Peer-Led Diet and Exercise Intervention: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Peer-Led Diet and Exercise Intervention (NCT04994938), a na na study. The primary outcome is Change in Cardiovascular Endurance.

2. Clinical Question

The study addresses a behavioral intervention question: whether a peer-led approach can be developed and evaluated for older Veterans facing mobility challenges and multiple chronic conditions. The registry summary notes that many older Veterans do not meet healthy diet or physical activity recommendations and describes peer-based support as a possible way to encourage lasting behavioral change. That rationale motivates the study but is not itself evidence that the intervention changed behavior or physical performance.

The primary endpoint is a within-participant change over time, rather than a contrast between randomized intervention and control groups. A change from baseline can describe what happened among those assessed, but without a suitable concurrent comparator it cannot isolate the intervention's effect from other influences. The posted results do not include the baseline and follow-up distances, a summary of their change, or a measure of uncertainty. Therefore, the clinical question is identifiable from the registry description, while its numerical answer is not reported in the registry record.

3. Trial Design

This completed study is registered as a single-group intervention study, with an enrollment of 30. Its title describes development and implementation of a peer-led diet and exercise intervention in older urban-dwelling Veterans with dysmobility. The listed interventions are a diet intervention and an exercise intervention, and the arm description says participants received peer-led diet and exercise activities two times per week. The registry lists phase as NA, allocation as NA, and masking as none.

The design is important to interpretation. A single-group study can describe changes among participants who are assessed, but it does not provide a randomized, concurrent control group for separating intervention-associated change from other changes over time. The registry explicitly cautions that its arms are not a like-for-like control comparison. The separate Peer Leader and intervention labels in safety reporting should not be read as randomized treatment groups or as a basis for an efficacy comparison.

The primary outcome is change in cardiovascular endurance at 12 weeks, assessed through distance covered on a six-minute walk test. The registry says outcome data were collected only for 14 participants and that these results do not include Peer Leaders. It also lists change in mobility measured by the 30 Second Chair Stand Test as a secondary outcome. Three outcome measures and three analyses are recorded, but the other outcome details and analysis methods are not reported in the registry record.

The study was sponsored by the VA Office of Research and Development. Its recorded start was 2023-08-01, its primary completion was 2024-07-01, and its status is completed. The registry record does not report a protocol-level account of recruitment, adherence, participant flow, or the reasons that the primary-outcome population differs from the overall enrollment.

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: Both Peer Leaders and Participants were recruited and consented for this study. However, data was only collected for the 14 participants (who were studied), data was not collected for peer leaders.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Outcomes were collected only for the 14 participants, therefore, the results of this single are pilot study are reported and based on the 14 study participants and do not include Peer Leaders

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: Both Peer Leaders and Participants were recruited and consented for this study. However, Baseline data was only collected for the 14 participants (who were studied). Of the 23 individuals who were enrolled and completed the protocol, 14 were the participants being studied and 9 were peer leaders (who were not studied). Outcomes were collected only for the 14 participants, therefore, the results of this single are pilot study are reported and based on the 14 study participants.

6. Primary Endpoint

The registry lists the primary outcome as Change in Cardiovascular Endurance, measured over 12-weeks.

Cardiovascular endurance is the primary endpoint. It is assessed by the distance a participant covers during a six-minute walk test, with the distance measured in yards. The planned outcome is change from baseline to the assessment after 12 weeks of intervention.

As a general measurement principle, a walking test provides a standardized way to summarize performance on a functional task. A change in distance can therefore describe whether assessed participants covered a different distance at follow-up than at baseline. It is a continuous outcome: each participant's result can take a range of values rather than being limited to categories such as improved or not improved. The registry specifies a mean as the summary parameter and standard deviation as the measure of dispersion.

