Novel Executive Function Training for Obesity: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Novel Executive Function Training for Obesity (NCT03724396), a randomized na study. The primary outcome is Feasibility as Measured by Attendance.

2. Clinical Question

The trial addresses a feasibility question about attendance, rather than directly establishing whether either program changes weight or another health outcome. Its rationale is that neurocognitive difficulties, particularly involving executive function, may make it harder for some adults with obesity to adhere to behavioral treatment recommendations. NEXT was proposed as a way to address those difficulties in the context of behavioral weight-loss treatment.

The registry describes NEXT as BWL with additional strategies targeted at improving executive function to help adherence to BWL skills. The brief study summary describes the proposed NEXT approach as being administered prior to behavioral treatment. The precise delivery sequence is not reported in the registry record, so the arm description and study rationale should not be taken as a full account of the schedule.

The posted primary outcome is the number of treatment sessions attended. Attendance can indicate whether participants engage with a treatment program, but it does not by itself establish weight change, treatment adherence outside sessions, or the effectiveness of either program. Those are separate questions, and results for them are not reported in the primary outcome details summarized in the registry record.

3. Trial Design

The registry identifies this as a randomized, single-masked, parallel-group trial. Participants were assigned to NEXT or BWL. A parallel design compares groups receiving different assigned approaches during the same trial, while randomization is intended to reduce systematic differences between groups at assignment. The registry records single masking but does not report which people were masked or how masking was implemented.

The record lists an enrollment of 67 and marks the study as completed. It gives a start date of 2019-06-05 and a primary completion date of 2023-01-14. The trial is listed as phase NA, and its study kind is recorded as other. The sponsor is the University of California, San Diego. These administrative details describe the registry entry; they do not by themselves establish how consistently the interventions were delivered or how complete outcome follow-up was.

The two arms are NEXT and BWL. NEXT is described as BWL with additional strategies aimed at executive function and adherence to BWL skills. The BWL description includes instruction on a balanced deficit diet of conventional foods, individual energy-intake goals based on initial body weight, and instruction in measuring portions and counting calories. The complete details of the BWL description are not reported in the registry record excerpt.

The primary outcome is attendance, assessed over 6 months of treatment. Its target population is described as the total intention-to-treat sample evaluated. The posted group summaries report a median of 18.0 sessions for each arm. The inter-quartile range is 17.0 to 19.0 for NEXT and 16.0 to 19.0 for BWL. No inferential analysis for this primary comparison is reported in the registry record. The record also does not describe the randomization sequence, allocation concealment, masking procedures, or a detailed analysis plan.

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: total intention to treat sample evaluated

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 Feasibility as Measured by Attendance, measured over Over the course of 6 months of treatment.

The primary endpoint is the number of treatment sessions attended over the course of 6 months of treatment. It measures participation in the scheduled treatment program, making it a direct feasibility indicator: if participants attend sessions, they are engaging with at least that part of the intervention. Attendance is not a direct measure of executive function, weight change, dietary behavior, or adherence to recommendations between sessions.

The endpoint is summarized using the median and inter-quartile range. The median identifies the middle of the observed attendance distribution, while the inter-quartile range describes the span from the lower to the upper quartile. These summaries are useful when the distribution may not be well represented by a mean and standard deviation, for example if attendance is uneven or includes unusually low or high values. This is a general statistical rationale; the registry record does not report the shape of the attendance distributions.

The median was 18.0 sessions in both NEXT and BWL. The reported inter-quartile ranges were 17.0 to 19.0 for NEXT and 16.0 to 19.0 for BWL. These summaries describe the observed attendance in each arm. They do not show how individual attendance values were distributed within those ranges, and they do not establish that the arms are equivalent. No formal comparison estimate or uncertainty interval for the attendance contrast is reported in the registry record.

Attendance is appropriate to a feasibility question, but its interpretation is limited to participation in sessions. It cannot on its own establish whether the additional executive-function strategies changed participants’ abilities or outcomes.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the median describe?

The median is a measure of the center of a distribution. It is the value separating the lower half of observations from the upper half, subject to the conventions used when observations are ordered. Unlike the mean, it is not pulled as strongly by extreme values. That can make it useful for outcomes such as attendance, where participants may have quite different levels of participation. The registry reports a median of 18.0 sessions in each arm. This statistic describes the middle of each observed group; it does not describe every participant or the full distribution.

What does the inter-quartile range describe?

The inter-quartile range runs from the lower quartile to the upper quartile and describes the central spread of the observed values. The registry reports 17.0 to 19.0 sessions for NEXT and 16.0 to 19.0 for BWL. In general, this summary is less affected by extreme observations than a range from the minimum to the maximum. It does not reveal the exact pattern of observations within the interval, the tails of the distribution, or whether individual values are clustered at particular session counts.

Why is a separate comparison needed?

