PARQuit Smoking Cessation Intervention for Adults With Serious Mental Illness: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for PARQuit Smoking Cessation Intervention for Adults With Serious Mental Illness (NCT03950427), a randomized phase 4 study. The primary outcome is Total Number of Videogame Sessions Attended.

2. Clinical Question

The central statistical question is therefore whether participants attended sessions in the two program groups at different levels, and how precisely any such difference can be estimated. The posted outcome values offer a descriptive view, but the registry record does not post a comparison estimate, uncertainty interval, or analysis result. Attendance alone also cannot establish whether participants quit smoking, changed tobacco use, or experienced other health outcomes.

Random allocation is listed, but details of sequence generation, allocation concealment, and the timing of assignment are not reported in the registry record. The record identifies a parallel design with no masking. These design features describe how the study was organized; they do not by themselves determine what conclusions can be drawn from an outcome. The available results need to be interpreted in light of the outcome definition, sample sizes, and missing inferential information.

3. Trial Design

The registry lists this as a Phase 4, randomized, parallel-group study with no masking. The study is marked completed, and enrollment is listed as 108. The sponsor is the University of California, San Francisco. Adults with serious mental illness are the focus, and the study investigates a smoking-cessation program that includes videogame-based physical activity, counseling, and medication as described in the registry summary.

The two current outcome groups are the game-based physical activity group and the sedentary videogame group. Their posted sample sizes are 49 and 50, respectively. The activity group used active videogames with a Kinect system or activity outdoors in a public park. The sedentary group played videogames while seated, using a console or seated outdoor play. The posted primary outcome is the number of videogame sessions attended, measured over up to 12 weeks.

The registry also lists closed, pre-COVID versions of the physical activity and sedentary groups. Those groups appear in the serious adverse event records with sample sizes of 4 and 5. They are distinct from the two current outcome groups, and the primary-outcome values listed for the current groups should not be conflated with those closed groups. The registry record does not explain the relationship between enrollment, the current outcome groups, and the closed groups in enough detail to reconcile the counts.

Although the study summary describes counseling and bupropion, the full delivery details and any changes in study procedures are not reported in the registry record. Specific eligibility criteria, sites, recruitment methods, allocation procedures, and whether the groups differed only in videogame activity are also not reported in the registry record. The design label and arm descriptions establish the broad comparison, but not every operational detail needed to reproduce the study or evaluate all possible sources of bias.

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.

Before assignment: 131 potential participants consented, but 23 participants were lost to contact prior to being randomized to any study intervention. These 23 participants are not considered enrolled due to the fact they were never assigned to, nor received, any study intervention. The pre-covid version of the interventions were dropped from the protocol and analyses due to the extensive changes and were amended to include an outdoor park-based intervention implemented after covid.

Baseline

Week 6

Week 12

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.

Population: The pre-covid version of the interventions (VIP groups) were removed from the protocol and analyses plan via an amendment, due to the extensive changes to the intervention introduced to accommodate concerns regarding COVID restrictions at the time the study was enrolling (2020) which was re-designed to include an outdoor park-based intervention and re-named PARQuit. Only participants enrolled in the PARQuit conditions are included in the analyses per protocol.

6. Primary Endpoint

The registry lists the primary outcome as Total Number of Videogame Sessions Attended, measured over Up to 12 weeks.

The primary endpoint is the total number of videogame sessions attended, with a timeframe of up to 12 weeks. The description says that attendance was documented by the graduate student researcher. The registry classifies the endpoint as a number and reports 12 sessions for the game-based physical activity group and 10 for the sedentary videogame group. The reported values are session counts, not smoking-cessation outcomes.

Attendance is useful as a feasibility measure because it records whether participants took part in the scheduled program. In general, attendance can help describe engagement with an intervention and whether the study activities were used. It does not, by itself, measure the quality of participation, adherence to medication or counseling, or change in tobacco use. The registry does not report a threshold defining adequate attendance or explain how sessions were scheduled and counted beyond the stated documentation process.

The endpoint is a count, so its statistical behavior may differ from that of a continuous measurement. In general, count data can be unevenly distributed, may include many low values, and can vary more than a simple count model expects. These are general considerations, not claims about the actual distribution of attendance in this trial. The registry does not provide a measure of spread, participant-level attendance values, or an analysis model that would show how these features were handled.

