Seborrheic Dermatitis: Ketoconazole 2% Foam Versus Ketoconazole 2% Shampoo: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Seborrheic Dermatitis: Ketoconazole 2% Foam Versus Ketoconazole 2% Shampoo (NCT01203189), a randomized na study. The primary outcome is Total Dandruff Severity Score (TDSS).

2. Clinical Question

The clinical question concerns two formulations of the same named active ingredient, used on different schedules. The registry describes a comparison of their effects on scalp dandruff severity, while also listing participant compliance and satisfaction as secondary outcomes. The study population is specifically described as African American females with dandruff who wash their hair less than once weekly. The record does not report further demographic details.

The primary outcome is Total Dandruff Severity Score (TDSS), a scalp assessment that combines the extent of involvement and the severity of findings across scalp quadrants. Lower scores represent less scale, and the stated range runs from 0 to 48. However, a numerical comparison of outcomes between the foam and shampoo groups is not reported in the registry record. Therefore, the clinical question can be described from the registered design and endpoint, but the posted record does not establish the direction or size of any observed difference.

3. Trial Design

The registry describes a randomized, single-masked, crossover study with a listed enrollment of 23. Its focus was seborrheic dermatitis of the scalp among people practicing less frequent hair washing. The summary specifies African American females with dandruff who washed their hair less than once weekly. The sponsor is St. Louis University. The study is marked completed, with a start date of 2010-09 and primary completion of 2013-06.

The shampoo group was assigned to wash hair twice weekly for four weeks using ketoconazole 2% shampoo. The foam group was assigned to apply ketoconazole 2% foam to the scalp twice daily for four weeks. The registry also describes a crossover: shampoo-group participants could cross over to foam if their TDSS score did not improve by 60% at the end of the four-week shampoo treatment period. The separate description of the crossover group says participants applied foam twice daily for four weeks.

The registry identifies the design as crossover, but details needed to reconstruct the sequence of treatment periods, any washout interval, or the timing of outcome assessments are not reported in the registry record. It reports that only 3 participants completed eight weeks of crossover treatment; data at eight weeks were not collected for the shampoo-only and foam-only groups. This limits interpretation of the eight-week assessment as a comparison across all treatment groups. The record lists three outcome measures, including TDSS and measures of compliance and satisfaction, but does not provide numerical results for those outcomes.

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.

First 4 Weeks Treatment

Cross Over Period 4 Weeks Treatment

Analysis population for the primary outcome, as defined in the registry: Data were not collected for the Shampoo only group and Foam Only group at 8 weeks. Only 3 participants completed the 8 weeks of cross over treatment.

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: Subjects in the S group were able to cross over into the F group if the TDSS score does not improve by 60% at the end of the 4 week treatment period. These cross over subjects remained in the study for an additional 4 weeks to apply ketoconazole foam 2%. The 4 subject in the cross over group were originally in the shampoo group.

6. Primary Endpoint

The registry lists the primary outcome as Total Dandruff Severity Score (TDSS), measured over up to 8 weeks.

The primary endpoint is Total Dandruff Severity Score (TDSS), measured in units on a scale and summarized using the mean and standard deviation. The scalp is divided into quadrants. For each quadrant, the assessment records the percent of involvement and the degree of severity. Involvement is scored from 0 to 4, with 0 indicating less than 10% involvement and 4 indicating more than 76% involvement. Severity is scored from 0 to 3, with 0 indicating normal skin and 3 indicating marked erythema with thick, confluent plates of yellowish-white scales.

For each quadrant, the involvement score is multiplied by the severity score; quadrant scores are then summed to obtain the total scalp score. TDSS ranges from 0 to 48. A score of 0 represents no scale and is described as the best outcome; 48 represents the most severe outcome. This combined measure is intended to capture both how much of the scalp is involved and how pronounced the findings are, rather than recording either feature alone.

The registry gives a timeframe of up to eight weeks, but the primary outcome result is not reported in the registry record. It also states that eight-week data were not collected for the shampoo-only and foam-only groups and that only 3 participants completed eight weeks of crossover treatment. Those details matter when interpreting the endpoint’s timeframe and the extent of data available at the later assessment.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a randomized, single-masked, crossover trial and names TDSS as its primary endpoint. It characterizes the endpoint as a continuous measure summarized by a mean and standard deviation. However, no analysis record is listed, and the statistical analysis plan is not reported in the registry record. The following concepts explain what design and analysis features can matter in general; they do not establish which methods the investigators used.

What does randomization contribute?

General statistical context: randomization assigns treatment according to a chance-based process. When implemented as planned, it can help balance measured and unmeasured characteristics between groups on average, reducing selection-related differences in a treatment comparison. The registry identifies the trial as randomized, but the randomization sequence, allocation concealment, and allocation procedures are not reported in the registry record. The listed enrollment is 23; the record does not provide a detailed participant flow or a randomized count for each initial assignment.

What does a crossover design require?

