Trial Outcomes & Findings for Project MARS: Mobile-Assistance for Regulating Smoking (NCT NCT04376489)

NCT ID: NCT04376489

Last Updated: 2026-07-29

Results Overview

Within-person randomization occurred (2:1:1) up to 6 times daily for 10 days to (a) no intervention prompt (b) prompt to engage with a low effort strategy or (c) prompt to engage with a more effortful strategy. Proximal Engagement (PE) with strategies is a binary indicator of engagement, coded as 1 (engaged) if the participant answered "Yes" to at least one of the three items below and as 0 (not engaged) if they answered "No" to all three items below. The three EMA items used to operationalize PE were: 1. "Think about the most recent tip or activity recommended by MARS. Did you use it in the last hour?" (Yes or No); 2. "In the last hour, did you use any other tip or activity recommended by MARS?" (Yes or No); 3. "In the last hour, did you use any other tip or activity not included in MARS?" (Yes or No). Proportions were first determined for each participant, then averaged across participants. There were up to 60 decision points per participant.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

114 participants

Primary outcome timeframe

1 hour following micro-randomization

Results posted on

2026-07-29

Participant Flow

Participant milestones

Participant milestones
Measure
Current Smoker
Within-participant micro-randomization occurred up to six times daily (2:1:1) to either (a) no intervention prompt; (b) a prompt recommending a brief (low effort) self-regulatory strategy; or (c) a prompt recommending a more effortful self-regulatory strategy.
Overall Study
STARTED
114
Overall Study
COMPLETED
63
Overall Study
NOT COMPLETED
51

Reasons for withdrawal

Reasons for withdrawal
Measure
Current Smoker
Within-participant micro-randomization occurred up to six times daily (2:1:1) to either (a) no intervention prompt; (b) a prompt recommending a brief (low effort) self-regulatory strategy; or (c) a prompt recommending a more effortful self-regulatory strategy.
Overall Study
Death
1
Overall Study
Attended the visit with staff but did not complete the questionnaire
16
Overall Study
Lost to Follow-up
25
Overall Study
Withdrawal by Subject
9

Baseline Characteristics

Project MARS: Mobile-Assistance for Regulating Smoking

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
Current Smoker
n=111 Participants
Within-participant micro-randomization occurred up to six times daily (2:1:1) to either (a) no intervention prompt; (b) a prompt recommending a brief (low effort) self-regulatory strategy; or (c) a prompt recommending a more effortful self-regulatory strategy.
Age, Continuous
43.8 years
STANDARD_DEVIATION 11.5 • n=9 Participants
Sex: Female, Male
Female
71 Participants
n=9 Participants
Sex: Female, Male
Male
40 Participants
n=9 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
30 Participants
n=9 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
81 Participants
n=9 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants
n=9 Participants
Race (NIH/OMB)
American Indian or Alaska Native
2 Participants
n=9 Participants
Race (NIH/OMB)
Asian
0 Participants
n=9 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
n=9 Participants
Race (NIH/OMB)
Black or African American
39 Participants
n=9 Participants
Race (NIH/OMB)
White
64 Participants
n=9 Participants
Race (NIH/OMB)
More than one race
6 Participants
n=9 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants
n=9 Participants
Region of Enrollment
United States
111 participants
n=9 Participants
Partner Status
Has Partner
47 Participants
n=9 Participants
Partner Status
Does Not Have Partner
60 Participants
n=9 Participants
Partner Status
Did not disclose
4 Participants
n=9 Participants
Tobacco History
13.7 number of cigarettes smoked per day
STANDARD_DEVIATION 7.97 • n=9 Participants
Income
Less than or equal to $9,999:
15 Participants
n=9 Participants
Income
$10,000 - $19,999:
13 Participants
n=9 Participants
Income
$20,000 - $29,999:
17 Participants
n=9 Participants
Income
$30,000 - $39,999:
8 Participants
n=9 Participants
Income
$40,000 - $49,999:
10 Participants
n=9 Participants
Income
$50,000 - $59,999:
9 Participants
n=9 Participants
Income
$60,000 - $69,999:
8 Participants
n=9 Participants
Income
$70,000 - $79,999:
5 Participants
n=9 Participants
Income
$80,000 - $89,999:
3 Participants
n=9 Participants
Income
$90,000 - $99,999:
3 Participants
n=9 Participants
Income
$100,000 and greater:
10 Participants
n=9 Participants
Income
Did not disclose:
10 Participants
n=9 Participants

PRIMARY outcome

Timeframe: 1 hour following micro-randomization

Population: Of the 114 who started the study, 111 were non-beta participants. However, due to sub-par fidelity to the study protocol, 99 were used for analyzing results.

