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 Premie Pouch to Manage Deformational Plagiocephaly in Very Low Birth Weight Infants (NCT03184441), a na na study. The primary outcome is Safety of Use of the Premie Pouch in VLBW Infants.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03184441 |
| Phase | NA |
| Condition | Plagiocephaly |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 11 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Boston Children's Hospital |
| Results posted | Yes |
2. Clinical Question
Population
Prematurely born infants weighing < 1 kilogram, described in the registry as very low birth weight infants. The condition of interest is deformational plagiocephaly.
Intervention
All participants received the Premie Pouch device, an experimental device intended to manage deformational plagiocephaly. The registry describes management as resolving, prohibiting, inhibiting, or preventing development of the condition.
Comparator
There is no comparator group. The record identifies a single-group study and does not report an allocation scheme for a controlled comparison.
Primary question
The registered primary question concerns safety: how many participants had adverse events reported using the Premie Pouch Adverse Event Data Collection Tool, from enrollment to study completion. The recorded timeframe is 19-47 days.
This is a safety and pilot question rather than a comparative treatment-effect question. A single-group record can describe what was reported among participants receiving the device, but it cannot directly contrast those reports with an untreated group or another device. The registry also lists feasibility of use, normal cranial index, normal cranial symmetry, and ease of use as secondary outcomes. Results for those outcomes are not reported in the registry record. The listed safety fields therefore provide only part of the information needed to characterize the registered questions: they describe serious and other adverse-event counts, while the overall primary endpoint analysis is not reported. The record does not establish whether changes in cranial shape occurred, how those changes were measured in practice, or whether any observed changes would be attributable to the device.
3. Trial Design
The registry describes a completed, single-group device study sponsored by Boston Children's Hospital. It lists 11 participants as enrolled. Every participant was assigned to receive the experimental Premie Pouch device; no comparison arm is described. Allocation is recorded as NA, and masking is recorded as NONE. The record identifies the study as a pilot project to develop and test a device intended to manage deformational plagiocephaly in prematurely born infants weighing < 1 kilogram.
The study start is recorded as 2016-06, and primary completion as 2016-08. The status is COMPLETED. The timeframe for the primary safety outcome runs from enrollment to study completion, with a recorded range of 19-47 days. That is a relatively short observation window for describing events during device use; the registry record does not describe follow-up beyond that timeframe.
A single-group design can document whether particular events or outcomes were recorded while participants received the device. It does not create a like-for-like control comparison, because there is no separate group under another condition. Consequently, differences from usual care or from another intervention cannot be estimated from this design. Masking is listed as NONE, so the record does not describe blinded assessment. It does not report further details about how participants were selected, how device use was standardized, or how outcome assessments were scheduled. Those design details are not reported in the registry record.
The registry lists one primary safety outcome and secondary outcomes concerning feasibility, cranial index, cranial symmetry, and ease of use. Although the study is marked completed, completion status alone does not indicate that every listed outcome has a posted result. The primary endpoint analysis and the secondary outcome results are not reported in the registry record. No analysis count is reported there.
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 | Premie Pouch |
|---|---|
| STARTED | 11 |
| COMPLETED | 10 |
| NOT COMPLETED | 1 |
Reasons for not completing this period:
| Reason | Premie Pouch |
|---|---|
| Withdrawal by Subject | 1 |
Analysis population for the primary outcome, as defined in the registry: Participants with adverse events
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 | Premie Pouch |
|---|---|---|
| Participants analysed | 10 | |
| Age, Categorical: <=18 years | Participants | 10 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | days | 17.9 (5 to 38) |
| Sex: Female, Male: Female | Participants | 2 |
| Sex: Female, Male: Male | Participants | 8 |
| Race and Ethnicity Not Collected | Participants | — |
| Region of Enrollment: United States | Participants | 10 |
| Cranial Abnormalities Were Measured at Enrollment | participants | 10 |
6. Primary Endpoint
The registry lists the primary outcome as Safety of Use of the Premie Pouch in VLBW Infants, measured over From date of enrollment to date of study completion (range 19-47 days).
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is titled “Safety of Use of the Premie Pouch in VLBW Infants.” It is defined as the frequency of participants with adverse events reported using the Premie Pouch Adverse Event Data Collection Tool. Its unit is participants, and the registry describes the measure as a number of participants with an event. The observation period extends from enrollment to study completion, recorded as a range of 19-47 days.
