Combining Topical Corticosteroid and LCD Treatment for Localized Plaque Psoriasis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Combining Topical Corticosteroid and LCD Treatment for Localized Plaque Psoriasis (NCT00769184), a randomized na study. The primary outcome is Percentage of Patients Who Are Clear (PGA Score 0) or Have Minimal Disease (PGA Score 1) on Each Treated Side at Each Visit..

2. Clinical Question

The question concerns the course of disease severity across treatment and follow-up, rather than a single end-of-treatment measurement. The primary outcome is defined separately for each treated side at each listed visit. This makes the within-participant structure important: the two sides may provide paired observations, but the registry record does not state how the side-level results were analyzed. It also does not report whether the study had a prespecified primary visit or a prespecified comparison of change over time. The outcome description and bilateral design establish what was intended to be assessed; they are not evidence of an observed benefit or difference.

3. Trial Design

The registry record identifies NCT00769184 as a completed pilot study of topical corticosteroid and LCD treatment for localized plaque psoriasis. It lists the phase as NA, randomization as the allocation method, quadruple masking, and a single-group model. Enrollment was 15. These labels do not, by themselves, clarify how participants or treated sides were assigned, or precisely who was masked. The record does not explain the apparent tension between a single-group model and its description of two treatment conditions in a bilateral study.

The study is described as lasting 12 weeks, with 6 weeks of treatment and 6 weeks of follow-up. The two arm descriptions specify corticosteroid with LCD for 2 weeks, then LCD alone for 4 weeks, and corticosteroid with placebo for 2 weeks, then placebo alone for 4 weeks. The brief summary describes the study as bilateral. Together, these details indicate that the treatment conditions were intended to be assessed on separate sides, but the exact assignment and handling of sides are not reported in the registry record.

The primary outcome was assessed at weeks 2, 6, and 12. A secondary outcome is listed as mean percent improvement in disease severity using PGA and OTLS scores of target lesions. The registry record lists two outcome measures and zero analyses. It does not report the primary or secondary outcome values, a statistical analysis plan, or results of a comparison. The study is marked completed; its listed start and primary completion dates are 2008-10 and 2009-04. The registry record does not report details of sample-size justification or interim analyses. Since this is a pilot study with 15 enrolled participants and no outcome estimates posted, the design description alone cannot establish the size or precision of any treatment difference.

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.

Corticosteroid + LCD/ +Placebo (2 Weeks)

Reasons for not completing this period:

+LCD / +Placebo Only (4 Weeks)

No Treatment (6 Weeks)

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All randomized patients were included in analyses. Missing scores within each study phase only were filled in by last observation carried forward.

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: Fifteen patients with localized chronic plaque psoriasis (less than or equal to 6% BSA and PGA score greater than or equal to 3) were enrolled. Eleven patients completed the study. Three patients were removed due to an adverse event, and 1 patient was lost to follow-up after week 2.

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Patients Who Are Clear (PGA Score 0) or Have Minimal Disease (PGA Score 1) on Each Treated Side at Each Visit., measured over Weeks 2, 6, & 12..

The primary endpoint is the percentage of participants who are clear or have minimal disease on each treated side at each visit. Clear disease is defined as a PGA score of 0, and minimal disease as a score of 1. The stated PGA scale runs from clear (0) to very severe (5). The endpoint is recorded at weeks 2, 6, and 12, spanning the described treatment and follow-up periods.

A global assessment is used to summarize the clinician’s overall rating of disease severity in a target lesion. Expressing the outcome as a percentage focuses on how often participants meet the specified clear-or-minimal threshold. This is a binary classification for the endpoint, even though the underlying PGA scale has several ordered severity categories. Participants just inside or outside the threshold are classified differently, while variation within either category is not represented in the percentage.

For a bilateral study, a side-specific outcome can support comparison of treatment conditions within the same participant, if the conditions were indeed assigned to opposite sides and the analysis accounts for that pairing. The registry record does not report the planned analysis or the observed percentages. It therefore does not show how frequently participants met the endpoint, whether results differed by side, or how uncertain any such difference was. The secondary outcome uses PGA and OTLS scores to assess mean percent improvement, but its results are also not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes the primary endpoint as a percentage of participants who meet a defined PGA threshold at each visit. In general, a percentage endpoint counts participants classified as having the event of interest and expresses that count relative to an analysis population. Here, the event is reaching a PGA score of 0 or 1. The registry record does not post the counts or percentages, so the endpoint’s calculation cannot be checked against observed results.

What does a binary endpoint capture?

Although PGA is an ordered score with multiple severity levels, the primary endpoint combines scores 0 and 1 into one category and treats other scores as not meeting the endpoint. This can make the result straightforward to communicate, but it discards distinctions among the scores outside the threshold and between 0 and 1. In general, a threshold should be interpreted as the specific classification chosen for the outcome, not as a complete description of every change in severity. The secondary outcome, which uses mean percent improvement in PGA and OTLS scores, is a different summary and should not be assumed to agree with the binary endpoint.

