Background
Relapse remains an unresolved issue in smoking cessation. Extended stop smoking medication use can help, but uptake is low and several behavioural relapse prevention interventions have been found to be ineffective. However, opportunistic ‘emergency’ use of fast-acting nicotine replacement treatment or electronic cigarettes may be more attractive and effective, and an online behavioural Structured Planning and Prompting Protocol has shown promise. The present trial aimed to evaluate the clinical effectiveness and cost-effectiveness of these two interventions.
Design
A randomised controlled trial.
Setting
English stop smoking services and Australian quitlines, Australian social media and St Vincent’s Hospital Melbourne, Fitzroy, VIC.
Participants
Ex-smokers abstinent for at least 4 weeks, with some participants in Australia also recruited from 1 week post quit date. The planned sample size was 1400, but the trial was curtailed when 235 participants were recruited.
Interventions
Participants were randomised in permuted blocks of random sizes to (1) oral nicotine replacement treatment/electronic cigarettes to use if at risk of relapse, plus static text messages (n = 60), (2) the Structured Planning and Prompting Protocol and interactive text messages (n = 57), (3) oral nicotine replacement treatment/electronic cigarettes plus the Structured Planning and Prompting Protocol with interactive text messages (n = 58) or (4) usual care plus static text messages (n = 59).
Outcome measures
Owing to delays in study set-up and recruitment issues, the study was curtailed and the primary outcome was revised. The original objective was to determine whether or not the two interventions, together or separately, reduced relapse rates at 12 months compared with usual care. The revised primary objective was to determine whether or not number of interventions received (i.e. none, one or two) affects relapse rate at 6 months (not biochemically validated because of study curtailment). Relapse was defined as smoking on at least 7 consecutive days, or any smoking in the last month at final follow-up for both the original and curtailed outcomes. Participants with missing outcome data were included as smokers. Secondary outcomes included sustained abstinence (i.e. no more than five cigarettes smoked over the 6 months), nicotine product preferences (e.g. electronic cigarettes or nicotine replacement treatment) and Structured Planning and Prompting Protocol coping strategies used. Two substudies assessed reactions to interventions quantitatively and qualitatively. The trial statistician remained blinded until analysis was complete.
Results
The 6-month relapse rates were 60.0%, 43.5% and 49.2% in the usual-care arm, one-intervention arm and the two-intervention arm, respectively (p = 0.11). Sustained abstinence rates were 41.7%, 54.8% and 50.9%, respectively (p = 0.17). Electronic cigarettes were chosen more frequently than nicotine replacement treatment in Australia (71.1% vs. 29.0%; p = 0.001), but not in England (54.0% vs. 46.0%; p = 0.57). Of participants allocated to nicotine products, 23.1% were using them daily at 6 months. The online intervention received positive ratings from 63% of participants at 6 months, but the majority of participants (72%) completed one assessment only. Coping strategies taught in the Structured Planning and Prompting Protocol were used with similar frequency in all study arms, suggesting that these are strategies people had already acquired. Only one participant used the interactive texting, and interactive and static messages received virtually identical ratings.
Limitations
The inability to recruit sufficient participants resulted in a lack of power to detect clinically relevant differences. Self-reported abstinence was not biochemically validated in the curtailed trial, and the ecological momentary assessment substudy was perceived by some as an intervention.
Conclusions
Recruiting recent ex-smokers into an interventional study proved problematic. Both interventions were well received and safe. Combining the interventions did not surpass the effects of each intervention alone. There was a trend in favour of single interventions reducing relapse, but it did not reach significance and there are reasons to interpret the trend with caution.
Future work
Further studies of both interventions are warranted, using simpler study designs.
Trial registration
Current Controlled Trials ISRCTN11111428.
Funding
This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 68. See the NIHR Journals Library website for further project information. Funding was also provided by the National Health and Medical Research Council, Canberra, ACT, Australia (NHMRC APP1095880). Public Health England provided the funds to purchase the nicotine products in England.
Relationships of PROP Taste Phenotype, Taste Receptor Genotype, and Oral Nicotine Replacement Use