Evaluation of Sleep Mode Within the Respironics SimplyGo Portable Oxygen Concentrator: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of Sleep Mode Within the Respironics SimplyGo Portable Oxygen Concentrator (NCT01679301), a randomized na study. The primary outcome is Oxygen Saturation Values Obtained From Pulse Oximetry.

2. Clinical Question

3. Trial Design

This was a randomized, unmasked crossover study at a single site, as described in the brief summary and registry design fields. Participants were assigned to a sequence: one oxygen-delivery mode during the first part of the night, followed by the other mode during the second part. The two modes were continuous dose and pulse dose, also called sleep mode, delivered with the SimplyGo Portable Oxygen Concentrator. Because each participant was intended to experience both modes, the design differs from a study in which separate groups remain on separate treatments.

The registry lists an enrollment of 11. The brief summary states that the study aimed to enroll a maximum of 30 participants to allow for 20 completed data sets. It does not say how many participants completed both parts, or whether the target for completed data sets was reached. The study is listed as completed, with a start date of 2012-09 and a primary completion date of 2014-07. These dates describe the registry record; they do not supply information about the timing or completeness of individual measurements.

Randomization is reported, but the sequence-generation procedure, allocation concealment, and the way the order was implemented are not reported in the registry record. The record also does not describe a washout period, the duration of either mode, or how measurements from each part of the night were summarized. Those details matter when interpreting a crossover because results can depend on order, period, and the relationship between measurements from the same participant. No specific handling of those issues can be inferred.

The registry lists one primary outcome measure and zero analysis entries. The study’s planned comparison is understandable from the endpoint description, but the posted record does not give a single numerical result for that comparison. The tables and plots elsewhere on the page should be read alongside that limitation: they cannot replace an outcome estimate that the registry record does not report.

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.

Screening Period

Reasons for not completing this period:

Study Period

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: 11 participants were consented for the trial, after consent 3 were found to be not eligible and 8 continued into the trial and completed.

6. Primary Endpoint

The registry lists the primary outcome as Oxygen Saturation Values Obtained From Pulse Oximetry, measured over Day 1.

The primary endpoint is described as oxygen saturation values obtained from pulse oximetry, summarized as a mean. The unit is percentage of oxygen saturation, or SpO2, and the stated timeframe is Day 1. The registry’s description frames the endpoint as a comparison of average oxygen saturation while participants were sleeping on continuous flow oxygen versus sleep mode.

Pulse oximetry provides a measure of oxygen saturation. As a general statistical point, a mean can summarize the typical level of a continuous measurement over a specified set of readings or period. The meaning of that summary depends on how readings were collected, which readings were included, and how the period was defined. The registry record does not describe those measurement details beyond identifying pulse oximetry, a mean, the oxygen saturation unit, and Day 1.

Comparing saturation between oxygen-delivery modes addresses whether the measured average differs across those conditions in this study. That is the question the endpoint is suited to describe; it does not, by itself, answer every question about night-time oxygenation or other outcomes. The registry does not report a single mode-specific mean, standard deviation, difference, confidence interval, or test result. It also does not give a reduced single comparison for this endpoint. Consequently, the endpoint’s intended measurement is clear, but its numerical result and precision cannot be assessed from this registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What the design implies in general

In a crossover study, the same participant receives more than one condition, here continuous dose and pulse dose sleep mode. This can be useful for a comparison of measurements that vary substantially between people: each participant can serve as their own reference. In general, an analysis can compare the two measurements within each participant, which accounts for the fact that readings from one person are related. This is different from comparing two independent groups as if no participant contributed under both conditions.

The design description says participants switched modes between the first and second parts of the night. That establishes an order and a sequence, but it does not specify the statistical method. The analysis might need to consider whether measurements differ by period or sequence, and whether exposure to the first mode could influence measurements in the later period. These are general considerations for crossover designs, not claims about what occurred in this study. The registry record does not report how these considerations were evaluated or handled.

What a mean and standard deviation describe

The endpoint is a mean of a continuous measurement: oxygen saturation from pulse oximetry, expressed as percentage of oxygen saturation (SpO2). In general, a mean summarizes the central level of observed measurements. A standard deviation describes how dispersed individual observations are around their mean. It is not the same as uncertainty in a treatment comparison. To understand a mode contrast, readers would need the reported summaries and a method that reflects the crossover design and the amount of paired information.

The registry specifies standard deviation as the dispersion measure but does not give the values. It also does not define precisely which pulse-oximetry readings were aggregated into each mean, how many readings contributed, or whether the reported mean would be calculated per participant or over readings pooled across participants. Such details affect the interpretation of a mean and the appropriate analysis. They are not reported in the registry record.

Estimates and uncertainty

In general, an estimated difference summarizes the direction and size of a contrast, while a confidence interval conveys the range of values compatible with the data and analysis assumptions. A confidence interval is not a guarantee that the true value lies within its endpoints; it is a measure of statistical uncertainty under the method used. A p-value, when reported, addresses compatibility of the data with a specified null hypothesis under an analysis model. Neither a p-value nor a confidence interval alone explains clinical relevance.

