Helping people cope with temptations to smoke to reduce relapse (Relapse Prevention Study): A curtailed randomised controlled trial

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 were found ineffective. However, opportunistic ‘emergency’ use of fast acting nicotine replacement treatment (NRT) or electronic cigarettes may be more attractive and effective and an online behavioural Structured Planning and Prompting Protocol (S3P) has shown promise. The present trial aimed to evaluate the effectiveness of these two interventions.

Design: RCT

Setting/participants: Recent (four week) ex-smokers (234 rather than the planned 1400) recruited from English stop smoking services and Australian quitlines. Participants in Australia were also later recruited via social media and St Vincent’s Hospital, Melbourne from one week quit.

Interventions: Participants were randomised in permuted blocks of random sizes to 1) Oral NRT/e-cigarette to use if at risk of relapse, plus static text messages (N=60), 2) S3P and interactive text messaging (N=57), 3) Oral NRT/e-cigarette plus S3P with interactive text messaging (N=58), 4) usual care plus static text messages (N=59).

Outcome measures: Due to delays in study set-up and recruitment issues, the study was curtailed, and the primary outcome was revised. The original objective was whether the two interventions, together or separately, reduced relapse rates at 12 months compared to usual care. The revised primary objective was whether number of interventions received (none, one or two) affects relapse rate at six months (not biochemically validated due to study curtailment). Relapse was defined as smoking on at least seven 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 (≤5 cigarettes smoked over the six months), nicotine product preferences (e.g. e-cigarette or NRT) and S3P coping strategies used. Two sub studies assessed reactions to interventions quantitatively and qualitatively. The trial statistician remained blinded until analysis was complete.

Results: The six-month relapse rates were 60.0%, 43.5% and 49.2% in the usual care, one intervention, and both intervention arms, respectively (p=0.11). Sustained abstinence rates were 41.7%, 54.8% and 50.9%, respectively (p=0.17). E-cigarette was chosen more frequently than NRT in Australia (71.1% versus 29.0%, p=.001), but not in England (54.0% versus 46.0%, p=0.57). Of participants allocated to nicotine products, 23.1% were using daily at six months. The online intervention received positive ratings from 63% of participants at six months, but the majority of participants (72%) only completed one assessment. Coping strategies taught in S3P were used with similar frequency in all study arms, suggesting 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 lack of power to detect clinically relevant differences. Self-reported abstinence was not biochemically validated in the curtailed trial, and the EMA sub study 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.