Development of a Mindfulness-Based Treatment for the Reduction of Alcohol Use and Smoking Cessation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Development of a Mindfulness-Based Treatment for the Reduction of Alcohol Use and Smoking Cessation (NCT03734666), a randomized na study. The primary outcome is Aim 2: Number of Participants Scoring >3.

2. Clinical Question

The study also lists smoking-abstinence and heavy-alcohol-use outcomes at the end of treatment and at follow-up. The posted results include comparisons for smoking abstinence, while numerical results for the listed heavy-alcohol-use outcomes are not reported in the registry record. Thus, the central clinical question is about development and evaluation of a combined behavioral approach, but the primary posted result specifically concerns participants’ satisfaction with treatment.

3. Trial Design

This was a randomized, parallel-group behavioral study with no masking. The registry lists the study phase as not applicable. Enrollment was 67. The listed study start was 2019-01-14, primary completion was 2021-11-04, and the study status is completed.

One group received Mindfulness Based Relapse Prevention, modified to focus explicitly on smoking cessation and reduced alcohol use. The other received cognitive behavioral therapy, described as a commonly used treatment for substance-abuse behaviors that uses problem solving and coping skills. The registry identifies both interventions as behavioral.

The primary outcome was assessed at the end of treatment at 8 weeks. It is a count of participants scoring >3 on the Client Satisfaction Questionnaire Version 8. The registry says satisfaction was determined using 8 items on a 4-point scale and describes the reported result as clients with a patient-satisfaction score over 80%. The population specified for the primary outcome is participants analyzed who responded to the survey.

The registry lists secondary outcomes for smoking abstinence and heavy alcohol use at the end of treatment and at 16-week follow-up. It does not report detailed allocation procedures, masking procedures beyond no masking, treatment-session frequency, retention procedures, or participant characteristics in the record summarized for these results. Details of the protocol and statistical analysis plan are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Number of participants analyzed who responded to the survey

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Aim 2: Number of Participants Scoring >3, measured over End of Treatment at 8 Weeks.

The primary endpoint is the number of analyzed survey respondents whose Client Satisfaction Questionnaire Version 8 score was >3, measured at the end of treatment at 8 weeks. This is a treatment-satisfaction outcome: it describes how respondents rated their experience, rather than whether they stopped smoking or reduced alcohol use.

The registry describes the questionnaire as 8 items, each using a 4-point response scale from very dissatisfied to very satisfied. It also says the reported results indicate clients with a patient-satisfaction score over 80%. The precise rule connecting that description to the endpoint threshold is not further explained in the registry record, so interpretation should follow the posted endpoint description rather than assume a different scoring convention.

A satisfaction endpoint can be useful in a treatment-development study because participant experience is relevant to whether an intervention is acceptable to those who respond. However, satisfaction alone does not establish behavioral change, durability of change, or comparative clinical benefit. The registry’s outcome description also specifies that the denominator is respondents analyzed, so it does not by itself describe satisfaction among people who did not respond to the survey.

7. Results Posted in the Registry

• Cognitive Behavioral Therapy: 100.0% (16/16) versus 94.7% (18/19) on control; risk difference 5.3 percentage points (95% CI -4.8 to 15.3), risk ratio 1.06 (0.95–1.17); unadjusted two-proportion z-test p = 0.352.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Aim 3: Percent of Smoking Abstinence End of Treatment

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Cognitive Behavioral Therapy: 31.2% (10/32) versus 34.3% (12/35) on control; risk difference -3.0 percentage points (95% CI -25.5 to 19.4), risk ratio 0.91 (0.46–1.82); unadjusted two-proportion z-test p = 0.792.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Cognitive Behavioral Therapy and the control. The interval gives the range of effects that remain compatible with the data.

Aim 3: Percent of Smoking Abstinence at 16 Week Follow-up

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Cognitive Behavioral Therapy: 3.1% (1/32) versus 14.3% (5/35) on control; risk difference -11.2 percentage points (95% CI -24.2 to 1.9), risk ratio 0.22 (0.03–1.77); unadjusted two-proportion z-test p = 0.110.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Cognitive Behavioral Therapy and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes broaden the focus beyond satisfaction to smoking abstinence and heavy alcohol use, assessed at the end of treatment and at follow-up. The posted numerical comparisons describe smoking abstinence at the two time points; numerical results for the listed heavy-alcohol-use outcomes are not reported in the registry record. The smoking outcomes are distinct from the primary satisfaction endpoint and should be understood as separate measures of behavior.

