Table 2.
Primary and secondary outcomes at 4, 26, and 52 weeks post-quit date
| Primary outcome | Treatment | Control | χ 2 | P-value | RR | 95% CI | |
|---|---|---|---|---|---|---|---|
| 7-day point prevalence abstinence 4 weeks (ITT) (n = 530) 4 weeks (PP) (n = 456) |
118 (44.5%) 118 (52.4%) |
75 (29.3%) 75 (32.5%) |
13.7 17.8 |
N/A | <.001*** <.001*** |
1.55 1.62 |
1.23 to 1.96 1.29 to 2.0 |
| Secondary outcomes | Treatment | Control | χ 2 | t-test (df) | p-value | RRa | 95% CI |
| 7-day point prevalence abstinence week 26 (ITT) week 26 (PP) week 52 (ITT) week 52 (PP) |
95 (35.9%) 95 (44.6%) 92 (34.7%) 92 (44.0%) |
73 (27.6%) 73 (33.2%) 78 (29.4%) 78 (36.8%) |
4.2 5.9 1.7 2.3 |
0.03* 0.01* 0.19 0.13 |
1.32 (1.03 to 1.69) 1.38 (1.08 to 1.75) 1.20 (0.94, 1.54) 1.24 (0.99, 1.57) |
||
| Quit attempts beyond initial QD Week 4 Week 26 Week 52 |
68 (25.6%) 94 (35.5%) 104 (39.2%) |
86 (32.6%) 115 (43.4%) 135 (50.9%) |
2.6 3.2 6.9 |
N/A | 0.10 0.07 0.009** |
0.79 0.82 0.77 |
0.60 to 1.03 0.66 to 1.01 0.64 to 0.93 |
| Change in self-efficacy Week 4 Week 26 Week 52 |
4.2 (7.0) 3.8 (8.5) 3.3 (8.6) |
3.1 (6.7) 2.0 (6.9) 2.2 (7.8) |
N/A | 1.7 (527) 2.6 (506) 1.6 (524) |
0.09 0.01* 0.12 |
N/A | 1.0 (-0.16 to 2.17) 1.75 (0.42 to 3.07) 1.12 (-0.28 to 2.52) |
| Change in Mental Well-being Week 4 Week 26 Week 52 |
0.7 (7.0) 1.4 (8.2) 1.5 (8.4) |
0.6 (6.5) 1.0 (7.8) 0.1 (8.3) |
N/A | 0.2 (525) 0.7 (527) 1.9 (528) |
0.83 0.51 0.06 |
N/A | 0.13 (-1.02 to 1.28) 0.45 (-0.90 to 1.81) 1.39 (-0.03 to 2.82) |
| Consecutive 7-day abstinence Week 26: ITT (n = 530) Week 26: PP (n = 433) (participant is abstinent at 4 and 26 weeks) |
72 (27.2%) 72 (33.8%) |
44 (16.6%) 44 (20.0%) |
8.7 10.5 |
N/A | 0.003** 0.001** |
1.70 1.79 |
1.22 to 2.37 1.30 to 2.46 |
| Consecutive 7-day abstinence 52 weeks: ITT (n = 530) 52 weeks: PP (n = 421) (participant is abstinent at 4, 26, and 52 weeks) |
60 (22.6%) 60 (28.7%) |
35 (13.2%) 35 (16.5%) |
8.01 8.9 |
N/A | 0.005** 0.003** |
1.71 1.77 |
1.17 to 2.50 1.22 to 2.54 |
| Sustained abstinence, Week 26, Week 52 (participant ≤ 5 cigs since QD) | 73 (27.5%) 58 (21.9%) |
40 (15.1%) 30 (11.3%) |
11.5 9.9 |
N/A | <0.001*** 0.002** |
1.82 1.93 |
1.29 to 2.58 1.29 to 2.90 |
χ 2 = Chi-squared test; QD, quit date; RR, relative risk ratio; ITT, intention-to-treat analysis; PP, per-protocol analysis.
*p < .05; **p < .01; ***p < .001.