Within-person randomization occurred (2:1:1) up to 6 times daily for 10 days to (a) no intervention prompt (b) prompt to engage with a low effort strategy or (c) prompt to engage with a more effortful strategy. Proximal Engagement (PE) with strategies is a binary indicator of engagement, coded as 1 (engaged) if the participant answered "Yes" to at least one of the three items below and as 0 (not engaged) if they answered "No" to all three items below. The three EMA items used to operationalize PE were: 1. "Think about the most recent tip or activity recommended by MARS. Did you use it in the last hour?" (Yes or No); 2. "In the last hour, did you use any other tip or activity recommended by MARS?" (Yes or No); 3. "In the last hour, did you use any other tip or activity not included in MARS?" (Yes or No). Proportions were first determined for each participant, then averaged across participants. There were up to 60 decision points per participant.

Outcome measures

Outcome measures
Measure
Intervention Prompt
n=1924 decision points
Participants were randomized to a prompt recommending a self-regulatory strategy during these decision points.
No Intervention Prompt
n=1934 decision points
Participants were randomized to no intervention prompt during these decision points.
Proportion of Randomized Decision Points in Which Participant Reported Proximal Engagement by Randomized Assignment
0.655 Proportion of decision points
Interval 0.589 to 0.716
0.584 Proportion of decision points
Interval 0.506 to 0.658

PRIMARY outcome

Timeframe: 1 hour following micro-randomization

Population: Of the 114 who started the study, 111 were non-beta participants. However, due to sub-par fidelity to the study protocol, 99 were used for analyzing results.

Within-person randomization occurred (2:1:1) up to 6 times daily for 10 days to (a) no intervention prompt (b) prompt to engage with a low effort strategy or (c) prompt to engage with a more effortful strategy. Proximal Engagement (PE) with strategies is a binary indicator of engagement, coded as 1 (engaged) if the participant answered "Yes" to at least one of the three items below and as 0 (not engaged) if they answered "No" to all three items below. The three EMA items used to operationalize PE were: 1. "Think about the most recent tip or activity recommended by MARS. Did you use it in the last hour?" (Yes or No); 2. "In the last hour, did you use any other tip or activity recommended by MARS?" (Yes or No); 3. "In the last hour, did you use any other tip or activity not included in MARS?" (Yes or No). Proportions were first determined for each participant, then averaged across participants. There were up to 60 decision points per participant.

Outcome measures

Outcome measures
Measure
Intervention Prompt
n=997 decision points
Participants were randomized to a prompt recommending a self-regulatory strategy during these decision points.
No Intervention Prompt
n=927 decision points
Participants were randomized to no intervention prompt during these decision points.
Proportion of Randomized Decision Points in Which the Participant Reported Proximal Engagement by Randomized Assignment.
0.602 Proportion of decision points
Interval 0.53 to 0.67
0.713 Proportion of decision points
Interval 0.641 to 0.776

SECONDARY outcome

Timeframe: approximately 1 hour following the decision point

Population: Of the 114 who started the study, 111 were non-beta participants. However, due to sub-par fidelity to the study protocol, 99 were used for analyzing results.

Proximal Cigarette Use (PCU) was assessed with the EMA item, "Since the last assessment, did you use any of the following (check all that apply): Cigarettes; Vape pen, JUUL, or e-cigarettes; Cigars, cigarillos, or little cigars; Smokeless tobacco/snus/dissolvable tobacco; Marijuana/Cannabis; Alcohol; None." A binary indicator of Proximal Cigarette Use was created, coded as 1 if the response included "Cigarettes" and 0 otherwise. This outcome measure reports the proportion that reported PCU at 1 hour following micro-randomization. The intent of this Outcome Measures is to report overall PCU use according to participant's self-reported engagement with self-regulatory strategies.