Across the smoking results, the direction of the point estimates differs by assessment time: the end-of-treatment comparison and the follow-up comparison do not point in the same direction. The uncertainty intervals for both comparisons include zero. This pattern calls for caution rather than a simple conclusion that one approach consistently performed better. The secondary results do not alter what the primary endpoint measures, and satisfaction cannot serve as a proxy for abstinence.

Secondary outcomes generally carry less evidential weight than a prespecified primary outcome, particularly when several outcomes or assessment times are examined. Testing multiple outcomes increases the chance that at least one comparison may look unusual even when no underlying difference exists. A multiplicity adjustment or a prespecified hierarchy can address this concern, but such a plan is not reported in the registry record. The posted secondary p-values are unadjusted.

The registry lists four secondary outcomes, including heavy-alcohol-use outcomes, but the available outcome information is incomplete for assessing the overall set of stated aims. The secondary findings are best treated as descriptive and hypothesis-generating. They do not provide an independently conclusive answer to the broader question of whether the adapted behavioral treatment changes smoking or alcohol-use behavior.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Aim 3: Percent of Smoking Abstinence End of Treatment
• Aim 3: Percent of Smoking Abstinence at 16 Week Follow-up
• Aim 3: Percent of Heavy Alcohol Use at End of Treatment
• Aim 3: Percentage of Heavy Alcohol Use at 16 Week Follow-up

9. Statistical Interpretation

10. Statistical Methods Explained

What does the primary comparison estimate?

The primary comparison is expressed as a risk difference: the proportion meeting the satisfaction threshold in cognitive behavioral therapy minus the proportion in Mindfulness Based Relapse Prevention. A risk difference is an absolute contrast between two proportions. A value of zero corresponds to equal proportions; a positive value indicates a higher proportion in the first-named comparison group under this direction convention. This is a general explanation of the statistic. The posted estimate is 0.053, and its 95% confidence interval is -0.048 to 0.153.

The endpoint itself is posted as a participant count, while the comparison expresses a difference in proportions. The registry gives the number meeting the threshold and the number analyzed for each arm. These are not interchangeable descriptions: the counts retain the observed scale of the endpoint, while the comparison puts the groups on a common proportion scale.

How should the p-value be read?

The unadjusted p-value for the primary comparison is 0.352. In general, a p-value describes how unusual the data would be under a specified null model and analysis procedure. It is not the probability that the null hypothesis is true, the chance that the result is due to chance, or a measure of clinical importance. An unadjusted value does not account for any multiplicity adjustment. The registry record does not report a multiplicity plan or a detailed analysis procedure.

What does the confidence interval add?

A confidence interval communicates uncertainty about the estimated contrast. In general, a wider interval indicates less precision, while an interval that includes zero leaves open both positive and negative differences for a risk-difference measure. The primary interval runs from -0.048 to 0.153, so it includes zero. The interval does not establish that the treatments are equivalent, and its endpoints should not be interpreted as a guarantee that the true effect lies within them.

What can be inferred from the analysis record?

The posted comparisons are unadjusted. The registry record does not describe covariate adjustment, the model used to calculate intervals, handling of missing outcomes, or an intention-to-treat analysis population. Those details are not reported in the registry record. Therefore, the estimates should be read as the posted group summaries and unadjusted comparisons, not as evidence of an undocumented adjusted analysis.

How are the planning illustrations different from trial results?

The sample-size illustrations use fractions of the observed smoking-abstinence effects and are planning calculations, not observed power. The stated assumptions are a two-sided significance level of 0.05, equal allocation, and a normal approximation. For smoking abstinence at the end of treatment, the illustration gives participants per arm for 80% power of 3,752 when planning for 100% of the observed effect, 6,710 for 75%, and 15,184 for 50%. For 90% power, the corresponding figures are 5,022, 8,982, and 20,327. At 16-week follow-up, the participants-per-arm illustrations for 80% power are 99, 203, and 512 for those same effect fractions; the 90% figures are 132, 271, and 685.

These calculations are prospective planning illustrations based on observed effects. They do not show the power of the completed trial, do not establish what sample size was planned for the trial, and do not establish that the study was designed around these endpoints. The trial’s own sample-size justification is not reported in the registry record. The registry also does not report interim analyses or a prespecified statistical analysis plan.

