Trial Outcomes & Findings for An Innovative Conversational Agent (Quitbot) for Smoking Cessation (NCT NCT04308759)
NCT ID: NCT04308759
Last Updated: 2026-05-22
Results Overview
The primary endpoint is 30-day point prevalence abstinence for cigarette smoking at 12 months post-randomization. At 12 months, smoking abstinence is assessed by asking participants: "When was the last time you smoked, or even tried, a cigarette?" Response choices are "Earlier today", "24 hours ago", "2-7 days ago", "8-30 days ago", and "Over 30 days ago". Participants reporting no cigarette consumption in the past 30 days are considered abstinent for the 30-day outcome. Missing outcome data are handled using standard intent-to-treat analysis, with all missing data coded as smoking.
COMPLETED
NA
1647 participants
At 12 months after randomization
2026-05-22
Participant Flow
Adults who smoke were recruited nationally from 07/24/2022 to 01/25/2024 via Facebook ads, search engine results, and referral from friend and family.
Participant milestones
| Measure |
Group II (SmokefreeTXT Control)
Participants participate in the SmokefreeTXT program for 42 days to support quitting smoking. SmokefreeTXT is a standard of care smoking cessation text messaging program from the NCI.
|
Group I (QuitBot Experimental)
Participants participate in the QuitBot program for 42 days to support quitting smoking. QuitBot is a novel chatbot smartphone application for smoking cessation.
|
|---|---|---|
|
3-Month Follow-up Survey
STARTED
|
826
|
821
|
|
3-Month Follow-up Survey
COMPLETED
|
758
|
734
|
|
3-Month Follow-up Survey
NOT COMPLETED
|
68
|
87
|
|
6-Month Follow-up Survey
STARTED
|
826
|
821
|
|
6-Month Follow-up Survey
COMPLETED
|
733
|
720
|
|
6-Month Follow-up Survey
NOT COMPLETED
|
93
|
101
|
|
12-Month Follow-up Survey
STARTED
|
826
|
821
|
|
12-Month Follow-up Survey
COMPLETED
|
723
|
704
|
|
12-Month Follow-up Survey
NOT COMPLETED
|
103
|
117
|
Reasons for withdrawal
| Measure |
Group II (SmokefreeTXT Control)
Participants participate in the SmokefreeTXT program for 42 days to support quitting smoking. SmokefreeTXT is a standard of care smoking cessation text messaging program from the NCI.
|
Group I (QuitBot Experimental)
Participants participate in the QuitBot program for 42 days to support quitting smoking. QuitBot is a novel chatbot smartphone application for smoking cessation.
|
|---|---|---|
|
3-Month Follow-up Survey
Lost to Follow-up
|
68
|
87
|
|
6-Month Follow-up Survey
Lost to Follow-up
|
93
|
101
|
|
12-Month Follow-up Survey
Lost to Follow-up
|
103
|
117
|
Baseline Characteristics
An Innovative Conversational Agent (Quitbot) for Smoking Cessation
Baseline characteristics by cohort
| Measure |
Group II (SmokefreeTXT Control)
n=826 Participants
Participants participate in the SmokefreeTXT program for 42 days to support quitting smoking. SmokefreeTXT is a standard of care smoking cessation text messaging program from the NCI.
|
Group I (QuitBot Experimental)
n=821 Participants
Participants participate in the QuitBot program for 42 days to support quitting smoking. QuitBot is a novel chatbot smartphone application for smoking cessation.
|
Total
n=1647 Participants
Total of all reporting groups
|
|---|---|---|---|
|
Race (NIH/OMB)
Asian
|
2 Participants
n=2 Participants
|
4 Participants
n=4 Participants
|
6 Participants
n=6 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
2 Participants
n=2 Participants
|
0 Participants
n=4 Participants
|
2 Participants
n=6 Participants
|
|
Race (NIH/OMB)
Black or African American
|
108 Participants
n=2 Participants
|
110 Participants
n=4 Participants
|
218 Participants
n=6 Participants
|
|
Age, Continuous
|
42.4 Years
STANDARD_DEVIATION 9.8 • n=2 Participants
|
42.5 Years
STANDARD_DEVIATION 10.0 • n=4 Participants
|
42.4 Years
STANDARD_DEVIATION 9.8 • n=6 Participants
|
|
Sex/Gender, Customized
Sex: Female, Male · Female
|
504 Participants
n=2 Participants
|
501 Participants
n=4 Participants
|
1005 Participants
n=6 Participants
|
|
Sex/Gender, Customized
Sex: Female, Male · Male
|
312 Participants
n=2 Participants
|
314 Participants
n=4 Participants
|
626 Participants
n=6 Participants
|
|
Sex/Gender, Customized
Sex: Female, Male · Unknown
|
10 Participants
n=2 Participants
|
6 Participants
n=4 Participants
|
16 Participants
n=6 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
13 Participants
n=2 Participants
|
14 Participants
n=4 Participants
|
27 Participants
n=6 Participants
|
|
Race (NIH/OMB)
White
|
638 Participants
n=2 Participants
|
641 Participants
n=4 Participants
|
1279 Participants
n=6 Participants
|
|
Race (NIH/OMB)
