Adherence to Topical Hydrocortisone 17-butyrate 0.1% (Locoid®) Using Different Vehicles in Adults With Atopic Dermatitis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Adherence to Topical Hydrocortisone 17-butyrate 0.1% (Locoid®) Using Different Vehicles in Adults With Atopic Dermatitis (NCT00693693), a randomized phase 4 study. The primary outcome is Adherence to Locoid.

2. Clinical Question

The clinical question concerns whether adherence differs across topical vehicles, rather than whether the active ingredient treats atopic dermatitis. The preparations share the stated concentration of hydrocortisone 17-butyrate 0.1%; the registry descriptions distinguish them by vehicle. The record does not report a separate clinical disease outcome among its primary results.

The registry lists Cream as the control and reports randomized allocation. However, the study model is labeled single-group, and the record does not explain how this label relates to the three named preparation arms. It is therefore safest to describe the posted arm-specific adherence results without assuming a particular sequence, crossover, or contrast structure. Those design details are not reported in the registry record.

3. Trial Design

This is a completed Phase 4 study sponsored by Wake Forest University. The registry identifies the allocation as randomized and masking as none. It lists a single-group model, while also reporting results for three preparation arms: Cream, Ointment, and Lipocream. How participants were assigned, whether they received more than one preparation, and the rationale for the single-group classification are not reported in the registry record.

The posted enrollment is 26. The arm-level outcome records include 6 participants for Cream, 7 for Ointment, and 8 for Lipocream. The record does not explain how these reported arm sizes relate to the enrollment figure, nor does it state whether every enrolled participant contributed to the primary endpoint. A participant flow, withdrawals, and analysis population are not reported in the registry record.

Each arm description specifies topical application twice daily to all lesions of atopic dermatitis. The primary adherence outcome was assessed over 2 weeks with a MEMS cap. The device-based definition counts the percentage of days on which the two total prescribed doses were applied. The record does not report further measurement procedures, such as how device records were handled or how adherence data were summarized for each participant.

The study start is listed as 2006-11 and primary completion as 2008-09; status is completed. The record does not report a protocol rationale for the design, a sample-size justification, or details about any interim analyses. Those details should not be inferred from the randomized label, the arm counts, or the posted endpoint.

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

Reasons for not completing this period:

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Adherence to Locoid, measured over 2 weeks.

The primary endpoint is titled “Adherence to Locoid.” It is a continuous measure, reported as a mean with standard deviation, with the unit described as percentage of days. The stated timeframe is 2 weeks. Adherence was measured by MEMS cap as the percentage of days that the two total prescribed doses were applied.

Conceptually, this endpoint describes the regularity of application during the observation period. A device-based measure can document patterns of opening associated with use, while the endpoint definition in the registry focuses on days when both prescribed doses were applied. The record does not describe how the device determined that medication was actually applied to lesions, so the posted endpoint should be read according to its stated operational definition rather than as a direct measure of skin response.

Adherence is relevant to interpreting topical treatment use because the prescribed application schedule can only be assessed in the context of whether doses were taken. However, this outcome is not itself a measure of disease severity, symptom relief, or treatment benefit. Those outcomes are not reported as primary results in the registry record. The posted means therefore address application behavior over 2 weeks, not the clinical effect of the preparations.

The record reports numeric mean values and standard deviations but no confidence limits for the arm results. It does not further clarify whether the numeric scale is expressed as a proportion or in another form, so the values are best quoted as posted rather than converted.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as continuous and summarizes it with a mean and standard deviation. These statistics describe a distribution differently: the mean indicates its central value, while the standard deviation describes the spread of observations around that value. General statistical explanation: neither statistic alone gives the uncertainty around the estimated mean. An interval estimate would help show a range of values compatible with the data under a specified statistical procedure, but confidence intervals are not reported for these arm summaries.

What does a mean and standard deviation tell us?

For this endpoint, each arm has one posted mean and one standard deviation. The mean represents the average value for the adherence measure as defined in the registry. The standard deviation reflects variability among recorded participant-level values, assuming the reported summary is calculated in the usual way. It does not describe the range of observations, and it does not tell whether observations were evenly distributed around the mean. Individual observations and distributional plots are not reported in the registry record.

General statistical explanation: estimates based on small groups can be imprecise, even when the standard deviation appears modest. Precision is usually conveyed by a standard error or confidence interval, interpreted in light of a suitable analysis. The record gives arm sizes but no such uncertainty measures. Without those estimates, readers cannot judge the precision of each mean from the reported summary alone. No additional calculation is made from the posted arm statistics.

What would a between-preparation analysis require?

A formal comparison would require a defined contrast and an analysis suited to how the observations were collected and assigned. The registry labels the allocation randomized, lists Cream as the control, and reports Ointment and Lipocream arms. It also labels the model single-group. The record does not explain this combination or report whether participants contributed observations to one preparation or more than one. That matters because an analysis for separate groups differs from one for repeated observations on the same participants.