A participant count can make the endpoint clinically interpretable as a tally of people for whom an event was recorded, rather than a measure of event severity or duration. A safety endpoint is useful in a pilot because it can identify events requiring further attention and show what was observed during the defined use period. However, interpreting such a count depends on having a clearly reported denominator, event definitions, follow-up completeness, and an account of how events were collected. The registry record does not report an overall primary endpoint result or analysis. The posted safety fields separately give counts for serious and other adverse events, but those fields do not substitute for a reported analysis of the registered primary endpoint. They also do not describe the nature, timing, or clinical course of any events beyond the listed counts.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record supports a limited description of the study design and of the safety counts that are posted. It describes a single-group pilot in which participants received the Premie Pouch. For the safety fields, the registry lists 0 participants with a serious adverse event among 10 at risk, and 0 participants with an other adverse event among 10 at risk. These are counts for the categories recorded in the adverse-event summary. The registry lists 11 enrolled participants, while each safety category lists 10 at risk; the reason for that difference is not reported in the registry record.
The registered primary endpoint is the frequency of participants with adverse events collected using the named tool. An overall result for that endpoint is not reported in the registry record. The posted serious and other event fields should therefore be read as safety-summary entries, not as a complete reported analysis of every component of the primary endpoint. The record does not give confidence intervals, an analysis method, or an explanation of the relationship between the primary endpoint and the two event categories.
In general, a zero count means that no events of the specified type were recorded in the stated at-risk group during the stated observation. It does not establish that the underlying event risk is zero. With a limited amount of observation, uncommon events may not occur in the observed participants even when their true frequency is not zero. A confidence interval can express the uncertainty around an estimated frequency; no such interval is reported for these safety fields. The record also does not report whether all participants completed follow-up or whether event ascertainment was complete.
The absence of a comparator is central to interpretation. The counts cannot show whether the observed event experience differs from what would have occurred without the device or with another approach. The study is not described as randomized, and allocation is listed as NA. The findings are descriptive rather than a controlled estimate of a causal effect. The study's completion status does not fill these evidentiary gaps, and no results for the listed cranial outcomes or feasibility outcomes are reported in the registry record.
Accordingly, the posted data describe zero recorded participants with serious events and zero with other events in the respective reported safety fields, each with 10 at risk. They do not amount to a broad demonstration of safety, do not establish the absence of adverse events of every kind, and do not answer whether the device changes cranial outcomes. The observed counts should be interpreted within the short recorded timeframe, the single-group design, and the incomplete outcome reporting.
9. Statistical Methods Explained
The registry identifies the study as single-group and the primary measure as a number of participants with an event. That makes the endpoint a count-based safety outcome. The information posted does not include a statistical analysis plan, a reported estimate for the overall primary endpoint, or an inferential analysis. The discussion below explains general statistical concepts relevant to this kind of outcome; it does not describe methods as having been used in this study unless the registry record says so.
What does a participant count represent?
For a binary event outcome, each participant is classified according to whether the event occurred during the defined observation period. A count reports how many participants were classified as having the event. A denominator indicates the group in which those participants were assessed or considered at risk. The posted safety fields give 0 affected participants and 10 at risk for each of the serious and other event categories. The enrollment figure is 11, and the registry does not explain why the safety-field denominators are 10. These figures should be kept distinct rather than treated as interchangeable.
A count alone does not communicate uncertainty as fully as an estimate accompanied by an interval. In general, a confidence interval gives a range of values compatible with the data under a statistical model and expresses the imprecision of an estimate. When no events are observed, uncertainty remains: zero observed events does not logically rule out a nonzero underlying event frequency. No confidence interval is reported for the safety fields in the registry record.
Why does the design matter?
In a single-group study, the observed event count describes participants who received the device. There is no concurrent group that provides a direct reference for comparison. General statistical methods can describe a group, but they cannot recover a controlled treatment contrast where the design contains no comparator. Factors that may affect outcomes, including the natural course of a condition or other aspects of care, cannot be separated from device exposure by a within-study control comparison in this design.
Allocation is recorded as NA, masking as NONE, and the model as SINGLE GROUP. These design features constrain what can be inferred, regardless of the statistical method used. Statistical adjustment would require appropriate data and a specified analysis; neither an adjustment plan nor an adjusted result is reported in the registry record. The record also does not report an analysis plan for the primary endpoint.
What is the role of event definitions and follow-up?
