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 PMP-300E (Smart Watch): Portable Monitoring Device Study (NCT01364740), a na phase 3 study. The primary outcome is AHI.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01364740 |
| Phase | Phase 3 |
| Condition | Obstructive Sleep Apnea |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 10 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Stanford University |
| Results posted | Yes |
2. Clinical Question
Population
The condition listed is obstructive sleep apnea. The registry record does not report participant eligibility criteria or further describe the study population.
Intervention
The PMP-300E is described as a Level 3 portable monitor with seven channels for measuring sleep-related breathing and related signals.
Comparator
The stated reference method is conventional in-lab polysomnography, described as the gold-standard sleep study. This is a measurement comparison, not a randomized treatment-control comparison.
Primary question
The primary endpoint is the Apnea-Hypopnea Index (AHI), defined as events per hour of sleep, measured over one night. The study asks how the portable monitor’s measurement relates to the in-lab measurement; the registry record does not report the comparison results.
The registry record frames the study as validation of a portable monitoring device for identification of obstructive sleep apnea. Its listed primary outcome, AHI, counts apnea and hypopnea events relative to sleep time. The description specifies that hypopneas were scored without EEG arousals, a detail that matters when interpreting which events contribute to the index.
The record lists both PMP-300E and in-lab PSG in the single group description. It does not describe a randomized allocation, masking, or a separate treatment-control arm. The clinical question is therefore about measurement against a reference method, rather than whether one treatment changes a health outcome relative to another. The record does not report a threshold for diagnosis, a sensitivity or specificity analysis, or an estimate of agreement between methods. It also does not give the actual AHI values from either method. Consequently, the registry information establishes the intended question and endpoint, but it does not establish how closely the methods agreed or how well the device identified the condition.
3. Trial Design
This is a completed Phase 3 device study sponsored by Stanford University. The registry record lists enrollment of 10 and a single-group model. Allocation is recorded as NA, and masking is recorded as none. Those entries are consistent with a study organized around device validation rather than randomized allocation to competing treatment arms. The group description lists PMP-300E and in-lab polysomnography together, with the portable monitor to be tested against conventional in-lab PSG.
The PMP-300E is described as a Level 3 portable monitor with nasal pressure, effort, snoring, oxygen saturation (SpO2), pulse rate, body position, and movement channels. In-lab PSG is identified as the reference sleep study. The primary outcome timeframe is one night. The registry dates the study start as 2008-06 and primary completion as 2012-05, and reports its status as completed.
The design information does not establish exactly how the measurement comparison was analyzed. The record does not report whether each participant had usable measurements from both methods, how recordings were synchronized or scored, or how discrepancies between readings were handled. It also does not give the exact analysis population or describe participant flow. These details affect interpretation: a comparison of measurements from the same people calls for different uncertainty calculations from a comparison of independent groups, and missing or technically unusable recordings can affect which observations enter an analysis. The registry does not specify these procedures.
There is no like-for-like randomized control comparison in the record. In-lab PSG is a reference measurement, not a treatment arm assigned to estimate a causal treatment effect. The enrollment figure describes the planned or recorded study enrollment; it does not, on its own, establish how many participants contributed to the primary endpoint analysis.
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 | SmartWatch PMP-300E |
|---|---|
| STARTED | 10 |
| COMPLETED | 10 |
| NOT COMPLETED | 0 |
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 | PMP-300E, In-Lab PSG |
|---|---|---|
| Participants analysed | 10 | |
| Age, Customized: Men | years | 54.3 (SD 15.46) |
| Age, Customized: Women | years | 56.8 (SD 14.24) |
| Gender: Female | Participants | 4 |
| Gender: Male | Participants | 6 |
| Body Mass Index: Men | kg/m^2 | 29.5 (SD 9.54) |
| Body Mass Index: Women | kg/m^2 | 30.8 (SD 11.76) |
| Epworth Sleepiness Scale score | units on a scale | 6.9 (SD 5.61) |
6. Primary Endpoint
The registry lists the primary outcome as AHI, measured over One night.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | events/hour |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is AHI, the Apnea-Hypopnea Index, measured in events per hour of sleep over one night. It expresses the frequency of scored apnea and hypopnea events relative to sleep time. The outcome description specifies that hypopneas were scored without EEG arousals. That scoring convention defines which events are counted and can affect the resulting index.
