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 Home-Based Exercise to Treat Decreased Physical Function in Patients With Varying Levels of Kidney Function (NCT04745169), a na na study. The primary outcome is Change in Short Physical Performance Battery Score.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04745169 |
| Phase | NA |
| Condition | Chronic Kidney Disease |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 15 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Baylor College of Medicine |
| Results posted | Yes |
2. Clinical Question
Population
People with chronic kidney disease who were candidates for kidney transplantation. The registry describes the study as involving patients with varying levels of kidney function; further eligibility details are not reported in the registry record.
Intervention
An 8-week home-based exercise program. Participants were asked to complete the intervention at home.
Comparator
No separate control group is described. The primary outcome is framed as a comparison of participants’ 8-week scores with their baseline scores.
Primary question
How did the Short Physical Performance Battery score change from baseline over the 8 weeks of home-based exercise? The registry record does not report the observed change or its uncertainty.
The study’s stated purpose was to investigate home-based exercise as a way to address decreased physical function among kidney transplant candidates. The primary outcome was change in the Short Physical Performance Battery (SPPB) score. The registry also describes interest in frailty parameters, health-related quality of life, physical activity, and adverse clinical outcomes, including hospitalizations.
This is a before-and-after question within a single group, not a question about the difference between exercise and a concurrent control intervention. A change between baseline and follow-up can describe what happened during the study period, but by itself it cannot distinguish an intervention effect from other explanations for change. The registry record does not report a primary outcome estimate, so the direction and size of any observed SPPB change cannot be assessed from the posted information.
3. Trial Design
The registry describes a completed pilot study with a single-group model and no masking. The listed intervention is an 8-week home-based exercise program, and participants were asked to complete it. The record does not describe a parallel control group or randomized allocation. It lists enrollment as 15.
The design is relevant to interpretation. The primary outcome compares the 8-week SPPB score with the baseline score, so each participant’s measurements are intended to be considered over time. That within-participant framing differs from a randomized comparison, where outcomes in intervention and control groups can be contrasted. Without a concurrent control group, changes over time cannot be attributed specifically to the exercise program on the basis of this design alone.
The registry lists the study status as completed and gives the primary completion date as 2023-11-16. It identifies Baylor College of Medicine as the sponsor. Phase and allocation are recorded as NA. These entries do not supply additional details about recruitment, adherence, the analysis population, or the statistical model used for the outcome analyses; those details are not reported in the registry record.
The study is identified as a pilot. The registry record does not report a sample-size justification or describe a formal design objective such as estimating a particular treatment effect with a specified precision. The sample-size assumptions attached to planning illustrations should not be read as a description of the study’s actual design: the study itself is listed as single-group, whereas those assumptions refer to equal allocation between two arms.
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 | Intervention |
|---|---|
| STARTED | 15 |
| COMPLETED | 9 |
| NOT COMPLETED | 6 |
Reasons for not completing this period:
| Reason | Intervention |
|---|---|
| Kidney transplantation | 1 |
| Participant health problems | 3 |
| Physician Decision | 2 |
Analysis population for the primary outcome, as defined in the registry: Median difference in 8-week score compared to baseline score
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 | Intervention |
|---|---|---|
| Participants analysed | 15 | |
| Age, Continuous | years | 64 (58 to 68) |
| Sex: Female, Male: Female | Participants | 4 |
| Sex: Female, Male: Male | Participants | 11 |
| Race/Ethnicity, Customized: White race | Participants | 11 |
| Region of Enrollment: United States | participants | 15 |
| Dialysis dependent | Participants | 8 |
| Diabetes | Participants | 12 |
| Never smoked | Participants | 10 |
| Body mass index | kg/m^2 | 30.3 (27.7 to 37.6) |
| Physical Frailty Phenotype score | units on a scale | 2 (1 to 2) |
| Short Physical Performance Battery score | units on a scale | 9 (8 to 10) |
6. Primary Endpoint
The registry lists the primary outcome as Change in Short Physical Performance Battery Score, measured over 8 weeks of home-based exercise.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | units on a scale |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is change in the Short Physical Performance Battery score over 8 weeks of home-based exercise. The record describes the reported quantity as the median difference in the 8-week score compared with the baseline score, with the inter-quartile range as the dispersion measure. The observed median difference and inter-quartile range are not reported in the registry record.
