Summary of the design and outcomes from the two published trials of e-cigarettes for 6 month smoking cessation
| ECLAT Caponnetto et al 11 | ASCEND Bullen et al 12 13 | |
| Population | Unmotivated to quit | Motivated to quit |
| Eligibility | ≥10 CPD for at least 5 years, 18–70 years | ≥10 CPD for last year, ≥18 years |
| E-cigarette brand | Categoria (First generation) | Elusion (First generation) |
| Sample size | 300 (1:1:1) | 657 (4:4:1) |
| Intervention | 7.2 mg e-cigarette (n=100)* 7.2–5.4 mg e-cigarette (n=100)* 0 mg e-cigarette (n=100)* No behavioural support | 16 mg e-cigarette (n=289)* 21 mg nicotine patch (n=295) 0 mg e-cigarette (n=73)* Minimal behavioural support |
| Intervention period | 12 weeks | 13 weeks (includes 1 week pre-quit) |
| Follow-up | 12 months | 6 months |
| Power | 75% | 80% |
| Continuous abstinence at 6 months† | 7.2 mg e-cigarette: 12% 7.2–5.4 mg e-cigarette: 10% 0 mg e-cigarette: 5% P=0.39 | Nicotine e-cigarette: 7.3% Nicotine patches: 4.1% RD=1.51 95% CI −2.49 to 5.51 Nicotine e-cigarette: 7.3% Placebo e-cigarette: 5.8% RD=3.16 95% CI −2.29 to 8.61 |
| Smoking reduction |
Percentage reduction in CPD at 6 months
7.2 mg e-cigarette: 17% 7.2–5.4 mg e-cigarette: 19% 0 mg e-cigarette: 15% P=0.39 |
Reduced CPD by ≥50% at 6 months
Nicotine e-cigarette: 57% Nicotine patches: 41% P=0.0002 Nicotine e-cigarette: 57% Placebo e-cigarette: 45% P=0.08 |
| Time to relapse (median) | Not reported | Nicotine e-cigarette: 35 days Nicotine patches: 14 days Placebo e-cigarette: 12 days |
| Adverse events | No difference in frequency of events between groups at week 12 and 52 | Nicotine e-cigarette: 137 events in 107 participants over 6 months. 0.8 events per person month Nicotine patches: 119 events in 96 participants over 6 months. 0.8 events per person month Placebo e-cigarette: 36 events in 26 participants over 6 months. 0.9 events per person month Nicotine e-cigarette vs Nicotine patches: IRR=1.05, 95% CI: 0.82 to 1.34, p=0.7 |
| Serious adverse events | None reported | None related to treatment |
*Ad libutum use.
†Primary outcome.
CPD, cigarettes per day; IRR, incidence rate ratio; RD, risk difference.; CI, confidence interval