Safety summaries depend on the definition of an event, the way events are sought, and the period during which participants are observed. The primary endpoint description names the Premie Pouch Adverse Event Data Collection Tool and gives a period from enrollment to completion, with a range of 19-47 days. The registry does not report the tool's detailed event definitions, the frequency of assessments, or participant-level follow-up completeness. Without those details, readers cannot determine whether event capture was uniform or whether some participants contributed less observation than others.
In general, differences in observation time can affect how event counts are interpreted. A count over a shorter observation may offer fewer opportunities to identify an event than a count over longer observation. The record does not provide person-time or a rate analysis, so the posted safety fields should be read as participant counts, not rates adjusted for time at risk.
What can and cannot be learned from zero observed events?
General statistical reasoning distinguishes an observed sample from the underlying population process. A sample with no recorded events is compatible with a range of possible underlying event frequencies, especially when the amount of information is limited. Larger or longer observations may reduce uncertainty, but no new estimate can be derived from the registry fields alone without selecting and applying a method. No such recalculation is reported, and no numerical interval or modeled risk should be inferred from the counts.
The study's enrollment figure and its safety denominators indicate the scale of the evidence available, but they do not by themselves establish how representative the participants are. The registry record does not provide a sample-size justification, a target enrollment, or a rationale for the number enrolled. It also does not report interim analyses. Those matters should be treated as unreported rather than inferred from the pilot designation.
How should the listed outcomes be considered?
The record lists feasibility, normal cranial index, normal cranial symmetry, and ease of use as secondary outcomes. In general, a prespecified statistical plan can clarify how each outcome is defined, which population is analyzed, and how multiple outcome tests are interpreted. The registry does not report results or analytic details for these outcomes. It is therefore not possible to assess their estimates, precision, or relationship to the safety endpoint from the registry record.
Overall, the available information supports a descriptive reading of the posted safety counts, not a reconstruction of an unreported inferential analysis. The design, observation period, event ascertainment details, denominator discrepancy, and absence of outcome analyses all matter when judging precision and scope.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary safety outcome and secondary outcomes for feasibility of use, normal cranial index, normal cranial symmetry, and ease of use. The record does not report results for the secondary outcomes or a statistical plan for testing them. It also does not report a strategy for handling multiplicity.
In general, multiplicity arises when several outcomes or statistical tests are considered. Repeated testing can make it more likely that at least one result appears notable by chance, even when there is no underlying effect. A prespecified approach can clarify which questions are primary, whether secondary findings are exploratory, and whether any adjustment is planned. That information is not reported in the registry record, so the listed outcomes cannot be treated as a set of confirmed findings.
Missing-data handling and analysis populations are also not reported. The record does not explain whether every enrolled participant contributed to each outcome, how incomplete follow-up was handled, or how the safety denominators relate to enrollment. Enrollment is listed as 11, while the serious and other adverse-event categories each list 10 at risk. The reason is not reported in the registry record. No participant flow or outcome-specific analysis population is described.
These omissions limit assessment of both completeness and precision. They do not establish that data were missing or that a particular analysis population was used; they mean those details are not reported in the registry record.
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 |
|---|---|---|---|
| Premie Pouch | 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 |
|---|---|
| Premie Pouch | 0 of 10 |
The adverse-event summary lists 0 participants with a serious adverse event among 10 at risk and 0 participants with an other adverse event among 10 at risk. These are category-specific participant counts. The registry also lists 11 enrolled participants, and it does not explain why each safety category has 10 at risk. Deaths are not reported in the registry record. Specific serious adverse-event terms are not listed in the record.
In general, a count of zero means no event in that category was recorded among the participants included in the corresponding safety field. It does not prove that the event could not occur, nor does it establish that all types of adverse events were absent. The observation period for the primary safety outcome is from enrollment to completion, with a recorded range of 19-47 days. The registry does not provide confidence intervals, event-level details, or information about completeness of follow-up. These counts should therefore be read as limited descriptive safety information, not as a precise estimate of risk or a comparative safety assessment.
12. What the Result Does, and Does Not, Mean
The trial addresses a practical question: whether the Premie Pouch could be used in a pilot study intended to manage deformational plagiocephaly in prematurely born infants weighing < 1 kilogram. The registry identifies safety as the primary outcome and also lists feasibility, cranial index, cranial symmetry, and ease of use. The posted safety fields report 0 serious adverse events among 10 at risk and 0 other adverse events among 10 at risk. The registry does not report the overall primary endpoint analysis or results for the secondary outcomes.
