Mobile phone-based interventions for smoking cessation (Review)

Transcription

1 Mobile phone-based interventions for smoking cessation (Review) Whittaker R, McRobbie H, Bullen C, Borland R, Rodgers A, Gu Y This is a reprint of a Cochrane review, prepared and maintained by The Cochrane Collaboration and published in The Cochrane Library 2012, Issue 11

2 T A B L E O F C O N T E N T S HEADER ABSTRACT PLAIN LANGUAGE SUMMARY BACKGROUND OBJECTIVES METHODS RESULTS Figure Figure DISCUSSION AUTHORS CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES CHARACTERISTICS OF STUDIES DATA AND ANALYSES Analysis 1.1. Comparison 1 Mobile phone intervention v. control, Outcome 1 26wk continuous abstinence WHAT S NEW HISTORY CONTRIBUTIONS OF AUTHORS DECLARATIONS OF INTEREST SOURCES OF SUPPORT DIFFERENCES BETWEEN PROTOCOL AND REVIEW INDEX TERMS i

3 [Intervention Review] Mobile phone-based interventions for smoking cessation Robyn Whittaker 1, Hayden McRobbie 2, Chris Bullen 1, Ron Borland 3, Anthony Rodgers 4, Yulong Gu 1 1 National Institute for Health Innovation, University of Auckland, Auckland, New Zealand. 2 Wolfson Institute of Preventive Medicine, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London, UK. 3 VicHealth Centre for Tobacco Control, The Cancer Council Victoria, Carlton, Australia. 4 Department of Medicine, University of Auckland, Clinical Trials Research Unit (CTRU), Auckland, New Zealand Contact address: Robyn Whittaker, National Institute for Health Innovation, University of Auckland, Tamaki Campus, Private Bag 92019, Auckland, 1142, New Zealand. r.whittaker@nihi.auckland.ac.nz. Editorial group: Cochrane Tobacco Addiction Group. Publication status and date: New search for studies and content updated (conclusions changed), published in Issue 11, Review content assessed as up-to-date: 29 September Citation: Whittaker R, McRobbie H, Bullen C, Borland R, Rodgers A, Gu Y. Mobile phone-based interventions for smoking cessation. Cochrane Database of Systematic Reviews 2012, Issue 11. Art. No.: CD DOI: / CD pub3. Background A B S T R A C T Innovative and effective smoking cessation interventions are required to appeal to those who are not accessing traditional cessation services. Mobile phones are widely used and are now well-integrated into the daily lives of many, particularly young adults. Mobile phones are a potential medium for the delivery of health programmes such as smoking cessation. Objectives To determine whether mobile phone-based interventions are effective at helping people who smoke, to quit. Search methods For the most recent update, we searched the Cochrane Tobacco Addiction Group Specialised Register in May We also searched UK Clinical Research Network Portfolio for current projects in the UK and the ClinicalTrials register for on-going or recently completed studies. We searched through the reference lists of identified studies and attempted to contact the authors of ongoing studies, with no restrictions placed on language or publication date. Selection criteria We included randomized or quasi-randomized trials. Participants were smokers of any age who wanted to quit. Studies were those examining any type of mobile phone-based intervention. This included any intervention aimed at mobile phone users, based around delivery via mobile phone, and using any functions or applications that can be used or sent via a mobile phone. Data collection and analysis Information on risk of bias and methodological details was extracted using a standardised form. Participants who dropped out of the trials or were lost to follow-up were considered to be smoking. We calculated risk ratios (RR) for each included study. Meta-analysis of the included studies was undertaken using the Mantel-Haenszel fixed-effect method. Where meta-analysis was not possible, summary and descriptive statistics are presented. 1

4 Main results Five studies with at least six month cessation outcomes were included in this review. Three studies involve a purely text messaging intervention that has been adapted over the course of these three studies for different populations and contexts. One study is a multiarm study of a text messaging intervention and an internet QuitCoach separately and in combination. The final study involves a video messaging intervention delivered via the mobile phone. When all five studies were pooled, mobile phone interventions were shown to increase the long term quit rates compared with control programmes (RR 1.71, 95% CI 1.47 to 1.99, over 9000 participants), using a definition of abstinence of no smoking at six months since quit day but allowing up to three lapses or up to five cigarettes. Statistical heterogeneity was substantial as indicated by the I² statistic (I² = 79%), but as all included studies were similar in design, intervention and primary outcome measure, we have presented the meta-analysis in this review. Authors conclusions The current evidence shows a benefit of mobile phone-based smoking cessation interventions on long-term outcomes, though results were heterogenous with findings from three of five included studies crossing the line of no effect. The studies included were predominantly of text messaging interventions. More research is required into other forms of mobile phone-based interventions for smoking cessation, other contexts such as low income countries, and cost-effectiveness. P L A I N L A N G U A G E S U M M A R Y Can interventions delivered by mobile phones help people to stop smoking? Combined, evidence from five studies included in this review finds that interventions delivered by mobile phones can help people stop smoking, though the results from individual studies varied. The interventions included in this review mainly use text messaging to provide motivation, support and tips for quitting. There are no published studies on smartphone applications designed to help people stop smoking. B A C K G R O U N D Since the introduction of mobile phone networks in the 1980s the use of mobile phones has grown exponentially. The International Telecommunications Union (ITU) reports that at the end of 2011 there were nearly six billion mobile cellular subscriptions worldwide, corresponding to global penetration of 87% with some countries (e.g. United Kingdom and parts of Europe) having greater than 100% penetration (ITU 2011). In their 2010 report, the ITU commented on the rapid expansion in the use of text messaging with an estimated 6.1 trillion text messages sent that year (approximately 200,000 per second) compared with 1.8 trillion in 2007 (ITU 2010). Mobile phones are becoming increasingly useful in health information and health care delivery around the world. Text messaging has been used for reminders for health service appointments, preventive activities and medication adherence. Mobile phones have also been used in monitoring and self-management of chronic disorders such as diabetes (Ferrer-Roca 2004; Gammon 2005; Kim 2006; Tasker 2007; Quinn 2011). Smartphones (mobile phones with computer operating systems) have broadened the functions of mobile phones considerably. Smartphone applications for health and wellness are proliferating although there is little published research in this area. Medical smartphone applications are being used by clinicians and health care workers in many countries. Access to the internet via mobile phones is rapidly increasing worldwide (ITU 2011) and is likely to become more important in access to health-related information and services in the coming years. Smoking cessation services are also starting to use mobile phones to deliver support, particularly as adjuncts to quitlines and Internet quit coaches, e.g. the NHS Stop Smoking Service s Together programme, the U.S. National Cancer Institute s smokefreetxt programme, and the New Zealand Quitline Txt2quit programme. The potential benefits of mobile phone-based smoking cessation interventions include: the ease of use anywhere at anytime; costeffective delivery and scalability to large populations regardless of location; the ability to tailor messages to key user characteristics (such as age, sex, ethnicity); the ability to send time-sensitive messages with an always on device; the provision of content that can distract the user from cravings; and the ability to link the user with 2

