This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Project Impact: An Innovative Approach to Weight Loss Maintenance (NCT02363010), a randomized na study. The primary outcome is Change in Body Weight.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02363010 |
| Phase | NA |
| Condition | Obesity, Weight Loss, Overweight |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 320 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Drexel University |
| Results posted | Yes |
2. Clinical Question
Population
The registry record lists obesity, weight loss, and overweight as conditions. It reports enrollment of 320 participants. Further eligibility criteria and participant characteristics are not reported in the registry record, so the intended population cannot be described more specifically from this information.
Intervention
Two behavioral approaches incorporated a larger emphasis on physical activity goals after an initial period of standard group-based behavioral treatment. One continued standard behavioral therapy with that emphasis; the other used acceptance-based strategies as well as the physical activity emphasis.
Comparator
The comparator was standard, group-based behavioral treatment for weight loss and maintenance over 18 months. The record describes three randomized groups, but does not state the allocation ratio or identify a single primary comparison among them.
Primary question
The primary outcome was change in body weight, expressed as percent weight loss and measured at baseline and follow-up visits. The study’s broad question was whether behavioral treatment could be improved by focusing on physical activity after initial weight-loss treatment, including through an acceptance-based approach. The comparative outcome results are not reported in the registry record.
3. Trial Design
This was a randomized, parallel-group behavioral study with three treatment arms. The registry lists single masking, but does not report whose treatment assignment was masked or how masking was maintained. The record gives an enrollment of 320 and a completed status. The study start date is 2014-08-01, and the primary completion date is 2019-08-01. Phase is listed as NA.
The standard-treatment arm received 18 months of group-based behavioral treatment for weight loss and weight-loss maintenance. The physical-activity-emphasis arm received six months of standard group-based treatment followed by 12 months of standard group-based treatment with a larger emphasis on physical activity goals. The acceptance-based arm also began with six months of standard group-based treatment, then received 12 months of group-based therapy using acceptance-based strategies and a larger emphasis on physical activity goals.
The primary measure was change in body weight, expressed as percent weight loss. Measurements were scheduled at baseline, 6 months, 12 months, 18 months, 24 months, and 36 months. The registry describes the measurement as objective, conducted in a research clinic on a scale. Cardiorespiratory fitness and waist circumference are listed as secondary outcomes. The record does not specify the randomization procedure, allocation ratio, recruitment setting, eligibility criteria, or whether participants could receive additional care outside the assigned programs.
Although the registry describes the study’s broad aim and intervention structure, it does not identify a single primary contrast among the three groups. The detailed statistical analysis plan, including any prespecified contrasts and the timing of analyses, is 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
| Stage | Standard Behavior Therapy for Weight Loss | Behavior Therapy for Weight Loss With PA Emphasis | Acceptance-based Behavior Therapy With PA Emphasis |
|---|---|---|---|
| STARTED | 110 | 105 | 105 |
| COMPLETED | 88 | 94 | 89 |
| NOT COMPLETED | 22 | 11 | 16 |
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.
| Characteristic | Unit | Standard Behavior Therapy for Weight Loss | Behavior Therapy for Weight Loss With PA Emphasis | Acceptance-based Behavior Therapy With PA Emphasis | Total |
|---|---|---|---|---|---|
| Participants analysed | 110 | 105 | 105 | 320 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 95 | 96 | 98 | 289 |
| Age, Categorical: >=65 years | Participants | 15 | 9 | 7 | 31 |
| Age, Continuous | years | 51.3 (SD 11.4) | 54.3 (SD 9.01) | 52.7 (SD 10.4) | 52.7 (SD 10.4) |
| Sex: Female, Male: Female | Participants | 90 | 78 | 82 | 250 |
| Sex: Female, Male: Male | Participants | 20 | 27 | 23 | 70 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 3 | 5 | 4 | 12 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 107 | 99 | 101 | 307 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 1 | 0 | 1 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 2 | 2 |
| Race (NIH/OMB): Asian | Participants | 1 | 3 | 1 | 5 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 28 | 26 | 26 | 80 |
| Race (NIH/OMB): White | Participants | 78 | 73 | 73 | 224 |
| Race (NIH/OMB): More than one race | Participants | 3 | 3 | 3 | 9 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 |
| Region of Enrollment: United States | participants | 110 | 105 | 105 | 320 |
| BMI | kg/m2 | 35.1 (SD 4.3) | 34.5 (SD 4.6) | 35.8 (SD 5.3) | 35.1 (SD 4.8) |
6. Primary Endpoint
The registry lists the primary outcome as Change in Body Weight, measured over Baseline, 6 months, 12 months, 18 months, 24 months, 36 months.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | percent weight loss |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change in body weight, expressed as percent weight loss. Body weight is a continuous measure: each participant’s measurement can take a range of values rather than belonging to a simple event category. The registry describes the measure as objectively assessed in a research clinic using a scale.