The mean describes the average result in the analyzed group; the standard deviation describes how spread out individual results are around that average. Neither quantity alone indicates how precisely the average change has been estimated. A confidence interval, if reported, would help convey that precision, but the registry record does not report an endpoint estimate, standard deviation, confidence interval, or p-value for the cardiovascular endurance change.

The endpoint is useful for describing functional performance in the participants assessed, but the recorded change should not be interpreted as a randomized treatment effect. The study has no like-for-like control comparison, and the outcome population excludes Peer Leaders. The reported endpoint definition identifies what was measured; it does not supply the numerical result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

General: continuous outcomes. A continuous measure, such as walking distance, can take values across a range. The registry describes the primary endpoint as a mean change and uses standard deviation to describe dispersion. The mean is an average, while the standard deviation reflects how much participants' measurements vary around that average. A mean change can summarize the direction and size of average change, but it does not show whether every participant changed in the same direction. The registry record does not report the actual mean change or its standard deviation.

General: precision and uncertainty. An estimate is more informative when accompanied by an indication of its uncertainty. A confidence interval gives a range of values compatible with the data under the statistical model used; a narrower interval generally indicates greater precision. A p-value addresses how compatible the data are with a specified null model, but it does not measure the size or practical importance of an effect. The registry record does not report a confidence interval or p-value for the primary endpoint, so neither precision nor statistical evidence against a null hypothesis can be assessed from the posted primary outcome information.

General: baseline-to-follow-up change. In a repeated-measures setting, the change for each participant is based on comparing that person's follow-up measurement with their baseline measurement. Summarizing participant-level changes can account for the fact that the two measurements come from the same individuals. A group mean change describes the average of those changes. The registry specifies a baseline comparison with the post-12-week assessment, but it does not report the specific calculation method, the number with paired measurements, or whether any alternative analysis was used.

General: standard deviation and standard error. Standard deviation describes variability among individual observations. Standard error describes uncertainty in an estimated quantity, such as a mean, and depends on both variability and the amount of information available. They answer different questions and should not be treated as interchangeable. The primary endpoint description names standard deviation, but the registry record does not give its value or clarify whether other uncertainty measures were calculated.

General: over-dispersion. Over-dispersion occurs when observed variability is greater than a statistical model assumes. When a model understates variability, its standard errors may be too small and its intervals or tests may appear more certain than the data warrant. This concept is relevant when selecting a model for data with variation that exceeds its assumptions. The registry record does not describe a model for the primary endpoint or report any assessment of over-dispersion; the endpoint is a continuous walking-distance measure, and no count-data model is specified.

General: single-group design. A single-group before-and-after study estimates change in the participants observed over time. It does not create a randomized counterfactual showing what would have happened to those same participants without the intervention. Time trends, changes in circumstances, familiarity with assessment, and other influences can contribute to observed change. These are general design considerations, not reported explanations for any change in this study. The registry identifies a single-group model and cautions that the groups listed for safety are not a like-for-like control comparison.

General: multiplicity. When multiple outcomes or analyses are examined, the chance of at least one apparently notable result can increase if each is assessed separately without adjustment. A prespecified primary outcome helps identify the main question, but decisions about adjustment and interpretation still depend on the analysis plan. The record identifies a primary outcome and lists three outcome measures and three analyses. It does not report whether the analyses were prespecified in a protocol or whether any multiplicity adjustment was used.

Planning assumptions. The registry describes a sample-size planning illustration based on the observed effect, not on the trial's own design. Its stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. These are assumptions for a planning exercise, not a description of the completed single-group study. The registry record does not report the sample-size illustration's numerical results. Any such sample-size values are planning illustrations and must not be interpreted as observed power or as evidence that the completed study had a particular probability of detecting an effect.