Group summaries are descriptive. To quantify a treatment contrast, an analysis would typically state what measure of difference is being estimated and how uncertain that estimate is. A confidence interval is a range of values compatible with the data and the assumptions of the analysis; it communicates precision as well as direction. A p-value, when reported, addresses compatibility with a specified null hypothesis under a statistical model, but does not measure the size or importance of an effect. The registry record does not report a confidence interval, p-value, or other inferential result for attendance. The summaries alone therefore do not establish whether the arms differ statistically or whether a difference is precisely estimated.

What does randomization contribute?

In general, random allocation aims to make assignment unrelated to participants’ baseline characteristics, on average, so that a comparison of assigned groups can support causal interpretation under appropriate conditions. It does not guarantee that groups are identical at baseline, and it cannot correct for all problems after assignment. The registry identifies the trial as randomized and parallel-group, but does not report the sequence-generation method, allocation concealment, baseline balance, or adherence to assigned treatment. The record also says single-masked without identifying who was masked or how masking was maintained.

How should the analysis population be understood?

The primary outcome description refers to the total intention-to-treat sample evaluated. In general, an intention-to-treat approach analyzes participants according to their randomized assignment, regardless of treatment received, but the label alone does not document exactly how a particular endpoint was analyzed. The record does not explain missing-data handling, whether all randomized participants contributed attendance information, or whether any alternative analysis populations were used. The posted arm counts accompany the outcome summaries, but are not a complete account of participant flow or outcome availability.

What do the planning illustrations mean?

Any sample-size illustrations associated with the results are planning exercises, not observed trial outcomes and not a measure of the trial’s observed power. The registry’s planning assumptions describe a two-sided significance level of 0.05, equal allocation, a normal approximation, and effects set as stated fractions of the observed effect. For time-to-event outcomes, the stated convention is total events; for other outcomes, it is participants per arm. These are general planning assumptions, not evidence that the trial was designed using those exact calculations. The trial’s own sample-size justification and statistical plan are not reported in the registry record. Planning estimates should not be read as evidence that a trial did or did not have adequate power.

The registry indicates that no analysis records are posted. This means the outcome summaries should be interpreted as descriptive reporting rather than as a complete inferential analysis. In general, interpreting a randomized trial requires knowing the planned estimand, analysis model, handling of missing observations, and uncertainty around the estimate. Those details are not reported in the registry record, so no additional analytical conclusions can be drawn from the attendance medians and inter-quartile ranges alone.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures overall, but the primary attendance outcome is the only outcome described in the registry record for these results. No secondary outcome results are reported in the registry record. The record also indicates that no analysis records are posted. It does not provide a statistical analysis plan explaining which outcomes were primary or secondary for hypothesis testing, how many comparisons were planned, or whether any multiplicity adjustment was intended.

Multiplicity matters when several outcomes or comparisons are tested: the chance of at least one apparently unusual result can increase as the number of tests grows. This is a general statistical concern, not a claim that the trial made a particular set of tests. Without the full analysis plan and results, it is not possible to determine how multiplicity was handled or whether it affected interpretation.

Missing-data methods are not reported in the registry record. The endpoint description refers to the total intention-to-treat sample evaluated, but it does not explain how missing attendance observations were identified or handled, whether all randomized participants contributed, or whether any sensitivity analyses were conducted. The reported group counts do not answer those questions.

The record also does not report a participant-flow account for this endpoint or an analysis population beyond the stated intention-to-treat description. Missing outcome data can affect both the precision and interpretation of a comparison, especially if outcome availability differs by arm or relates to attendance. Without details on completeness and handling, the effect of missingness cannot be assessed. No assumptions about missing-data mechanisms or imputation should be attributed to the trial.

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 5% reporting threshold.

The registry reports zero serious adverse events among 34 participants at risk in the NEXT arm and zero among 33 participants at risk in the BWL arm. It also reports zero other adverse events in each arm, with the same respective at-risk counts, and zero deaths in both arms. These are the posted event counts for the groups.

A reported zero means that no event of the specified category was recorded in the listed at-risk group during the registry’s safety reporting period. It does not prove that an event is impossible, nor does it establish that the interventions have no safety risks. The registry record does not report further details about event definitions, monitoring procedures, exposure time, or the period used for safety collection. Serious adverse event terms are not listed.

Safety counts should also be interpreted in the context of the size and duration of observation. A zero count can coexist with uncertainty about uncommon events, and these figures alone do not permit a precise comparison of safety between arms. No formal safety comparison or uncertainty interval is reported in the registry record. The counts describe recorded events and should not be treated as proof of safety or as a basis for treatment decisions.

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

The results show that the median reported attendance was 18.0 sessions in both NEXT and BWL during 6 months of treatment. The inter-quartile ranges describe the central spread of attendance in each group: 17.0 to 19.0 for NEXT and 16.0 to 19.0 for BWL. These findings provide descriptive information relevant to the feasibility question of session participation.