5 others for social support. It is likely that the use of mobile phones for smoking cessation will continue to grow as they become even more ubiquitous and as technological advances increase the number of applications and functions available. Therefore it is important to determine if mobile phones can be effective at helping people who smoke, to quit. O B J E C T I V E S To determine whether mobile phone-based interventions are effective at helping people who smoke, to quit. M E T H O D S sms, or mms in the title, abstract, or keyword fields. The Specialised Register includes reports of possible controlled trials of smoking cessation interventions identified from sensitive searches of databases. At the time of the search the Register included the results of searches of the Cochrane Central Register of Controlled trials (CENTRAL), issue 1, 2012; MEDLINE (via OVID, to update ), and EMBASE (via OVID, to update week ). See the the Cochrane Tobacco Addiction Module in the Cochrane Library for full search strategies and a list of other resources searched. We also searched the UK Clinical Research Network Portfolio for current projects in the UK and the ClinicalTrials register for ongoing or recently completed studies. We searched through the reference lists of identified studies and attempted to contact the authors of on-going studies. There were no restrictions placed on language or publication date. Criteria for considering studies for this review Data collection and analysis Types of studies Randomized or quasi-randomized trials. Types of participants All smokers who want to quit smoking. No age restrictions applied. Types of interventions We included studies which examine any type of mobile phonebased intervention. This included any intervention aimed at mobile phone users, based around delivery via mobile phone, and using any functions or applications that can be used or sent via a mobile phone. We excluded trials where mobile phones were seen as an adjunct to face-to-face or Internet based programmes such as to remind participants of appointments or where the effects of the various components of a multi-faceted programme could not be separated. Types of outcome measures The primary outcome of interest was smoking abstinence at six months or longer after the start of the intervention. When available, we preferred sustained abstinence to point prevalence abstinence and biochemically validated results to self report. Search methods for identification of studies For the present update of the review, we searched the Specialised Register of the Cochrane Tobacco Addiction Review Group in May 2012 using the terms mobile phone, cell phone, txt, pxt, Selection of studies The Tobacco Addiction Group Trial Search Co-ordinator prescreened the titles and abstracts of records identified from the Register search to exclude reports that had no relevance to the topic and to provide a list of potentially relevant citations. Two authors (RW, YG, or HM) identified potentially eligible studies and obtained full text copies. The same authors independently selected studies to be included against the criteria listed above and any disagreements were resolved by discussion, by contacting study authors, or by referring to RB to act as arbiter where required. Reasons for exclusion of studies were recorded. Data extraction and management We extracted from the included studies information on the following methodological details. These are presented in the Characteristics of included studies table. The articles were not blinded for authors, institution and journal, because the review authors who performed the quality assessment are familiar with the literature. If an article did not contain enough information on methodological criteria, i.e. if one or more of the risk of bias criteria were scored unclear, we contacted the trial authors for additional information. Characteristics of the study participants 1) Definition of smoking status as used in the study 2) Age and any other recorded characteristics of people who smoke in the study 3) Other inclusion criteria 4) Exclusion criteria Interventions used 1) Type and dose of mobile phone intervention used 2) Type of control used 3

6 3) Duration of intervention 4) Length of follow-up Assessment of risk of bias in included studies We extracted from the included studies information on the following criteria: 1) Method of randomization 2) Presence or absence of blinding to treatment allocation (nonblinded/open label, single blind, double blind, triple blind) 3) Quality of allocation concealment (adequate, unclear, inadequate, not used) 4) Number of participants randomized, excluded and lost to follow-up 5) Whether an intention-to-treat analysis was carried out 6) Whether a power calculation was reported 7) Duration, timing and location of the study Measures of treatment effect We recorded the below information where available: 1) Smoking cessation at six months (self reported abstinence and/ or biochemically verified abstinence) 2) Smoking cessation at final follow-up (if follow-up greater than six months and where these data were available) 3) Smoking cessation at four weeks (self reported abstinence and/ or biochemically verified abstinence) 4) Definition of smoking cessation as used in the study We calculated risk ratios for each included study. Dealing with missing data RW and YG independently extracted the data using a standardised form. We regarded those trial participants who dropped out of the trials or were lost to follow-up as continuing to smoke according to the Cochrane Tobacco Group s guidelines. Data synthesis We conducted a meta-analysis of the included studies, using the Mantel-Haenszel fixed-effect method to pool risk ratios. We originally did not pool studies in the presence of substantial statistical heterogeneity as assessed by the I 2 statistic (Higgins 2003). However, in this update we consider that the studies are all similar in design, intervention and primary outcome measure and therefore present the results of a meta-analysis despite the presence of substantial statistical heterogeneity. Where meta-analysis was not possible we present summary and descriptive statistics. R E S U L T S Description of studies See: Characteristics of included studies; Characteristics of excluded studies; Characteristics of ongoing studies. Results of the search For this update of our review, 68 studies were identified by the literature search strategy outlined above. Many were unrelated and were immediately excluded, leaving 17 potentially relevant papers. Some were not trials (Bennett 2011, Snider 2011), and some were excluded as they were small, non-randomized feasibility studies (Haug 2008; Lazev 2004; Obermayer 2004; Riley 2008). Others were excluded because follow-up was less than six months (Applegate 2007; Haug 2009; Naughton 2011). Several studies (Vidrine 2006; Gritz 2011) describe an intervention where mobile phones are used to make proactive counselling phone calls for free to an HIV-positive population who are given mobile phones for this purpose. To date these have not been included in this systematic review as six month results have not been available. Longer term follow-up is planned and we hope will be included in future updates. One trial used text messaging to increase compliance with varenicline, the control group receiving varenicline with no text messages (Yuhongxia 2011). Along with compliance this trial did consider cessation as an outcome, however this was reported only as a poster abstract in conference proceedings, and our attempts to contact the author for more details were not successful. We found two studies of multicomponent interventions targeted at improving blood pressure control with text message support that included information about smoking and measured smoking cessation as a secondary outcome (Wizner 2009; Kiselev 2011). We considered these studies were not relevant to this review (Kiselev 2011, only available in Russian). Similarly, another published protocol is using text messaging to reduce overall cardiovascular risk in people with cardiovascular disease that includes smoking cessation (NCT ). This and another protocol paper have been included in on-going studies here (Haug 2012). Details of excluded and ongoing studies can be found in the Characteristics of excluded studies and Characteristics of ongoing studies tables, respectively. In the previous review, we included two trials (Brendryen 2008a; Brendryen 2008b) of the same internet and mobile phone intervention, as the mobile phone component was treated by the authors as equally important and involved similar elements to those in other included studies (daily information, motivational text messages and pre-recorded audio messages). These were analysed separately from the mobile-only interventions (and were shown to be effective) and, as no other similar studies came up in our literature search, we have decided not to include these in this update. In this update we add two new randomised controlled trials with six month outcomes that were identified in the literature search: one that followed on from the Free pilot study (Free 2011) and 4

