Table 3

Secondary outcome measures

InterventionControlAbsolute difference
(95% CI)
P value
Number of cigarettes smoked at 6 months, median (IQR)0 (0–10)
n=314
10 (0–15)
n=283
−8 (−10.41 to 5.59)<0.0001
Number of quit attempts, median (IQR)2 (1–4)
n=183
1 (0–3)
n=229
<0.0001
Number of times using an e-cigarette per day at 6 months, median (IQR)5 (0–10)
n=176
0 (0–3)
n=239
5 (4.04 to 5.96)<0.0001
Frequency of e-cigarette use in past 6 months, n (%)<0.0001
Not used47 (14.8%)165 (54.5%)
Once a month or less39 (12.3%)24 (7.9%)
On 2–4 days a month32 (10.1%)25 (8.3%)
On 2–3 days a week52 (16.4%)23 (7.6%)
 On 5–6 days a weeks22 (6.9%)13 (4.3%)
 Daily125 (39.4%)53 (17.5%)
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%)154 (52.7%)
260 (19.4%)57 (19.5%)
346 (14.8%)47 (16.1%)
417 (5.5%)22 (7.5%)
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%)176 (60.1%)
246 (14.8%)49 (16.7%)
331 (10.0%)41 (14.0%)
417 (5.5%)19 (6.5%)
5 (extremely)10 (3.2%)8 (2.7%)
Motivation to stop smoking4 (3–5)
n=177
4 (2–5)
n=227
0.432
Mean (SD) Fagerström test for nicotine dependence score3.70 (2.21)
n=185
4.17 (2.24)
n=224
−0.51 (−0.95 to −0.07)0.022