They do not show that attendance was identical for every participant, or that the underlying distributions were the same. They do not establish a statistically significant difference, equivalence, or non-inferiority. No effect estimate with a confidence interval or p-value is reported for the comparison. In particular, equal medians alone are not evidence that the additional executive-function strategies have no effect on attendance.

The endpoint also has a narrow meaning. Session attendance is not the same as adherence to behavioral recommendations outside treatment sessions, nor is it a measure of executive-function change or weight change. The posted attendance summaries cannot establish whether either approach improved those outcomes. Results for the other listed outcome measures are not reported in the registry record details.

The randomized parallel design is relevant to a comparative question, but the registry record does not supply key information for evaluating the analysis in depth, including the statistical plan, handling of missing attendance data, and details of masking. The descriptive summaries therefore should be read as an account of observed attendance, not as a complete estimate of the causal effect of NEXT relative to BWL.

In general, feasibility outcomes can inform whether a program is delivered and attended in a study setting. They do not by themselves establish clinical effectiveness or generalizability to other settings or populations. The registry record does not report enough information to judge how attendance relates to outcomes beyond sessions or whether the observed pattern would apply elsewhere. The results support a limited statement about the attendance summaries recorded in this trial, with uncertainty about the between-arm contrast and no basis for broader treatment claims.

13. Why This Trial Matters Statistically

This trial is statistically relevant because it frames an intervention question through a feasibility outcome. Attendance is an observable feature of program participation and may help describe whether participants engaged with scheduled treatment. For interventions that require repeated sessions, measuring attendance can provide information distinct from clinical outcomes. It is important, however, to keep those questions separate: an attendance summary is not a substitute for an outcome measuring weight, executive function, or adherence outside sessions.

The choice to report a median and inter-quartile range makes the center and central spread visible without assuming that attendance follows a symmetric distribution. This is useful because session counts are bounded by the treatment schedule and may not have a distribution well summarized by a mean alone. The posted summaries describe each arm, but do not quantify uncertainty in the contrast between them. A clear distinction between descriptive results and inferential claims is therefore essential.

The randomized design offers a structure for comparing NEXT and BWL, while the registry’s incomplete account of the statistical analysis limits the conclusions that can be drawn from the posted outcome information. The absence of a reported comparison estimate, missing-data procedures, and a detailed analysis plan leaves important questions about precision and robustness unresolved. These are not minor interpretive details: they determine how a descriptive group contrast should be evaluated.

The registry record also illustrates why safety counts with no recorded events must be interpreted cautiously. Such counts are useful to report, but do not establish the absence of risk or provide a precise comparison. Overall, the trial’s statistical contribution in the posted primary results is a description of session attendance in the randomized groups. Broader conclusions require outcomes and analytical details not reported in the registry record.

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 primary results are limited to a feasibility endpoint: sessions attended over 6 months. Attendance does not directly measure weight change, executive function, or adherence outside sessions. The registry lists four outcome measures, but the other results are not reported in the registry record details. The scope of interpretation is therefore narrow.

The posted primary summaries are medians and inter-quartile ranges, without a reported between-arm effect estimate, confidence interval, p-value, or test statistic. The descriptive values do not reveal the full distributions or quantify the precision of a comparison. The record does not report a statistical analysis plan, so the intended comparison method and any prespecified decisions cannot be assessed.

Although the outcome description refers to the total intention-to-treat sample evaluated, procedures for missing attendance data and the exact analysis population are not reported in the registry record. The record does not explain participant flow for the endpoint, exclusions, or sensitivity analyses. This prevents assessment of whether incomplete outcome data could have affected the summaries.

Other design details are also limited in the registry record. It identifies randomization, parallel groups, and single masking, but does not describe the allocation process or identify who was masked. The full intervention delivery details are not available in the registry record for this account, including the precise timing of NEXT relative to BWL. Finally, the safety figures are event counts without details about definitions, collection period, or uncertainty. These limitations call for restraint: the posted results describe attendance and recorded safety counts, but do not establish comparative effectiveness, equivalence, or generalizability.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Novel Executive Function Training for Obesity — NCT03724396.
• Registry record last updated 2024-02-15; status last verified 2024-02.
• Results first posted 2024-02-15.
• 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

NCT03724396 is a completed, randomized, single-masked, parallel-group study sponsored by the University of California, San Diego. It enrolled 67 participants and compared Novel Executive Function Training (NEXT) with Behavioral Weight Loss (BWL) for overweight and obesity. The primary outcome was the number of treatment sessions attended over 6 months, summarized by median and inter-quartile range.

The median attendance was 18.0 sessions in both arms. The inter-quartile range was 17.0 to 19.0 for NEXT and 16.0 to 19.0 for BWL. No inferential comparison for this endpoint is reported in the registry record. The posted safety counts report zero serious adverse events, zero other adverse events, and zero deaths in each arm.

The record lists four outcome measures overall but does not report additional outcome results in the primary information. Details of the statistical plan, missing-data handling, and the identity of the masked party are not reported in the registry record. The attendance results are descriptive and do not establish treatment effectiveness or equivalence.