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 Exercise Intervention to Reduce Postural Instability in Osteoarthritis (NCT00708734), a na na study. The primary outcome is Gait and Balance Measures.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00708734 |
| Phase | NA |
| Condition | Osteoarthritis |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 10 |
| Arms in the primary outcome | n/a |
| Lead sponsor | US Department of Veterans Affairs |
| Results posted | Yes |
2. Clinical Question
Population
People with knee osteoarthritis were the intended population. The registry lists osteoarthritis as the condition and describes the pilot as evaluating a structured group exercise program in this population. It does not report further eligibility details or participant characteristics.
Intervention
The intervention was functional exercise training, delivered as group functional exercise sessions. The brief summary describes a 10 week program with sessions twice weekly. The record frames the work as a feasibility pilot as well as an assessment of gait and balance measures.
Comparator
There was no separate comparator group in the registry record. The study model is single group, and allocation is listed as NA. Consequently, the record does not provide a like-for-like control comparison for distinguishing changes associated with the program from changes over time or other influences.
Primary question
The primary outcome is listed as Gait and Balance Measures, assessed at 5 months. The registry describes balance assessments and gait assessment using 3D motion capture. Its stated purpose was to evaluate feasibility; the posted description says only 3 of 10 participants completed the study and that the data was not analyzed. Thus, the record does not answer whether gait or balance changed.
3. Trial Design
This was a completed, single-group pilot study of functional exercise training for osteoarthritis. The registry lists enrollment as 10. It describes group functional exercise sessions over 10 week, conducted twice weekly, within a one year pilot study. The record gives the study start as 2008-07 and primary completion as 2009-07.
There was no randomized allocation: allocation is listed as NA, and the registry identifies the model as SINGLE GROUP. Masking is listed as NONE, and phase is listed as NA. No control arm is described, so the design does not support a direct between-group comparison. The single intervention arm is identified as Functional Exercise Training.
The registry’s stated purpose was to assess feasibility and evaluate gait and balance measures. It reports that only 3 of 10 participants completed the study, with high attrition, and states that the data was not analyzed. The outcome timeframe is listed as 5 months; the record does not clarify how this relates to the intervention schedule or the study’s one year description.
Further details about recruitment, eligibility, intervention adherence, protocol changes, and the planned analysis are not reported in the registry record. The sample-size justification and any planned interim analyses are also not reported in the registry record. Given the pilot purpose and limited completion, this record is most useful for understanding feasibility concerns and what was measured, rather than estimating a treatment effect.
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 | Arm 1 |
|---|---|
| STARTED | 10 |
| COMPLETED | 3 |
| NOT COMPLETED | 7 |
Reasons for not completing this period:
| Reason | Arm 1 |
|---|---|
| scheduling conflict | 2 |
| moved | 1 |
| leg injury | 1 |
| knee replacement | 1 |
| vertigo | 1 |
| leg fracture | 1 |
Analysis population for the primary outcome, as defined in the registry: The purpose of this pilot study was to evaluate the feasibilty of a structured, group exercise program in this population. Only 3 of 10 participants completed the study, due to high attrition, the project was considered unfeasible and data was not analysis.
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: age over 50 and gender
| Characteristic | Unit | Functional Exercise Training |
|---|---|---|
| Participants analysed | 10 | |
| Age, Continuous | years | 66.5 (50 to 77) |
| Sex: Female, Male: Female | Participants | 1 |
| Sex: Female, Male: Male | Participants | 9 |
6. Primary Endpoint
The registry lists the primary outcome as Gait and Balance Measures, measured over 5 months.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is titled Gait and Balance Measures, with a timeframe of 5 months. The registry describes balance assessment using the sensory organization test, limits of stability, and Berg balance, and gait assessment using 3D motion capture. These assessments concern different aspects of movement and balance; the record does not specify a single combined score, the units for any measure, or the summary parameter intended for analysis.