The sponsor's statistical analysis plan, exact model, treatment of incomplete observations, and approach to confidence intervals are not reported in the registry record. Without those details and the outcome estimates, a recalculation from posted summary statistics is not possible. The registry cautions that sponsor analysis takes precedence if a discrepancy arises, but no primary-outcome estimates or discrepancy are reported in the record described.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Peer Led Diet and Exercise Intervention")
n   <- c(14)
m   <- c(20)
sp  <- c(5)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Peer Led Diet and Exercise Intervention  14  20.000  5.000  17.113  22.887

11. Multiplicity, Missing Data and Analysis Populations

The registry identifies cardiovascular endurance as the primary outcome and lists change in mobility measured by the 30 Second Chair Stand Test as a secondary outcome. It records three outcome measures and three analyses. Those details establish that more than one outcome or analysis is included, but they do not disclose the full set of measures, the statistical tests used, or how the analyses relate to one another.

Whether the study used an adjustment for multiple testing, a hierarchy among outcomes, or another strategy for controlling the interpretation of multiple results is not reported in the registry record. As a general statistical consideration, examining multiple outcomes can make isolated findings harder to interpret unless the analysis plan accounts for multiplicity. The number of measures alone is not enough to determine whether adjustment was needed or applied.

The record says the primary-outcome results are based on 14 participants and do not include Peer Leaders. The overall enrollment is 30, but reasons for the difference between enrollment and the outcome population are not reported in the registry record. The record also does not specify whether all 14 had complete measurements at both time points, how missing observations were handled, or whether any participants were excluded after enrollment.

Accordingly, the analysis population cannot be reconstructed from the registry description. It is unclear whether the reported outcome set corresponds to all eligible intervention participants, only those with complete data, or another defined group. The record does not report an intention-to-treat approach, a per-protocol approach, imputation, or sensitivity analyses. These details matter because the population included and the handling of missing data affect what the resulting estimate describes. No specific missing-data method should be inferred.

12. 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: hospitalization (7.1%), vertigo (7.1%).

Safety information is reported separately for Peer Leaders and participants in the Peer Led Diet and Exercise Intervention. In the Peer Leader group, 9 were at risk for serious adverse events, none had a serious adverse event, 9 were at risk for other adverse events, 2 had other adverse events, and 2 deaths were recorded. In the intervention group, 14 were at risk for serious adverse events, 2 had serious adverse events, 14 were at risk for other adverse events, none had other adverse events, and 2 deaths were recorded.

The registry lists Hospitalization and Vertigo as the most frequent serious adverse-event terms, each reported as 7.1%. Those terms are descriptive event categories. The registry record does not provide additional context on timing, relatedness to the intervention, severity beyond the serious-event classification, or whether an individual could contribute more than one event term.

These counts should not be read as a randomized safety comparison. The study is single-group, and the registry cautions that its arms are not like-for-like control groups. The group sizes and labels alone do not establish that one group had greater or lesser risk, nor do the counts establish whether events were caused by participation. The record also does not explain the two recorded deaths in each group or provide further attribution. The figures describe what is recorded, without establishing causality.

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

The registry record documents a completed pilot of a peer-led diet and exercise intervention and defines a primary measure of cardiovascular endurance: change in six-minute walk distance from baseline to 12 weeks. It also records a secondary mobility measure and safety counts for Peer Leaders and intervention participants. These details show the type of question the study was designed to address and the outcomes it registered.

The primary outcome's numerical result is not reported in the registry record. There is no posted estimate of mean change, no accompanying standard deviation or confidence interval, and no p-value. Consequently, the record does not establish the direction, size, or precision of the change in cardiovascular endurance. It also does not show whether individual participants generally improved, remained similar, or changed in different directions.

Even a reported before-and-after change would describe observed change in the assessed group rather than a randomized intervention effect. This is a general limitation of single-group designs: change over time can have explanations other than the intervention, and there is no like-for-like randomized control comparison in this study. The registry itself cautions against treating the listed arms as a control comparison.

