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 Effect of Nike FuelBand on Exercise and Function in Claudicants; a Randomised Controlled Trial (NCT01822457), a randomized na study. The primary outcome is Maximum Walking Distances.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01822457 |
| Phase | NA |
| Condition | Peripheral Vascular Disease, Intermittent Claudication |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 37 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Imperial College London |
| Results posted | Yes |
2. Clinical Question
Population
People with intermittent claudication, a condition listed alongside peripheral vascular disease in the registry record. The record does not report additional eligibility details or describe the population contributing to the primary endpoint.
Intervention
Participants assigned to the Nike FuelBand (NFB) arm received a Nike FuelBand intended to encourage exercise. The record does not report how often participants wore it or how consistently they used it.
Comparator
The control arm received standard follow-up. Further details about what standard follow-up involved are not reported in the registry record.
Primary question
At 12 months, what maximum distance could participants walk during a standardized treadmill test? The registry names maximum walking distances, in meters, as the primary endpoint. It posts arm-level summaries but no formal between-arm estimate, confidence interval, or test of statistical significance.
3. Trial Design
The registry describes a randomized, single-masked, parallel-group study of the Nike FuelBand in people with intermittent claudication. The trial is listed as completed, with a recorded enrollment of 37. The recorded start is 2013-08 and the primary completion date is 2015-12. Imperial College London is listed as the sponsor.
One arm received the Nike FuelBand, with the stated purpose of encouraging exercise; the other received standard follow-up. Random allocation is reported, but the method used to generate the allocation sequence and how allocation was concealed are not reported in the registry record. The record says the study was single-masked but does not specify which people were masked or how masking was maintained.
The primary endpoint was maximum walking distance on a standardized treadmill test at 12 months. The registry lists pain-free treadmill walking distance, disease-specific quality of life, and mood as secondary outcomes. It does not report numerical results for those secondary outcomes in the information available for this analysis.
The posted primary endpoint summaries are based on 16 participants in the Nike FuelBand arm and 12 in the control arm. These endpoint counts are not the same as the enrollment figure of 37. Reasons for the difference, including any exclusions, loss to follow-up, or missing endpoint measurements, are not reported in the registry record. The actual analysis population and whether participants were analyzed according to their randomized assignment are also not reported.
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 | Nike FuelBand (NFB) | Control |
|---|---|---|
| STARTED | 20 | 17 |
| COMPLETED | 16 | 12 |
| NOT COMPLETED | 4 | 5 |
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 | Nike FuelBand (NFB) | Control | Total |
|---|---|---|---|---|
| Participants analysed | 20 | 17 | 37 | |
| Age, Continuous | Years | 67.8 (SD 10.3) | 70.7 (SD 10.8) | 69.1 (SD 10.4) |
| Sex: Female, Male: Female | Participants | 2 | 5 | 7 |
| Sex: Female, Male: Male | Participants | 18 | 12 | 30 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Maximum Walking Distances, measured over 12 months.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Inter-Quartile Range |
| Unit | Meters |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is maximum walking distance, measured in meters during a standardized treadmill test at the end of the study period. The recorded timeframe is 12 months. A treadmill test provides a defined setting for assessing how far a participant can walk under a standardized exercise procedure. Maximum distance captures walking capacity, while pain-free distance, listed separately as a secondary outcome, concerns a different point in the walking test.
The registry labels the primary measure as a mean and identifies the dispersion as an interquartile range. The Nike FuelBand arm has a posted value of 147.0 meters, with limits of 135.0 and 405.0 meters; the control arm has a posted value of 68.0 meters, with limits of 40.0 and 75.0 meters. These are arm-level summaries, not a reported comparison adjusted for any other factors. The record does not clarify further how the stated mean and interquartile-range labels correspond to the posted values.
As a general statistical point, a central summary describes the location of measurements, while a spread summary conveys how dispersed individual observations are. A standardized assessment can make measurements more comparable, but it does not by itself establish that a difference between arm summaries is statistically reliable or attributable to the intervention. The registry does not report a between-arm estimate or its uncertainty.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary endpoint summaries are 147.0 meters for the Nike FuelBand arm and 68.0 meters for the control arm. The corresponding posted spread limits are 135.0 to 405.0 meters and 40.0 to 75.0 meters. These summaries describe the recorded endpoint values in the two arms; they are not a formal estimate of the intervention’s effect.