7 a video messaging mobile phone intervention trial (Whittaker 2011). On approaching known authors of previous or ongoing studies, we were also able to add a currently unpublished multi-arm trial of an internet quit coach and a text messaging intervention (Borland 2012). This strategy also identified two papers awaiting publication of trials of text messaging interventions in Turkey (Ybarra 2012a) and the U.S. (Ybarra 2012b), however both did not have follow-up data at six months or longer. A further U.S. trial of a text messaging and internet intervention has not yet collected sixmonth data (Abroms 2012). Included studies Three trials (Rodgers 2005; Free 2009; Free 2011) were based on the same programme, initially developed by Rodgers et al in New Zealand and later adapted for use in the UK by Free et al. In all three trials, people wanting to quit who owned a mobile phone were recruited via advertising. The original intervention involved participants setting a quit day within three weeks and then receiving an automated personalised programme of regular text messages. The messages were selected from a database according to participant characteristics and time from quit day - with daily messages leading up to quit day, an intensive month of five to six messages per day, followed by a maintenance phase of one message every two weeks. Messages included quitting advice and motivational messages to encourage abstinence mixed in with some distraction/ general interest messages. A database of Maori messages was included in the programme for Maori participants. Interaction with the programme consisted of polls and quizzes, and the ability to request further text messages on demand to help beat cravings. Participants could also opt to be paired up with a Quit Buddy whom they could text message directly for extra social support. The control group in this trial received one text message every two weeks that provided information about the study. In the case of Free 2009 and Free 2011, the intervention was adapted for a UK population with some alterations in wording of the messages and topics covered. One trial (Borland 2012) involved a web-based Quit Coach and a text messaging intervention. In this study, participants were recruited via quitline or invitation to a study about the effectiveness of internet and telephone-based resources and were then randomised to one of five conditions with no obligation to use the offered resources. The conditions were a personalised, automated tailored internet-based cessation programme only, a text message programme only, both internet and text message programmes, a choice of all three, and minimal treatment control. The text messaging intervention provided advice on strategy and motivational messages relevant to individual participants stage of quitting which they could change by texting the program, and messages on demand in crisis situations. The frequency of messages varied according to quit attempts and reported crises. The final included trial (Whittaker 2011) was of a video messaging intervention. This intervention was developed from social cognitive theory and used observational learning of other ordinary role models undergoing a quit attempt to prompt participants to try the strategies described and enhance their self-efficacy for quitting. Participants received text messages containing a URL web address which would lead to the appropriate small video clip (less than 30 seconds duration) being automatically downloaded and played on their phone. Messages were video diary style clips of the role model talking to the camera about their struggles to quit and strategies used. Participants chose from six role models and could ask for more messages (and role models) on demand. The intervention included daily messages in the countdown to quit day, then two messages per day, then messages reduced in frequency over six months. The definition of smoking status at enrolment was similar in all studies: daily smokers in Rodgers 2005, Free 2009, Free 2011, Whittaker 2011 and current smokers in Borland Where recorded, participants in most of the studies had similar degrees of nicotine dependence, with mean Fagerstrom Test of Nicotine Dependence (FTND) scores of 5 in Rodgers 2005 and 60% of participants in Free 2011 scoring 5 or less. However, in Whittaker 2011 the Hooked on Nicotine Checklist mean scores of 8 indicated a highly addicted group (Wellman 2006). Participants in Rodgers 2005 and Whittaker 2011 were younger (mean age 22 years and 27 years respectively) than in the other trials (36 years Free 2009, 37 years in Free 2011, and 42 years in Borland 2012). Rodgers 2005, Free 2009 and Borland 2012 had more women than men (58%, 63% and 60%). The other trials had 45% (Free 2011) and 47% (Whittaker 2011) women. The studies varied in the extent to which they had prior agreement from participants to engage in the intervention. Most used direct advertising for smokers ready to quit, however Borland 2012 recruited into a trial about understanding smoking cessation and subsequently offered the allocated intervention, but did not seek any commitment to use. This may have reduced rates of engagement (or adherence) with the intervention. Indeed only 50.2% accepted the offer, and fewer actually used it (Borland 2012). Control groups in all studies received usual care but this differed according to the study, from one text (or video) message a fortnight (Rodgers 2005; Free 2009; Free 2011, Whittaker 2011) to information on internet and phone-based cessation services available (Borland 2012). Further details on the included studies can be found in the Characteristics of included studies table. Risk of bias in included studies Randomization was considered adequate in all trials. In all trials except for Borland 2012, participants would have been aware whether they were receiving the intervention or not, although research staff were blind to allocation at follow-up data collection. 5

8 As seen in Figure 1, all trials but Rodgers 2005 were rated at low risk of bias in all domains. Figure 1. Risk of bias summary: review authors judgements about each risk of bias item for each included study. In Rodgers 2005, incentives for providing final follow-up data differed between groups - one month of free text messaging was received by the control group on completion of follow-up whereas the intervention group had already received their month of free text messaging from their Quit Day and did not receive a further incentive at follow-up. This is likely to have caused the differential loss to follow-up seen at six months (69.4% providing data at six 6

