We examined the clinical and economic implications of two smoking cessation and relapse prevention strategies, MI and UC. The cost-effectiveness of MI for relapse prevention compared to UC was estimated to be $851/LY saved and $628/QALY saved. When cessation was considered, MI cost more than UC but provided no additional benefit. One-way sensitivity analysis revealed that the incremental cost-effectiveness of MI compared to UC was $86,300/QALY saved if 8% of smokers had quit. Including maternal medical costs in sensitivity analysis resulted in incremental “cost savings” for MI versus UC for relapse prevention, for smoking cessation MI was dominated by UC. In two-way sensitivity analysis, MI was still cost-effective compared to UC for relapse prevention ($17,300/QALY saved), if it cost $2000 per participant and was less effective (5/21). For smoking cessation, a higher level of effectiveness (9/110) and higher cost ($400/participant) resulted in a higher incremental cost-effectiveness ratio ($112,000/QALY).
In general, our analysis supports previous findings about the economic implications of smoking cessation programs among pregnant women, although the results of this study are difficult to compare to other work. When Ershoff et al. [11
] evaluated an intervention consisting of an initial interview, smoking counseling by a health educator, mailed self-help books, and reinforcement at prenatal care visits, they found that the cost savings for a 100,000-member Health Maintenance Organization (HMO) was $13,432, with a net benefit of $9202 and a benefit–cost ratio of 3:1. They did not extend their analysis to the societal perspective. Assessing three cessation protocols for women in public health maternity clinics, Windsor et al. [9
] found that 2%, 6%, and 14% of the participants in their respective groups stopped smoking, with costs per percentage who quit of $104, $118, and $50, respectively. Our study produced quit rates of 6% for MI and 8% for UC, although differences were not statistically significant. Marks et al. [16
] modeled the benefits that would accrue from shifting low-birth-weight infants into the normal-birth-weight category, averting deaths attributable to prematurity, and avoiding the long-term costs of caring for premature infants, concluding that the ratio of savings to costs could be as high as 6:1. They did not, however, separate smoking from nonsmoking attributable infant costs. When Shipp et al. [17
] modeled the break-even cost of a smoking cessation program during pregnancy, they obtained an estimate of around $32 per pregnant woman. Their sensitivity analysis revealed that this cost varied from $10 to $237, depending on the probability of adverse outcomes in various populations. Our costs exceed their estimates but fall within their range in real terms. To our knowledge, studies assessing the clinical and economic implications of relapse prevention for pregnant women are limited.
Our study has limitations. First, we studied low-income women in Boston; therefore, our findings cannot be generalized to other economic (high-income) and geographic groups. Second, we analyzed savings in maternal and infant medical costs but did not have long-term morbidity and mortality data for children related to smoking-related illnesses. Because published estimates might be overestimates or underestimates, we performed sensitivity analyses to determine their impact on cost-effectiveness ratios. Third, it is difficult to know how income and pregnancy might affect health-related quality of life and life-expectancy measures. Fourth, we did not measure some nonsmoking-related costs and benefits of MI (e.g., results from instruction on general health and social services), since the intervention was broader than smoking, but the CEA did not assess those outcomes [30
]. Fifth, because of the small sample size, we may not have had enough power to detect differences between groups on a number of study variables. Sixth, our study may under-estimate the importance of relapse prevention during pregnancy because it does not consider the impact of reducing maternal smoking during pregnancy on the risk of nicotine dependence among offspring.
From a policy perspective, the choice of whether to implement UC or MI will depend on available resources, alternative uses of resources, and other constraints. Comparing our results with cost-effectiveness ratios of other accepted preventive interventions demonstrates that resources devoted to smoking cessation [31
] and relapse prevention during and after pregnancy might be worthwhile [32
]. For example, cervical cancer screening costs have been estimated to range from $7100 (every 5 years compared to no screening) to $175,000 (every 2 years compared to every 3 years) per LY saved [33
In conclusion, our analysis suggests that, among low-income pregnant women, MI can prevent relapse at relatively low cost whereas MI was more costly and no more effective than UC in promoting smoking cessation. Inclusion in sensitivity analyses of net medical cost savings for infants and mothers as a result of sustained cessation and abstinence results in more favorable incremental cost-effectiveness ratios.