For this trial, the registry record does not provide a treatment contrast, confidence interval, or p-value for the primary endpoint. It therefore does not permit an assessment of statistical precision or evidence against a null hypothesis. The outcome description alone cannot be used to reconstruct those results. There are zero analysis entries, and the registry indicates that the primary outcome has several categories or time points and was not reduced to a single comparison.

Randomization and masking

Randomization assigns treatment order by chance and can help reduce systematic differences in assigned sequences. The record labels the allocation randomized, but does not report the sequence-generation or allocation-concealment procedures. It lists masking as none. In general, lack of masking can influence behavior, measurement, or assessment depending on the outcome and how measurements are collected. Pulse oximetry is a device-based measurement, but the registry does not describe who operated it, whether data were reviewed without knowledge of mode, or what steps were used to limit measurement or recording bias. No conclusion about the practical effect of unmasked conduct can be made from the record alone.

Sample-size planning is not observed evidence

The brief summary describes a maximum enrollment of 30 to allow for 20 completed data sets. This is a stated study aim, not a reported justification for the sample size and not evidence that the intended number of completed data sets was achieved. The registry record does not report a formal sample-size rationale, assumed treatment difference, variability assumption, or statistical power target for the original study. It also does not report how many participants posted usable paired measurements.

General planning illustrations based on an observed effect, where shown elsewhere on the page, are not the trial’s original design justification and are not observed power. Such illustrations depend on assumptions and should not be interpreted as results. In this record, no primary endpoint estimate is available to support a numerical assessment of the observed contrast. Any planning display should therefore be read as a separate, assumption-based exercise rather than a substitute for the missing outcome analysis.

What is not stated

The registry record does not state the statistical model, whether analysis was paired, the approach to sequence or period effects, the handling of incomplete crossover data, or the confidence-interval method. It does not report interim analyses or a detailed analysis plan. These omissions prevent verification of how the design was translated into an analysis. General methodological explanations can clarify what such choices mean, but they cannot establish which choices this study used.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome measure, but its description includes several categories or time points and the record does not reduce it to one comparison. It also lists zero analysis entries. The record therefore does not identify a single primary contrast with a reported estimate and uncertainty. Although only one outcome measure is listed, the presence of multiple categories or time points can create more than one possible comparison. The registry does not report how those comparisons were prioritized or whether any multiplicity adjustment was planned or used.

In general, multiplicity arises when several hypotheses or comparisons are considered. Looking across multiple comparisons can make an isolated result harder to interpret unless the analysis plan explains which result is primary or how error rates are handled. This is a general concern, not evidence that any particular adjustment was needed or performed in this study. A multiplicity strategy is not reported in the registry record.

The record also does not report missing-data procedures or define the analysis population. It does not say how many participants completed both modes, how many contributed a primary endpoint measurement, or how incomplete measurements were handled. The stated enrollment of 11 and the planned maximum of 30 to allow for 20 completed data sets do not establish the number included in an outcome analysis. The safety record’s at-risk counts are not a substitute for an endpoint analysis population.

In general, missing measurements can affect a crossover comparison if participants with incomplete data differ from those with complete data, or if missingness is related to treatment, sequence, or outcome. Without the analysis population and missing-data method, readers cannot determine whether the reported record would represent all enrolled participants or only a subset. Here, no such analysis result is reported, so those questions remain unresolved.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

The registry safety record lists 8 participants at risk in the Continuous Dose group and 8 at risk in the Pulse Dose (Sleep Mode) group. It reports zero serious adverse events in each group and zero deaths in each group. The listed counts for other adverse events are also zero in both groups. The record supplies no serious adverse event terms.

These figures should be read as the counts recorded in the safety table, not as a complete account of safety under every possible definition or observation period. The registry does not explain the safety collection window, event definitions, or how the group denominators relate to crossover exposure. Since both modes were planned for participants in a crossover, group labels in the safety table should not automatically be interpreted as separate sets of people exposed only to one mode.

The safety table’s 8 at-risk participants in each group do not match the recorded enrollment of 11, and the registry does not explain the relationship between these counts. They should not be used to infer how many participants completed the primary endpoint. Zero recorded events in these entries means no events are listed in those cells; it does not establish that no adverse events of any kind occurred outside the reported categories or observation period. These safety counts do not answer the primary oxygen-saturation comparison.

12. What the Result Does, and Does Not, Mean

The record supports a clear description of the intended question: in a randomized crossover study, participants were to receive continuous-dose oxygen and pulse-dose sleep mode during different parts of the night, with mean pulse-oximetry oxygen saturation on Day 1 as the primary endpoint. It also records an enrollment of 11 and identifies the study as completed. These registry entries describe the design and registry status, not the result of the primary comparison.

