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 Reliability of Consumer Sleep Trackers in Patients Suffering From Obstructive Sleep Apnea Syndrome (NCT02967367), a na na study. The primary outcome is Time in Bed.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02967367 |
| Phase | NA |
| Condition | Obstructive Sleep Apnea Syndrome |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 36 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Centre Hospitalier Universitaire Saint Pierre |
| Results posted | Yes |
2. Clinical Question
Population
Patients with obstructive sleep apnea syndrome. The registry record lists an enrollment of 36 participants. It does not describe further eligibility criteria or the characteristics of participants included in the primary-outcome analysis.
Intervention
Jawbone and Withings consumer sleep trackers, together with the BodyMedia SenseWear research actigraph, were added to classical polysomnography to assess how accurately they measure sleep parameters.
Comparator
Classical polysomnography is the reference measurement described in the study summary. The record identifies a single-group design, not a randomized comparison or a separate control group.
Primary question
How accurately do the consumer trackers and research actigraph measure time in bed, compared with polysomnography, in patients with obstructive sleep apnea syndrome? The registry record does not report the resulting estimates of accuracy or agreement.
The study addresses a measurement question rather than a treatment-effect question. Consumer devices are intended to provide feedback about sleep duration or quality, while polysomnography and research-grade sensors are used for objective sleep assessment. The registry record frames the work as a comparison of consumer-level trackers and validated tools in people with obstructive sleep apnea syndrome.
Time in bed is the listed primary outcome. Deep sleep and light sleep are named as secondary outcomes. The registry record does not state whether every participant used every device, how device readings were synchronized, or how comparisons were to be summarized. It also does not report numerical primary or secondary outcome findings. Therefore, the clinical question can be described from the stated purpose, but the accuracy of any tracker cannot be judged from the registry record alone.
3. Trial Design
The record describes a completed, single-group study with an enrollment of 36 participants. The listed condition is obstructive sleep apnea syndrome. The sponsor is Centre Hospitalier Universitaire Saint Pierre. The recorded start is 2016-09 and the primary completion is 2017-02. The study has no phase designation recorded beyond NA.
The study summary says that Jawbone and Withings consumer trackers and a BodyMedia SenseWear research actigraph were added to classical polysomnography. This arrangement is intended to assess measurement accuracy in patients with obstructive sleep apnea syndrome. The registry record identifies the study model as single group and allocation as NA; it is not a randomized treatment comparison. Masking is recorded as none. These design features fit a measurement-assessment question, not a comparison of clinical outcomes between assigned treatment groups.
Although the description places devices alongside classical polysomnography, details needed to reconstruct the measurement protocol are not reported in the registry record. These include the exact device-wearing procedure, whether all devices were used by each participant, how a valid recording was defined, and how readings were matched in time. The record also does not state the analysis population or the handling of unusable device recordings.
The listed primary outcome is time in bed, measured in minutes over one night, up to 600 minutes. Its planned summary is a mean with standard deviation. Deep sleep and light sleep are listed as secondary outcomes. Five outcome measures are recorded, but no analyses are listed. The registry record does not report a statistical analysis plan, a sample-size justification, or details of interim analyses. The study status is completed, but completion alone does not establish that results were analyzed or posted.
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 | Jawbone/Withings Sleep Trackers, Bodymedia Sensewear |
|---|---|
| STARTED | 36 |
| COMPLETED | 22 |
| NOT COMPLETED | 14 |
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 | Jawbone/Withings Sleep Trackers, Bodymedia Sensewear |
|---|---|---|
| Participants analysed | 22 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 18 |
| Age, Categorical: >=65 years | Participants | 4 |
| Age, Continuous | years | 53 (SD 13) |
| Sex: Female, Male: Female | Participants | 5 |
| Sex: Female, Male: Male | Participants | 17 |
| Race and Ethnicity Not Collected | Participants | — |
6. Primary Endpoint
The registry lists the primary outcome as Time in Bed, measured over one night (up to 600 minutes).
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | min |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is time in bed, expressed in minutes. The registry description defines it as time spent in bed during the night and gives a timeframe of one night, up to 600 minutes. The stated summary measure is the mean, with standard deviation as the measure of dispersion.
Time in bed is relevant to this measurement question because the study aims to determine whether consumer devices and a research actigraph can measure sleep parameters in people with obstructive sleep apnea syndrome. A duration measure gives a direct quantity that can be compared across device readings and the polysomnography reference. However, a mean and standard deviation describe the distribution of a measurement; on their own, they do not show how close device readings are to the reference for individual participants.