More generally, binary outcomes are influenced by the number of participants with and without the event. With sparse outcomes, estimates can be unstable and intervals can be broad. This is a general statistical consideration, not a separate finding about the validity of the posted analysis.

11. Confidence Intervals and Precision

The primary estimate is a risk difference of 0.053 for cognitive behavioral therapy compared with Mindfulness Based Relapse Prevention. Its 95% confidence interval extends from -0.048 to 0.153. Because zero lies within this interval, the posted data are compatible with no difference as well as with differences in either direction. The interval is a more informative description of uncertainty than the point estimate alone.

In general, a confidence interval is constructed using a method designed to capture the true parameter at a stated rate over repeated studies under its assumptions. It is not a probability statement about this particular interval. The registry record does not identify the interval-construction method, so the posted interval should be interpreted as reported rather than attributed to a particular model.

The primary outcome is based on analyzed survey respondents, and the group counts are close to the available respondent counts. Such limited information can constrain precision, especially for binary endpoints. The confidence interval reflects uncertainty in the group contrast, but it does not account for every possible source of uncertainty, such as missing responses, differences in who responded, or limitations of outcome measurement. Details about those issues are not reported in the registry record.

The p-value of 0.352 is consistent with the interval’s inclusion of zero, but it should not replace the interval when considering the range of differences compatible with the data. The interval also does not establish equivalence: that would require an appropriate design and a prespecified equivalence margin, neither of which is reported in the registry record.

12. Multiplicity, Missing Data and Analysis Populations

The registry lists multiple secondary outcomes across smoking abstinence and heavy alcohol use, with assessments at the end of treatment and at 16-week follow-up. The posted secondary comparisons are unadjusted. When several outcomes and time points are evaluated, the chance of at least one apparently notable result can increase. A multiplicity strategy can help control that risk, but whether one was planned or used is not reported in the registry record.

There is no detailed statistical analysis plan in the record summarized for these results. The registry does not report whether outcomes were analyzed according to randomized assignment, whether analyses were adjusted for baseline characteristics, or how any protocol deviations were handled. These analysis-population details are not reported in the registry record, so the posted denominators should not be assumed to represent a particular analysis strategy beyond the stated respondent population for the primary endpoint.

Missing-data handling is also not reported in the registry record. In particular, the record does not explain how missing surveys or follow-up assessments were treated, whether participants with missing data were excluded, or whether any imputation was used. This matters because outcome percentages among those with recorded results may differ from the experience of all randomized participants if response or follow-up is related to the outcome.

The registry record does not report interim analyses, a prespecified sample-size justification, or an approach for accounting for multiple comparisons. The absence of these details in the record should not be taken to mean that no such procedures existed; their presence or absence is not reported. In their absence, the safest reading is to emphasize the posted estimates and their uncertainty, and to treat secondary results as exploratory rather than confirmatory.

13. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: renal calculi (3.1%), torn ligament (3.1%), fall (3.1%), flu like symptoms (3.1%), general disorders and administration site conditions - other (2.9%).

The registry reports serious adverse events for the two groups, with one event in Mindfulness Based Relapse Prevention and three in cognitive behavioral therapy. The listed serious-event risk sets are 35 and 32, respectively. No deaths are reported in either group.

These counts describe events recorded in the registry; they do not by themselves establish whether an event was caused by treatment. The record also lists serious-event terms and their reported percentages, including renal calculi, torn ligament, fall, flu-like symptoms, and a general-disorders category. The listing does not provide enough information to infer a causal relationship or compare the clinical importance of the terms.

Event counts are small, so the figures offer limited precision for comparing safety between groups. The registry record does not report detailed event timing, relatedness assessments, or a statistical comparison of adverse events. The counts should therefore be read descriptively, not as a definitive estimate of comparative risk.

14. What the Result Does, and Does Not, Mean

The primary result describes satisfaction among survey respondents at the end of treatment. The posted group counts are similar in scale, and the unadjusted risk-difference interval includes zero. These data do not establish a clear difference in satisfaction between the two groups, but they also do not prove that the groups are equivalent.

The result does not directly answer whether either treatment reduces alcohol use or supports smoking cessation. Satisfaction and behavioral outcomes are different constructs. Although smoking-abstinence outcomes are also posted, they are secondary results, and the registry does not provide numerical results for the listed heavy-alcohol-use outcomes. Therefore, the posted primary result cannot support a claim about alcohol-use change.