The record does not report the numerical outcome comparison in a single form. It provides no mode-specific primary endpoint means, no contrast, and no estimate of uncertainty. Accordingly, the posted record cannot establish the direction or size of a difference, how precise any estimated difference was, or whether an analysis found evidence against a null hypothesis. It would be incorrect to interpret the missing summary as showing equivalence, no difference, or a favorable result for either mode.

Even if a numerical mean difference were available, a statistical comparison would need to be interpreted in light of the crossover structure, the measurement period, and the amount of complete paired data. Those details are not reported in the registry record. The record also does not provide participant characteristics or enough outcome information to assess how broadly the findings might apply beyond the study setting.

The safety entries list zero serious adverse events and zero deaths in each group among 8 participants at risk per group. These entries are limited to the recorded safety fields and do not fill the gap in the primary endpoint results. They should not be treated as proof that no adverse events occurred under all definitions or observation conditions.

In short, the registry record documents a planned comparison and some safety counts, but it does not present the primary endpoint analysis needed to interpret what the observed oxygen-saturation data showed. The appropriate conclusion is about the limits of the available record, not about which oxygen mode produced a higher or lower saturation measurement.

13. Why This Trial Matters Statistically

This study is statistically instructive because its design is a crossover: the same participants were scheduled to experience both oxygen-delivery modes during one night. In general, crossover designs can make within-person comparisons possible, which may help separate differences between modes from stable differences between participants. They also require careful attention to order, period, and the relationship between repeated measurements. The registry makes the treatment sequence structure visible but does not report how the analysis addressed those features.

The record also illustrates why a named primary endpoint is not the same as a reported primary result. It identifies mean oxygen saturation, the measurement method, unit, and timeframe. Yet the outcome is not reduced to one comparison, and there are zero analysis entries. Readers can understand what the study set out to measure without being able to assess the result or its precision.

Enrollment information raises a separate interpretive issue. The registry records 11 participants, while the brief summary describes a maximum of 30 intended to allow for 20 completed data sets. The record does not state the number of completed paired data sets or the reason for the difference between the aim and recorded enrollment. For a crossover, knowing how many participants contributed measurements under both conditions is particularly useful for understanding the information behind a paired estimate.

Finally, the safety figures demonstrate the importance of checking the denominator and the study structure before comparing counts. Both safety groups list 8 at-risk participants even though the study is described as a crossover and total enrollment is 11. The registry does not explain those counts, so they should not be treated as a straightforward comparison between independent groups. These features make the record useful for teaching how design, outcome reporting, and analysis transparency shape what statistical conclusions can be drawn.

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 central limitation for interpreting this trial from the registry record is that the primary endpoint is not presented as a single numerical comparison. The endpoint description states what was measured, but the record supplies no means, standard deviations, contrast, confidence interval, or test result. It also states that the primary outcome has several categories or time points and was not reduced to one comparison. Without a summarized result, the observed direction and precision cannot be evaluated.

The record reports an enrollment of 11, while the brief summary describes a maximum of 30 to allow for 20 completed data sets. It does not report how many participants completed both modes or contributed usable paired measurements. This makes it impossible to determine the endpoint analysis population from the record. The safety table lists 8 at risk in each group, but the relationship between those counts and the enrolled or completed participants is not explained.

Important design and analysis details are also absent. The registry does not describe the randomization procedure, allocation concealment, measurement schedule in detail, statistical model, handling of sequence or period effects, or method for incomplete crossover observations. It does not report a detailed analysis plan, interim analyses, or a formal sample-size justification. These omissions do not show that the study lacked such procedures; they mean they are not reported in the registry record.

The single-site description and the lack of participant characteristics further restrict what can be learned about the study population from this record. The masking field says none, but the registry does not explain who collected or reviewed the pulse-oximetry measurements. Finally, the safety entries report counts without event terms or a stated observation window. Taken together, these limitations concern both the missing primary result and the limited detail available to assess how the study was conducted and analyzed.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Evaluation of Sleep Mode Within the Respironics SimplyGo Portable Oxygen Concentrator — NCT01679301.
• Registry record last updated 2018-11-16; status last verified 2018-10.
• Results first posted 2018-11-16.
• 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.

18. Record Summary

The registry record describes a completed, randomized, unmasked crossover study at a single site comparing continuous-dose oxygen with pulse-dose sleep mode using the SimplyGo Portable Oxygen Concentrator. Participants were scheduled to switch modes between the first and second parts of the night. Recorded enrollment is 11; the brief summary states a maximum aim of 30 participants to allow for 20 completed data sets.

The primary endpoint is mean pulse-oximetry oxygen saturation (SpO2) on Day 1. The registry does not report a single comparison or numerical analysis result, and it lists zero analysis entries. The safety record lists zero serious adverse events and zero deaths in each group, with 8 participants at risk per group. The relationship between those safety counts and the enrolled or completed study population is not explained.