General statistical context: in a crossover study, a participant may receive more than one treatment in successive periods. Outcomes can then reflect both the current treatment and features of the treatment sequence, including the participant’s prior treatment and changes over time. Analyses may need to account for repeated measurements within the same participant and for treatment period or sequence. A washout interval can be relevant when effects might persist after a treatment period. The registry identifies a crossover model but does not report a washout interval, the treatment sequence for each participant, or a method for handling period and sequence effects.

The registry’s crossover description also makes the transition to foam conditional on TDSS response to shampoo: shampoo-group participants could cross over if their score did not improve by 60% at the end of four weeks. This means the treatment received after the initial period may depend on a participant’s earlier outcome. General statistical context: such response-dependent switching can make a later comparison different from a comparison based solely on initial assignment. A clear analysis description is needed to understand whether estimates concern initial assignment, treatment received, or outcomes after switching. The registry record does not report which estimand or approach was used.

How should means and standard deviations be read?

General statistical context: a mean locates the center of a set of continuous measurements, while a standard deviation describes how dispersed individual values are around that mean. A standard deviation is not a confidence interval and does not, by itself, show the precision of a comparison between groups. For comparative inference, readers would typically need an effect estimate and its uncertainty, interpreted alongside the design and analysis. The record describes TDSS as a mean with standard deviation but does not report the corresponding numerical outcome values or an inferential comparison.

Why can score distributions matter?

General statistical context: statistical methods based on means and standard deviations can be sensitive to unusual observations and to features of the score distribution. A bounded score may have values concentrated near one end of its range, and a small study may provide limited information about distributional shape. Depending on the observed data and chosen model, investigators may assess assumptions or use another appropriate method. The registry does not report score distributions, diagnostic checks, or the method used to analyze TDSS. It would be inappropriate to infer that a particular model was used from the endpoint summary alone.

What does a sample-size illustration mean?

General statistical context: a sample-size calculation is a planning exercise that links assumptions about an effect, variability, significance level, allocation, and a target power to a proposed enrollment. A calculation based on an observed effect is an illustration of what a future study might require under those assumptions, not evidence that the completed study had a particular probability of detecting an effect. The registry describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It does not report that this was the trial’s own design calculation. No planning sample-size values are reported in the registry record.

Because the TDSS results and analysis are absent, there is no basis in the registry record for independently interpreting an effect estimate, its precision, or model assumptions. The design description explains what types of statistical considerations may be relevant, but it does not identify the actual analysis conducted.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists three outcome measures, including TDSS and secondary outcomes concerning participants who were always compliant and participants who were very satisfied. It does not report numerical results for these measures or identify a hierarchy for testing them. A plan for controlling multiplicity, such as how to interpret several outcome tests together, is not reported in the registry record. Without that plan and the corresponding analyses, the chance of false-positive findings across multiple tests cannot be evaluated from the posted information.

The registry reports 0 analyses. This means no analysis records are listed in the registry record; it does not establish what analyses may or may not have been conducted outside the record. The statistical analysis plan, including the definition of analysis populations and handling of repeated measurements, is not reported in the registry record.

Missingness is a particular interpretive issue for the later assessment. The record says eight-week data were not collected for the shampoo-only and foam-only groups and that only 3 participants completed eight weeks of crossover treatment. It does not explain why those data were unavailable, whether any participants discontinued earlier, or how missing observations were handled. General statistical context: conclusions from incomplete follow-up can depend on why observations are missing and on the assumptions used to address them. No such assumptions or methods are reported in the registry record.

The record also does not define whether participants were analyzed according to initial randomized assignment, treatment actually received, or completion of a treatment period. Those populations can address different questions, especially when treatment switching is conditional on response. The registry’s design description alone is not enough to determine the analysis population or the implications of missing data.

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 0% reporting threshold.

The registry lists serious adverse events, other adverse events, and deaths for three named groups. For the Shampoo Only Group, 10 participants are listed as at risk for serious adverse events and 10 for other adverse events; 0 serious adverse events and 0 other adverse events are listed, and deaths are 0. For the Foam Only Group, the corresponding at-risk counts are 10 and 10, with 0 serious adverse events, 0 other adverse events, and 0 deaths. For the Cross Over Group, 3 participants are listed as at risk for each adverse-event category, with 0 serious adverse events, 0 other adverse events, and 0 deaths.

These figures describe the events recorded for the listed groups and the corresponding at-risk counts. They do not, by themselves, establish that no adverse events of any kind occurred: the record’s listed categories and reporting determine what these counts represent. The registry lists no top serious-event terms. It does not report further detail on event definitions, surveillance procedures, duration of safety follow-up, or the method used to assign events to groups. The relatively small listed at-risk groups also mean that zero recorded events should be read as an observation in this study record, not as proof that an event is impossible or that the two formulations have identical safety profiles.

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

The record establishes that a randomized, single-masked crossover study compared ketoconazole 2% foam and ketoconazole 2% shampoo for scalp seborrheic dermatitis in the described population. It identifies TDSS as the primary endpoint and explains how the score is formed. It also lists compliance and satisfaction among the outcomes and gives adverse-event counts for the named groups. These details clarify what the study was designed to examine.