No inferential analyses are posted. In particular, there are no reported pairwise estimates, confidence intervals, test statistics, or p-values for adherence comparisons. The registry also does not report an adjusted analysis or specify covariates. It is therefore not possible to describe the sponsor's statistical comparison procedure or to reproduce such a procedure from the record.

Why do the reported sample sizes matter?

The outcome summaries give arm sizes of 6 for Cream, 7 for Ointment, and 8 for Lipocream. General statistical explanation: the amount of information in a mean is affected by both the number of observations and their variability. Small arm counts can make estimates more sensitive to individual observations. The record does not provide participant-level values, so the influence of any individual observation cannot be assessed.

The registry includes assumptions for a planning illustration based on an observed effect, but no usable two-arm sample-size values are posted; the record states that values are missing or not estimable for a two-arm comparison of this continuous endpoint. No planning number should be interpreted as an observed result or as evidence about the study's power. A sample-size justification for the actual trial is not reported in the registry record.

What does the design information leave unresolved?

The randomized label concerns allocation, while masking is listed as none. General statistical explanation: lack of masking can affect how outcomes are recorded or interpreted, depending on the measurement and procedures. The MEMS-cap endpoint is device-based as described, but the record does not report whether device handling, data processing, or other outcome procedures were masked. It also does not explain whether participants or study staff knew which vehicle was in use beyond the masking field.

The record gives no statistical analysis plan, handling rules for missing adherence data, or definition of the analysis population. It does not report whether observations were excluded, whether missing records were imputed, or how repeated or incomplete device data were handled. Those issues cannot be resolved from the arm means and standard deviations.

General statistical explanation: over-dispersion arises when observed variability is greater than a statistical model expects; a model that ignores it may understate uncertainty. The posted summaries do not identify a count model, a variance assumption, or evidence of over-dispersion, and no such model should be presumed for this continuous endpoint. The applicable description is limited to the registry's mean-and-standard-deviation summaries.

The record's absence of inferential results is not equivalent to a finding that the preparations have identical adherence. It means that the registry does not report an analysis quantifying the uncertainty of differences. Descriptive values can be reported as observed, while conclusions about statistical evidence require methods and outputs not present in the registry record.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Cream", "Ointment", "Lipocream")
n   <- c(6, 7, 8)
m   <- c(0.55, 0.6, 0.5)
sp  <- c(0.07, 0.07, 0.07)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Cream  6  0.550  0.070  0.477  0.623
CARM  Ointment  7  0.600  0.070  0.535  0.665
CARM  Lipocream  8  0.500  0.070  0.441  0.559

11. Multiplicity, Missing Data and Analysis Populations

The record lists one primary outcome measure and no posted secondary outcome measures. It reports zero analyses. Although there are three preparation arms and Cream is identified as the control, the record does not report a multiplicity strategy for possible comparisons among them. Whether comparisons were prespecified, how many were intended, and whether any adjustment was planned are not reported in the registry record.

The registry gives arm-level sample sizes and outcome summaries, but it does not state the analysis population used for those summaries. A flow from enrollment to endpoint analysis, including withdrawals or exclusions, is not reported. The enrollment is 26, while the recorded arm sizes are 6, 7, and 8; the record does not explain the relation between these figures. No assumptions about missing participants or the reason for any difference should be made from these values alone.

Missing outcome data and their handling are not reported in the registry record. There is no description of whether device records were incomplete, whether missing days were treated as nonadherent, or whether any statistical imputation was used. The record also does not report an intention-to-treat, per-protocol, or other named analysis population.

General statistical explanation: missing-data choices can affect estimates, particularly when the likelihood of missingness is related to the outcome. Without a stated rule or information about missingness, the direction and magnitude of any such effect cannot be assessed. These reporting gaps also limit assessment of how multiple possible comparisons were handled. The posted summaries remain descriptive and should not be treated as a complete account of the planned analysis.

12. 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.

For Cream, the safety record lists 6 participants at risk, 0 affected by a serious adverse event, 0 affected by other adverse events, and 0 deaths. For Ointment, it lists 7 at risk and zero in each of those event categories. For Lipocream, it lists 8 at risk and zero in each category. No serious adverse-event terms are listed.

These are counts as posted for the recorded groups. They do not establish that no adverse events occurred outside the reported categories or observation period, and they do not provide detailed event definitions, follow-up duration, or methods for soliciting and classifying events. Those details are not reported in the registry record.

General statistical explanation: when no events are recorded in a group, the observed count remains a description of that study's reported experience; it does not by itself establish that the underlying event risk is zero. Precision around event rates would depend on the number at risk, follow-up, and analysis method. No confidence intervals or comparative safety analyses are reported. These figures should therefore be read as posted event counts, not as proof of safety or as a comparison among preparations.