Outcome measures

Outcome measures
Measure
Intervention Prompt
n=3858 decision points
Participants were randomized to a prompt recommending a self-regulatory strategy during these decision points.
No Intervention Prompt
Participants were randomized to no intervention prompt during these decision points.
Proximal Cigarette Use
0.33 Proportion of Decision Points
Interval 0.29 to 0.38

SECONDARY outcome

Timeframe: approximately 1 hour following the decision point

Population: Of the 114 who started the study, 111 were non-beta participants. However, due to sub-par fidelity to the study protocol, 99 were used for analyzing results.

Proximal Nicotine-Containing Non-Cessation Product Use (NCNCP) was assessed with the EMA item, "Since the last assessment, did you use any of the following (check all that apply): Cigarettes; Vape pen, JUUL, or e-cigarettes; Cigars, cigarillos, or little cigars; Smokeless tobacco/snus/dissolvable tobacco; Marijuana/Cannabis; Alcohol; None." A binary indicator of Proximal NCNCP Use was created, coded as 1 if the response included "Cigarettes", "Vape pen, JUUL, or e-cigarette," "Cigars, cigarillos, or little cigars," or "Smokeless tobacco/snus/dissolvable tobacco," and 0 otherwise. This outcome measure will report the proportion that reported NCNCP Use at 1 hour following micro-randomization.

Outcome measures

Outcome measures
Measure
Intervention Prompt
n=3858 decision point
Participants were randomized to a prompt recommending a self-regulatory strategy during these decision points.
No Intervention Prompt
Participants were randomized to no intervention prompt during these decision points.
Proximal Nicotine-Containing Non-Cessation Product (NCNCP) Use
0.34 Proportion of decision points
Interval 0.3 to 0.39

SECONDARY outcome

Timeframe: approximately 1 hour following the decision point

Population: Of the 114 who started the study, 111 were non-beta participants. However, due to sub-par fidelity to the study protocol, 99 were used for analyzing results.

Proximal Nicotine-Containing Non-Cessation Product Use (PTPU) was assessed with the EMA item, "Since the last assessment, did you use any of the following (check all that apply): Cigarettes; Vape pen, JUUL, or e-cigarettes; Cigars, cigarillos, or little cigars; Smokeless tobacco/snus/dissolvable tobacco; Marijuana/Cannabis; Alcohol; None." A binary indicator of PTPU was created, coded as 1 if the response included "Cigarettes", "Cigars, cigarillos, or little cigars," or "Smokeless tobacco/snus/dissolvable tobacco," and 0 otherwise. This outcome measure will report the proportion that reported PTPU at 1 hour following micro-randomization.

Outcome measures

Outcome measures
Measure
Intervention Prompt
n=3858 decision point
Participants were randomized to a prompt recommending a self-regulatory strategy during these decision points.
No Intervention Prompt
Participants were randomized to no intervention prompt during these decision points.
Proximal Tobacco Product Use (PTPU) Use
0.34 Proportion of decision points
Interval 0.3 to 0.39

Adverse Events

Current Smoker

Serious events: 0 serious events
Other events: 2 other events
Deaths: 1 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure
Current Smoker
n=114 participants at risk
Within-participant micro-randomization occurred up to six times daily (2:1:1) to either (a) no intervention prompt; (b) a prompt recommending a brief (low effort) self-regulatory strategy; or (c) a prompt recommending a more effortful self-regulatory strategy.
Skin and subcutaneous tissue disorders
Pain of Skin
1.8%
2/114 • Number of events 2 • Adverse events and serious adverse events were collected while participants were one study, up to 10 days

Additional Information

IIT Data Management Team

Research Compliance Office, Huntsman Cancer Institute

Phone: 801-213-6215

Results disclosure agreements

  • Principal investigator is a sponsor employee
  • Publication restrictions are in place