In general, gait and balance measures can be used to describe functional performance and postural control. Such measures may be relevant when a program is intended to address movement and stability, because they capture aspects of performance rather than only attendance or participation. That general rationale does not establish that any particular measure is reliable, clinically important, or responsive in this study population.
The registry describes feasibility as the pilot’s purpose and reports substantial attrition. It also says the data was not analyzed. Therefore, the endpoint description establishes what the investigators intended to assess, but the record does not give observed endpoint values, changes from baseline, uncertainty estimates, or a statistical comparison. It is not possible to use the posted record to quantify change in gait or balance.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central result in the registry is a feasibility finding: only 3 of 10 participants completed the study, and the project was considered unfeasible because of high attrition. The record also states that outcome data was not analyzed. It therefore contains no posted estimate of change in gait or balance, no uncertainty interval, and no statistical test for the primary outcome.
The adverse-event record lists 0 serious adverse events and 0 other adverse events among 10 participants at risk in the Functional Exercise Training group. Deaths are not reported in the registry record. These figures are counts recorded in the registry; they do not explain how events were defined, collected, or monitored, and they do not establish that the intervention is free of risk.
Because this was a single-group study without a control arm, even analyzed measurements could not by themselves separate any change over time from other influences. Here, the lack of analyzed outcome data is more fundamental: there is no posted estimate to interpret as improvement, decline, or no change. The small number of completions also means that observations from completers cannot be assumed to describe all participants or the wider intended population.
The registry does not report the planned statistical analysis, handling of missing data, or analysis population. It also does not report participant-level outcome data or a rationale for the enrollment target. No conclusion about the magnitude or precision of a gait or balance effect can be drawn from the record. The clearest statistical reading is that feasibility was undermined by attrition and the primary outcome was not analyzed.
These points should be kept separate: the registry does give a completion count and adverse-event counts, but it does not give efficacy estimates. Absence of an analyzed outcome is not evidence that the outcome did not change. Likewise, zero recorded adverse events in this registry entry is not equivalent to proving there were no events or no potential harms.
9. Statistical Methods Explained
The registry identifies a single-group study, with allocation listed as NA and masking as NONE. In general, a single-group design follows participants receiving an intervention without a separate control group. Such a design can describe feasibility and participant outcomes, but it has limited ability to attribute any observed change to the intervention. Changes may also reflect time, measurement variation, concurrent care, or other influences. Those are general design considerations, not findings about what happened to participants in this study.
What can a single-group outcome show?
In general, measuring an outcome before and after an intervention can describe the direction and size of change among those with measurements at both times. Interpretation is stronger when the outcome definition, measurement schedule, and analysis are specified in advance. A control group can help distinguish intervention-associated changes from changes that might have occurred anyway. There is no separate comparator in this record, and the registry does not report analyzed outcome values. Accordingly, neither a before-and-after change nor a controlled effect estimate is available.
What does an effect estimate describe?
In general, an effect estimate is a numerical summary of a comparison or change, such as a difference in means or a change from baseline. Its interpretation depends on the outcome scale, the analysis population, and the method used to account for repeated measurements or other features of the data. The registry does not report a summary parameter or units for the primary outcome, and it says the data was not analyzed. No effect estimate can therefore be interpreted from this entry.
How should uncertainty be understood?
In general, a confidence interval describes a range of values that are reasonably compatible with the data under the assumptions of the statistical method. A narrow interval indicates greater precision than a wide one, while an interval spanning meaningfully different effects may leave the result uncertain. A confidence interval does not repair bias from missing data, lack of a control group, or limitations in measurement. No confidence interval or other precision estimate for gait or balance is reported in the registry record.
Why does attrition matter?
In general, attrition reduces the amount of outcome information available and can make estimates less precise. It can also introduce bias if the participants who remain differ in relevant ways from those who leave. For example, the reasons for leaving might be associated with ability to participate or with the outcome being measured. That possibility is a general concern; the registry does not report reasons for individual withdrawals or compare completers with non-completers. It reports high attrition and that only 3 of 10 participants completed the study, but it does not provide enough detail to characterize the effect of missingness.