The registry reports 16 participants for the Nike FuelBand endpoint summary and 12 for the control summary. It also lists enrollment of 37. The reason the endpoint counts differ from total enrollment is not reported in the registry record. Without information about endpoint availability and the analysis population, the arm summaries cannot establish how missing measurements or exclusions were handled.
No formal comparison is posted: the record lists zero analyses. It therefore provides no between-arm estimate, confidence interval, p-value, or adjusted analysis for the primary endpoint. The numerical separation between the arm summaries should not be read as a finding of statistical significance. Nor can the precision of that separation be judged from the posted values alone.
As a general statistical point, a confidence interval expresses the uncertainty around an estimated quantity under the assumptions of the analysis. An interval for a between-arm contrast would help readers understand which effect sizes remain compatible with the data and method. No such interval is reported, so the evidence cannot be characterized by a reported range of plausible treatment effects.
The two sets of spread limits also indicate that the recorded values vary within each arm, but the registry does not report individual observations or a distributional plot description in the record considered for this analysis. Interquartile limits are not confidence limits: they describe the middle portion of observed values rather than uncertainty about an estimated effect. They should not be used in place of an inferential comparison.
The secondary outcomes named in the record are pain-free treadmill walking distance, disease-specific quality of life, and mood. Their numerical results and analyses are not reported in the registry record. Consequently, the available evidence is limited to the primary endpoint summaries and the safety counts. It does not establish whether the observed arm-level pattern is robust to different analytic choices, nor whether other outcomes show a similar pattern.
The result is best read descriptively: the registry reports different arm-level maximum-distance summaries at 12 months, with the posted values and spread limits stated above. It does not report the analysis needed to quantify the difference or its uncertainty. No conclusion about the effect of the device should be drawn solely from comparing the two summaries.
9. Statistical Methods Explained
The registry describes the trial as randomized, single-masked, and parallel-group. In a randomized study, assignment is intended to make the comparison groups similar on average with respect to factors that can affect an outcome. Randomization does not guarantee that groups are identical, especially in a small study, and the record does not give details of the randomization procedure or allocation concealment. The meaning of single masking is also not specified: the registry does not identify who was masked.
What the endpoint summaries describe
The primary endpoint is a continuous measurement: maximum treadmill walking distance in meters. The record identifies the summary parameter as a mean and the spread measure as an interquartile range. A mean is the arithmetic average of measurements. An interquartile range describes the central half of the observed measurements, bounded by the lower and upper quartiles. As a general statistical point, a mean and an interquartile range summarize different features of data. The posted registry values are 147.0 meters in the Nike FuelBand arm and 68.0 meters in the control arm; the posted limits are 135.0 and 405.0 meters for the first arm, and 40.0 and 75.0 meters for the control arm. The record does not provide additional detail reconciling its summary labels with the reported values.
Arm-level summaries alone do not estimate the uncertainty in a contrast between arms. A formal analysis would specify the comparison being estimated and report an estimate along with an uncertainty measure, commonly a confidence interval. As a general explanation, a confidence interval reflects sampling variability under the chosen statistical model and its assumptions. It is not a range that contains every participant’s result. No interval for a between-arm contrast is reported in the registry record, and no p-value or formal primary-outcome comparison is posted.
Distribution and model considerations
Walking-distance data are measured on a scale where participants can have different values, and the choice of statistical summary and model should account for the distribution and study design. As a general statistical point, marked skew or outlying observations can make a mean sensitive to a small number of measurements; medians and quantiles can provide complementary descriptions. Over-dispersion, in general, means that variability is greater than a model assumes. When a model is too restrictive about variability, its standard errors and resulting uncertainty statements can be unreliable. These are general considerations, not claims that a particular distributional problem or model failure occurred in this trial. The record does not report model diagnostics or the analysis method used for the primary endpoint.
Because the study is parallel-group, participants are assigned to one arm rather than crossing between study conditions. A comparison would ordinarily need to respect the randomized groups and the way endpoint measurements were collected. Whether the registry’s posted summaries are based on all randomized participants, only participants with available measurements, or another population is not reported. The analysis population and missing-data method are not reported either.