Measurements were scheduled at baseline and at 6, 12, 18, 24, and 36 months. A baseline measure gives a starting point for assessing change over follow-up, while repeated follow-up measures describe the pattern over time. The scheduled assessments extend beyond the 18-month treatment period described for the standard arm, allowing the registered outcome schedule to include later follow-up. The record does not explain how change was defined for each analysis, whether all scheduled time points were included in each comparison, or which time point was the principal endpoint for the primary analysis.
Body weight is relevant to a study concerned with weight-loss maintenance because repeated measurements can describe both initial change and subsequent maintenance or regain. That is a general reason for using this kind of measure, not a claim about what happened in this trial. The registry record does not report group means, standard deviations, estimated changes, or uncertainty intervals for the primary outcome. It therefore does not establish the size or precision of any between-group difference in body weight.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a randomized comparison of three behavioral programs, but it does not include numerical primary-outcome results. There are no reported group means or standard deviations for body-weight change, no between-group estimates, and no confidence intervals or p-values for this endpoint. Consequently, the relative outcome patterns and the precision of any estimated differences cannot be assessed from the registry record.
The outcome schedule includes baseline and repeated follow-up visits through 36 months. Repeated measurements can be useful for understanding whether a change is maintained, but an assessment schedule alone does not show that all participants contributed measurements at every visit. Participant counts at each outcome time point and the handling of missing measurements are not reported in the registry record.
The three treatment descriptions distinguish standard group-based behavioral treatment from programs that put a larger emphasis on physical activity goals; one of those programs also used acceptance-based strategies. These are differences in the assigned program, not evidence of a difference in outcomes. The registry’s stated aim is to evaluate whether behavioral treatment can be improved through a physical-activity focus and an acceptance-based approach. Without outcome estimates, the registry record cannot indicate whether those approaches produced different weight trajectories.
Nor can the record establish whether any observed differences, if available elsewhere, would be clinically important. Statistical significance and clinical importance are distinct: an estimate may be precise without representing a meaningful difference, or uncertain even when its point estimate appears substantial. Assessing either requires reported estimates, their uncertainty, and a relevant interpretation standard; these are not reported in the registry record.
The enrollment figure describes the number enrolled, not the number included in each outcome analysis. The registry lists three groups, but does not give analyzed sample sizes or explain whether analyses followed the randomized assignments. Enrollment alone therefore cannot establish how much information contributed to the primary comparison.
Any planning illustrations based on an observed effect should be read as hypothetical design calculations, not as observed power or proof that the trial was adequately or inadequately powered. The actual effect estimates required to assess such illustrations are not reported in the registry record. The registry also does not report the trial’s own sample-size justification. Overall, the posted information describes the question, intervention structure, and measurement schedule, but does not provide the outcome evidence needed to compare the groups statistically.
9. Statistical Methods Explained
What does a mean describe? The primary outcome is continuous body weight change, expressed as percent weight loss, and the registry identifies the summary parameter as a mean. A mean describes the central value of a set of measurements. In a randomized comparison, group means can describe the outcome distribution in each assigned group, while a contrast between groups can estimate how their average outcomes differ. The registry record does not report these means or contrasts for the primary outcome.
What does a standard deviation describe? The registered dispersion measure is the standard deviation. In general, a standard deviation describes how spread out individual observations are around their group mean. It is not the same as the uncertainty around an estimated mean: the standard deviation describes variability among measurements, while a confidence interval describes uncertainty about an estimate. Neither primary-outcome standard deviations nor confidence intervals are reported in the registry record.
Why do repeated measurements matter? The registered schedule includes baseline and follow-up measurements at 6, 12, 18, 24, and 36 months. Repeated measurements allow investigators to study the course of an outcome, rather than relying only on a single follow-up value. Measurements from the same participant are generally related to one another, so an analysis of repeated observations should account for that dependence. Otherwise, the analysis may treat related measurements as more independent information than they are. This is a general statistical consideration; the specific model used for this trial is not reported in the registry record.
Different analysis choices can answer different questions. A comparison at a particular follow-up visit addresses group differences at that time. A model using several visits may estimate an overall pattern or test whether the trajectories differ. A change-from-baseline analysis focuses on within-participant change, while an analysis of follow-up values adjusted for baseline addresses a related but not identical estimand. The registry record does not state which of these approaches was used, how baseline values were incorporated, or which follow-up contrast was primary.
How should uncertainty be read? In general, a confidence interval gives a range of values compatible with the data and the assumptions of the analysis. Wider intervals indicate less precision; narrower intervals indicate greater precision. A p-value summarizes how incompatible the observed data are with a specified null hypothesis under the analysis assumptions. It does not measure the probability that a treatment works, nor does it show the size or importance of an effect. No confidence intervals or p-values for the primary outcome are reported in the registry record, so these forms of uncertainty cannot be evaluated for the trial’s main question.