More than one race
|
49 Participants
n=2 Participants
|
46 Participants
n=4 Participants
|
95 Participants
n=6 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
14 Participants
n=2 Participants
|
6 Participants
n=4 Participants
|
20 Participants
n=6 Participants
|
|
Ethnicity (NIH/OMB)
Hispanic or Latino
|
82 Participants
n=2 Participants
|
46 Participants
n=4 Participants
|
128 Participants
n=6 Participants
|
|
Ethnicity (NIH/OMB)
Not Hispanic or Latino
|
744 Participants
n=2 Participants
|
775 Participants
n=4 Participants
|
1519 Participants
n=6 Participants
|
|
Ethnicity (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=2 Participants
|
0 Participants
n=4 Participants
|
0 Participants
n=6 Participants
|
|
Education Level
High school or less education
|
330 Participants
n=2 Participants
|
291 Participants
n=4 Participants
|
621 Participants
n=6 Participants
|
|
Education Level
Some college or more education
|
496 Participants
n=2 Participants
|
530 Participants
n=4 Participants
|
1026 Participants
n=6 Participants
|
|
CESD-20 Depression Screen
CESD-20 score greater than or equal to 16
|
630 Participants
n=2 Participants
|
639 Participants
n=4 Participants
|
1269 Participants
n=6 Participants
|
|
CESD-20 Depression Screen
CESD-20 score less than 16
|
196 Participants
n=2 Participants
|
182 Participants
n=4 Participants
|
378 Participants
n=6 Participants
|
|
Smoking Level
10 or fewer cigarettes per day
|
311 Participants
n=2 Participants
|
326 Participants
n=4 Participants
|
637 Participants
n=6 Participants
|
|
Smoking Level
11-20 cigarettes per day
|
413 Participants
n=2 Participants
|
392 Participants
n=4 Participants
|
805 Participants
n=6 Participants
|
|
Smoking Level
21 or more cigarettes per day
|
102 Participants
n=2 Participants
|
103 Participants
n=4 Participants
|
205 Participants
n=6 Participants
|
PRIMARY outcome
Timeframe: At 12 months after randomizationThe primary endpoint is 30-day point prevalence abstinence for cigarette smoking at 12 months post-randomization. At 12 months, smoking abstinence is assessed by asking participants: "When was the last time you smoked, or even tried, a cigarette?" Response choices are "Earlier today", "24 hours ago", "2-7 days ago", "8-30 days ago", and "Over 30 days ago". Participants reporting no cigarette consumption in the past 30 days are considered abstinent for the 30-day outcome. Missing outcome data are handled using standard intent-to-treat analysis, with all missing data coded as smoking.
Outcome measures
| Measure |
Group II (SmokefreeTXT Control)
n=826 Participants
Participants participate in the SmokefreeTXT program for 42 days to support quitting smoking. SmokefreeTXT is a standard of care smoking cessation text messaging program from the NCI.
|
Group I (QuitBot Experimental)
n=821 Participants
Participants participate in the QuitBot program for 42 days to support quitting smoking. QuitBot is a novel chatbot smartphone application for smoking cessation.
|
|---|---|---|
|
Number of Participants With 30-day Cigarette Smoking Cessation
|
191 Participants
Interval 20.3 to 26.2
|
186 Participants
Interval 19.9 to 25.7
|
SECONDARY outcome
Timeframe: At 6 months after randomizationThe primary endpoint is 30-day point prevalence abstinence for cigarette smoking at 6 months post-randomization. At 6 months, smoking abstinence is assessed by asking participants: "When was the last time you smoked, or even tried, a cigarette?" Response choices are "Earlier today", "24 hours ago", "2-7 days ago", "8-30 days ago", and "Over 30 days ago". Participants reporting no cigarette consumption in the past 30 days are considered abstinent for the 30-day outcome. Missing outcome data are handled using standard intent-to-treat analysis, with all missing data coded as smoking.
Outcome measures
| Measure |
Group II (SmokefreeTXT Control)
n=826 Participants
Participants participate in the SmokefreeTXT program for 42 days to support quitting smoking. SmokefreeTXT is a standard of care smoking cessation text messaging program from the NCI.
|
Group I (QuitBot Experimental)
n=821 Participants
Participants participate in the QuitBot program for 42 days to support quitting smoking. QuitBot is a novel chatbot smartphone application for smoking cessation.
|
|---|---|---|
|
Number of Participants With 30-day Cigarette Smoking Cessation
|
159 Participants
|
153 Participants
|
Adverse Events
Group I (QuitBot Experimental)
Group II (SmokefreeTXT Control)
Serious adverse events
Adverse event data not reported
Other adverse events
Adverse event data not reported
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place