The registry specifies a mean as the summary parameter and standard deviation as the dispersion measure. In general, a mean describes the central value of a continuous measurement, while a standard deviation describes how much measurements vary around that mean. These summaries can characterize AHI values, but by themselves they do not tell whether the portable monitor and PSG agree for individual participants. For a measurement-validation question, the comparison itself is central: readers need an estimate of the difference or agreement between methods, together with its uncertainty, to judge the precision of the evidence.
AHI is used as an index of the frequency of breathing events during sleep, making it relevant to a study intended to identify obstructive sleep apnea. That general role does not establish a diagnostic cutoff or show that the portable device classifies participants correctly. The registry record does not report a cutoff, AHI means, standard deviations, method differences, confidence intervals, or classification results. Thus, it identifies what the study set out to measure, but not the observed performance of the device.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record reports the study purpose, design, and primary endpoint, but it does not report the numerical primary outcome results. No AHI mean or standard deviation is listed for either PMP-300E or in-lab PSG. There is also no reported estimate of the difference between methods, confidence interval, test statistic, or p-value. Without those results, the direction, size, and precision of the observed measurement comparison cannot be assessed.
This absence is particularly important for a validation study. A difference in average AHI between methods would describe an overall tendency, but average similarity alone would not show whether readings were close for individual participants. Agreement methods can examine both systematic differences and the spread of individual discrepancies. The registry record does not report those analyses, so it cannot establish whether the device readings tracked PSG closely across the observed range.
Enrollment is listed as 10. That figure should not be treated as the number analyzed for AHI: the registry does not report the endpoint analysis population, missing measurements, exclusions, or the number of usable paired recordings. Nor does the record explain whether the study’s results were analyzed as paired measurements. If the same participants contribute measurements from both methods, the within-person relationship is relevant to uncertainty; treating such observations as independent would not account for that relationship. The actual analytical approach is not reported.
The record lists five outcome measures and four analyses. A primary outcome is identified, along with secondary outcomes named as Apnea Index, Hypopnea Index, and Oxygen Saturation. The record does not describe the fourth analysis or the remaining outcome measure by name. It also does not say whether any adjustment for multiple testing was used. The missing analysis details limit interpretation of both the primary and secondary findings.
The sample-size planning assumptions describe an illustration based on the observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. These assumptions are not a report of the study’s own design justification, and the illustration is not observed power. The registry record does not report a sample-size justification or the observed effect needed to interpret such planning figures. In the absence of reported effect estimates and uncertainty, no conclusion about the magnitude or precision of the device-versus-PSG comparison follows from the design information alone.
9. Statistical Methods Explained
The statistical information in the registry record is limited. It identifies a continuous primary outcome summarized as a mean with standard deviation, but it does not report the analysis model, the comparison estimate, or its uncertainty. The descriptions below are general statistical explanations; they should not be read as claims about methods actually used in this study.
What does a mean and standard deviation describe?
For a continuous measure such as AHI, the mean is an average that describes the center of the observed values. The standard deviation describes spread among values around that center. A mean and standard deviation can help describe a group’s AHI distribution, but these summaries alone do not quantify how well one measurement method corresponds to another. Two methods could have similar average values while differing substantially for particular individuals. Conversely, individual differences may be small even where a small average offset exists. The registry specifies these summary measures but gives no observed values.
Why does the measurement structure matter?
In general, when two methods are applied to the same participants, each participant’s readings are related. A paired analysis uses the within-participant comparison and accounts for that relationship. An analysis of independent groups makes a different assumption and uses a different uncertainty calculation. The registry describes the device as tested against PSG, but does not state whether every participant contributed readings from both methods or specify whether the analysis was paired. The appropriate method therefore cannot be confirmed from the record.
For method comparison, an estimate of the average difference can describe systematic bias. A confidence interval around that estimate conveys uncertainty about the average difference. Agreement analyses can also describe how individual method differences vary, which is distinct from the uncertainty around the mean difference. These are general concepts, not reported results from this study. The registry does not give a difference estimate, confidence interval, limits of agreement, or another agreement statistic.
What does a confidence interval add?
In general, a confidence interval presents a range of values compatible with the data and the specified statistical procedure. Its width communicates precision: a narrower interval indicates more precision under the model, while a wider interval indicates less. A confidence interval should be interpreted in relation to the question and the measurement scale, not simply as a test of whether a difference is statistically significant. No confidence interval for AHI or method agreement is reported in the registry record.