What does randomization contribute? Random assignment is intended to make comparison groups similar, on average, with respect to factors that could affect outcomes. It supports causal interpretation when the allocation is implemented as intended and when follow-up, outcome measurement, and analysis are appropriately handled. Randomization does not guarantee that groups are identical, and it does not remove concerns about missing outcomes or deviations from assigned treatment. The registry identifies the allocation as randomized but does not describe the randomization sequence, concealment, or analysis population.
What can masking tell readers? The registry labels the study as single-masked. Masking can reduce the influence of treatment knowledge on some parts of a study, depending on who is masked and how outcomes are assessed. Because the registry does not say who was masked, the scope of this feature cannot be determined. The body-weight outcome is described as objectively measured in a research clinic on a scale, but the registry does not report procedures for assessor masking or quality control.
What do sample-size illustrations mean? General planning calculations can show how many participants per arm might be required under stated assumptions about a target effect, significance level, allocation, and statistical approximation. Such calculations are illustrations, not results from the trial, and they do not describe observed power. The record’s stated illustration assumptions include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect described as a fraction of the observed effect. The registry does not report the trial’s own sample-size justification. Because the observed outcome estimates are not reported in the registry record, the illustrations cannot substitute for a result estimate or establish the precision achieved.
What analysis details remain unknown? The registry lists 8 outcome measures and 28 analyses, but does not provide the primary-outcome analysis model or its covariates. It does not report whether analyses were adjusted, how treatment adherence was handled, how multiple visits or outcomes were modeled, or how assumptions were checked. These omissions prevent readers from reproducing the analysis or determining how sensitive estimates might be to alternative reasonable methods.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 8 outcome measures and 28 analyses. Considering several outcomes, treatment comparisons, or follow-up times can create a multiplicity issue: the more statistical tests that are conducted, the greater the general chance of finding an apparently notable result by chance. Researchers may address this by prespecifying a primary contrast, adjusting for multiple comparisons, or clearly distinguishing confirmatory from exploratory analyses. The registry record does not report a multiplicity adjustment, a testing hierarchy, or which analyses were designated confirmatory.
The primary outcome has measurements scheduled at multiple time points. The registry record does not identify a single primary follow-up time or explain whether comparisons at the separate visits were treated as separate tests or as parts of a repeated-measures model. It also does not specify how secondary outcomes, including cardiorespiratory fitness and waist circumference, were handled in relation to the primary outcome.
Missing-data methods and outcome completion by visit are not reported in the registry record. This matters because the analysis can be affected when participants miss visits or withdraw, particularly if missingness is related to outcomes or treatment experience. The record also does not state whether analyses used all randomized participants, only participants with observed measurements, or another analysis population. The number randomized to each group and the number analyzed at each visit are not reported in the registry record. Without these details, the reader cannot assess attrition, compare completeness between groups, or judge the assumptions underlying the outcome analysis.
Interim analyses, stopping rules, and the detailed statistical analysis plan are not reported in the registry record. Their absence from the record does not establish whether such procedures were or were not used.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Standard Behavior Therapy for Weight Loss | 0 | 110 | 0.0% |
| Behavior Therapy for Weight Loss With PA Emphasis | 0 | 105 | 0.0% |
| Acceptance-based Behavior Therapy With PA Emphasis | 0 | 105 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Standard Behavior Therapy for Weight Loss | 0 of 110 |
| Behavior Therapy for Weight Loss With PA Emphasis | 0 of 105 |
| Acceptance-based Behavior Therapy With PA Emphasis | 0 of 105 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Standard Behavior Therapy for Weight Loss | 0 of 110 |
| Behavior Therapy for Weight Loss With PA Emphasis | 0 of 105 |
| Acceptance-based Behavior Therapy With PA Emphasis | 0 of 105 |
The registry reports serious adverse event figures separately for the three treatment groups. In the standard behavior therapy group, 110 participants were at risk and 0 were reported as affected; in the behavior therapy with physical-activity emphasis group, 105 were at risk and 0 were reported as affected; in the acceptance-based group with physical-activity emphasis, 105 were at risk and 0 were reported as affected. The listed death count is 0 in each group. The record also lists 0 other affected participants in each group, with the same at-risk counts.
These entries describe what the registry reports for the categories and groups shown; they do not, by themselves, provide a complete account of safety monitoring. The registry does not list serious adverse event terms, and no top serious terms are recorded. Details about event definitions, collection procedures, follow-up completeness, or the relationship of events to treatment are not reported in the registry record. A zero affected count in these fields should therefore be read as a registry entry, not as evidence that no event of any kind occurred or that the programs were risk-free.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a randomized, three-arm behavioral study was conducted and completed, with a planned primary outcome of change in body weight expressed as percent weight loss. It also documents intervention descriptions and a schedule of measurements extending from baseline through 36 months. Those details clarify the study question and the type of evidence that would be relevant to it.