The record does not report numerical TDSS results, a treatment-effect estimate, uncertainty intervals, or a p-value. As a result, it cannot establish the observed direction, magnitude, or precision of a difference between the foam and shampoo regimens. Nor can it support a conclusion that one regimen was better, worse, or equivalent on the primary endpoint. The absence of a posted result is not itself evidence of no difference.

The trial’s crossover and response-dependent switching also matter to the meaning of any later comparison. A participant who crossed from shampoo to foam had a different treatment history from a participant assigned to foam initially. At eight weeks, the registry reports data only for the 3 participants who completed crossover treatment, not for the shampoo-only and foam-only groups. This later assessment therefore does not provide a complete comparison among all described groups.

The safety counts show 0 reported serious adverse events, 0 reported other adverse events, and 0 deaths in each group as listed. These counts are limited to the registry’s recorded categories and the participants at risk; they do not prove absence of risk. Overall, the posted information describes study design, endpoint construction, and selected safety counts, but leaves the main comparative outcome and its statistical uncertainty unreported.

13. Why This Trial Matters Statistically

This trial raises statistical questions that are useful beyond the particular products studied. It compares two formulations with different schedules while using a crossover design. A crossover can allow within-participant comparisons, but interpretation depends on the sequence of treatments, timing, and any persistence of earlier effects. Those details are especially important when participants may change treatment according to their response. The registry identifies this response-based crossover but does not report the analysis approach used to address it.

The endpoint also illustrates how a clinical score can combine multiple components. TDSS incorporates both the extent of scalp involvement and the severity of findings across quadrants. Its construction gives an interpretable direction—lower scores indicate less scale—but the score’s clinical meaning depends on the measurement process and on results that are not reported in the registry record. A defined scale is not a substitute for a reported treatment estimate.

Missing follow-up creates another central issue. The registry says that eight-week data were not collected for the shampoo-only and foam-only groups and that only 3 participants completed eight weeks of crossover treatment. This makes the distinction between planned follow-up and analyzed observations important. It also highlights why outcome reporting should include participant flow, missing-data handling, and the population included in each analysis.

Finally, the record lists outcomes related to compliance and satisfaction alongside the primary severity measure, but does not report their numerical results or how multiple outcomes were handled. Taken together, the record is a reminder that trial design, endpoint definition, analysis methods, and complete result reporting are all needed to assess what the data say. Here, the design and measurement are described, while the main effect estimate and its precision are not reported.

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 principal limitation for interpreting the trial is that the primary TDSS results are not reported in the registry record. No means, standard deviations, comparative estimate, confidence interval, or p-value are listed. Without those results, the size and precision of any observed difference cannot be assessed. The record also lists 0 analyses, and the investigators’ statistical analysis plan is not reported in the registry record.

The registry describes randomized allocation and single masking but does not report the randomization procedure, allocation concealment, who was masked, or whether masking was maintained. Details of the crossover sequence and any washout period are also not reported. Because transition from shampoo to foam could depend on response after four weeks, the results may depend on how treatment periods and switching were analyzed; the analysis approach is not reported in the registry record.

The eight-week assessment has limited coverage: data were not collected for the shampoo-only and foam-only groups, and only 3 participants completed eight weeks of crossover treatment. The record does not explain why observations were unavailable or how missing data were addressed. It also does not report participant flow, group-specific primary outcome numbers, or the analysis populations.

Generalizability is limited by the study’s stated focus on African American females with dandruff who wash their hair less than once weekly. The registry does not report additional participant characteristics that would help describe the enrolled group. The posted information therefore supports a description of this trial’s registered question and measurement approach, but not a complete assessment of comparative efficacy, precision, or applicability to other populations.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Seborrheic Dermatitis: Ketoconazole 2% Foam Versus Ketoconazole 2% Shampoo — NCT01203189.
• Registry record last updated 2017-11-06; status last verified 2017-10.
• Results first posted 2017-11-06.
• 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 describes a completed, randomized, single-masked crossover study of ketoconazole 2% foam versus ketoconazole 2% shampoo for scalp seborrheic dermatitis. It lists enrollment of 23 and focuses on African American females with dandruff who practice less than once-weekly hair washing. Shampoo was used twice weekly and foam applied twice daily, each for four weeks; shampoo-group participants could cross over to foam if TDSS did not improve by 60% after four weeks.

TDSS, the primary outcome, combines involvement and severity scores across scalp quadrants and ranges from 0 to 48. The record lists compliance and satisfaction outcomes, but numerical results for the primary and secondary outcomes are not reported in the registry record. Eight-week data were not collected for the shampoo-only and foam-only groups; only 3 participants completed eight weeks of crossover treatment. Listed adverse-event counts are zero for serious events, other events, and deaths in each group. The statistical analysis plan and analysis results are not reported.