The findings also do not establish that the adapted mindfulness-based intervention is effective, ineffective, safer, or less safe than cognitive behavioral therapy. An unadjusted comparison in a completed randomized study is informative, but interpretation depends on the outcome definition, completeness of follow-up, and analysis procedures. Some of those details are not reported in the registry record.

In general, a statistically nonsignificant comparison is not evidence of no effect. Likewise, a point estimate in one direction does not establish a reliable difference when the interval remains compatible with values on both sides of zero. These are general statistical principles and do not add claims about the treatments. The registry results are best understood as estimates with uncertainty that may inform further study, rather than as final answers about treatment benefit.

15. Why This Trial Matters Statistically

This trial is statistically informative because it places an intervention-development question alongside an active behavioral comparator. A randomized parallel-group design can support a direct comparison, while the no-masking design and the subjective satisfaction endpoint make clear why outcome definition and interpretation matter. The primary result is not a behavioral outcome, so distinguishing acceptability from smoking and alcohol-use outcomes is essential.

The record also illustrates how a point estimate, confidence interval, and p-value answer related but different questions. The primary interval includes zero, leaving uncertainty about the direction and size of the satisfaction contrast. The p-value alone cannot establish equivalence or lack of effect. Reading the estimate together with its interval avoids treating a single threshold as the full statistical conclusion.

Finally, the posted smoking outcomes and planning illustrations show why secondary findings need careful framing. Multiple outcomes and follow-up times raise multiplicity concerns, and planning calculations based on observed effects are not evidence of the completed study’s power. The record’s missing details on analysis plans, missing data, and heavy-alcohol-use results also limit how confidently the broader aims can be assessed. These considerations are valuable for clinical researchers designing and interpreting behavioral trials.

16. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The primary measure is satisfaction among survey respondents, not a direct measure of smoking abstinence or alcohol use. The registry describes the threshold as a score >3 and also says the reported results indicate clients with a satisfaction score over 80%; the relationship between those descriptions is not fully explained. This limits how precisely the endpoint’s scoring can be interpreted.

The primary outcome includes analyzed survey respondents, and the registry record does not explain whether nonrespondents differed from respondents. Missing-data methods and the analysis population for other outcomes are not reported in the registry record. The posted results therefore may not fully represent outcomes for everyone enrolled.

The study was not masked, and satisfaction is a respondent-reported measure. The registry does not provide additional information about outcome assessment procedures or possible sources of response influence. The posted smoking-abstinence comparisons also have uncertainty intervals that include zero, while numerical heavy-alcohol-use results are not reported in the registry record.

Further limitations include the lack of reported detail on allocation procedures, participant characteristics, multiplicity handling, covariate adjustment, and a statistical analysis plan. The record’s planning illustrations are based on observed effects and do not establish the trial’s original sample-size rationale. These gaps constrain interpretation of the results and their generalizability; they do not establish that the procedures were absent, only that they are not reported in the registry record.

17. Related Tutorials

18. Related Statistical Calculators

19. Sources

• ClinicalTrials.gov: Development of a Mindfulness-Based Treatment for the Reduction of Alcohol Use and Smoking Cessation — NCT03734666.
• Registry record last updated 2026-01-15; status last verified 2025-12.
• Results first posted 2023-06-29.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

20. Record Summary

NCT03734666 is a completed randomized, parallel-group behavioral study with no masking. The registry lists enrollment of 67 and compares Mindfulness Based Relapse Prevention modified for smoking and alcohol use with cognitive behavioral therapy. The primary outcome is the number of survey respondents scoring >3 on a satisfaction measure at the end of treatment at 8 weeks.

The primary posted comparison is an unadjusted risk difference of 0.053 for cognitive behavioral therapy versus the mindfulness-based group, with a 95% confidence interval from -0.048 to 0.153 and p = 0.352. The interval includes zero. The record also lists smoking-abstinence and heavy-alcohol-use secondary outcomes; numerical heavy-alcohol-use results are not reported in the registry record.

The study dates listed are 2019-01-14 and 2021-11-04 for start and primary completion. The registry reports no deaths in either group. Details on the statistical analysis plan, missing-data handling, and multiplicity procedures are not reported in the registry record.