How does the bilateral design affect comparisons?

The study is described as bilateral and specifies one condition involving corticosteroid plus LCD followed by LCD alone, and another involving corticosteroid plus placebo followed by placebo alone. If each participant received both conditions on different sides, the side-specific observations would be paired: each participant would contribute information to both conditions. In general, paired analyses account for the fact that measurements from the same person may be related. Treating those observations as if they came from unrelated participants can misstate uncertainty. The registry record does not explain whether every participant received both conditions, how sides were assigned, or which statistical method was used. Its single-group model label does not resolve these details.

Why do visits and repeated measures matter?

The primary outcome is scheduled at weeks 2, 6, and 12. In general, repeated observations from the same participant are statistically related, and a method that accounts for this dependence can differ from a method that treats every visit as independent. Separate analyses at each visit also raise multiplicity concerns: the more outcomes or time points examined, the greater the chance that an apparently notable result could arise by chance when no true difference exists. An analysis plan can address this by defining a primary visit, adjusting for multiple comparisons, or using a model that evaluates the outcome over time. Which approach, if any, was used is not reported in the registry record.

What can a confidence interval and p-value tell readers?

In general, a confidence interval displays a range of effect estimates compatible with the data and assumptions of a statistical method. A narrower interval indicates greater precision than a wider interval, while the interval’s position helps readers assess the direction and plausible size of an effect. A p-value describes how compatible the observed data are with a specified null model; it does not state the probability that a treatment works, and it does not measure clinical importance. The registry record reports neither a confidence interval nor a p-value for the primary outcome. Without an estimate and uncertainty measure, readers cannot judge whether any apparent difference is precise or compatible with a wide range of effects.

What does last observation carried forward assume?

The record says missing scores within each study phase were filled in by last observation carried forward. In general, this method substitutes a participant’s most recently observed score for a later missing score within the specified phase. It can retain participants in an analysis, but the carried-forward value may not represent the participant’s unobserved status at the later visit. The method also treats the last observed value as if it remained unchanged for the relevant missing assessment. Whether that assumption is appropriate depends on why scores are missing and how the outcome may change over time. The registry record does not report missingness by visit, reasons for missing assessments, or sensitivity analyses using alternative assumptions.

The record states that all randomized patients were included in analyses. In general, an analysis population definition helps clarify which participants contribute to estimates and whether the randomized groups are preserved. Here, the stated population does not reveal how many had observed scores at each visit or how many scores were imputed. The registry record lists zero analyses, so it does not provide enough detail to assess the statistical implementation, estimate precision, or reproduce an inferential result. These general methods considerations explain what would be useful for interpretation; they do not establish which methods were actually used beyond the stated missing-score rule.

10. Multiplicity, Missing Data and Analysis Populations

The primary endpoint is assessed at weeks 2, 6, and 12, and a secondary outcome is also listed. Considering several visits and outcomes can create multiplicity: if each is tested separately, the chance of at least one apparently unusual result can increase. In general, an analysis plan may address this by selecting a primary time point, adjusting for multiple tests, or defining a model and interpretation strategy in advance. A multiplicity plan is not reported in the registry record. It also does not report whether any visit or outcome was designated as the main basis for inference.

The registry says all randomized patients were included in analyses and that missing scores within each study phase were filled in by last observation carried forward. It does not report how many scores were missing, when they were missing, why they were missing, or how many participants contributed observed data at each visit. The record also does not describe sensitivity analyses that would show whether conclusions changed under other assumptions about missing scores. The stated rule is therefore informative, but insufficient to evaluate its impact on results.

The registry record lists zero analyses and no primary outcome results. It is consequently not possible to determine how the analysis population was implemented, how repeated or paired measurements were handled, or whether any adjustment for multiple comparisons was performed. The stated use of all randomized patients should not be taken as a complete account of the analysis without those details.

11. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists 15 participants at risk for serious adverse events in each condition, with 0 affected in each. It lists 15 at risk for other adverse events in each condition, with 2 affected in the corticosteroid-plus-LCD condition and 1 affected in the corticosteroid-plus-placebo condition. No serious adverse event terms are listed. Death counts are not reported in the registry record.

These are descriptive safety figures. They do not establish that an event was caused by a treatment, and they do not provide enough detail to compare the overall safety of the conditions. The registry record does not give the types, timing, severity, or relatedness of the other adverse events. It also does not report additional context about event collection or follow-up. A count of zero serious adverse events in the listed group is not proof that the risk is absent; it describes only what is recorded for this study.

The counts should be read alongside the small enrollment and the limited information about events. They are not a substitute for a complete safety analysis, and the record does not post inferential comparisons. The figures do not establish whether any difference between conditions is meaningful or precise.

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

The registry record documents a pilot study designed to assess clear or minimal disease on treated sides during treatment and follow-up. It provides the endpoint definition, visit schedule, treatment descriptions, masking and allocation labels, and a rule for handling missing scores. It also records adverse-event counts. These details clarify the intended study question and some aspects of reporting.