The SPPB combines component tests of balance, gait speed, and chair stand time. Each component receives a score from 0-4, and the component scores are summed to form a total score from 0-12. Lower scores indicate worse physical function, both for the component tests and for the total score. This makes the SPPB a measure of physical performance across more than one task, rather than a measure of a single movement or activity.
In general, a composite measure can give a broader picture of function by combining related performance tasks. The score’s interpretation still depends on the observed results: without the baseline and follow-up values, or the reported median change, it is not possible to describe the amount or direction of change in this study. The endpoint definition alone does not establish that participants improved or worsened.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the primary outcome and how it was intended to be summarized, but does not report the primary result. In particular, it does not provide the median difference in SPPB score, its inter-quartile range, or a confidence interval. Consequently, the direction, magnitude, and precision of the primary outcome cannot be evaluated from the posted results. The endpoint description is not itself evidence of an observed change.
The study is a single-group, before-and-after pilot. If a change estimate were available, it would describe the observed change over the study period among participants included in that analysis. It would not, on its own, show what would have happened over the same period without the exercise program. A concurrent control group can help separate intervention-related change from changes associated with time, other care, measurement variation, or participant circumstances; no such group is described in this record.
The summary states that investigators intended to assess frailty parameters and SPPB scores, as well as health-related quality of life, physical activity, and adverse clinical outcomes. The registry lists secondary outcomes covering grip strength, gait speed, exhaustion, physical activity, quality of life, weight, percent body fat, and physical frailty phenotype. The actual estimates for these outcomes are not reported in the registry record. The record lists nine outcome measures and nine analyses, but does not explain how those analyses relate to each outcome or whether all were completed.
Without outcome estimates, measures of uncertainty, and information about missing observations, there is no basis for judging how precisely the study estimated change. The enrollment entry of 15 describes the registered study enrollment; the record does not report the number contributing data to each outcome. It is therefore important not to treat enrollment as proof that all participants completed the program or had complete follow-up data.
The safety information is also limited. The registry lists zero participants with serious adverse events and three with other adverse events, with 15 at risk in each category. No deaths are listed. The types of other adverse events and details about event timing, severity, or attribution are not reported in the registry record. These counts describe the recorded safety entries and do not establish whether events were caused by the intervention.
9. Statistical Methods Explained
The primary outcome is framed as a change from baseline, with the median difference and inter-quartile range specified. The registry record does not report the calculation details, the observed estimate, or an inferential analysis for that endpoint. The explanations below describe general statistical ideas; they are not claims about analyses performed in this study unless the registry explicitly says so.
What does a median change describe?
For a set of participant-level changes, the median is the central value after those changes are ordered. It can be useful when a distribution is skewed or contains values far from most observations, because it is less affected by extreme values than the mean. The inter-quartile range describes the spread of the central portion of the observed distribution. It conveys variability among participant changes, but is not the same as a confidence interval for the median and does not, by itself, quantify uncertainty about the population-level effect.
Interpreting a change score requires knowing how the score was formed and which observations contributed. Here, the registry defines the primary measure as the median difference between the 8-week SPPB score and baseline. However, it does not report the individual values, the resulting median difference, the inter-quartile range, or the number of participants with usable measurements. The magnitude and direction of the study’s observed change therefore remain unknown from the registry record.
What would a confidence interval add?
In general, a confidence interval expresses the statistical uncertainty around an estimate under the assumptions of the analysis. A narrower interval indicates greater precision, while a wider interval indicates less precision. It does not remove design limitations, and it cannot establish that an observed change was caused by an intervention. No confidence interval for the primary outcome is reported in the registry record.
A p-value, if reported, would address compatibility between the data and a specified statistical null model under the analysis assumptions. It would not measure the size or practical importance of a change, and it would not resolve the lack of a concurrent comparison group. The registry record does not report a primary-outcome p-value or describe the test used.
Why does the single-group structure matter?
In a single-group before-and-after study, each participant may contribute a baseline and follow-up value. General analyses can account for the fact that those two measurements come from the same person, rather than treating them as independent observations. The record does not report whether the analysis used paired methods, a model for repeated measurements, or another approach. It also does not describe how missing baseline or follow-up values were handled.