9 months in the active group compared with 79% in the control group), which in turn may have affected the long-term results of this study. The authors also suggested that some participants in the control group may have thought their month of free text messaging depended on reporting quitting. This could account for an unexpected increase in control group participants reporting quitting from six weeks (109 participants) to six months (202 participants reporting no smoking in the past seven days). Both of these elements may have potentially led to an underestimation of the effect of the intervention. The Whittaker 2011 trial of video messaging failed to recruit its target sample size which may have affected the study s ability to detect an effect. The authors comment that their inability to recruit may have resulted from the a reluctance to use this newer (at the time) technology or more general difficulties in targeting young adults who want to stop smoking and are willing to participate in a research study. All studies presented long-term outcomes at six months as both self-reported point prevalence (no smoking in past 7 to 28 days) and/or continuous abstinence defined as no smoking since quit day but with up to three lapses (Rodgers 2005) or five cigarettes (Free 2009; Free 2011; Whittaker 2011) allowed. Three of the trials attempted verification of self-reported quitting status with salivary cotinine (Rodgers 2005; Free 2009; Free 2011). However, in Rodgers 2005 only 49 of 125 invited self-reported quitters at six weeks (39%) provided a saliva sample. The UK trials were more successful with 79% (30/38) in the pilot and 92% (542/592) in the full trial providing samples. Intention-to-treat (ITT) analyses were presented in all trials, where those with missing data were assumed to be smokers. Any differential loss to follow-up by group can create potential bias when all are inferred to be smokers. Sensitivity analyses were used to test the effects of other possibilities on many of the results. The Free 2011 paper presented the primary analysis by multiple imputation, using the observed predictors of outcomes and the predictors of loss to follow-up to impute missing outcome data. A further potential source of bias could be any differential use of other cessation interventions. In Borland 2012, where use of the studied interventions was low, it is possible that participants were stimulated to try other cessation programmes. Effects of interventions We undertook a meta-analysis for the included studies (Rodgers 2005; Free 2009; Free 2011; Whittaker 2011; Borland 2012). Standard intention-to-treat analyses are presented here, with all participants lost to follow-up counted as continuing smokers. Complete case analyses made minimal difference to the findings. Mobile phone-only interventions When all five studies were pooled, mobile phone interventions were shown to increase the long term quit rates compared with control programmes (RR 1.71, 95% CI 1.47 to 1.99, P = 0.001, over 9000 participants total), using a definition of abstinence of no smoking at six months since quit day but allowing up to three lapses or up to five cigarettes (Figure 2, Analysis 1.1). While there is substantial statistical heterogeneity as indicated by the I² statistic (79%), in this update of the review we consider that the studies are all similar in design, intervention and primary outcome measure. Therefore we feel it is still of interest to present the meta-analysis here. Figure 2. Forest plot of comparison 1: Mobile phone intervention versus control, 26 week continuous abstinence For the Borland 2012 study, we included only the results for those offered the SMS intervention only (independent of whether they actually accepted or used it), and the control group in the metaanalysis in order to be more directly comparable with the other study results. However, the study did include other arms (Quitcoach internet programme, an integrated programme of both SMS 7

10 and Quitcoach, and a choice of both interventions). The authors reported that all four intervention arms were more effective than the control arm. The Free 2009 study was a pilot study which was followed by the Free 2011 full trial. The pilot was not powered to provide statistically significant results; although the short-term quit rates did show a benefit (26/102 (25.5%) versus 12/98 (12.5%), RR 2.08, 95% CI 1.11 to 3.89), this was not sustained at six months (15/102 (14.7%) versus 19/98 (19.4%), RR 0.76, 95% CI 0.41 to 1.41). The later trial was a very large and well-conducted trial that confirmed the short term benefit continued to six months with biochemical verification of self-reported quitting (268/2911 (9.2%) versus 124/2881 (4.3%), RR 2.14, 95% CI 1.74 to 2.63). This may be the most definitive trial of text messaging for smoking cessation and is by far the largest included in this review. The actual quit rates appear low due to the use of biochemically verified continuous abstinence as the primary outcome. Self-reported abstinence (continuous for the past 28 days) was higher at 28.7% in the intervention group and 12.1% in the control group (reported percentages using multiple imputation by chained equations). As well as the above three studies, Rodgers 2005 also used text messaging as the mobile phone intervention. The intervention in the fifth study (Whittaker 2011) was similar in that it delivered text messages in a similar regimen (proactive, chronologically based around a self-selected quit day and reducing in frequency out to six months). In this intervention, however, each text message contained a link to a short video clip hosted on a virtual web site (WAP site) and the participants phones would access the internet in order to automatically download and play the video clip (free of charge in this instance). So, while the intervention could be said to have been delivered in a very similar method to text messaging, much more content can be relayed in a 30 second video clip than in a 160 character text message. This particular study did not demonstrate a benefit of the intervention in comparison with the control group - six month continuous abstinence was similar in both groups at 26.4% (29/110) in the intervention group versus 27.6% (32/116) in the control group (P = 0.8). The authors report that they failed to recruit their target sample size so the study was underpowered. However, the failure to recruit sufficient participants may be indicative of a lack of interest in such an intervention, and this would need to be considered before further development in this area. Verified abstinence As mentioned above, the large Free 2011 trial used biochemically verified continuous abstinence as its primary outcome (data used in our meta-analysis). The authors reported that of 592 participants self-reporting continuous abstinence at six months, 92% (542) provided samples for verification and 50 subsequently reported smoking again (two refused cotinine testing but accepted carbon monoxide testing). Of the 542 samples, 150 (28%) demonstrated that the participants were smoking. Only two of the other studies attempted verification: Rodgers 2005 invited a random sample of 125 self-reported quitters at six weeks and less than 40% complied; 79% of self-reported quitters in the Free 2009 pilot provided samples. Both studies used salivary cotinine as the biochemical measure and, although numbers were small, over-reporting of quitting was evident in both intervention and control groups (Rodgers 54.8% (17/31) in the intervention group were verified as having quit, compared with 33.3% (6/18) in the control group; Free pilot study 53.3% (8/15) in the intervention group were verified as having quit by salivary cotinine level < 7ng/ml, and 40.0% (6/15) in the control group). D I S C U S S I O N Summary of main results Two further studies of mobile phone smoking cessation interventions meeting our inclusion criteria have been published since the previous version of this review. Another has been completed and is soon to be published; its unpublished results are included in this update. The first systematic review in 2009 showed shortterm benefits but failed to find long-term effects of mobile phoneonly interventions. This update, with the inclusion of three more studies and the addition of a meta-analysis, now shows an overall long-term benefit of mobile phone interventions for smoking cessation, though there was a high level of statistical heterogeneity in the pooled result. The pooled risk ratio for mobile phone interventions versus control was 1.71 (95% CI 1.47 to 1.99, I² = 79%). Overall completeness and applicability of evidence Our review currently includes five studies at overall low risk of bias with over 9000 participants in total. All of the studies have been conducted in high income countries. We have identified seven ongoing studies in this area that are likely to produce long-term results and to meet our inclusion criteria once published, and with the relatively small number of currently included trials, ongoing studies may affect our findings in future updates. Haug et al have published the protocol of their text message assesment and tailored intervention in vocational schools in Switzerland. Gritz and Vidrine are undertaking a large trial of an expanded version of the mobile phone proactive counselling intervention. The Text2Quit study in the U.S. is a randomised controlled trial of a text messaging and intervention. The Cell Phone-Based Expert Systems for Smoking Cessation study is comparing a tailored webbased intervention with and without text messaging in the veteran population in the U.S. The iquit in practice study is recruiting participants in the UK primary care setting for tailored text messages. Gram and colleagues in Norway are trialling an internet and text messaging intervention. A trial in Australia is delivering a text 8