Because the posted outcome values have no accompanying uncertainty measure or inferential comparison, they describe the recorded attendance outcome but do not establish how precisely the groups differ. The endpoint is most directly interpreted as an indicator of participation in the study program.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Several statistical ideas help clarify what the posted attendance outcome can and cannot establish. The registry identifies random allocation and a parallel-group design, but it does not report the statistical analysis plan or a formal analysis result for the primary endpoint. The explanations below are general statistical context; they are not descriptions of analyses confirmed to have been performed in this trial.

What does random allocation contribute?

In general, random allocation is intended to make the study groups comparable, on average, with respect to measured and unmeasured characteristics at the time of assignment. It supports a causal comparison when the allocation process is implemented properly and the analysis preserves the assigned groups. Randomization does not guarantee that the groups will be identical, particularly in a study with limited enrollment. It also does not resolve problems caused by missing outcomes, deviations from the assigned program, or selective reporting.

The registry lists the study as randomized, but the sequence-generation method, allocation concealment, and analysis according to assigned group are not reported in the registry record. Consequently, the label identifies the broad design but does not provide enough detail to assess those aspects of implementation.

Why does the count outcome matter?

Session attendance is a count. In general, counts take discrete values and may be concentrated at the lower end, may have a long upper tail, or may include substantial variability among participants. Some count-data methods assume that the variability follows a particular relationship with the average count. If actual variability is greater than that assumption allows, the data are over-dispersed. Over-dispersion matters because a model that understates variability can produce overly narrow uncertainty intervals or overly optimistic tests.

These are general properties to consider, not a diagnosis of this trial’s attendance data. The registry does not post participant-level counts, a measure of variability, a distributional summary, or a model specification. It is therefore not possible to determine whether attendance was over-dispersed or whether a count regression, a rank-based method, a simple group summary, or another approach was used. The appropriate method depends on the distribution, estimand, and analysis plan.

How should uncertainty be assessed?

A group estimate describes the endpoint in a sample; an uncertainty interval expresses how imprecise that estimate may be under a specified model. A test result, where reported, addresses compatibility with a null hypothesis under its assumptions. Neither a point estimate nor a p-value alone communicates the full magnitude and precision of an effect. For attendance, useful reporting would ordinarily make clear the group summary, a measure of variability, the contrast of interest, and an uncertainty interval. Those inferential details are not reported in the registry record.

The primary outcome entries provide values of 12 and 10 sessions, with sample sizes of 49 and 50. The record does not specify whether the values are means, medians, or another summary. No unadjusted recalculation is presented, and no inferential result can be derived from these entries without additional distributional information. The record identifies the comparison as unavailable or not estimable for this count endpoint; that is more informative than treating the posted values as a complete statistical analysis.

What do the planning assumptions mean?

The registry’s sample-size planning illustration is described as using a two-sided significance level of 0.05, equal allocation, and a normal approximation. It is based on a fraction of the observed effect. These are planning assumptions for an illustration, not a statement of the trial’s original design rationale. The protocol’s sample-size justification is not reported in the registry record. The illustration does not establish that the trial had adequate power for its endpoint, nor does it give observed power. Sample-size planning is prospective: it asks what sample size may be needed under stated assumptions. It does not measure the probability that a completed study’s result is true.

The record says that illustrations for non-time-to-event outcomes are expressed as participants per arm, while time-to-event illustrations use total events. No numerical planning results are available in the registry record for this trial, so none are reproduced. A planning calculation based on the observed effect also depends on assumptions about the effect size and variability; its meaning is conditional on those assumptions and should not be confused with a confirmed study-design target.

What does the absence of analysis output imply?

The registry lists zero posted analyses. That does not prove that no analysis was conducted outside the registry; it means that analysis results are not reported in this registry record. The primary attendance values remain descriptive, and no sponsor-reported inferential analysis is available to interpret. The sponsor’s analysis would take precedence if a recalculated result conflicted with it, but there is no such recalculation or reported discrepancy in this record.