Even a well-estimated within-group change is not the same as an estimate of the effect compared with no intervention or another treatment. Changes may reflect the intervention, but may also reflect time trends, changes in other care, measurement variability, or differences between those with and without follow-up data. A single-group design cannot directly estimate the counterfactual outcome that would have occurred without the intervention.
How should the planning assumptions be read?
The registry’s planning assumptions describe an illustration based on an observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They describe planning for a stated fraction of the observed effect. For time-to-event illustrations, the assumptions refer to total events; other illustrations refer to participants per arm.
These are assumptions for planning illustrations, not evidence that the trial was designed or conducted as a two-arm study. The registered study is single-group. The registry record does not report the observed effect used for the illustrations or the resulting planning values, so those values cannot be interpreted from this record. Such calculations are not observed power and do not establish the probability that the study detected an effect. No sample-size justification for the actual pilot is reported in the registry record.
More generally, planning calculations depend on the effect size and statistical assumptions chosen. If the assumed effect is optimistic, a study planned around it may not be informative about smaller effects. A planning illustration does not substitute for reporting the observed estimate with its uncertainty, nor does it remedy design constraints such as the absence of a control group.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists nine outcome measures and nine analyses. It identifies change in SPPB score as the primary outcome and lists other measures that include physical function, activity, quality of life, body composition, and frailty. The record does not report how the analyses were assigned to the listed outcomes, whether all planned analyses were completed, or whether the investigators prespecified a hierarchy among outcomes.
When several outcomes or analyses are considered, the chance of finding an apparently notable result by chance can increase. General approaches include designating a primary outcome in advance, adjusting inference for multiple comparisons, or treating secondary analyses as exploratory. The registry record does not report whether any multiplicity adjustment or other strategy was used. This absence makes it difficult to interpret any secondary findings as confirmatory, even if estimates were available.
Missing data also matter for a before-and-after outcome. A participant needs relevant measurements to contribute a change score. If follow-up is incomplete, the participants with observed data may differ from those without it, which can affect the interpretation of the estimate. The registry record does not report outcome-specific denominators, the amount or pattern of missing data, reasons for missingness, or methods used to address it.
The record does not identify the analysis population, such as whether analyses were based on all enrolled participants or only those with available measurements. It also does not report adherence to the exercise program or how deviations from the planned intervention were handled. These omissions limit assessment of who contributed to each result and how representative those results might be of the enrolled group.
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 |
|---|---|---|---|
| Intervention | 0 | 15 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Intervention | 0 of 15 |
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 |
|---|---|
| Intervention | 3 of 15 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Intervention |
|---|---|---|
| Transient musculoskeletal pain | Musculoskeletal and connective tissue disorders | 1 of 15 |
| Persistent musculoskeletal pain | Musculoskeletal and connective tissue disorders | 1 of 15 |
| Shortness of breath | Respiratory, thoracic and mediastinal disorders | 1 of 15 |
The registry adverse-event entries list 15 participants at risk for serious adverse events, with zero affected, and 15 at risk for other adverse events, with three affected. The record lists zero deaths. These are counts of participants affected, not descriptions of the number of events in each category.
The serious-event terms are not listed. The record also does not report the types of other adverse events, their severity, timing, duration, or whether investigators considered them related to the exercise program. Thus, the counts cannot identify what events occurred or establish their cause. A registry entry of zero participants with a recorded serious adverse event does not mean that all possible harms were ruled out; it describes the reported count for this study.
Safety counts are most informative when considered alongside clear event definitions, follow-up duration, and the number of participants actually assessed. The registry describes the intervention as lasting 8 weeks, but the safety entry does not separately explain the observation period or provide further follow-up details. Those details are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a completed pilot study examined an 8-week home-based exercise program in kidney transplant candidates with chronic kidney disease and varying levels of kidney function. It specifies the SPPB as the primary outcome and describes how the score is constructed and summarized. It also records adverse-event counts. These details clarify the question the study was intended to address.
The record does not report the primary outcome estimate or the results for the listed secondary outcomes. It therefore does not show whether SPPB scores, frailty measures, physical activity, quality of life, or other measures changed during the study. No conclusion about the size, direction, or precision of any change can be drawn from the outcome information in the registry record.