11 message intervention and collecting cessation outcomes within a broader study. Quality of the evidence Despite statistical heterogeneity in our pooled result, the included studies were clinically homogenous, with similar designs, interventions and outcome measures. However, in at least one study actual uptake of the offered intervention was low, likely reducing the magnitude of effect size. Those authors, (Borland 2012), attempted to estimate this bias and estimated the likely true RR as 1.73, very close to the overall estimate found here. Four out of the five included studies were rated at low risk of bias in all domains. Though three of the five included studies did not detect evidence of an effect, the largest study in this review (an extremely wellconducted study judged to be at low risk of bias in all domains) detected significant evidence of an effect. It outweighs some of the other trials in terms of size but also in terms of outcomes, with biochemically verified continuous abstinence at six months. We consider this to be a definitive trial that at the very least shows the efficacy of a mobile phone intervention in a developed country with good tobacco control policy. It should be stated that this does not necessarily follow that all text messaging interventions will be effective in all contexts. A U T H O R S C O N C L U S I O N S Implications for practice Mobile phone-based smoking cessation interventions have been shown to assist people to stop smoking. The interventions in this review are predominantly text messaging interventions that provide a mixture of motivational messages and quitting advice, and some degree of interactive messages that can be asked for when needed, e.g. for managing urges to smoke. Mobile phones have become a regular part of daily lives in many populations. Mobile phone programmes appear to be useful as an option to offer those who want to stop smoking. They have some advantages over most current treatment services: they can be delivered anywhere, at appropriate times, directly to the participant with minimal direct contact and lower resource requirements. For these reasons, mobile phone-based cessation interventions are likely to be useful in many low and middle income countries that have well-established mobile phone infrastructure, high smoking prevalence and few cessation services, though the studies included in this review have all been conducted in high income countries. Implications for research Further research into the components and aspects of text messaging interventions that are particularly helpful and effective could usefully inform others wishing to develop such interventions. There were no published or ongoing studies of the effectiveness of smartphone or downloadable applications for smoking cessation, although a published review of smoking cessation applications available on itunes found that few followed established guidelines (Abroms 2011). More research is required on different types of mobile phone-based interventions, such as smartphone applications, as these may have quite different mechanisms and effects than the text messaging interventions included here. There has been no cost-effectiveness research on mobile phone smoking cessation interventions published at this time. The Cochrane systematic review of telephone interventions shows that proactive support increases long-term continuous abstinence rates by two to four percentage points over control groups (Stead 2006). If, as it appears from our review, we can achieve similar improvements with mobile phone-based cessation interventions (albeit to possibly different populations) at lower costs than running telephone support lines, then it must surely be cost-effective. Actual cost information would be useful to support this (we are aware of a paper coming from the authors of Free 2011). Effectiveness research of mobile phone cessation services in low income countries would be worthwhile to determine if there are any differences in these different contexts. A C K N O W L E D G E M E N T S We acknowledge the assistance of the Cochrane Tobacco Addiction Review Group Editorial base in the preparation of this review. 9

