference in birth weight (3140g vs 3102g; p =0.67).
Firstly, the Fagerstrom questionnaire (assessing severity of nicotine addiction) was higher for all items in controls. Both groups only received a single form of nicotine replacement therapy (NRT) and four weekly support phone calls. Such NRT treatment may have led to inadequate dosing: a previous large randomized controlled trial (n= 3880) found success rates at 4-week follow-up of 16.3% for those without medication and 35.7% for those using a combination of various forms of NRT. Single form of NRT alone showed no benefit.(2)
Second, although Tappin et al reported a 22.5% success for the primary outcome (at 34-38 weeks’ gestation) in the incentive group versus 8.6% in controls, the details are not fully available. Patients in the financial incentive group may be more liable to ‘untruths’ when reporting (e.g. 30 were never contactable for validation vs 23 in the control group) or even ‘cheating’ when tested. The authors considered those who were lost to follow-up for the primary outcome had continued to smoke. For a true an intention-to-treat analysis, this would overestimate the success rate in the incentive group as controls who were lost to follow up and had quit smoking receive no reward from reporting. Can Tappin et al provide: a) the protocol for NRT dosing and for psychological support; b) the number of self-reported non-smokers who were positive for saliva or urine cotinine (for the primary outcome) indicating if the day for testing was planned, how women’s identity was checked for saliva and urine samples, and the number of self-reported non-smokers who were evaluated for saliva and for urine cotinine status in each group?
Third, while financial interventions appear to increase the proportion of smokers who attempt to quit and use treatments there is no evidence yet that smoking cessation shows higher quit rates at six months.(3) Similarly, although financial incentives for professionals increase the provision of cessation advice and referrals to stop smoking services there is not sufficient evidence to show that it leads to reductions in smoking rates.(4)
Lastly, are financial incentives fundamentally flawed? (5,6) There is far too little evidence for long-term efficiency; unsurprising given they do not promote autonomy. Additionally, the approach is far from fair; the most socially deprived citizens deserve better living conditions, an intervention which does work.(7) Financial incentives look more akin to lazy bribery (paying people to act against their wishes) or coercion (compelling people to behave using threats of not being paid). Is the improvement of healthcare providers’ motivational interviewing skills really so difficult? (8)
1 Tappin D, Bauld L, Purves D et al. Financial incentives for smoking cessation in pregnancy: randomised controlled trial. BMJ 2015 27;350:h134.
2 Brose LS, McEwen A, West R. Association between nicotine replacement therapy use in pregnancy and smoking cessation. Drug Alcohol Depend 2013;132:660-4.
3 Reda AA, Kotz D, Evers SM, van Schayck CP. Healthcare financing systems for increasing the use of tobacco dependence treatment. Cochrane Database Syst Rev 2012;6:CD004305.
4 Hamilton FL, Greaves F, Majeed A, Millett C. Effectiveness of providing financial incentives to healthcare professionals for smoking cessation activities: systematic review. Tob Control 2013;22:3-8.
5 Marteau TM, Ashcroft RE, Oliver A. Using financial incentives to achieve healthy behaviour. BMJ 2009;338:b1415.
6 Woolhandler S, Ariely D, Himmelstein DU. Why pay for performance may be incompatible with quality improvement. BMJ 2012;345:e5015
7 Ludwig J, Sanbonmatsu L, Gennetian L et al. Neighborhoods, obesity, and diabetes-a randomized social experiment. N Engl J Med 2011;365:1509-19.
8 Rollnick S, Butler CC, Kinnersley P, Gregory J, Mash B. Motivational interviewing. BMJ 2010 Apr 27;340:c1900.
Competing interests: No competing interests