General statistical context: For a device-validation study, the interpretation depends on the comparison method and the intended use of the device. Average difference can describe systematic over- or underestimation, while measures of agreement can describe how widely individual paired readings differ. Correlation alone would not establish close agreement. These are general principles, not methods reported for this study. The registry record does not report the observed mean, standard deviation, paired differences, agreement estimates, or confidence intervals for time in bed.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a study intended to compare consumer sleep trackers and a research actigraph with classical polysomnography in patients with obstructive sleep apnea syndrome. It identifies time in bed as the primary outcome and deep sleep and light sleep as secondary outcomes. Those details establish the measurement question, but they do not establish what the devices measured or how closely their readings matched the reference.
No primary or secondary outcome results are reported in the registry record. In particular, there is no reported mean time in bed, standard deviation, device-specific estimate, difference from polysomnography, confidence interval, or test result. The registry record lists no analyses. It is therefore not possible to describe whether readings tended to be higher or lower than the reference, whether device readings varied substantially between participants, or how precisely any agreement estimate was determined.
General statistical context: Accuracy is not a single property with a universal interpretation. An average difference near zero may coexist with large differences for individual readings. Conversely, a measure of association can be high even when readings are systematically offset. For practical interpretation, the acceptable amount of disagreement depends on the intended use and prespecified criteria. Such criteria and the analysis approach are not reported in the registry record, so there is no basis to classify a device as acceptable or unacceptable from the record.
The study is single group, with allocation recorded as NA and no masking. The described approach adds measurement devices to classical polysomnography rather than assigning participants to treatment arms. This supports framing the question as a comparison of measurements, but the record does not specify whether the measurements were paired for every participant or how missing readings were handled. Those details affect the interpretation of any device-to-reference comparison.
The enrollment is 36, but the registry record does not report how many participants contributed data to each outcome or device comparison. The safety figures list 22 participants at risk for the serious and other adverse-event categories in the recorded group, but that count does not supply an outcome-analysis denominator. It should not be substituted for the enrolled population or assumed to be the number with complete measurement data.
The record includes planning-illustration assumptions based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. These are planning illustrations, not the trial's actual single-group design or evidence of observed power. The record does not report a trial-specific sample-size justification. Because no numerical accuracy estimates or analysis results are reported, no conclusion about device performance follows from the registry record.
9. Statistical Methods Explained
What does the listed summary measure describe?
The primary endpoint is a continuous measurement: time in bed in minutes. The registry record specifies a mean and standard deviation. General statistical context: The mean describes the center of a set of measurements, while the standard deviation describes how dispersed the measurements are around that center. These summaries can describe readings within a device or participant group, but they do not by themselves quantify agreement between a tracker and polysomnography.
For a device comparison, the relevant data are usually paired readings: a tracker reading and a reference reading associated with the same participant and measurement period. A paired difference can show the direction and size of disagreement. A confidence interval around an estimate describes the range of values compatible with the data and model, reflecting statistical precision. The registry record does not report paired differences or confidence intervals, and it does not say which agreement method was planned or used.
Why distinguish association from agreement?
General statistical context: Two methods may rank participants similarly while giving readings that differ systematically. Association describes how measurements vary together; agreement asks how close the readings are in the units of measurement. If the purpose is to assess whether a consumer tracker can stand in for a reference measurement, an agreement-focused analysis is usually more directly informative than correlation alone. A small average discrepancy does not ensure close agreement for each individual, so the spread of paired differences matters as well.
These principles explain what an analysis could address, but they should not be mistaken for the method used in this study. The registry record does not report a correlation analysis, a paired-difference analysis, limits of agreement, an equivalence margin, or an acceptance threshold. It does not report whether measurements were adjusted for participant characteristics or recording conditions.
What does the single-group design imply?
The study is recorded as single group, with allocation NA and no masking. The described design adds consumer trackers and a research actigraph to classical polysomnography. General statistical context: In a measurement study, comparing devices within the same participants can reduce variation due to differences between people, provided readings are appropriately paired. The registry record does not specify whether every participant contributed readings from every device, so complete pairing should not be assumed.
This design is distinct from a randomized comparison of treatments. There are no treatment-arm effects to interpret from the listed design. The central issue is whether measurements from one device agree sufficiently with the reference for the intended measurement purpose. The registry record does not state a prespecified definition of sufficient agreement.