12 R E F E R E N C E S References to studies included in this review Borland 2012 {unpublished data only} James Balmford, Ron Borland, Peter Benda, Steve Howard. Factors associated with use of automated smoking cessation interventions: Findings from the equit study. Health Education Research in Press. Ron Borland, James Balmford, Peter Benda. Populationlevel effects of automated smoking cessation help programs: a randomized controlled trial. Addiction in press. Free 2009 {published and unpublished data} Free C, Whittaker R, Knight R, Abramsky T, Rodgers A, Roberts IG. Txt2stop: a pilot randomised controlled trial of mobile phone-based smoking cessation support. Tobacco Control 2009;18: Free 2011 {published and unpublished data} Free C, Hoile E, Robertson S, Knight R. Three controlled trials of interventions to increase recruitment to a randomized controlled trial of mobile phone based smoking cessation support. Clinical Trials 2010;7(3): Free C, Knight R, Robertson S, Whittaker R, Edwards P, Zhou W, et al.smoking cessation support delivered via mobile phone text messaging (txt2stop): a single-blind, randomised trial. Lancet 2011;378: Severi E, Free C, Knight R, Robertson S, Edwards P, Hoile E. Two controlled trials to increase participant retention in a randomized controlled trial of mobile phone-based smoking cessation support in the United Kingdom. Clinical Trials 2011;8(5): Rodgers 2005 {published data only} Bramley D, Riddell T, Whittaker R, Corbett T, Lin R- B, Wills M. Smoking cessation using mobile phone text messaging is as effective in Maori as non-maori. New Zealand Medical Journal 2005;118(1216): Rodgers A, Corbett T, Bramley D, Riddell T, Wills M, Lin R-B, et al.do u smoke after txt? Results of a randomised trial of smoking cessation using mobile phone text messaging. Tobacco Control 2005;14: [: doi: /tc ] Whittaker 2011 {published and unpublished data} Whittaker R, Dorey E, Bramley D, Bullen C, Denny S, Elley C, et al.a theory-based video messaging mobile phone intervention for smoking cessation: randomised controlled trial. Journal of Medical Internet Research 2011;13(1):e10. References to studies excluded from this review Applegate 2007 {published data only} Applegate BW, Raymond C, Collado-Rodriguez A, Riley WT, Schneider NG. Improving adherence to nicotine gum by sms text messaging: a pilot study (RPOS3-57). Society for Research on Nicotine and Tobacco, 13th Annual Meeting. 2007:14. Bennett 2011 {published data only} Bennett DA, Emberson JR. [Comment] Text messaging in smoking cessation: the txt2stop trial. Lancet 2011 Jul 2;378 (9785):6 7. Brendryen 2008a {published data only} Brendryen H, Kraft P. Happy Ending: a randomized controlled trial of a digital multi-media smoking cessation intervention. Addiction 2008;103: [: doi: / j x] Brendryen 2008b {published and unpublished data} Brendryen H, Drozd F, Kraft P. A digital smoking cessation program delivered through internet and cell phone without nicotine replacement (Happy Ending): randomized controlled trial. Journal of Medical Internet Research 2008; 10(5):e51. Gritz 2011 {published data only} Gritz ER, Vidrine DJ, Marks RM, Arduino RC. A randomized trial of an innovative cell phone intervention for smokers living with HIV/AIDS [SYM 10A]. Society for Research on Nicotine & Tobacco 17th Annual Meeting. Toronto, February 16 19, Haug 2008 {published data only} Haug S, Meyer C, Gross B, Schorr G, Thyrian JR, Kordy H, et al.continuous individual support of smoking cessation in socially deprived young adults via mobile phones -- results of a pilot study. Gesundheitswesen 2008;70(6): Haug 2009 {published data only} Haug S, Meyer C, Schorr G, Bauer S, John U. Continuous individual support of smoking cessation using text messaging: a pilot experimental study. Nicotine & Tobacco Research 2009;11(8): Kiselev 2011 {published data only} Kiselev AR, Shvarts VA, Posnenkova OM, Gridnev VI, Dovgalevskii P, Oshchepkova EV, et al.outpatient prophylaxis and treatment of arterial hypertension with application of mobile telephone systems and Internet techniques. Ter Arkh 2011;83(4): Lazev 2004 {published data only} Lazev A, Vidrine D, Arduino R, Gritz E. Increasing access to smoking cessation treatment in a low-income, HIV-positive population: The feasibility of using cellular telephones. Nicotine & Tobacco Research 2004;6(2): [: doi: / ] Naughton 2011 {published data only} Naughton F, Prevost A, Gilbert H, Sutton S. Randomized controlled trial evaluation of a tailored leaflet and SMS text message self-help intervention for pregnant smokers (MiQuit). Nicotine & Tobacco Research 2012;14(5): Obermayer 2004 {published data only} Obermayer J, Riley W, Asif O, Jean-Mary J. College smoking cessation using cell phone text messaging. Journal of American College Health 2004;53(2):

13 Riley 2008 {published data only} Riley W, Obermayer J, Jean-Mary J. Internet and mobile phone text messaging intervention for college smokers. Journal of American College Health 2008;57(2): Snider 2011 {published data only} Snider J. [News] Cell Phone Text Messaging May Boost Smoking Quit Rates. The Journal of the American Dental Association 2011 August 1;142(8): Vidrine 2006 {published data only} Vidrine D, Arduino R, Gritz E. Impact of a cell phone intervention on mediating mechanisms of smoking cessation in individuals living with HIV/AIDS. Nicotine & Tobacco Research 2006;8(Suppl 1):S Vidrine D, Arduino R, Lazev A, Gritz E. A randomized trial of a proactive cellular telephone intervention for smokers living with HIV/AIDS. AIDS 2006;20: [: ISSN ] Wizner 2009 {published data only} Wizner, BGaciong, ZNarkiewicz, K Grodzicki, T. Education using SMS increases efficacy of treatment of hypertensive patients [Zwi kszenie skuteczno ci terapii hipotensyjnej u pacjentów z nadci nieniem t tniczym dzi ki edukacji przez SMS]. Nadcisnienie Tetnicze 2009;13(3): Ybarra 2012a {unpublished data only} Ybarra M, Bagci T, Korchmaros J, Emri S. Pilot RCT results of SMS Turkey: a text messaging-based smoking cessation program for adult smokers in Ankara, Turkey. Under review. Ybarra 2012b {unpublished data only} Ybarra M, Hotrop J, Prescott T, Rahbar M, Strong D. Pilot RCT results of Stop My Smoking (SMS) USA: a text messaging-based smoking cessation program for young adults. Under review. Yuhongxia 2011 {published data only} Yuhongxia L. The compliance of varenicline usage and the smoking abstinence rate via mobile phone text messaging combine with varenicline: A single-blind, randomised control trial. Respirology. Conference publication: 16th Congress of the Asian Pacific Society of Respirology Shanghai China. November 2011;16 :46 7. References to ongoing studies Abroms 2012 {published data only} Abroms L, Ahuja M, Kodl Y, Thaweethai L, Sims J, Winickoff J, Windsor R. Text2Quit: Results from a pilot test of a personalised, interactive mobile health smoking cessation program. Journal of Health Communication 2012; 17(Suppl 1): Ferguson 2012 {unpublished data only} Ongoing study Gram 2011 {unpublished data only} Internet and text messaging intervention in Norway. Ongoing study Haug 2012 {published and unpublished data} Haug, S.Meyer, C.Dymalski, A.Lippke, S.John, U. Efficacy of a text messaging (SMS) based smoking cessation intervention for adolescents and young adults: study protocol of a cluster randomised controlled trial. BMC Public Health 2012/01/21;12:51. iquit in Practice {unpublished data only} ISRCTN :http: // trials.com/isrctn NCT {published data only (unpublished sought but not used)} NCT ClinicalTrials.gov 2007: clinicaltrials.gov/ct2/show/record/nct Chow CK, Redfern J, Thiagalingam A, Jan S, Whittaker R, Hackett M, et al.design and rationale of the tobacco, exercise and diet messages (TEXT ME) trial of a text message-based intervention for ongoing prevention of cardiovascular disease in people with coronary disease: a randomised controlled trial protocol. BMJ Open 2012;2(1): e NCT {published and unpublished data} NCT ClinicalTrials.gov 2011: clinicaltrials.gov/ct2/show/nct Additional references Abroms 2011 Abroms LC, Padmanabhan N, Thaweethai L, Phillips T. iphone apps for smoking cessation: a content analysis. American Journal of Preventitive Medicine 2011;40(3): Bramley 2005 Bramley D, Riddell T, Whittaker R, Corbett T, Lin R- B, Wills M. Smoking cessation using mobile phone text messaging is as effective in Maori as non-maori. New Zealand Medical Journal 2005;118(1216): Ferrer-Roca 2004 Ferrer-Roca O, Cardenas A, Diaz-Cardama A, Pulido P. Mobile phone text messaging in the management of diabetes. Journal of Telemedicine and Telecare 2004;10(5): 282. Gammon 2005 Gammon D, Arsand E, Walseth O, Andersson N, Jenssen M, Taylor T. Parent-child interaction using a mobile and wireless system for blood glucose monitoring. Journal of Medical Internet Research 2005;7(5):e57. Higgins 2003 Higgins JPT, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta-analyses. BMJ 2003;327 (7414): ITU 2010 Market Information and Statistics Division, International Telecommunication Union. The World in 2010: ICT Facts and Figures [: D/ict/] 11