Overall, the design and outcome definition establish the question the trial intended to address, while the posted statistical detail is insufficient to evaluate the precision or robustness of a group comparison. The concepts of count-data distribution, over-dispersion, uncertainty intervals, and prospective sample-size planning are useful for interpreting what would be needed for a fuller analysis, but none should be mistaken for a method documented as used in this study.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 10 outcome measures, while zero secondary outcomes are posted in the record. The number of outcome measures alone does not show how many statistical tests were performed or which outcomes were designated as primary at each stage. A prespecified multiplicity strategy, such as a hierarchy of outcomes or an adjustment to control the chance of false-positive findings across tests, is not reported in the registry record. The statistical analysis plan and any interim-analysis procedures are also not reported in the registry record.

Multiplicity matters when several outcomes or comparisons are tested. In general, the more opportunities there are to find an apparently unusual result, the more important it is to understand which analyses were planned and how the overall error rate was handled. That general concern does not establish that the trial conducted multiple tests or that any particular result is biased. The registry does not provide the analysis details needed to assess this issue.

Missing-data methods are not reported in the registry record. The record does not state how many participants had missing attendance information, whether all randomized participants contributed outcome data, or how nonattendance and missing attendance records were distinguished. A participant with no attended sessions and a participant whose attendance was not recorded are not necessarily the same statistical situation. The posted group values do not resolve that distinction.

The analysis population is also not reported in the registry record. It is not stated whether results were analyzed according to randomized assignment, among participants who started the program, or under another definition. No information is given about protocol deviations or exclusions from an analysis. These details are important because different analysis populations can answer different questions and may produce different estimates.

Accordingly, the registry record does not permit assessment of multiplicity control, missing-data assumptions, or the population used for analysis. These are limitations of the reporting available for interpretation, not evidence that a particular procedure was or was not used outside the registry.

11. 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.

The serious adverse event records list zero serious adverse events in each of the four groups: the current game-based physical activity group, the current sedentary videogame group, and the two closed pre-COVID groups. The numbers listed as at risk are 49, 50, 4, and 5, respectively. The registry also lists zero other adverse events and zero deaths in each group.

These are counts recorded in the registry, not estimates of comparative risk. The record does not provide a safety comparison, uncertainty intervals, event definitions, or a detailed observation period for these entries. A count of zero recorded events does not establish that the true risk is zero; it means that no events of the listed type were recorded in these group summaries. The size and duration of observation affect how much can be learned from an absence of recorded events.

The closed pre-COVID groups are listed separately from the two current outcome groups. Their safety counts should therefore not be combined with the current groups or treated as part of the primary attendance comparison without further information. The registry does not report detailed event narratives or top serious event terms. The safety entries are limited evidence about recorded events and do not support broader conclusions about safety.

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

The result directly describes participation in a videogame-based study program. The primary outcome is the total number of sessions attended over up to 12 weeks, documented by the graduate student researcher. The registry reports 12 sessions for the game-based physical activity group and 10 for the sedentary videogame group. Those values are the posted attendance results, with recorded sample sizes of 49 and 50.

They do not establish that the physical activity format increased or reduced attendance. The record does not specify the summary statistic represented by each value, provide a measure of within-group variation, or report a formal estimate of the contrast. Without those elements, the precision and statistical uncertainty of a comparison cannot be judged. The registry also marks the two-arm comparison as not available or estimable for this count outcome.

The result does not show whether participants quit smoking, reduced tobacco use, or changed any other clinical outcome. The study summary describes a smoking-cessation program, but the posted primary endpoint is attendance, and no smoking-cessation results are included in the registry record for this record. Attendance may be relevant to feasibility because it documents participation, but participation is not the same as treatment benefit.

The registry record also does not provide enough information to determine how missing attendance records were handled, which analysis population was used, or whether any adjusted analyses were conducted. The study’s completed status indicates that the registry identifies it as completed; it does not fill these reporting gaps. The appropriate interpretation is therefore narrow: the record contains descriptive attendance values and safety counts, but lacks inferential results needed for a precise comparison or conclusions about clinical effectiveness.

General statistical principles can explain why additional information matters. A point summary without variability gives no direct indication of how similar or different individual participants’ attendance was. An estimate without an uncertainty interval gives no direct measure of precision. These cautions apply to interpreting the registry output and do not imply that a particular unreported result would favor either group.

