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 Blue Light Phototherapy (NCT04343586), a na na study. The primary outcome is Efficacy of Blue Light Therapy for Patients With Grover's Disease.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04343586 |
| Phase | NA |
| Condition | Grover's Disease, Psoriasis Vulgaris |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 11 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Northwestern University |
| Results posted | Yes |
2. Clinical Question
Population
Adults enrolled in a study of psoriasis vulgaris or Grover’s disease. The registry record reports enrollment of 11, but does not report the endpoint population in more detail.
Intervention
Blue light phototherapy, delivered to one area of the body affected by psoriasis or Grover’s disease. The record describes the intervention as a device.
Comparator
Untreated areas affected by disease on the same patient. This is a within-patient comparison described in the treatment arm, not a randomized comparison between separate groups.
Primary question
For Grover’s disease, the stated primary measure is lesion count at 5 weeks, summarized as a mean with a 95% confidence interval. The registry record does not report the observed mean or interval.
The clinical question is whether a treated area of affected skin shows a preliminary change in lesion count relative to untreated affected areas on the same patient. The registry describes this as a study of blue light phototherapy for psoriasis vulgaris and Grover’s disease, while the named primary outcome specifically concerns patients with Grover’s disease. The record does not clarify whether the primary endpoint was also intended to characterize psoriasis, or how the endpoint population was selected.
The within-patient arrangement can make the treated and untreated areas more comparable in some respects because they belong to the same person. But it does not create random allocation: the record lists allocation as NA and describes an adult treatment arm. It also does not state how the treatment area was chosen, how the untreated areas were selected, or whether lesion counts were assessed without knowledge of treatment status. Those details matter when interpreting a difference between areas.
The registry record does not report the numerical lesion-count result, a comparison estimate, or an inferential test. It therefore does not establish the direction or size of any observed difference, nor how precisely that difference was estimated. The question can be described from the planned outcome and design, but the posted record does not provide the result needed to answer it quantitatively.
3. Trial Design
The registry record describes a completed study of blue light phototherapy, with enrollment of 11 and a single-group model. The study is marked as having no masking, and allocation is listed as NA. Its listed conditions are Grover’s disease and psoriasis vulgaris. The start date is 2020-09-01, the primary completion date is 2021-12-20, and the status is completed.
The adult treatment arm description says that treatment was applied to one affected area, with untreated affected areas on the same patient serving as the comparison. Thus, the comparison is within patient and within disease-affected skin, rather than between separately allocated treatment and control groups. The registry record does not report random assignment of body areas, a sham device, or blinding of participants or assessors. It also does not describe the method for choosing or matching treated and untreated areas.
The listed intervention is blue light phototherapy, categorized as a device. The brief description says the study will use blue-light phototherapy to treat patients with psoriasis vulgaris and Grover’s disease. The official title refers to development and preliminary clinical validation of blue light phototherapy systems for T-cell, but the registry record does not provide additional details about device characteristics or the development process.
The primary outcome is titled “Efficacy of Blue Light Therapy for Patients With Grover’s Disease.” It uses lesion count, is summarized as a mean with a 95% confidence interval, and has a timeframe of 5 weeks. The record lists two outcome measures and zero analyses. It does not report analysis populations, statistical tests, a model, a prespecified comparison method, or numerical outcome results. A sample-size justification or the reasoning behind the enrollment target is not reported in the registry record.
Because the study is single-group and non-randomized, its design does not support the same causal interpretation as a randomized, parallel-group comparison. The treated and untreated areas may offer a useful descriptive contrast, but the registry record does not establish that the areas were otherwise exchangeable or that differences between them can be attributed to treatment alone.
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 | Adult Treatment Arm |
|---|---|
| STARTED | 11 |
| COMPLETED | 10 |
| NOT COMPLETED | 1 |
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 | Adult Treatment Arm |
|---|---|---|
| Participants analysed | 11 | |
| Age, Continuous | years | 63 (SD 14) |
| Sex: Female, Male: Female | Participants | 2 |
| Sex: Female, Male: Male | Participants | 9 |
| Race/Ethnicity, Customized: White | Participants | 11 |
6. Primary Endpoint
The registry lists the primary outcome as Efficacy of Blue Light Therapy for Patients With Grover's Disease, measured over Time Frame: 5 weeks.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | lesion count |
| Endpoint classification | Continuous Endpoint |
The stated primary endpoint is lesion count for patients with Grover’s disease, measured at 5 weeks. Lesion count is a count-based way to describe visible disease burden in a defined area. The registry describes the endpoint as a measure intended to demonstrate preliminary skin efficacy. It specifies that the result is to be expressed as a mean with a 95% confidence interval.