14 ITU 2011 ICT Data, Statistics Division. International Telecommunication Union. The World in 2011: ICT Facts and Figures [: Kim 2006 Kim HS, Kim NC, Ahn SH. Impact of a nurse short message service intervention for patients with diabetes. Journal of Nursing Care Quality 2006;21(3): Quinn 2011 Quinn C, Shardell M, Terrin M, Barr E, Ballew B, Gruber- Baldini B. Cluster-randomized trial of a mobile phone personalized behavioral intervention for blood glucose control. Diabetes Care 2011;34: Stead 2006 Stead LF, Perera R, Lancaster T. Telephone counselling for smoking cessation. Cochrane Database of Systematic Reviews 2006, Issue 3. [DOI: / CD pub2] Tasker 2007 Tasker A, Gibson L, Franklin V, Gregor P, Greene S. What is the frequency of symptomatic mild hypoglycaemia in type1 diabetes in the young?: assessment by novel mobile phone technology and computer-based interviewing. Pediatric Diabetes 2007;8: Wellman 2006 Wellman RJ, Savageau JA, Godiwala S, Savageau N, Friedman K, Hazelton J, et al.a comparison of the Hooked on Nicotine Checklist and the Fagerstrom Test for Nicotine Dependence in adult smokers. Nicotine and Tobacco Research 2006;8(4): References to other published versions of this review Whittaker 2009 Whittaker R, Borland R, Bullen C, Lin RB, McRobbie H, Rodgers A. Mobile phone-based interventions for smoking cessation. Cochrane Database of Systematic Reviews 2009, Issue 4. [DOI: / CD pub2] Indicates the major publication for the study 12

15 C H A R A C T E R I S T I C S O F S T U D I E S Characteristics of included studies [ordered by study ID] Borland 2012 Methods Country: Australia Participants 3530 participants in total (control = 422; onq = 756; QuitCoach = 809; Both = 785; Participant Choice = 758): 60% female; mean age 42.1; 87.4% were currently smoking; participants smoked an average of 16.9 cigarettes per day Interventions Outcomes Notes The onq program provides a stream of SMS messages to the person that mixes snippets of advice on strategy and motivational messages. The user can interact with it by indicating their stage of quitting so that appropriate stage-specific messages are sent, and once quit can also call up messages in crisis situations QuitCoach is a personalised, automated tailored cessation program delivered via the Internet. It generates letters of advice based on answers to an assessment questionnaire, including suggestions about strategy and motivational messages. It also provides further untailored supplementary resources Control: brief information on web- and phone-based assistance available in Australia Self-reported 6-month sustained abstinence at 7-month follow-up Intention to quit analysis and sensitivity analysis around treatment of missing data Data from author, not yet published. Only onq and control arms used in analysis Risk of bias Bias Authors judgement Support for judgement Random sequence generation (selection bias) Low risk Computerised random number generator embedded within the baseline survey Allocation concealment (selection bias) Low risk This was not a typical RCT as participants were enrolled in a study described to them as being about the effectiveness of Internet and telephone-based resources in helping smokers quit, and were only then randomised to a condition which they were offered with no obligation to use Blinding (performance bias and detection bias) All outcomes Incomplete outcome data (attrition bias) All outcomes Low risk Low risk This was not a typical RCT as participants were enrolled in a study described to them as being about the effectiveness of Internet and telephone-based resources in helping smokers quit, and were only then randomised to a condition which they were offered with no obligation to use Loss to follow up 475 (13% total) with similar numbers across groups (in control 66, in onq 89, in QuitCoach 104, in Integrated 121, in Choice 95); 2 excluded as reported to have died at 7 month follow-up 13

16 Free 2009 Methods Participants Interventions Outcomes Country: UK 200 participants 16yrs and over; smoking daily and interested in quitting; current owner of mobile phone. Characteristics: 63% male; median age 36yrs; median 20 cigarettes/day; 7% FTND dependence score > 5 Six month programme delivered solely over mobile phone based on programme in Rodgers 2005 but messages adapted for UK population. Participant nominates Quit Date (QD) and receives regular personalised text messages with advice, support and distraction, with a countdown to QD, intensive 4wks of 5 to 6 messages/day then maintenance phase of 1 message/2wks. Messages selected from database matched to participant characteristics. Free month of text messaging from QD. Optional Quit Buddy, and Text Crave (messages on demand). Interactive polls and quizzes. Control: 1 text message/fortnight Primary: point prevalence abstinence (no smoking in past 7 days) at 6wks post randomization (approximates 4wks post-qd). Secondary: point prevalence abstinence and continuous abstinence (<5 cigarettes) at 26 wks. Verification with salivary cotinine in quitters at 26wks. Intention-to-treat analysis Notes Pilot study - full trial is Free 2011 Risk of bias Bias Authors judgement Support for judgement Random sequence generation (selection bias) Low risk Central computerised randomization Allocation concealment (selection bias) Low risk Concealed until after assignment Blinding (performance bias and detection bias) All outcomes Low risk Single blind (participants not blinded) Incomplete outcome data (attrition bias) All outcomes Low risk Lost to follow-up: 4 (control) and 1 (intervention) at 4wks (98% follow-up); 8 (control) and 8 (intervention) at 6 months (92% follow-up) Free 2011 Methods Participants Country: United Kingdom 5800 participants 16yrs and over, willing to make an attempt to quit smoking in the next month and own a mobile phone; 45% are female; mean age is 37; 89% are white; 25% are student/unemployed; 60% have a FTND dependence score of <= 5 14