Why can variability and skew matter?
General statistical methods often rely on assumptions about the distribution of observations or residuals. AHI is a nonnegative event-rate measure, and continuous outcomes can have uneven distributions or observations that differ markedly from the center. If data are strongly skewed or contain unusually high values, a mean and standard deviation may not fully describe the pattern. Analysts may consider transformations, robust procedures, or summaries suited to the distribution. The registry record does not report distribution checks or any such methods, so it is not possible to say whether these issues arose or how they were addressed.
Over-dispersion is a general concern when observed variability exceeds what a statistical model assumes. If a model underestimates variability, standard errors can be too small and confidence intervals too narrow. This concept is relevant to statistical modeling broadly, but the registry does not identify a model for the primary endpoint or report an over-dispersion assessment. It should not be inferred that over-dispersion was present.
What can the planning assumptions tell readers?
The record describes sample-size planning illustrations using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The target effect is stated as a fraction of the observed effect. Such calculations are general planning exercises: they show how a hypothetical future design might be sized under the chosen assumptions. They are not observed power, and they do not change the precision of the results from this study. The record does not report a sample-size justification for the study’s own design. Since it does not report the observed effect estimate, readers cannot assess the numerical basis of the illustrations from the registry information.
For a measurement-validation study, planning around an effect alone may not capture every important objective. A future design might be planned around precision of a mean difference or an agreement measure, depending on the intended question. This is general context, not a description of the trial’s protocol. The registry record does not state a target precision or identify the statistical criterion used to judge validation.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists five outcome measures and four analyses. AHI is identified as the primary outcome. The named secondary outcomes are Apnea Index, Hypopnea Index, and Oxygen Saturation. The registry does not name every outcome measure or explain how the four analyses relate to the outcomes.
When multiple outcomes or analyses are examined, the chance of at least one apparently notable result can increase. General approaches include prespecifying a primary analysis, controlling an error rate across tests, or treating secondary analyses as exploratory. Which approach is appropriate depends on the study objectives and analysis plan. The registry record does not report a multiplicity adjustment, a testing hierarchy, or whether secondary findings were considered confirmatory or exploratory. Consequently, the statistical status of any unreported secondary results cannot be assessed.
Missing-data handling is also not reported. The record does not state whether any recordings were incomplete, how unusable signals were defined, whether participants were excluded from particular analyses, or how missing outcomes were handled. These details matter because the observations contributing to an analysis may differ across endpoints. The enrollment figure of 10 does not establish the analysis population for AHI or any secondary measure.
The record does not specify analysis populations, such as whether analyses included all enrolled participants or only those with evaluable recordings. It also does not describe protocol deviations or participant flow. Without these details, readers cannot determine how representative the analyzed measurements were of the enrolled group. These are reporting gaps; they do not establish that missing data, exclusions, or multiplicity problems occurred.
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 |
|---|---|---|---|
| PMP-300E, In-Lab Polysomnography | 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 |
|---|---|
| PMP-300E, In-Lab Polysomnography | 0 of 10 |
The registry lists one group titled PMP-300E, In-Lab Polysomnography. For this group, the serious adverse event figures report 0 affected among 10 at risk, and the other adverse event figures report 0 affected among 10 at risk. These are counts recorded for the listed group; they do not provide information about the nature of possible events beyond the zero counts.
The death figure is recorded as null, which means deaths are not reported in the registry record. It should not be interpreted as a reported count of zero. The record also lists no top serious adverse event terms.
These figures describe what the registry reports for the recorded group. They do not, by themselves, establish that no events occurred outside the registry’s reporting scope, nor do they provide a comparison with another group. Because the listed group combines the PMP-300E and in-lab PSG in its title, the record does not separately attribute adverse events to either measurement method. The safety information should therefore be read as registry reporting, not as a comparative safety analysis.
12. What the Result Does, and Does Not, Mean
The record identifies a completed Phase 3 validation study of the PMP-300E portable monitor against conventional in-lab PSG. It names AHI as the primary endpoint and describes how that endpoint is defined and summarized. This establishes the intended measurement question and the registry’s stated design framework.
It does not establish the observed performance of the portable monitor. The registry record contains no reported AHI results, method differences, confidence intervals, agreement statistics, or diagnostic classification estimates. Without those results, there is no basis in the record for describing the size or direction of a discrepancy, the precision of the comparison, or the extent to which the measurements corresponded for individual participants.