Counting lesions can provide a concrete measure that can be compared across assessment times or between affected areas. In this design, the treatment area is compared with untreated affected areas on the same patient. A count-based outcome is also distinct from a rating of symptoms or an overall judgment of improvement; no such measures are described as the primary endpoint in the registry record.
Important measurement details are not reported in the registry record. These include the precise rules for defining and counting a lesion, the size or boundaries of the assessment areas, whether counts were assessed at baseline as well as follow-up, and how the mean was calculated across patients or areas. The record also does not state whether the endpoint is an absolute count at follow-up, a change from baseline, or a treated-versus-untreated contrast.
The posted results do not contain a numerical mean or confidence interval for this endpoint. Without those values and their analysis context, the size, direction, and precision of the lesion-count result cannot be assessed. The endpoint’s stated purpose and measurement type are available, but its observed result is not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a preliminary clinical study and a lesion-count endpoint, but does not report numerical results for that endpoint. Although the primary outcome is described as a mean with a 95% confidence interval, neither the mean nor the interval appears in the record. No numerical treated-versus-untreated estimate, test result, or analysis output is reported. Consequently, the posted record does not show whether lesion counts differed, in which direction they differed, or how precise an estimate might be.
The described comparison is between a treated area and untreated affected areas on the same patient. That structure can be informative as a descriptive within-patient comparison, but it is not a randomized comparison. Differences between areas could reflect features of the areas, the way they were selected, or other aspects of assessment; the record does not report enough detail to determine how such factors were handled. The absence of masking is also relevant: the registry lists masking as NONE. It does not specify whether outcome assessors knew which area received treatment.
Enrollment was 11. The record does not explain whether all enrolled participants contributed to the primary endpoint, whether any data were missing, or how the analysis handled missing observations. It also does not report a statistical analysis plan or a sample-size justification. The registry lists two outcome measures and zero analyses, which means the record does not provide analysis entries from which to evaluate the primary result or any other outcome.
The 95% confidence interval is a planned summary format, not a reported finding in this record. General explanation: a confidence interval conveys uncertainty around an estimated quantity; a wider interval indicates less precision than a narrower interval in the same measurement context. Since the interval’s endpoints are absent, no conclusion about precision can be drawn for this study’s lesion-count estimate.
The record’s completed status indicates that the study is marked completed, but completion alone does not supply an outcome result. The title and brief description frame the work as preliminary, and the record describes an early clinical validation purpose. These features describe the study’s stated scope; they do not substitute for numerical evidence. The available information supports a description of design, endpoint, and reported safety counts, but not a quantitative assessment of treatment-associated lesion-count change.
Any sample-size illustration should be interpreted separately from an observed study result. The stated illustration assumptions include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. The record does not report a numerical observed effect or the resulting planning values. These assumptions are not a description of the actual single-group design, and any planning values would not represent observed power or a result from this trial.
9. Statistical Methods Explained
The registry specifies a mean and a 95% confidence interval for the primary lesion-count measure. It does not report a numerical estimate or interval, and it does not describe the analysis method used to produce them. The explanations below are general statistical context, not claims about methods used in this study.
What does a mean describe?
General: a mean is an average that summarizes a set of measurements. It can be useful when the scientific question concerns the average lesion count in the measured population or area. But a mean alone does not show how observations are distributed. For count data, a few large values can have a noticeable influence on an average, while many observations may be concentrated at low counts. The record does not provide the individual counts, a distribution summary, or enough detail to know precisely which observations contribute to the stated mean.
It is also important to know what quantity is being averaged. The registry identifies lesion count and a 5-week timeframe, but it does not state whether the mean is a follow-up count, a change from baseline, a mean within each area, or a mean contrast between treated and untreated areas. These quantities answer different questions. Without the operational definition and analysis population, the label alone does not resolve which one was intended.
What does a confidence interval communicate?
General: a confidence interval expresses uncertainty around an estimate under the assumptions of the method used to calculate it. Its width reflects both the amount of information and the variability of the data, as well as the calculation method. A confidence interval is not a guarantee that the true value lies within the interval, and it does not by itself establish clinical importance. Interpretation also depends on the endpoint scale and the contrast being estimated.
The record names a 95% confidence interval as the dispersion measure, but the interval limits are not reported in the registry record. There is therefore no basis to characterize its width, whether it includes a null or reference value, or whether it supports a precise estimate. The record also does not state whether the interval is for a mean count in one area or for a difference or change. Those distinctions are essential before interpreting an interval.
Why does the comparison structure matter?
