This large-scale randomized trial evaluated Internet only and Internet plus telephone treatment for smoking cessation with encouraging short- and long-term cessation outcomes. The conservative measure of multiple PPA favored the EI+P condition throughout the follow-up time points, likely reflecting initial, sustained gains. Significant between group differences in the more commonly reported 30-day PPA rates during the first 12 months of the study were driven by superior outcomes in the EI+P condition achieved early in the study period and maintained over time. The addition of telephone counseling significantly increased cessation at 3 and 6 months over the 2 Internet conditions, although these differences were eventually attenuated at 18 months because of improvement in the BI and EI conditions.
This study has several strengths. Designed largely as a pragmatic randomized trial,33
the study sought to maximize generalizability and real-world relevance while preserving internal validity. The use of a recruitment method to obtain a representative sample of the Internet population entirely in vivo, in this case in the moment of searching online for information about cessation, is innovative and demonstrates the feasibility of conducting large-scale randomized trials via the Internet. It is one of the few randomized trials of a widely disseminated Internet cessation intervention that will advance the science of Internet research.21
The study evaluates treatments as used in the real world, bridging what is often a critical gap between tightly controlled clinical research and the applicability of research findings in practice.34
The interventions are practical, can be scaled up to meet demand, and can be combined with other modalities of intervention provision (eg, primary care, managed care, and work site). These results extend and are consistent with the uncontrolled study of Internet and telephone treatment by Zbikowski et al.13
Triage of smokers via the Internet may represent an effective and efficient way to provide combined cessation treatment to a large number of smokers, of whom approximately 20% can be expected to quit.
It is noteworthy that EI+P treatment yielded relatively high quit rates early in the study (19% at 3 months), which were observed over time. The integration of Internet and telephone programs may encourage greater immediate use and adherence to the information and support available through both modalities, may prevent early relapse by virtue of the timing of the counseling calls, and/or may provide direct social support that allows the counselor to tailor the intervention to the smoker’s needs. The specific contribution of telephone counseling to the higher level of success of the combined program over each of the Internet-only interventions is unclear. It is possible that telephone counseling encouraged participants to set an early quit date and helped them sustain that early quit. Future studies will need to explore the optimum dose and format of adjuvant telephone treatment, as well as the mechanisms of action. The equivalent performance of EI and BI in this trial is consistent with other studies that found no significant differences between static and interactive Web sites.5, 6, 10
Identifying the active ingredients and optimal levels of intensity and tailoring of Internet cessation programs will be an important next step for the field. Future research should address this issue, perhaps with the use of adaptive research methods to ensure that interventions continue to improve as technology, consumer expectations, and scientific understanding advance.
Several limitations should be noted. In designing this study, one might have considered other comparison or no-treatment control conditions, especially in light of the unexpectedly high long-term quit rates in the information-only BI condition. However, the selection of an appropriate control condition raises pragmatic, ethical, and methodologic challenges that are not easy to resolve.21
Because participants were recruited online from within a search engine query, a basic information Website (minimum treatment control) condition was deemed the best option. We considered using or adapting to an online format a self-help manual commonly used as a minimal treatment control in smoking studies but determined that it would lack important qualities of usability, credibility, and interactivity that Internet users expect. The relatively high abstinence rates observed in the BI condition should be considered in the context of the recruitment approach, which may have self-selected participants with unusually high motivation to quit. Although recruitment was conducted from a real-world sample of smokers on the Internet and data were collected on enrollees and nonenrollees,17
generalizability is limited to that sample frame. As a related issue, it is possible that a bias against using a telephone intervention exists among individuals who turn to the Internet for smoking cessation assistance. The lower follow-up assessment rate among EI+P participants at 3 months may have been owing to “telephone fatigue” among Internet users randomized to receive proactive telephone counseling. Telephone counseling was provided within the first 3 months of the study, which was the only assessment period for which higher loss to follow-up was observed. If present, this bias could have attenuated the effectiveness of the combined intervention. Future research will need to determine the extent to which recruitment modality (ie, Internet vs telephone) affects treatment preference, use, and outcomes.
Despite these caveats, the potential public health significance (impact = reach x efficacy35
) of these findings is striking. Combining evidence-based cessation interventions such as Internet and telephone counseling could substantially accelerate cessation in the United States.16, 36
The broad reach of the Internet to more than 10 million smokers seeking assistance each year2
and the ubiquitous use of telephones, combined with the efficacy demonstrated in this study (7.7%–19.6% quit at 18 months), suggests that the potential population impact of this treatment approach is high.