The record does not include the primary outcome estimates or the uncertainty around them. It therefore does not show whether the three groups had similar or different average weight changes, whether any differences persisted across follow-up, or how precise the estimates were. No conclusion about the comparative effects of the assigned programs can be drawn from the registered information alone. This is not a conclusion that the programs are equivalent, nor is it a conclusion that one is superior.
Even with outcome estimates, interpretation would require attention to the analysis population, missing measurements, prespecified comparisons, and multiplicity. The registry does not report those details. The recorded enrollment of 320 should not be treated as the analyzed sample size for every outcome or visit, since the numbers contributing to analyses are not reported in the registry record.
The study’s broad aim was to assess a physical-activity-centered approach after initial weight-loss treatment and an acceptance-based variant of that approach. The descriptions show how the programs differed, but do not establish whether those components changed outcomes. The registry’s adverse-event fields report zero affected participants in the listed serious and other categories, while detailed event information and collection methods are not reported. Overall, the record conveys the design and intended measurement framework, but not enough outcome or analysis information to judge comparative effectiveness, precision, or the robustness of the findings.
13. Why This Trial Matters Statistically
This trial’s registered question involves more than comparing two treatments at a single visit. The three arms represent standard group-based behavioral treatment, standard treatment with a later emphasis on physical activity, and an acceptance-based approach with that emphasis. The outcome schedule includes repeated assessments through 36 months. That structure makes the intended distinction between treatment approaches and the pattern of weight change over time central to interpretation.
Statistically, repeated assessments create opportunities to describe both change and maintenance, while also requiring care about the relationship among measurements from the same participant. The three-group design also raises the question of which contrasts were primary and how multiple comparisons were handled. The registry record does not report the analysis plan needed to answer those questions. It lists 8 outcome measures and 28 analyses, making clear that the analytic scope is broader than a single outcome measurement, but does not explain how inferential claims were prioritized.
The record’s value is therefore primarily in documenting the randomized design, intervention structure, enrollment, measurement schedule, and registered outcomes. Its limitations are equally important: no primary outcome estimates, uncertainty intervals, analysis populations, or missing-data methods are reported in the registry record. Readers cannot use the design description alone to infer a treatment effect. Recognizing that distinction is essential when assessing registry information: a well-defined question and outcome schedule describe what a study set out to examine, while comparative evidence depends on reported results and transparent analysis details.
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.
A central limitation of the available registry information is that numerical results for the primary endpoint are not reported. Group-level outcomes, between-group comparisons, and measures of uncertainty are absent, so the comparative findings cannot be assessed. The registry identifies multiple measurement visits but does not specify which follow-up time was the principal basis for the primary analysis.
Important design and analysis details are also not reported in the registry record. These include eligibility criteria, participant characteristics, the allocation ratio, the randomization procedure, who was masked, and the primary statistical model. The record does not describe how adherence, treatment deviations, baseline measurements, repeated observations, or multiplicity were handled. Sample-size justification and interim analyses are not reported.
Outcome completeness and analysis populations are unclear because participant counts by group and visit are not reported. Missing-data methods are not described, so the potential impact of incomplete follow-up cannot be assessed. The registry lists cardiorespiratory fitness and waist circumference as secondary outcomes, but does not present their results or explain their role in the analysis hierarchy.
The safety entries report zero affected participants in the listed categories, but event terms and detailed monitoring procedures are not reported. These gaps limit interpretation of the safety fields. More broadly, registry information alone cannot establish whether the registered methods were followed in the final analyses or whether any later analysis decisions changed the planned approach. These are limitations of what the registry record reports, not claims about unreported conduct or results.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Project Impact: An Innovative Approach to Weight Loss Maintenance — NCT02363010.
- Registry record last updated 2023-03-03; status last verified 2023-03.
- Results first posted 2021-11-17.
- 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.
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18. Record Summary
The registry describes a completed, randomized, parallel-group behavioral study with three arms and enrollment of 320 participants. The programs compared standard group-based behavioral treatment with approaches adding a larger physical-activity emphasis, including an acceptance-based variant. Single masking is listed, but who was masked is not reported in the registry record.
The primary outcome was change in body weight, expressed as percent weight loss, measured at baseline and at 6, 12, 18, 24, and 36 months. Cardiorespiratory fitness and waist circumference are listed as secondary outcomes. The registry reports zero affected participants in its serious and other adverse-event fields for each group.
Primary outcome estimates, uncertainty measures, analysis populations, missing-data methods, multiplicity procedures, and the detailed analysis plan are not reported in the registry record. The design and registered question can be described, but comparative outcome conclusions cannot be drawn from the posted results.