The absence of results in the registry record is not evidence that the device performed well or poorly. Likewise, the recorded enrollment does not by itself establish that the study was adequately powered, and the planning illustrations are not observed power. The record does not provide the protocol’s sample-size justification or the analysis details needed to assess the design’s ability to answer the validation question.
In general, evidence about a measurement device depends on more than a comparison of average values. Readers may need information about systematic differences, individual-level agreement, the range of measurements, missing or unusable recordings, and the statistical uncertainty around estimates. Which analyses are appropriate depends on the study’s prespecified objectives and data structure. The registry does not report these details.
The most supportable interpretation is therefore limited: the registry describes the intended comparison of PMP-300E with in-lab PSG for AHI over one night, but does not report the findings needed to judge the result. This distinction separates the existence and purpose of a validation study from evidence about its outcome.
13. Why This Trial Matters Statistically
This study is statistically important because device validation asks a different question from a conventional treatment trial. The central issue is whether measurements from a portable device correspond sufficiently to a reference method for the intended use. A randomized treatment comparison is designed to estimate differences between assigned interventions; a measurement study instead needs a clear account of how readings compare and how uncertain that comparison is.
AHI is a continuous event-rate measure, and the record specifies a mean and standard deviation as summary statistics. Those summaries are useful for describing values, but measurement validation also raises questions about bias and individual-level agreement. General statistical reasoning distinguishes similarity of group averages from closeness of measurements for each person. This distinction is important when a device is intended to identify a condition, because average similarity alone does not describe classification performance.
The registry provides useful design context: a single group, no masking, and a reference comparison with in-lab PSG. It also identifies the one-night timeframe and the scoring convention for hypopneas. These details define the intended measurement setting. At the same time, absent outcome estimates and analysis details prevent readers from judging the comparison’s precision or practical measurement behavior.
The record’s limitations illustrate why transparent reporting matters in biostatistics. Effect estimates, uncertainty intervals, analysis populations, missing-data handling, and prespecified analysis methods allow readers to distinguish a design description from empirical evidence. For this record, the study purpose is clear, but the reported information is not enough to assess whether the portable and reference measurements agreed.
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 for interpretation is that the registry record does not report the AHI results. No group means, standard deviations, method comparison estimates, or uncertainty measures are available in the record. This prevents assessment of the primary endpoint’s magnitude, direction, or precision.
The record does not describe the statistical model or the exact comparison procedure. Although the portable monitor was to be tested against PSG, it is not clear from the registry information whether each participant contributed measurements from both methods, how paired observations were handled, or how agreement was assessed. The analysis population and participant flow are also not reported. Enrollment of 10 should not be treated as a confirmed endpoint analysis count.
Outcome reporting is incomplete for interpreting multiplicity: the record lists five outcome measures and four analyses but names only three secondary outcomes in addition to AHI. It does not report a testing hierarchy or any adjustment for multiple analyses. Missing-data rules, recording quality criteria, and handling of unusable signals are not reported either.
Finally, the registry does not give a diagnostic threshold, sensitivity, specificity, or other classification performance estimates. The record’s safety figures combine the PMP-300E and in-lab PSG in the group title, and deaths are not reported in the registry record. These limitations describe gaps in the registry information; they do not establish what procedures were used outside the record or what the unreported study results were.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: PMP-300E (Smart Watch): Portable Monitoring Device Study — NCT01364740.
- Registry record last updated 2017-01-27; status last verified 2016-12.
- Results first posted 2017-01-27.
- 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
NCT01364740 is a completed Phase 3 study sponsored by Stanford University. It is listed as a single-group device validation study with enrollment of 10, no masking, and allocation recorded as NA. The study dates are 2008-06 to primary completion in 2012-05.
The study description says the PMP-300E portable monitor was tested against conventional in-lab PSG for identification of obstructive sleep apnea. The primary outcome is AHI, measured in events per hour of sleep over one night; hypopneas were scored without EEG arousals. The registry specifies a mean and standard deviation but does not report the outcome values or comparison analysis.
The listed serious and other adverse event counts are both 0 among 10 at risk in the combined group. Deaths are not reported in the registry record. Overall, the registry describes the study question and design, but does not report results sufficient to assess measurement agreement or device performance.