General: observations from the same person are often related. A within-person analysis should account for that pairing when it estimates a contrast, rather than treating each area as if it came from an unrelated person. Pairing can reduce some person-level variation, but it does not remove differences between areas or correct for non-random selection. The registry describes treated and untreated areas on the same patient, but does not report the statistical handling of that structure.
In this study, allocation is NA and the model is single-group. The record therefore does not describe a randomized allocation between treatment and control groups. The area-level contrast could be affected by baseline differences, location, extent of disease, or assessment procedures; these are general considerations for this kind of comparison, not documented imbalances in this trial. The record does not say whether the areas were matched, how treatment area size was determined, or whether assessment was blinded.
How should count outcomes be considered?
General: count data are nonnegative and may have a distribution that differs from the symmetric distributions often assumed by simple methods. Depending on the data, counts can be concentrated at low values, have a long upper tail, or vary more than a basic model expects. Over-dispersion means that the observed variability is greater than the model’s assumed variability; if it is ignored, uncertainty estimates may be too small. These are general issues in count analysis and are not evidence that over-dispersion occurred in this study.
The registry does not report a count-data model, distributional assessment, transformation, or other method for handling the endpoint. It also does not report whether counts were analyzed at the participant level, body-area level, or another unit. It would therefore be inappropriate to attribute a particular statistical method to the trial or to infer that the mean and confidence interval were calculated using any specific model.
What does a planning illustration mean?
General: sample-size calculations describe how much information a future study might need under stated assumptions. A planning illustration is conditional on those assumptions and is not an estimate of what the current study achieved. The stated illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect set as a stated fraction of an observed effect. The description says that time-to-event planning uses a total number of events and other planning uses participants per arm.
Those assumptions do not match the registry’s single-group, within-patient description as a direct account of the trial’s design. The record does not report the numerical observed effect used for the illustration or the resulting participant requirements. Any such values would be planning illustrations, not observed power and not evidence of efficacy. A planning calculation cannot replace a reported estimate and its uncertainty.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists two outcome measures and zero analyses. It does not report the additional outcome’s details in the information available for this record, nor does it provide analysis results for either measure. The primary outcome is identified as lesion count for Grover’s disease, but the registry record does not explain how the primary endpoint was selected or whether outcomes were prioritized in a prespecified statistical analysis plan.
Multiplicity arises when several outcomes or comparisons are tested: the more opportunities there are to declare a finding, the more important it can be to define in advance which results are confirmatory and whether any adjustment is appropriate. This is general statistical context. The registry record does not report a multiplicity strategy, a hierarchy of outcomes, or an adjustment for multiple testing. With no analysis results reported, it is not possible to assess how multiple outcomes were handled in practice.
Missing-data methods are also not reported in the registry record. It does not state whether all enrolled participants had evaluable endpoint data, how missing measurements were identified, or whether any imputation, exclusion, or sensitivity analysis was used. The enrollment figure alone cannot establish the number included in the endpoint analysis.
The analysis population is not reported in the registry record. In particular, the record does not explain which participants or body areas would be included in the primary analysis, how multiple affected areas were treated, or how incomplete paired observations would be handled. These omissions limit reproducibility and make it difficult to determine which population an estimate would represent, even if a result were 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 |
|---|---|---|---|
| Adult Treatment Arm | 0 | 11 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Adult Treatment Arm | 0 of 11 |
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 |
|---|---|
| Adult Treatment Arm | 0 of 11 |
The safety fields list the Adult Treatment Arm with 11 at risk for serious adverse events and zero affected, 11 at risk for other adverse events and zero affected, and zero deaths. These are the registry’s reported counts for the listed categories. The record does not provide serious adverse event terms, and no top serious terms are listed.
These zero counts should be read as no events reported in the specified registry fields, not as proof that no adverse events occurred or that the intervention is free of risk. The registry record does not describe how adverse events were collected, the definitions used, the observation period for safety, or whether events were assessed for relatedness to treatment. It also does not provide event-level descriptions or a narrative explaining the counts.
General: safety counts depend on how events are defined, collected, and reported, as well as the time and population under observation. A zero count in a limited study does not establish that an event cannot occur. In this record, the reported enrollment is 11 and the listed safety category counts are zero; the available information does not support broader conclusions about safety beyond those reported figures.
12. What the Result Does, and Does Not, Mean
The registry record documents a completed, single-group study of blue light phototherapy involving adults with psoriasis vulgaris or Grover’s disease. It describes treatment of one affected area and comparison with untreated affected areas on the same patient. The primary outcome is lesion count for patients with Grover’s disease at 5 weeks, summarized as a mean with a 95% confidence interval. These details clarify the intended question and the measurement approach at a high level.