Planning illustrations and inference
The registry’s planning assumptions describe an illustration using a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The illustration is based on the observed effect, with the effect to detect expressed as a fraction of that effect. These are planning assumptions, not evidence that the original trial was designed using those assumptions. The trial’s own sample-size justification and design assumptions are not reported in the registry record. No numerical sample-size outputs are stated in the record, so no participant count for a planning scenario can be described.
As a general point, a planning calculation estimates how many participants may be needed to detect a specified effect under a set of assumptions. It is not an estimate of the probability that a completed study’s result is true, and it should not be presented as observed power. An illustration based on an observed effect is especially dependent on that effect estimate; it does not replace the trial’s original design rationale. The registry does not report an interim-analysis plan or any interim analyses.
The record lists four outcome measures and zero analyses. Thus, it supplies endpoint summaries but not a documented inferential procedure for the primary comparison. Without the planned or performed analysis method, the significance level applied to the primary outcome, or an uncertainty estimate, readers cannot assess the result under a stated statistical model.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists three secondary outcomes: pain-free treadmill walking distance, disease-specific quality of life, and mood. It does not report numerical results or analyses for these outcomes in the record. No multiplicity strategy—such as a prespecified hierarchy, adjustment, or distinction between confirmatory and exploratory outcomes—is reported in the registry record. Consequently, it is not possible to assess how the several listed outcomes were handled as a family of statistical questions.
Missing-data information is also limited. Enrollment is recorded as 37, while the primary endpoint summaries list 16 participants in the Nike FuelBand arm and 12 in the control arm. The reasons for the different counts are not reported. There is no account of participants who did not complete the treadmill test, the amount or pattern of missing data, or any imputation or sensitivity analysis. The record does not say whether the endpoint summaries use all randomized participants or only those with observed measurements.
As a general statistical point, missingness can affect an estimate when the likelihood of having an observed outcome is related to participant characteristics or outcomes. The direction and extent of any such effect cannot be determined without information about missingness and the analysis. The analysis population, intention-to-treat approach, and per-protocol approach are not reported in the registry record. The registry also lists zero analyses, so there is no posted analysis description against which to evaluate these choices.
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 |
|---|---|---|---|
| Nike FuelBand (NFB) | 0 | 20 | 0.0% |
| Control | 0 | 17 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Nike FuelBand (NFB) | 0 of 20 |
| Control | 0 of 17 |
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 |
|---|---|
| Nike FuelBand (NFB) | 0 of 20 |
| Control | 0 of 17 |
The registry reports safety counts for 20 participants at risk in the Nike FuelBand arm and 17 in the control arm. In each arm, the number affected by serious adverse events is recorded as 0, the number affected by other adverse events is recorded as 0, and deaths are recorded as 0. No serious adverse-event terms are listed.
These figures describe the safety counts posted in the registry record. They should be read in relation to the stated at-risk counts and not assumed to use the same participant population as the primary endpoint summaries, which list 16 and 12 participants. The record does not explain the difference in counts or provide further detail about safety monitoring, event collection, duration of follow-up for safety, or how events were attributed.
As a general statistical point, zero recorded events does not establish that the underlying risk is zero. Safety counts are informative about events recorded in the observed participants, while the amount of information they provide also depends on the number observed and the way events were collected. The registry’s posted figures do not support a broader claim about safety beyond the counts recorded.
12. What the Result Does, and Does Not, Mean
The registry documents a randomized comparison of the Nike FuelBand with standard follow-up in people with intermittent claudication. Its primary outcome is maximum walking distance on a standardized treadmill test at 12 months. The posted arm summaries are 147.0 meters and 68.0 meters, with interquartile limits of 135.0 to 405.0 meters and 40.0 to 75.0 meters, respectively.
Those figures show the values recorded in the registry for each arm. They do not, by themselves, quantify a reliable between-arm effect. The record does not report a comparison estimate, confidence interval, p-value, or analysis method for the primary outcome. Accordingly, it is not possible to determine from the registry results how precisely the arm summaries differ or whether a formal analysis would support a difference under a specified statistical model.
The record also does not report numerical findings for the named secondary outcomes. It does not explain why the primary endpoint counts are smaller than total enrollment, identify the analysis population, or describe how missing outcomes were handled. These omissions limit what can be learned about the completeness and robustness of the primary outcome summaries.