How should precision and planning illustrations be read?
General statistical context: Precision concerns the uncertainty around an estimate, often conveyed by a confidence interval. A narrow interval indicates greater precision under the analysis assumptions than a wide interval, but precision does not establish that the estimate is unbiased or clinically useful. An estimate may be precise yet show systematic disagreement with the reference.
The record's planning illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is stated as a fraction of the observed effect. The record also distinguishes total events for time-to-event settings from participants per arm for other settings. These are planning conventions, not a report of this study's design. This study is recorded as single group, and no trial-specific sample-size justification is reported in the registry record. Any resulting sample-size scenario is an illustration and must not be read as observed power or as evidence that the study had a particular ability to detect an effect.
What analysis details are absent?
The registry record lists five outcome measures but no analyses. It does not report the model, estimator, hypothesis test, confidence-interval method, or missing-data procedure. It also does not state whether the primary outcome was analyzed for all enrolled participants, only participants with valid recordings, or another analysis population. The descriptive endpoint specification therefore cannot be expanded into a complete statistical analysis plan.
General statistical context: Agreement can vary across the measurement range, and repeated observations can require methods that account for within-participant dependence. If observations are incomplete or invalid, the analysis can also depend on why they are missing and whether missingness differs across devices. These considerations are relevant to device studies generally; the registry record does not report how they were addressed in this study.
10. Multiplicity, Missing Data and Analysis Populations
The registry record names time in bed as the primary outcome and deep sleep and light sleep as secondary outcomes. It also records five outcome measures, but lists no analyses. No multiplicity procedure, testing hierarchy, or adjustment for multiple comparisons is reported in the registry record. Without the analysis details and results, it is not possible to determine whether or how the outcome measures were analyzed together.
General statistical context: Examining multiple outcomes or several device comparisons can increase the chance of observing an apparently notable result by chance if each is tested separately. A prespecified primary outcome and a declared testing strategy can help clarify which findings are confirmatory and which are exploratory. The record identifies the primary endpoint but does not report a plan for controlling multiplicity across device comparisons or outcomes.
Missing-data procedures are also not reported in the registry record. It does not state how failed recordings, incomplete device data, or participants without a usable polysomnography measurement were handled. Nor does it report the number of complete observations for each outcome. These omissions matter because measurement comparisons generally rely on paired readings, and exclusions or incomplete pairs may affect both the estimated agreement and its precision.
The registry record does not identify an intention-to-treat or per-protocol analysis population. Such treatment-trial labels may not map neatly to a single-group measurement study, but the record still needs to define who contributed data to each analysis for results to be interpreted. That population definition is not reported.
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 |
|---|---|---|---|
| Jawbone/Withings Sleep Trackers, Bodymedia Sensewear | 0 | 22 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Jawbone/Withings Sleep Trackers, Bodymedia Sensewear | 0 of 22 |
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 |
|---|---|
| Jawbone/Withings Sleep Trackers, Bodymedia Sensewear | 0 of 22 |
The adverse-event record lists one combined group titled Jawbone/Withings Sleep Trackers, Bodymedia Sensewear. It records 22 participants at risk for serious adverse events and 0 affected, with 22 at risk for other adverse events and 0 affected. Deaths are recorded as 0. No serious adverse-event terms are listed.
These figures describe the safety entries in the registry record; they are not a measurement-accuracy result. The record does not explain why the adverse-event denominator is 22 when enrollment is 36, nor does it report whether the same participants were included across the categories. The listed figures should therefore be read with their recorded at-risk counts, not treated as complete follow-up information for all enrolled participants.
General statistical context: A count of zero observed events does not prove that an event is impossible or that no unrecorded event occurred. Interpretation depends on the observation period, event definitions, and completeness of reporting. Those details are not reported in the registry record. The adverse-event entries alone do not establish broader safety conclusions.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a completed, single-group study was intended to assess consumer sleep trackers and a research actigraph against classical polysomnography in patients with obstructive sleep apnea syndrome. It specifies time in bed as the primary endpoint and deep sleep and light sleep as secondary outcomes. These details identify a relevant measurement question: whether consumer-level devices can capture sleep parameters in this population in a way that corresponds with the stated reference measurement.
The record does not report the numerical outcome findings or statistical analyses. Consequently, it does not show the size or direction of any difference between tracker readings and polysomnography, the variability of those differences, or the precision of an agreement estimate. It also does not report a threshold for acceptable measurement agreement. No conclusion that a device is accurate, inaccurate, or interchangeable with polysomnography can be drawn from the registry record alone.
