Continuing efforts to improve cessation outcomes with pregnant cigarette smokers.

We are pleased to have this opportunity to comment on the excellent report by Ierfino and colleagues [1]. We begin by underscoring that smoking during pregnancy is the leading preventable cause of poor pregnancy outcomes in developed countries, also increasing the risk for numerous adverse neonatal outcomes, including sudden infant death and childhood behavior problems, as well as risk for later-in-life metabolic disorder and other chronic diseases [2–4]. The 0% cessation rate among the historical controls in the Ierfino et al. report provides a useful context for considering how urgent is the need for improvements in the effectiveness of strategies for managing this serious public health problem. It appears that the historical controls in this trial were offered the opportunity to receive individual cognitive behavioral therapy (CBT) and nicotine replacement therapy (NRT). Results from a highly influential meta-analysis of interventions for smoking cessation among pregnant women, including CBT and NRT, indicates that they produce an approximately 6% increase above control levels in late-pregnancy abstinence rates [5]. Therefore, perhaps the 0% outcome may not conform perfectly to expectations, but is not inaccurate by a great deal. It is important to note that such lackluster outcomes in routine care for pregnant smokers are not novel, especially among more disadvantaged women. Ierfino and colleagues supplemented routine care with an intervention using voucher-based financial incentives in the present effectiveness trial, which according to the same meta-analysis is expected to increase abstinence rates by approximately 24% above control levels. Ierfino et al. achieved a 20% late-pregnancy abstinence rate which, again, is somewhat, although not greatly, below predicted outcomes. These differences from predicted outcomes are probably attributable to the relatively high levels of socio-economic disadvantage among the women treated, which Ierfino and colleagues demonstrated predict poor outcomes with this incentives intervention. We have reported the same in our own research with the same incentives model, as well as a control intervention [6]. With both the historical controls and incentives intervention it appears that the outcomes obtained by Ierfino and colleagues are reasonable representations of how these interventions perform among economically disadvantaged pregnant smokers. In our opinion, the adverse impacts of smoking during pregnancy are too serious and well documented to accept 0% when it could be 20% unless there is good reason for doing so. This report by Ierfino and colleagues addressed one of the major rationales against adopting this incentives model: the intervention is too complex and time-consuming to integrate into routine obstetrical care. To the contrary, Ierfino and colleagues demonstrated that the intervention can be implemented effectively within the obstetrical service of a large hospital by adding only the additional support of the smoking-cessation staff person that the Community Health Service already provides. This is an enormously important contribution. There are seven controlled clinical trials supporting the efficacy of this voucher-based financial incentives model for smoking cessation among pregnant and newly postpartum pregnant women [7–13], along with evidence that the intervention increases fetal growth and improves birth outcomes [11,12,14] increases breastfeeding duration [15] and decreases postpartum depressive symptoms among depression-prone women who are at increased risk for postpartum depression [16]. Rather than making assumptions about the feasibility of moving this promising model into routine care we should test the assumptions empirically, as was performed in this study. We commend Ierfino and colleagues for keeping the parameters of the intervention largely consistent with those used in the efficacy trials, especially maximum potential incentive earnings. In this effectiveness trial, those incentives were extended to 24 weeks postpartum whereas in the efficacy trials they were terminated after 8–12 weeks postpartum. There were other minor procedural differences (e.g. how abstinence was biochemically confirmed) that do not merit detailing here and are to be expected. What we can say unequivocally, however, is that when we have had discussions with our local health department officials about such an effectiveness trial they have not been nearly as sensitive to the importance of maintaining the integrity of the intervention tested in the efficacy trials. Indeed, the suggested changes to the intervention in those initial discussions were sufficiently concerning to us to silence further discussion. We now plan to re-open those discussions with the Ierfino et al. report in hand. Our health department also assigns a smoking-cessation specialist to each regional hospital, so the staffing model used by Ierfino and colleagues appears to have potential for broad generalizability. Also important to note is that when we strip away the considerable research elements of our prior four trials on this incentives model, the actual clinical intervention duties have been handled almost exclusively by a primary interventionist, so our experience on this staffing point is consistent with that outlined by Ierfino and colleagues. Another benefit of keeping the effectiveness model close to the efficacy trials is that it creates the opportunity for meaningful comparisons and scientific dialogue between the efficacy and effectiveness investigators. In addition to the agreement noted above regarding socio-economic status as a predictor, we have also tested the predictive utility of delay discounting of hypothetical monetary rewards and similarly failed to find a significant association with cessation outcomes [17]. We have observed significant associations between discounting and spontaneous quitting after learning of a pregnancy, although these were conditional on smoking rate (i.e. significant negative association among light but not heavier smokers) [18]. This brings us to our final point regarding predictors. Ierfino and colleagues report no significant association between nicotine dependence level and treatment response, using the Heaviness of Smoking Questionnaire to assess nicotine dependence [19]. This instrument assesses time to first cigarette after awakening in the morning and number of cigarettes smoked per day, using an algorithm to combine across those two measures to arrive at a single score. Cigarettes smoked per day has been a robust, reliable predictor of antepartum abstinence levels achieved with this incentives model in our predictor studies [6,17]. We encourage Ierfino and colleagues to examine whether the same is also true in their data set if cigarettes/day is looked at separately. We close on the topic of cost-effectiveness, which Ierfino and colleagues mention appropriately as an important next step in the evaluation of this incentives model. We agree, and currently have such a trial under way comparing usual care alone versus usual care plus this incentives model through 1-year postpartum examining smoking status and maternal and infant health outcomes. Ierfino and colleagues appear to be well positioned to conduct a similar trial in their setting. Should that happen, we look forward to the opportunity to learn from each other. We note an irony in both groups concurring on the importance of this next step in trying to disseminate this incentives model into routine care. Where are those cost-effectiveness trials for the interventions currently being offered as routine care to pregnant smokers in the host hospital for this effectiveness trial or in our home community hospital? Indeed, where are the efficacy trials showing that NRT reduces smoking among pregnant smokers? Food for thought. We commend Ierfino and colleagues on an excellent study and report.