As a general statistical distinction, a descriptive contrast between two group summaries is not equivalent to a causal estimate with quantified uncertainty. Random allocation is a design feature intended to support a fair comparison, but interpretation of the observed outcomes also depends on follow-up, outcome availability, and analysis choices. Those details are not reported sufficiently to evaluate them in this record.
The result does not establish that the device improves or fails to improve walking distance, quality of life, or mood. It also does not establish the absence of safety risks. It records arm-level endpoint summaries and zero reported adverse-event counts in the stated safety populations. The appropriate interpretation is limited to those posted observations and the substantial uncertainty left by the absence of a reported comparative analysis.
13. Why This Trial Matters Statistically
This trial is statistically instructive because the registry offers numerical arm summaries without a reported inferential comparison. Readers can see the maximum-distance values and the spread limits, but there is no estimate of the between-arm contrast or its uncertainty. That distinction is central to interpreting clinical trial results: descriptive summaries characterize observed data, while an analysis of the randomized comparison addresses the estimated effect and its precision.
The record also illustrates why participant counts should be read in context. Total enrollment is 37, while the primary endpoint summaries are based on 16 participants in the Nike FuelBand arm and 12 in control. Without an account of outcome availability or analysis populations, readers cannot tell why the counts differ or assess possible consequences for interpretation.
The distinction between an endpoint’s central summary and its spread is also important. The registry labels the primary endpoint as a mean with interquartile-range dispersion. Such summaries describe different aspects of the observed data, and neither provides an uncertainty interval for the treatment contrast. A separate, clearly specified comparison would be needed for that purpose.
Finally, the record names several secondary outcomes but reports no associated analyses in the information. When multiple outcomes are studied, analysis plans and multiplicity handling help readers distinguish confirmatory evidence from exploratory findings. Their absence, together with the absence of a primary comparison, makes this trial a useful example of how registry endpoint results may be informative descriptively while remaining limited for statistical inference.
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 available primary endpoint summaries cover 16 participants in the Nike FuelBand arm and 12 in control, compared with a recorded enrollment of 37. The registry does not explain the difference. Without participant-flow information, reasons for missing endpoint measurements, or a description of exclusions, the completeness of the outcome data cannot be evaluated.
No formal primary-outcome analysis is reported. In particular, the record does not provide a between-arm estimate, confidence interval, p-value, model specification, or adjustment strategy. The summaries therefore cannot communicate the precision of a comparative effect. The record also labels the endpoint parameter as a mean and the dispersion as an interquartile range without further explanation of how those labels correspond to the posted arm values.
The record does not specify the randomization procedure, allocation concealment, or which people were masked. It does not provide details of standard follow-up, participant adherence to the device, or the amount of exposure to the intervention. These omissions limit assessment of how the intervention and comparator were implemented, but do not establish that any particular implementation problem occurred.
Three secondary outcomes are named, but their numerical results and analyses are not reported in the registry record. The multiplicity approach, analysis population, missing-data methods, and sensitivity analyses are also not reported. The trial’s sample-size justification and interim-analysis plan are not reported. Together, these limitations mean that the available information supports a description of posted values, but not a comprehensive assessment of comparative effectiveness or statistical robustness.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Effect of Nike FuelBand on Exercise and Function in Claudicants; a Randomised Controlled Trial — NCT01822457.
- Registry record last updated 2020-02-17; status last verified 2020-02.
- Results first posted 2020-02-17.
- 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.
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18. Record Summary
The record describes a completed, randomized, single-masked, parallel-group trial sponsored by Imperial College London. It lists enrollment of 37 and dates of 2013-08 for study start and 2015-12 for primary completion. Participants with intermittent claudication were assigned to a Nike FuelBand intended to encourage exercise or to standard follow-up.
The primary endpoint was maximum walking distance in meters on a standardized treadmill test at 12 months. The registry posts arm-level summaries for 16 Nike FuelBand participants and 12 control participants, but lists zero analyses. It names pain-free treadmill walking distance, disease-specific quality of life, and mood as secondary outcomes; numerical results for those outcomes are not reported in the registry record.
Safety counts report zero serious adverse events, zero other adverse events, and zero deaths in both stated at-risk groups. The registry does not report a formal primary comparison, uncertainty estimates, reasons for the difference between enrollment and endpoint counts, or details of missing-data handling.