17 Free 2011 (Continued) Interventions Outcomes Six-month programme delivered solely over mobile phone based on programme in Rodgers Participants in the intervention group were asked to set a quit date within 2 weeks of randomisation. They received five text messages a day for the first 5 weeks and then three a week for the next 26 weeks. The intervention included motivational messages and behaviour-change techniques. The programme was also personalised with an algorithm based on demographic and other information gathered at baseline, such as smokers concerns about weight gain after quitting. The core programme consisted of 186 messages and the personalised messages were selected from a database of 713 messages. For instance, by texting the word lapse, participants would receive a series of three text messages that encouraged them to continue with their quit attempt. Participants could also request the mobile phone number of another trial participant so that they could text each other for support. Participants in the intervention group using pay-as-you-go mobile phone schemes were given a 20 top-up voucher to provide sufficient credit to participate in the intervention Control: fortnightly, simple, short, text messages related to the importance of trial participation No more than 5 cigarettes smoked since the start of the abstinence period at 6 months of follow-up, self reported and verified by postal salivary cotinine testing or a carbon monoxide test in person Notes Risk of bias Bias Authors judgement Support for judgement Random sequence generation (selection bias) Low risk An independent telephone randomisation system Allocation concealment (selection bias) Low risk Concealed until after assignment Blinding (performance bias and detection bias) All outcomes Incomplete outcome data (attrition bias) All outcomes Low risk Low risk Single blind (participants not blinded) 176 intervention and 92 control lost to follow-up (less than 5% total) Rodgers 2005 Methods Country: New Zealand Participants 1705 participants 16yrs and over; smoking daily; want to quit within next month; able to send & receive text messages on own mobile phone. Characteristics: 58% female; median age 22yrs; 20.8% indigenous NZ (Maori); 3.5% Pacific Islanders; average 15 cigarettes/day; mean FTND dependence score = 5 15

18 Rodgers 2005 (Continued) Interventions Outcomes Six month programme delivered solely over mobile phone. Participant nominates Quit Date (QD) and receives regular personalised text messages with advice, support and distraction, with a countdown to QD, intensive 4wks of 5 to 6 messages/day then maintenance phase of 1 message/2wks. Messages selected from database matched to participant characteristics. Free month of text messaging from QD. Optional Quit Buddy, and Text Crave (messages on demand). Interactive polls and quizzes. Control: 1 text message/fortnight Primary: point prevalence abstinence (no smoking in past 7 days) at 6wks post-randomization (approximates 4wks post-qd). Verification with salivary cotinine in small number of quitters at 6wks. Secondary: point prevalence abstinence at 12wks and 26wks, and continuous abstinence at 26wks. Intention-to-treat analysis. Notes Risk of bias Bias Authors judgement Support for judgement Random sequence generation (selection bias) Low risk Central computerised randomization Allocation concealment (selection bias) Low risk Concealed until after assignment Blinding (performance bias and detection bias) All outcomes Incomplete outcome data (attrition bias) All outcomes Low risk High risk Single blind (participants not blinded) Lost to follow-up: 35 control (95.9%) and 46 intervention (94.6%) followed up at 6wks; but differential loss to followup at 6m (79% control vs 69% intervention). Possibly due to incentive being offered to control group for follow-up, may in turn have affected long-term results of study (by underestimating effect) Other bias High risk The authors suggest that some participants in the control group may have thought their incentive at follow-up (month of free text messaging) depended on reporting quitting. This could account for an unexpected increase in control group participants reporting quitting from six weeks (109 participants) to six months (202 participants reporting no smoking in the past seven days), which could have led to an underestimation of the effect of the intervention 16

19 Whittaker 2011 Methods Participants Interventions Outcomes Country: New Zealand 226 participants 16yrs and over; current daily smokers ready to quit, have a video message-capable phone; 47% female; 24% Maori; mean age = 27; highly addicted cohort due to Hooked on Nicotine Checklist mean scores of 8 (SD 1.9) out of 10 The intervention group received an automated package of video and text messages over 6 months that was tailored to self-selected quit date, role model, and timing of messages. Video messages were video diary-style from a selected ordinary person going through a quit attempt in advance of the participant. Frequency of messages varied from 1/day in the lead up to Quit Day (QD), 2/day from QD for 4 weeks, then reducing to 1 every 2 days for 2 weeks and then 1 every 4 days for about 20 weeks until 6 months after randomization. Extra messages were available on demand to beat cravings and address lapses. Additional website for intervention group participants to review video messages they had been sent (and rate them if desired), change their selected time periods, and change (or add to) their selected role model. Control: also set a quit date and received a general health video message sent to their phone every 2 weeks Self-reported continuous abstinence - no more than 5 cigarettes smoked since the start of the abstinence period at 6 months of follow-up Notes Risk of bias Bias Authors judgement Support for judgement Random sequence generation (selection bias) Low risk Central computerised randomisation Allocation concealment (selection bias) Low risk Concealed until after assignment Blinding (performance bias and detection bias) All outcomes Incomplete outcome data (attrition bias) All outcomes Low risk Low risk Single blind (participants not blinded) 32% intervention and 22% control lost to follow-up at 6m FTND: Fagerstrom Test of Nicotine Dependence m: month(s) QD: quit date SD: standard deviation wks: weeks yrs: years 17

20 Characteristics of excluded studies [ordered by study ID] Study Applegate 2007 Bennett 2011 Reason for exclusion Abstract describing intervention to increase adherence to the use of nicotine replacement gum in people attempting to quit smoking. Duration 8 weeks Editorial comment on the Free 2011 trial Brendryen 2008a Mobile phone intervention confounded with internet intervention (previously included in Whittaker 2009) Brendryen 2008b Mobile phone intervention confounded with internet intervention (previously included in Whittaker 2009) Gritz 2011 Haug 2008 Haug 2009 Kiselev month follow-up only Non-randomized feasibility study. Duration 12 weeks Mainly about acceptability, 3 month follow-up Not focused on smoking cessation Lazev 2004 Not randomized. No control group. Feasibility study for the programme presented in Vidrine Naughton 2011 Obermayer 2004 Riley 2008 Snider 2011 Vidrine 2006 Wizner 2009 Ybarra 2012a Ybarra 2012b Yuhongxia 2011 Randomized controlled trial with pregnant smokers, follow-up to 3 months Not randomized. No control group. Small non-randomized study with only 6 weeks follow-up Not a trial Randomised trial of phone counselling with mobile phones, follow-up only 3 months Not focused on smoking cessation Pilot randomised controlled trial, follow-up only 3 months Pilot randomised controlled trial, follow-up only 3 months Single-blind randomised control trial, follow-up 24 weeks, but with no details available on the randomisation method or the intervention content. Abstract only, unable to contact authors 18