What is the role of a statistical analysis plan?
In general, a statistical plan specifies the outcomes and contrasts to analyze, how measurements are summarized, which participants are included, and how missing observations and uncertainty are handled. Prespecification can reduce the risk of choosing analyses after seeing results. The planned analysis and analysis population are not reported in the registry record. The registry also reports no outcome analyses. It is therefore not possible to assess whether a particular analysis was planned or whether the posted results follow a prespecified approach.
What does a pilot study contribute?
In general, a pilot study can assess whether recruitment, attendance, intervention delivery, and outcome measurement are workable. Feasibility findings can inform the design of later research, but a pilot is not necessarily designed to provide a precise estimate of an intervention effect. The record explicitly frames this work as a feasibility pilot and states that the project was considered unfeasible because of high attrition. It does not report a sample-size justification, so the reason for the enrollment target is not reported in the registry record.
Statistical methods can describe data only when the relevant measurements and analysis are available. In this entry, the assessment instruments are named, but numerical results and analyses are absent. General principles about effect estimates, precision, and missing data help explain what would be needed for an outcome interpretation; they do not supply a result that the registry does not report.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome description includes multiple balance assessments—the sensory organization test, limits of stability, and Berg balance—and a gait assessment using 3D motion capture. The registry does not specify how these measures would be combined, which individual measurements would be analyzed, or whether one would be designated as the main analysis. It reports one outcome measure entry and no outcome analyses. A multiplicity adjustment or a plan for handling multiple outcome tests is not reported in the registry record.
In general, testing many outcomes or time points can increase the chance that at least one result appears noteworthy by chance. A prespecified hierarchy, a composite outcome, or an adjustment can address some multiplicity concerns, but the record does not report whether any such approach was planned. Since no outcome analyses are posted, there are no statistical test results for which to evaluate multiplicity in practice.
Missing outcome data are a central concern because the registry reports high attrition and says only 3 of 10 participants completed the study. It does not report the amount of missingness for each measure, reasons for withdrawal, or whether any measurements were available from participants who did not complete the study. The method for handling missing data is not reported in the registry record.
The record does not define an analysis population, such as all enrolled participants or only those who completed the intervention. It also does not report whether any analysis population was specified in a protocol. In general, the choice of population and approach to missing data affect the interpretation of results, especially when attrition is substantial. Here, the absence of outcome analyses means there is no posted estimate to evaluate under any such approach.
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 |
|---|---|---|---|
| Functional Exercise Training | 0 | 10 | 0.0% |
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 |
|---|---|
| Functional Exercise Training | 0 of 10 |
The registry lists 10 participants at risk for both serious and other adverse events in the Functional Exercise Training group. It records 0 serious adverse events and 0 other adverse events. Deaths are not reported in the registry record.
These are registry counts, not a detailed safety analysis. The record does not describe how adverse events were defined, how they were solicited, the observation period used for event collection, or whether events were independently assessed. It also does not provide event narratives or information about the completeness of safety follow-up.
In general, zero recorded events means no events of that category were entered in the reported record for the stated group; it does not prove that the underlying risk is zero. That caution matters when interpreting a small pilot with high attrition, because incomplete follow-up can limit what safety observations capture. The counts should therefore be read as the posted registry figures, not as proof that no adverse events occurred or that the intervention has no safety concerns.
12. What the Result Does, and Does Not, Mean
The record supports a limited but important conclusion about feasibility: the study had high attrition, only 3 of 10 participants completed it, and the project was considered unfeasible. The entry also identifies the intended intervention and describes gait and balance assessments. It does not report analyzed results for those assessments.
That means the record cannot establish the direction, magnitude, or precision of any change in gait or balance. It cannot show that the measures improved, worsened, or remained unchanged. No effect estimate, confidence interval, or statistical test for the primary outcome is reported. The absence of an analysis should not be interpreted as a finding of no effect.
