Table 2.
Associations between subscriber characteristics and dropout, response, and abstinence rates on Days 0 (quit day), 7, 42 (intervention end), and 72 (1 month follow-up), imputed data
| Response ratea | Abstinence rate (intent-to-treat)b | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Dropout N = 2,205 | Quit Day n = 2,205 | Day 7 n = 1,468 | Day 42 n = 956 | Day 72 n = 910 | Quit Day n = 2,205 | Day 7 n = 2,205 | Day 42 n = 2,205 | Day 72 n = 2,150 | |
| Characteristic | HR (95% CI) | aOR (95% CI) | aOR (95% CI) | aOR (95% CI) | aOR (95% CI) | aOR (95% CI) | aOR (95% CI) | aOR (95% CI) | aOR (95% CI) |
| Age | 1.01 (0.98–1.05) | 1.07 (0.99–1.15) | 0.97 (0.90–1.05) | 1.07 (0.92–1.25) | 1.02 (0.89–1.17) | 1.12 (1.00–1.24) | 0.99 (0.90–1.09) | 1.02 (0.85–1.21) | 1.00 (0.84–1.20) |
| Gender (ref: Female) | |||||||||
| Male | 0.97 (0.87–1.09) | 0.92 (0.73–1.14) | 0.80 (0.63–1.02) | 0.74 (0.47–1.16) | 0.84 (0.55–1.28) | 0.81 (0.59–1.11) | 0.91 (0.67–1.23) | 0.73 (0.43–1.26) | 0.78 (0.45–1.35) |
| Region (ref: South) | |||||||||
| Northeast | 0.75 (0.63–0.89) | 1.02 (0.73–1.43) | 0.74 (0.52–1.04) | 1.02 (0.57–1.84) | 1.06 (0.59–1.90) | 0.94 (0.56–1.58) | 0.87 (0.55–1.38) | 1.54 (0.79–3.00) | 1.11 (0.51–2.43) |
| Midwest | 0.85 (0.73–0.99) | 1.50 (1.13–2.00) | 0.88 (0.64–1.20) | 0.63 (0.33–1.18) | 0.83 (0.46–1.47) | 1.53 (1.02–2.32) | 0.84 (0.55–1.29) | 0.56 (0.24–1.30) | 0.52 (0.21–1.28) |
| West | 0.96 (0.83–1.12) | 1.63 (1.21–2.18) | 1.03 (0.75–1.41) | 0.84 (0.45–1.58) | 1.31 (0.75–2.28) | 2.28 (1.54–3.39) | 1.64 (1.13–2.37) | 0.86 (0.40–1.81) | 1.51 (0.78–2.94) |
| Smoking intensity (ref: Light) | |||||||||
| Moderate | 0.97 (0.82–1.14) | 1.08 (0.77–1.52) | 1.02 (0.68–1.52) | 0.74 (0.35–1.55) | 0.75 (0.42–1.37) | 1.77 (1.09–2.86) | 0.82 (0.46–1.45) | 0.66 (0.26–1.68) | 0.74 (0.33–1.66) |
| Heavy | 1.04 (0.86–1.26) | 0.91 (0.62–1.34) | 0.83 (0.53–1.29) | 0.70 (0.26–1.88) | 0.61 (0.23–1.62) | 1.34 (0.73–2.46) | 0.66 (0.35–1.25) | 0.65 (0.19–2.20) | 0.52 (0.13–2.12) |
| Smoking frequency (ref: Nondaily) | |||||||||
| Daily | 0.93 (0.81–1.07) | 0.99 (0.74–1.33) | 0.94 (0.68–1.29) | 0.77 (0.43–1.37) | 0.89 (0.53–1.50) | 0.68 (0.45–1.03) | 0.75 (0.52–1.09) | 0.95 (0.49–1.86) | 0.89 (0.46–1.71) |
| Prequit time | 0.94 (0.93–0.95) | 0.94 (0.92–0.96) | 0.94 (0.92–0.96) | 0.98 (0.94–1.02) | 0.99 (0.95–1.02) | 0.96 (0.93–0.99) | 0.95 (0.92–0.98) | 1.01 (0.96–1.06) | 1.04 (0.99–1.09) |
| Number of quit attempts (ref: 1) | |||||||||
| Two or more | 0.88 (0.73–1.06) | 1.79 (1.29–2.48) | 1.61 (1.16–2.23) | 1.53 (0.87–2.69) | 1.14 (0.65–1.98) | 1.42 (0.89–2.24) | 1.91 (1.25–2.92) | 1.30 (0.63–2.69) | 1.03 (0.49–2.18) |
Cell represents significant result if the confidence interval does not cross the null hypothesis (1). Smoking and response statuses were captured and analyzed for eight assessment points. Quit day is Day 0, Day 42 is intervention end, and Day 72 is 1 month follow-up. Results for the other assessment points appear in Supplementary Table 3.
aOR adjusted odds ratio; CI confidence intervals; HR adjusted hazards ratio.
aResponse rate ns reflect the number of subscribers who had not dropped out and had the opportunity to respond to the once-a-week smoking status prompt.
bFor intent-to-treat analysis, n = 2,205 reflects the number of subscribers who made it to quit day. Nonresponders and dropouts were considered smokers. On Day 72, n = 2,150 because 55 subscribers did not have sufficient follow-up time to reach Day 72 before the end of the study on December 31, 2018.