However, the primary outcome results are not reported in the registry record, and the record lists zero analyses. There is no posted estimate for either condition, no comparison between conditions, and no uncertainty measure. Accordingly, the available record cannot show whether the outcome was more frequent on one side, whether it changed over time, or how precisely any difference was estimated. The absence of posted results is not evidence of no difference or of an effect in either direction.

The study is described as a pilot and enrolled 15 participants. In general, pilot studies can help characterize procedures and inform later research, but the term alone does not indicate whether the study was adequately sized for a particular hypothesis. The registry record does not report a sample-size justification or a statistical plan, so it is not possible to assess the design’s intended precision or inferential goals.

The bilateral description may permit within-participant comparison, but the registry record does not explain assignment of the conditions to sides or how the analysis accounted for the paired structure. The combination of randomized allocation and a single-group model label also leaves important design details unclear. Those ambiguities matter because interpretation depends on how the conditions were assigned and how outcomes were compared.

The posted information therefore supports a description of the research question and selected design and safety features, not a conclusion about treatment effects. It does not establish whether the combination condition differed from the placebo condition, whether any difference was clinically important, or whether results were robust to missing-data assumptions. Those judgments require outcome estimates, analysis details, and measures of uncertainty that are not reported in the registry record.

13. Why This Trial Matters Statistically

This study raises several statistical issues that are common in clinical research. Its primary outcome turns an ordered severity assessment into a binary threshold: clear or minimal disease versus not meeting that threshold. That choice can make results easier to communicate, but it also means the endpoint does not retain all information in the underlying PGA scale. The listed secondary measure, mean percent improvement using PGA and OTLS scores, addresses change differently. Without results for either outcome, their relationship cannot be examined.

The bilateral design makes the unit of analysis especially important. If each participant contributes a treated side to each condition, the measurements are paired rather than independent. A valid comparison should reflect that structure. The registry’s single-group model label and randomized allocation label do not fully explain how the study was organized or analyzed. This illustrates why design labels are not a substitute for a clear account of assignment and analysis.

Assessments at multiple visits also create interpretive choices. A prespecified primary visit and an approach to multiple comparisons can help readers understand whether a reported finding was selected from several opportunities. The registry record does not report those decisions or any analysis. Its missing-score rule is stated, but the amount and pattern of missingness and the effect of the rule are not described.

Most importantly, a carefully defined question is not the same as an interpretable result. No primary outcome estimates, confidence intervals, or statistical tests are posted. The record therefore highlights the distinction between registering a study’s intended assessment and reporting the evidence needed to evaluate an effect. These limitations are relevant to statistical interpretation, regardless of the direction a reader might expect from the treatments.

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 registry record leaves several trial-specific details unresolved. It describes the study as bilateral and lists two treatment sequences, but does not explain whether every participant received both conditions, how sides were assigned, or how randomization was carried out. It also labels allocation as randomized and masking as quadruple while identifying the model as single group. The record does not clarify the meaning of these labels or which people were masked.

Outcome reporting is a major limitation: the primary outcome values and secondary outcome results are not reported, and the registry lists zero analyses. There is no reported comparison between conditions, confidence interval, p-value, or explanation of how repeated measurements were handled. The record does not identify a primary visit among weeks 2, 6, and 12 or describe a plan for multiplicity.

Although the record says all randomized patients were included and missing scores within each study phase were filled in by last observation carried forward, it does not give the amount, timing, or reasons for missing data. It does not describe sensitivity analyses or clarify how imputed values contributed to each visit’s result. The analysis population and missing-data handling therefore cannot be evaluated in detail.

The record lists 15 enrolled participants and marks the study completed, but does not report a sample-size justification. The adverse-event information is limited to group counts; event types and other clinical details are not reported. These gaps constrain assessment of outcome precision, safety reporting, and reproducibility. They do not show that the study findings were positive, negative, or null; the findings themselves are not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Combining Topical Corticosteroid and LCD Treatment for Localized Plaque Psoriasis — NCT00769184.
• Registry record last updated 2015-08-19; status last verified 2015-07.
• Results first posted 2015-08-19.
• 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

NCT00769184 is a completed pilot study of topical corticosteroid treatment with supplemental LCD for moderate-to-severe localized plaque psoriasis. The registry record lists 15 participants, randomized allocation, quadruple masking, and a single-group model. It describes a bilateral study with two treatment conditions: corticosteroid plus LCD followed by LCD alone, compared with corticosteroid plus placebo followed by placebo alone.

The primary endpoint is the percentage of participants with a PGA score of 0 or 1 on each treated side at weeks 2, 6, and 12. The record states that all randomized patients were included in analyses and that missing scores within each study phase were handled by last observation carried forward. Primary and secondary outcome results are not reported, and the record lists zero analyses. It also does not report the statistical plan, sample-size justification, or details of side assignment. Serious adverse events were recorded for 0 of 15 participants in each condition; other adverse events were recorded for 2 and 1 participants, respectively.