The single-group design also limits causal interpretation. Without a separate comparator, an observed change—if it had been reported—could not be cleanly distinguished from other changes occurring over time. In this record, the lack of analyzed outcome data prevents even a descriptive account of outcome change.
The adverse-event counts are part of the registry record, but they are not a complete characterization of safety. The record lists zero serious and zero other adverse events, while details about event definitions and follow-up are not reported. These counts do not demonstrate the absence of risk.
Overall, the statistical contribution is chiefly a documented feasibility concern and a record of intended outcome measurement. The registry does not supply an efficacy estimate or enough information to judge the precision or robustness of outcome findings. The study should not be treated as evidence for or against an effect on gait or balance.
13. Why This Trial Matters Statistically
This trial matters statistically because it illustrates why feasibility and outcome estimation are different goals. A pilot can reveal whether participants complete a program and whether study procedures appear workable. In this case, the registry reports high attrition and concludes that the project was unfeasible. That information is meaningful even though the primary outcome was not analyzed.
Attrition is not merely a reduction in the number of observations. In general, it may affect both precision and validity: fewer completed measurements leave less information, and missingness related to participant characteristics or outcomes can distort an estimate. The registry does not describe withdrawal reasons or missing-data handling, so the extent and direction of any such distortion cannot be assessed.
The record also highlights the limits of a single-group design. Without a comparator, a measured change would be difficult to attribute to the intervention rather than to time or other factors. Here, the issue is compounded by the absence of analyzed outcome data. Naming gait and balance assessments does not produce an estimate of change or establish its uncertainty.
For clinical researchers, the entry separates three questions that are often conflated: whether a study can be carried out as intended, what happened to measured outcomes, and whether any outcome change can be attributed to an intervention. The posted record addresses the first through its feasibility statement, but does not provide analyzed results for the second or a controlled comparison for the third. Recognizing these distinctions prevents overinterpretation of a small pilot 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 limitation is that the registry says the outcome data was not analyzed. It provides no gait or balance values, changes, effect estimates, or precision measures. As a result, the primary outcome cannot be statistically interpreted from this record.
Attrition was high: only 3 of 10 participants completed the study, and the project was considered unfeasible. Reasons for withdrawal, measurement availability among those who did not complete, and differences between completers and non-completers are not reported in the registry record. These omissions prevent assessment of how attrition affected the available outcome information.
The study was single group, with no separate control arm. The registry lists allocation as NA and masking as NONE. Even if outcome changes had been analyzed, the design would not provide a direct controlled estimate. The record also does not report participant characteristics, eligibility criteria, adherence, or details of intervention delivery beyond the group format and session schedule.
The outcome description names several balance assessments and 3D motion capture for gait but does not report units, a summary parameter, or how the measures would be handled analytically. The analysis plan, sample-size justification, interim analyses, analysis population, missing-data method, and multiplicity approach are not reported in the registry record. The adverse-event entry gives counts but not event definitions or collection details. Together, these limits mean the record is most informative about the stated feasibility problem, not outcome effects or comprehensive safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Exercise Intervention to Reduce Postural Instability in Osteoarthritis — NCT00708734.
- Registry record last updated 2014-10-23; status last verified 2014-10.
- Results first posted 2014-10-23.
- 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
NCT00708734 is a completed, single-group pilot of functional exercise training for osteoarthritis. The registry describes group sessions conducted twice weekly over 10 week and lists enrollment as 10. The study aimed to evaluate feasibility and gait and balance measures, with the primary outcome timeframe listed as 5 months.
The registry reports that only 3 of 10 participants completed the study, cites high attrition, and states that the project was considered unfeasible. It also says the outcome data was not analyzed. No primary outcome estimates or statistical tests are posted. The adverse-event record lists 0 serious and 0 other adverse events among 10 participants at risk; deaths are not reported in the registry record.
Overall, the entry documents a feasibility concern but does not provide an analyzed estimate of change in gait or balance.