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

The posted results describe measured adherence to three formulations over 2 weeks. Mean values are reported as 0.55 for Cream, 0.6 for Ointment, and 0.5 for Lipocream, with a standard deviation of 0.07 for each. The corresponding arm sizes are 6, 7, and 8. These results address application behavior as defined by the MEMS-cap endpoint: the percentage of days that the two total prescribed doses were applied.

The record does not report confidence intervals or tests for differences among the means. It therefore does not establish that one preparation had higher adherence than another in a statistical sense. Nor does it establish that any differences would persist in a different population or setting. The record's combination of randomized allocation and a single-group model is unexplained, and the analysis structure is not reported.

These values also do not establish clinical benefit. The primary endpoint is adherence, not disease severity or symptom change, and no clinical response outcome is posted among the primary results. The values should not be interpreted as evidence that a preparation improves atopic dermatitis or as evidence that it does not.

Interpretation is limited by the absence of analysis details, population information, missing-data rules, and uncertainty estimates. The numeric scale is described as percentage of days, but no additional scale convention is given for the posted values. They are therefore presented in the registry's recorded form without conversion. The safety counts report zero events in the listed categories, but do not remove the limits of the study's size and reporting detail.

14. Why This Trial Matters Statistically

This trial is statistically notable for separating a behavioral endpoint from a clinical outcome. Its primary measure concerns whether both prescribed daily doses were applied on a given day, using a MEMS cap over 2 weeks. That definition makes clear what the recorded outcome represents, while also limiting conclusions to the measured adherence behavior.

The record offers three arm-level means and standard deviations, but no inferential analysis. This distinction is useful for readers: observed summaries describe the data reported for the groups, whereas a formal comparison would quantify uncertainty around a contrast. Without confidence intervals, tests, or an explained analysis structure, apparent differences in the means cannot be treated as established between-preparation effects.

The trial also illustrates why design labels and analysis descriptions need to be read together. The registry calls allocation randomized and lists three preparation arms, but labels the model single-group. It does not explain the relationship between these features. This omission makes it difficult to know what comparison assumptions would be appropriate or how a statistical contrast should be interpreted.

Finally, the record's limited reporting of missing data and analysis populations matters even when the outcome is straightforward to state. Arm counts, endpoint definitions, and summary values alone do not show whether all enrolled participants contributed to the analysis or how incomplete device records were handled. Careful statistical interpretation distinguishes a clear descriptive endpoint from a complete account of the design and analysis.

15. 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 has several trial-specific reporting limitations. Although allocation is described as randomized, the model is labeled single-group while three preparation arms and a control arm are also identified. The record does not explain the assignment process, whether participants received one or multiple preparations, or how the arm structure should be understood. This uncertainty prevents a confident description of the intended comparison framework.

The total enrollment is listed as 26, while the endpoint arm sizes are 6, 7, and 8. Participant flow and an explanation of these counts are not reported. The record does not identify an analysis population or indicate whether withdrawals, exclusions, or unavailable device records affected the results.

The primary outcome is defined in terms of MEMS-cap measurement, but details of data collection and processing are not reported. The record does not describe how missing days were handled, whether device records were reviewed or validated, or whether participants' application behavior was confirmed by another method. The endpoint's unit is given as percentage of days, but the scale convention for the numeric results is not further clarified.

Only means and standard deviations are posted. Confidence intervals, hypothesis tests, and between-arm estimates are absent, as are statistical analysis details and a sample-size justification. No multiplicity approach is reported. These limitations mean the results can be described but not used to infer a statistically supported difference between vehicles. A clinical outcome is not included among the posted primary results, so adherence cannot be linked to disease response from this record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Adherence to Topical Hydrocortisone 17-butyrate 0.1% (Locoid®) Using Different Vehicles in Adults With Atopic Dermatitis — NCT00693693.
• Registry record last updated 2018-09-10; status last verified 2018-08.
• Results first posted 2017-03-17.
• 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.

19. Record Summary

NCT00693693 is a completed Phase 4 randomized study sponsored by Wake Forest University, with masking listed as none and a single-group model designation. It enrolled 26 participants with atopic dermatitis and recorded adherence for topical hydrocortisone 17-butyrate 0.1% Cream, Ointment, and Lipocream preparations.

The primary endpoint was adherence measured by MEMS cap over 2 weeks, defined as the percentage of days that the two total prescribed doses were applied. Posted means are 0.55 for Cream, 0.6 for Ointment, and 0.5 for Lipocream; each has a standard deviation of 0.07. The reported arm sizes are 6, 7, and 8, respectively.

No analyses are posted. Confidence intervals, between-arm tests, missing-data procedures, and the analysis population are not reported in the registry record. The safety entries list zero serious adverse events, zero other adverse events, and zero deaths in each group.