13. Why This Trial Matters Statistically

This trial is statistically noteworthy because it evaluates a feasibility-oriented endpoint within a program designed for adults with serious mental illness. Counting attended sessions can describe engagement with study activities, an important part of understanding whether a program is being used. At the same time, a participation measure answers a different question from a clinical endpoint such as smoking cessation. Keeping those questions distinct is essential when interpreting a trial’s headline purpose and its posted primary outcome.

The endpoint is a count, which raises useful methodological issues. In general, count outcomes may have distributions and variability that are not well represented by methods designed for continuous, symmetric data. Readers need enough information about the distribution and analysis method to assess whether uncertainty has been estimated appropriately. The registry record gives the attendance values and group sizes but does not report the spread, model, or inferential comparison. That makes this study a clear example of why arm summaries alone are not a complete statistical report.

The study is randomized and parallel-group, features that can support a structured comparison. But design labels do not replace reporting of how randomization was implemented, how missing observations were handled, or which population was analyzed. Statistical credibility depends both on design and on transparent analysis. Here, several elements needed to interpret the comparison are not reported in the registry record.

The record also separates current groups from closed pre-COVID groups in its safety listings. Maintaining that distinction is important when interpreting sample sizes and event counts; combining groups without a stated rationale could obscure differences in study context. More generally, clearly identifying the analysis set and the outcomes linked to each group helps readers understand exactly what a reported number represents.

Finally, this record underscores the difference between a planning illustration and an observed finding. Sample-size illustrations depend on assumptions and are not evidence of achieved power. A completed randomized study can still have limited posted statistical detail. The attendance figures are useful descriptive information, but they do not answer the clinical efficacy question or establish the precision of a group contrast.

14. 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 principal limitation for statistical interpretation is the absence of a reported inferential analysis for the primary count endpoint. The registry lists values of 12 and 10 sessions and group sizes of 49 and 50, but does not identify the summary statistic, give a measure of spread, or report a confidence interval or test. The record also marks the two-arm comparison as unavailable or not estimable. The values therefore support description, not a precise estimate of the group contrast.

The attendance endpoint is a feasibility measure, not a direct measure of smoking cessation. Although the study summary concerns a smoking-cessation program, no smoking-cessation outcome results are included in the registry record for this trial. The endpoint description states that attendance was documented by a graduate student researcher but does not explain whether attendance records were independently checked or how missed sessions were handled.

Important design and analysis details are not reported in the registry record, including eligibility criteria, randomization procedures, the analysis population, missing-data methods, and the statistical model. The protocol’s sample-size justification and any multiplicity strategy are also not reported. These omissions limit assessment of bias, precision, and reproducibility.

The registry lists overall enrollment of 108, current outcome groups with sample sizes of 49 and 50, and closed pre-COVID safety groups with sample sizes of 4 and 5. The record does not reconcile these counts. The safety listings report zero serious adverse events, other adverse events, and deaths, but do not include event definitions or detailed observation information. Each of these limitations concerns the information available in the registry record; it does not establish what additional analyses or documentation may exist elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: PARQuit Smoking Cessation Intervention for Adults With Serious Mental Illness — NCT03950427.
• Registry record last updated 2026-07-17; status last verified 2026-07.
• Results first posted 2026-07-17.
• 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.

18. Record Summary

The completed registry record describes a Phase 4 randomized, parallel-group study sponsored by the University of California, San Francisco, with enrollment listed as 108. The comparison is between a game-based physical activity program and a sedentary videogame program for adults with serious mental illness. The summary also identifies counseling and bupropion as components of the smoking-cessation program.

The primary outcome is the number of videogame sessions attended over up to 12 weeks. The posted values are 12 sessions in the physical activity group and 10 in the sedentary group, with sample sizes of 49 and 50. No formal comparison, uncertainty interval, or analysis result is reported in the registry record. No secondary outcomes are posted, although 10 outcome measures are listed.

The serious adverse event records list zero serious adverse events, zero other adverse events, and zero deaths in the two current groups and two closed pre-COVID groups. The registry does not report the analysis population, missing-data methods, multiplicity strategy, or statistical analysis plan. The posted attendance values are descriptive feasibility results and do not establish a smoking-cessation effect.