The record does not report the lesion-count estimate, confidence interval limits, a treated-versus-untreated contrast, or an inferential analysis. Thus, it does not provide a numerical answer about the direction, magnitude, or precision of the primary result. It also does not provide information needed to judge whether any observed difference would be attributable to treatment rather than to area selection, measurement, or other factors.
The within-patient comparison may be useful for describing differences between treated and untreated affected areas, but it is not a randomized comparison. The record lists no masking and does not explain whether outcome assessors knew treatment status. It also does not report the selection or matching process for areas. These design features limit causal interpretation even if numerical results were available.
The safety record reports zero serious adverse events, zero other adverse events, and zero deaths in the listed fields. Those entries describe what the registry reports; they do not demonstrate an absence of risk. The methods and observation details for safety reporting are not reported in the registry record.
Overall, the record supports a description of the trial’s design, endpoint, timing, enrollment, and registered safety counts. It does not support a conclusion about treatment benefit, lack of benefit, or the size of any effect. The stated preliminary purpose should not be confused with a reported quantitative finding: the endpoint result and its uncertainty are not reported in the registry record.
13. Why This Trial Matters Statistically
This trial is statistically notable because its clinical comparison is within patient, while the registry identifies the study as single-group and non-randomized. Comparing treated and untreated affected areas from the same person can be a useful way to describe local outcomes, but analysis must respect the relationship between areas and must distinguish a descriptive contrast from a causal treatment effect. The registry record does not report how that structure was analyzed.
The endpoint is a lesion count, a type of outcome for which the distribution and variability can matter to statistical inference. General: a model designed for continuous measurements may not automatically describe count data well, and unusually variable counts can affect uncertainty estimates. The record specifies a mean with a 95% confidence interval, but does not identify the calculation method or report the resulting interval. This makes it impossible to evaluate the actual precision or assumptions behind the endpoint result.
The record also illustrates why trial status and outcome reporting are different matters. It marks the study completed and provides a primary outcome description, yet lists zero analyses and does not report a numerical primary result. Completion establishes the registry status, not the availability of an estimate, its uncertainty, or an interpretation of the outcome.
Finally, the stated sample-size assumptions concern a planning illustration with two-arm equal allocation, while the registered trial is described as single-group with a within-patient comparison. Keeping those concepts separate prevents a planning calculation from being mistaken for the study’s design or as evidence of observed power. Without reported estimates and analysis methods, the statistical contribution that can be assessed from the record is principally one of design description and endpoint specification, rather than outcome inference.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
Several limitations specific to interpretation of this trial arise from the details absent from the registry record. The primary outcome is named for Grover’s disease, although the study description includes both Grover’s disease and psoriasis vulgaris. The endpoint population and the relationship between the two conditions in the analysis are not reported. The record also does not clarify whether the primary measure was intended to apply to both conditions.
The comparison uses one treated area and untreated affected areas on the same patient, but the method for selecting the areas is not reported. The record does not give the assessed area boundaries, lesion-counting rules, baseline measurement details, or whether treated and untreated areas were matched. These omissions make it hard to know exactly what the count represents and what contrast the analysis was intended to estimate.
Masking is listed as NONE, and no assessor procedures are reported. The record does not specify who counted lesions or whether those individuals knew treatment status. For an outcome requiring observation and counting, this missing information limits assessment of potential measurement influence. The statistical model and handling of within-patient observations are also not reported.
No numerical primary result, confidence interval, or analysis output is present. Missing-data procedures, analysis populations, multiplicity handling, and the basis for the enrollment target are not reported in the registry record. Safety collection and follow-up details are also absent. These limitations mean the registered information is insufficient to evaluate the size and reliability of the outcome estimate or to reproduce its analysis.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Blue Light Phototherapy — NCT04343586.
- Registry record last updated 2023-03-17; status last verified 2023-02.
- Results first posted 2023-03-17.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry record describes NCT04343586, titled “Blue Light Phototherapy,” as a completed, single-group study sponsored by Northwestern University. Enrollment was 11. The listed conditions are Grover’s disease and psoriasis vulgaris, and the intervention is blue light phototherapy, categorized as a device. The record lists no masking and allocation as NA.
The adult treatment arm description says one affected area received treatment and untreated affected areas on the same patient served as the comparison. The primary outcome concerns lesion count for Grover’s disease at 5 weeks, with a mean and 95% confidence interval specified. The numerical endpoint result and interval are not reported in the registry record. Two outcome measures are listed, and zero analyses are reported.
The safety fields report zero serious adverse events, zero other adverse events, and zero deaths. Further details on outcome analysis, missing data, area selection, and safety ascertainment are not reported in the registry record.