The study's purpose is described as development and pilot evaluation, with preliminary data intended to inform a larger multisite trial. A pilot can help characterize implementation and identify questions for further study, but the record does not report enough outcome or process detail to assess those aspects quantitatively. The available information therefore supports a description of the study design, registered endpoint, outcome population, and recorded safety counts. It does not support a numerical conclusion about cardiovascular endurance change or a causal claim about the intervention.

14. Why This Trial Matters Statistically

This trial matters statistically because it illustrates how a clearly stated outcome and a completed study record can still leave the central effect estimate unavailable. The primary endpoint is defined as change in six-minute walk distance, and the record identifies the assessment interval and the population used for the reported results. But without the numerical estimate and its uncertainty, readers cannot judge the size or precision of the observed change.

The design also makes the distinction between change and treatment effect especially important. A single-group study can document a before-and-after pattern, but it does not provide a randomized comparison that separates intervention-associated change from other influences over time. This is not a defect in the stated purpose of a pilot study; it is a constraint on the conclusions the design can support. The registry's warning about the listed arms reinforces that they should not be treated as a control comparison.

The difference between the enrollment of 30 and the 14 participants whose outcomes are reported raises a further interpretive question. The record does not explain participant flow or missing data, so the representativeness of the analyzed group cannot be assessed from the registry description. Reporting the analysis population and how incomplete measurements are handled is important for understanding what an estimate applies to.

Finally, the registry lists multiple outcomes and analyses but does not describe the statistical plan or any approach to multiplicity. Such information would help readers distinguish primary from exploratory findings and understand how results were interpreted. The record's value is therefore in documenting the pilot's aims and structure, while its statistical limits highlight why numerical outcomes, uncertainty, analysis populations, and planned methods are all needed for a fuller interpretation.

15. 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 most direct limitation for interpreting cardiovascular endurance is that its numerical result is not reported in the registry record. Without the mean change, variability, or uncertainty measure, the direction, size, and precision of the primary outcome cannot be evaluated. The record specifies the six-minute walk test and the 12-week timeframe, but an endpoint definition is not a result.

The study used a single-group model and does not provide a like-for-like control comparison. Therefore, a change from baseline, if reported, could not by itself identify the intervention as the cause. The registry also says outcomes were collected only for 14 participants and excluded Peer Leaders, whereas enrollment was 30. It does not report why those counts differ, how many participants had measurements at both time points, or whether missing data affected the analyzed group.

Other trial-specific details that would aid interpretation are not reported in the registry record. These include the complete outcome set, analysis methods, handling of missing observations, multiplicity strategy, adherence to the twice-weekly activities, and the reasons for any exclusions. The record also does not provide additional context or attribution for the recorded deaths and adverse events.

The study is described as a pilot intended to contribute preliminary data for a larger multisite trial. Its single-group design and limited reported outcome information constrain the conclusions that can be drawn from the registry record. These limitations do not establish that the intervention did or did not change participants' outcomes; rather, they define what can be evaluated from the information recorded.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Peer-Led Diet and Exercise Intervention — NCT04994938.
• Registry record last updated 2026-02-17; status last verified 2026-01.
• Results first posted 2026-02-17.
• 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.

19. Record Summary

NCT04994938 is a completed single-group study of a peer-led diet and exercise intervention for older urban-dwelling Veterans with dysmobility. The registry records enrollment of 30, no masking, and an intervention involving diet and exercise activities two times per week. The sponsor is the VA Office of Research and Development.

The primary outcome is change in cardiovascular endurance, measured as six-minute walk distance in yards from baseline to the 12-week assessment. Results are described for 14 participants and exclude Peer Leaders. A secondary outcome is change in mobility on the 30 Second Chair Stand Test. The numerical primary outcome result and detailed statistical methods are not reported in the registry record.

Safety information is listed separately for Peer Leaders and intervention participants, including serious adverse events, other adverse events, and deaths. The registry cautions that these groups are not a like-for-like control comparison. The study's described aim is to develop and pilot the intervention and generate preliminary data for a larger multisite trial.