Original research
Table 2 Abstinence rates at different time points Intervention (n=484)
Control (n=488)
Absolute difference (95% CI)
Relative risk (95% CI) 1.76 (1.03 to 3.01)
P value
P value
Primary outcome: biochemically validated self-reported continuous smoking abstinence at 6 months Self-reported 7-day abstinence at 1 month Self-reported 7-day abstinence at 3 months Self-reported 7-day abstinence at 6 months
35 (7.2%)
20 (4.1%)
3.3 (0.3 to 6.3)
0.032
0.038
94 (19.4%)
49 (10.0%)
9.0 (4.9 to 13.7)* 11.3 (6.6 to 16.1) 10.6 (5.86 to 15.41)
<0.0001
1.92 (1.39 to 2.64) 1.97 (1.47 to 2.63) 1.80 (1.36 to 2.38)
<0.0001
113 (23.3%)
58 (11.9%)
<0.0001
<0.0001
113 (23.3%)
63 (12.9%)
<0.0001
<0.0001
*Based on Gaussian model with robust variances due to lack of convergence.
more likely to achieve sustained smoking abstinence than those who received signposting to stop smoking services alone. The biochemically-verified quit rate was not as high as the assump- tions underpinning the power calculation; however, the differ- ence found achieved statistical significance, with the potential to impact on population smoking prevalence. There was a much larger difference in self-reported abstinence compared with the power calculation, which may indicate that the biochemically- verified quit rate is an underestimate of the true effect of the intervention.
Comparison with previous studies These results strengthen previous findings that ED-based smoking cessation interventions are effective. 7 To our knowl- edge, the 6-month self-reported quit rate is the highest reported by any ED-based smoking cessation intervention trial to date. As the first ED-based trial to include an e-cigarette starter kit as part of the intervention, this suggests that the e-cigarette itself, in addition to brief advice, may have contributed to the size of the effect. The findings are in keeping with existing evidence that e-cigarettes are effective in aiding smoking cessation, 8 22 but
Table 3 Secondary outcome measures
Absolute difference (95% CI)
Intervention
Control
P value
Number of cigarettes smoked at 6 months, median (IQR)
0 (0–10) n=314 2 (1–4) n=183 5 (0–10) n=176
10 (0–15) n=283
−8 (−10.41 to 5.59)
<0.0001
Number of quit attempts, median (IQR)
1 (0–3) n=229 0 (0–3) n=239
<0.0001
Number of times using an e-cigarette per day at 6 months, median (IQR)
5 (4.04 to 5.96)
<0.0001
Frequency of e-cigarette use in past 6 months, n (%)
<0.0001
Not used
47 (14.8%) 39 (12.3%) 32 (10.1%) 52 (16.4%) 22 (6.9%) 125 (39.4%)
165 (54.5%) 24 (7.9%) 25 (8.3%) 23 (7.6%) 13 (4.3%) 53 (17.5%)
Once a month or less On 2–4 days a month On 2–3 days a week On 5–6 days a weeks
Daily
Dry cough in last week, at 6 months, median (IQR), n (%)
1 (1–2) n=310
1 (1–3) n=292
0.344
1 (not at all)
174 (56.1%) 60 (19.4%) 46 (14.8%) 17 (5.5%)
154 (52.7%) 57 (19.5%) 47 (16.1%) 22 (7.5%)
2 3 4
5 (extremely)
13 (4.2%)
12 (4.1%)
Throat/mouth irritation in last week, at 6 months, median (IQR), n (%)
1 (1–2) n=310
1 (1–2) n=293
0.117
1 (not at all)
206 (66.5%) 46 (14.8%) 31 (10.0%) 17 (5.5%)
176 (60.1%) 49 (16.7%) 41 (14.0%) 19 (6.5%)
2 3 4
5 (extremely)
10 (3.2%)
8 (2.7%) 4 (2–5) n=227
Motivation to stop smoking
4 (3–5) n=177
0.432
Mean (SD) Fagerström test for nicotine dependence score
3.70 (2.21) n=185
4.17 (2.24) n=224
−0.51 (−0.95 to −0.07)
0.022
Pope I, et al . Emerg Med J 2024; 41 :276–282. doi:10.1136/emermed-2023-213824
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