These data do not establish that the device changes cranial shape, prevents deformational plagiocephaly, or improves any clinical outcome. The record offers no reported outcome results for normal cranial index or symmetry, and it contains no comparator group against which changes could be assessed. It also does not report a full analysis of feasibility or ease of use. The study's completed status is not itself evidence that the intended effects were achieved.
Nor do the safety counts establish that the device is free of risk. They describe the absence of recorded events in two listed categories within the reported at-risk groups and timeframe. The registry does not explain the difference between enrollment and the safety denominators, report confidence intervals, or describe the completeness of event collection. A zero count in a pilot observation is not equivalent to proof of no underlying risk.
The most defensible interpretation is therefore narrow: the registry describes a completed single-group pilot and posts zero affected participants in each of two safety categories, with 10 at risk in each. The available record does not provide enough information to make a comparative claim, estimate a causal effect, or draw a conclusion about the device's effect on plagiocephaly.
13. Why This Trial Matters Statistically
This trial is statistically instructive because it separates a descriptive safety observation from a controlled estimate of treatment effect. A single-group study can show what was recorded among participants using a device, but it cannot establish what would have happened under a different condition. The absence of a comparator is not repaired by a statistical test; it is a feature of the design that limits the questions the data can answer.
The record also illustrates why denominators and outcome definitions matter. It lists 11 enrolled participants, whereas the serious and other adverse-event fields each list 10 at risk. Without an explanation, readers cannot determine how those safety groups relate to the enrolled group. The registered primary endpoint concerns participants with adverse events collected using a named tool, but an overall analysis of that endpoint is not reported. A clearly stated count and denominator are useful, yet they do not replace information about event ascertainment, follow-up completeness, and uncertainty.
Finally, the study lists several secondary outcomes without reporting their results. In general, pilot studies can inform the feasibility of future research and help identify questions that need better measurement or more complete reporting. They should not be treated as confirmatory evidence when outcome estimates, analysis details, and a comparison are unavailable. The record's short observation timeframe and limited reporting make the distinction between “no event recorded” and “risk ruled out” especially important. These statistical considerations help readers interpret the evidence at the level it supports, without extending the findings beyond the posted information.
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 single-group design is the principal limitation for causal interpretation. All participants received the Premie Pouch, and the registry does not describe a comparator. The record therefore cannot provide a direct estimate of how outcomes differ from another intervention or from no device. Masking is listed as NONE, and the record does not describe blinded outcome assessment.
The registry lists 11 participants enrolled, but the safety categories each list 10 at risk. The reason for the difference is not reported. The observation period is recorded as 19-47 days, and participant-level follow-up or completeness of event collection is not described. The safety fields report zero participants with serious events and zero with other events, but no confidence intervals or overall primary endpoint analysis are reported. Deaths are not reported in the registry record.
Results for the secondary outcomes concerning feasibility, cranial index, cranial symmetry, and ease of use are also not reported. The registry does not report a statistical analysis plan, missing-data approach, analysis populations, multiplicity strategy, or sample-size justification. These details cannot be inferred from the pilot designation or the study's completed status. Together, these limitations mean that the posted record supports only a narrow descriptive account of the listed safety counts, rather than a complete assessment of the registered outcomes.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Premie Pouch to Manage Deformational Plagiocephaly in Very Low Birth Weight Infants — NCT03184441.
- Registry record last updated 2019-03-19; status last verified 2018-07.
- Results first posted 2018-08-14.
- 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 registry describes a completed, single-group pilot of the Premie Pouch device in prematurely born infants weighing < 1 kilogram. It lists 11 participants enrolled, a study start of 2016-06, and primary completion in 2016-08. Allocation is NA, masking is NONE, and the observation period for the primary safety outcome is 19-47 days.
The primary outcome concerns the frequency of participants with adverse events reported using the Premie Pouch Adverse Event Data Collection Tool. The registry does not report an overall analysis of that endpoint. Its safety fields list 0 participants with serious adverse events among 10 at risk and 0 participants with other adverse events among 10 at risk. The record does not explain the difference between enrollment and those denominators.
Secondary outcomes address feasibility, cranial index, cranial symmetry, and ease of use; their results are not reported in the registry record. With no comparator and no reported outcome analyses, the available information supports a limited descriptive reading of the posted safety counts, not a comparative or causal conclusion.