General statistical context: Agreement depends on the intended use. A device used for broad personal feedback may be judged against different requirements from a device used to support clinical or research decisions. The study description does not specify an acceptable-error margin or an intended-use threshold. Even complete numerical results would need to be read alongside those criteria and the analysis methods.
The record also does not provide enough detail to assess which participants contributed to each comparison, how missing readings were handled, or whether every device was tested under comparable recording conditions. Those limitations constrain interpretation independently of the absence of results. The study's completion status and enrollment count describe the record, not the size or reliability of any observed device effect.
In short, the registry record documents the planned measurement question and some design features, but it does not document the evidence needed to answer that question. The safety counts are separate from device accuracy and do not fill the gap in outcome reporting.
13. Why This Trial Matters Statistically
Consumer sleep trackers are designed to make sleep information accessible outside specialist testing. For clinical and research settings, the practical question is not simply whether a device produces a sleep-related number; it is whether that number is sufficiently consistent with an appropriate reference for its intended use. A study in people with obstructive sleep apnea syndrome is relevant because the registry record explicitly identifies this population as the setting for the measurement comparison.
The study's design places consumer devices and a research actigraph alongside classical polysomnography. This makes the work a device-measurement assessment rather than a randomized treatment trial. That distinction matters statistically: the central evidence would be the size and precision of discrepancies between measurement methods, not a treatment-group contrast.
General statistical context: Measurement studies can expose differences between a device's average reading and its individual-level agreement with a reference. They can also show whether uncertainty is small enough for a particular use. These insights require clearly described paired data, analysis methods, and criteria for acceptable agreement. The registry record does not report those analyses or criteria, so the statistical importance of the question should not be mistaken for evidence of a particular result.
The record is also a reminder that registering a study and reporting its purpose do not substitute for reporting findings. Enrollment, completion status, outcome definitions, and safety counts help describe what was recorded, but they do not show how closely the devices measured time in bed. For readers assessing the evidence, the absence of posted outcome analyses is itself an important limitation on what can be concluded.
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 principal limitation for interpreting this study is that the registry record does not report results for the primary endpoint or any statistical analyses. There are no reported device-specific time-in-bed estimates, differences from polysomnography, uncertainty intervals, or agreement measures. The record therefore cannot answer its stated measurement-accuracy question.
The measurement protocol is incompletely described. The record says that the trackers and research actigraph were added to classical polysomnography, but does not report whether all devices were used by each participant, the exact recording and synchronization procedures, or criteria for valid data. The analysis population and the handling of incomplete or failed recordings are also not reported. These details are important for understanding whether comparisons are paired and representative.
The record identifies a single-group design, allocation NA, and no masking. It does not report a prespecified agreement threshold, a statistical analysis plan, or a sample-size justification. Although planning illustrations are described, those are not the trial's design and should not be treated as evidence of observed power. The record also lists five outcome measures but no analyses, leaving multiplicity handling and the relationship between primary and secondary findings unclear.
Enrollment is 36, while the adverse-event record lists 22 participants at risk in the recorded group. The registry record does not explain this difference or report outcome-specific denominators. The available safety counts should not be assumed to describe the measurement-analysis population.
Finally, the study summary names specific devices and one population, but the registry record does not report enough findings to assess applicability beyond that setting. Without numerical results and methodological detail, neither device performance nor generalizability can be evaluated from the record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Reliability of Consumer Sleep Trackers in Patients Suffering From Obstructive Sleep Apnea Syndrome — NCT02967367.
- Registry record last updated 2020-03-24; status last verified 2019-02.
- Results first posted 2020-03-24.
- 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
This completed, single-group study concerns consumer sleep trackers in patients with obstructive sleep apnea syndrome. Enrollment is recorded as 36. Jawbone and Withings trackers and the BodyMedia SenseWear research actigraph were added to classical polysomnography to assess sleep measurement accuracy. Allocation is NA and masking is recorded as none.
The primary endpoint is time in bed in minutes over one night, up to 600 minutes, summarized as a mean and standard deviation. Deep sleep and light sleep are listed as secondary outcomes. The registry record lists five outcome measures and no analyses. It does not report primary or secondary outcome results, a statistical analysis plan, or a sample-size justification. Safety entries list 0 serious adverse events, 0 other adverse events, and 0 deaths among the recorded at-risk counts of 22.