Even if within-group changes were reported, this design would describe change over time rather than establish the difference that would occur because of exercise compared with a control condition. The absence of a control group is a central limitation for causal interpretation. The record also does not report adherence, outcome-specific sample sizes, or missing-data methods, which are relevant to assessing how the observed participants and measurements relate to the enrolled group.
The safety entries report zero participants with serious adverse events, three with other adverse events, and zero deaths. They do not include the event terms or establish whether any event was related to the intervention. These counts should be understood as limited registry safety information, not as a complete account of risks.
Overall, the posted information describes the study’s design, intended outcomes, and limited safety counts, but not the efficacy results needed to characterize change. The record does not support a claim that the program improved or failed to improve physical function, and it does not support a treatment recommendation.
13. Why This Trial Matters Statistically
This study is statistically informative as an example of the difference between measuring change and estimating a comparative effect. The primary question uses a baseline-to-follow-up SPPB change in a single group. Such a measure can describe the experience of participants with available data, but it does not by itself separate intervention-related change from other influences over time.
The registry’s use of the median and inter-quartile range is also meaningful. These summaries focus on the center and spread of observed changes without requiring that the change distribution be well represented by a mean and standard deviation. Yet the choice of summary cannot compensate for missing results: the registry record does not report the median change, its inter-quartile range, or an uncertainty interval.
The pilot designation and enrollment of 15 make clear why transparent reporting of estimates and limitations matters. A pilot can contribute information about feasibility or potential outcome patterns, but the registry record does not report feasibility findings, adherence, or a justification for the enrollment target. Nor should planning calculations based on an observed effect be confused with evidence of a well-powered test. The recorded planning assumptions describe a hypothetical two-arm illustration, unlike the single-group design described for the study.
Finally, the record lists a range of secondary outcomes but does not explain multiplicity handling, analysis populations, or missing-data methods. These are important elements of interpretation when several measures are considered. Clear reporting of outcome estimates, uncertainty, denominators, and analysis decisions would help readers distinguish descriptive findings from stronger inferential claims.
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.
Several trial-specific limits follow directly from the registry record. The study is single-group and does not describe a concurrent control arm, so changes from baseline cannot be compared with changes under a control condition. This constrains causal interpretation regardless of the statistical method used.
The primary outcome result is not reported in the registry record. Neither the median difference nor its inter-quartile range is available, and no confidence interval or p-value is listed. Results for the secondary outcomes are also not reported. This prevents assessment of the observed changes, their variability, and their precision.
The record lists enrollment as 15, but does not report the number of participants contributing to each outcome or whether all enrolled participants completed follow-up. It does not describe adherence, missing observations, analysis populations, or procedures for handling missing data. The extent to which the analyzed measurements represent the enrolled participants therefore cannot be assessed.
The registry does not report the statistical analysis plan, sample-size justification, or multiplicity strategy. Although it lists nine outcome measures and nine analyses, the relationships among those entries and the status of each analysis are not explained. Safety information is similarly limited: serious-event terms are not listed, and details about the other adverse events are not reported.
These reporting limits should not be mistaken for evidence that analyses or procedures were absent. They mean that the relevant details are not reported in the registry record and cannot be evaluated from the posted information.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Home-Based Exercise to Treat Decreased Physical Function in Patients With Varying Levels of Kidney Function — NCT04745169.
- Registry record last updated 2025-08-17; status last verified 2025-08.
- Results first posted 2025-08-17.
- 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 record describes a completed, single-group pilot study sponsored by Baylor College of Medicine. It lists enrollment of 15 and an 8-week home-based exercise program for kidney transplant candidates with chronic kidney disease and varying levels of kidney function.
The primary outcome is change in SPPB score from baseline to the 8-week assessment, summarized using a median difference and inter-quartile range. The registry record explains the score’s components and direction but does not report the observed outcome result. It lists secondary outcomes related to physical function, frailty, activity, quality of life, weight, and body composition.
Safety entries list zero participants with serious adverse events, three with other adverse events, and zero deaths. Event terms and further safety details are not reported in the registry record. The single-group design, absent outcome estimates, and unreported analysis details limit interpretation of efficacy, precision, and safety.