Effectiveness of Artificial Balneotherapy, Phototherapy and Artificial Balneophototherapy in the Treatment of Psoriasis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effectiveness of Artificial Balneotherapy, Phototherapy and Artificial Balneophototherapy in the Treatment of Psoriasis (NCT02713711), a randomized na study. The primary outcome is Percentage Change in Psoriatic Plaque Area.

2. Clinical Question

The trial was intended to compare three treatment approaches within a randomized, controlled study. Its primary measure concerned change in plaque area, while listed secondary outcomes concerned plaque erythema, PASI change, quality of life, and psoriasis-related disability. The registry record does not give the numerical results for these outcomes or establish which pairwise comparisons were planned. It also does not report how assignment was carried out or whether randomization applied to participants, plaques, or both. Those details matter because multiple plaques from the same person may share characteristics and may not represent independent observations.

3. Trial Design

The registry record identifies a completed, randomized, parallel-group study of artificial balneotherapy, phototherapy, and artificial balneophototherapy for psoriasis. The brief summary describes the study as prospective and single-blind, whereas the registry’s masking field says none. The record does not clarify this difference or identify who, if anyone, was blinded. The trial began in 2013-12 and had primary completion in 2014-06.

Four groups are described: an untreated control group, a phototherapy group, a balneotherapy group, and a balneophototherapy group. The active-treatment descriptions specify twelve sessions. Phototherapy used UV-B applied to plaques according to an individual initial assessment of Minimal Erythema Dose. Balneotherapy involved 15-minute sessions using warm water at 32 °C and natural sea salt at 250 g/L. The combined group received both procedures under the conditions described for the separate treatments. Control-group plaques received no treatment.

The brief summary reports 14 participants and says all completed the study’s twelve sessions. The primary-outcome description reports 58 plaques divided among the four groups. The participant count and plaque count describe different units: several plaques could come from the same person. The record does not report group-specific participant counts, group-specific plaque counts, the unit of randomization, or whether analysis accounted for plaques clustered within participants.

Assessments were scheduled before the first session and after the sixth and twelfth sessions. The primary-outcome timeframe labels these as day 1, day 12, and day 26. The study measured plaque area from photographs and also listed outcomes related to erythema, PASI, quality of life, and psoriasis disability. The record does not report a detailed statistical analysis plan or a sample-size justification.

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

Analysis population for the primary outcome, as defined in the registry: 14 subjects (7 female and 7 male) with 58 total psoriatic plaques divided in the 4 groups

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: In all the study were 14 participants with 58 total psoriatic plaques divided in 4 groups (14 in C group, 15 in AB group, 14 in PT group, and 15 in BPT group)

6. Primary Endpoint

The registry lists the primary outcome as Percentage Change in Psoriatic Plaque Area, measured over Before first session (day 1), after the six session (day 12) and after the twelve session (day 26).

The primary endpoint was percentage change in psoriatic plaque area. Plaques were photographed before the first session and after the sixth and twelfth sessions. The record describes photographs taken at a distance of 20 cm with a 12 pixel Lumix digital camera and says ImageJ software was used to quantify area. A single area value per plaque was calculated after twelve sessions as a percentage of decrease.

Plaque area is a continuous measure: it can take a range of values rather than only categories such as improved or not improved. The registry identifies the planned summary as a mean with standard deviation. In general, a mean describes the central value of a set of measurements, while a standard deviation describes how spread out individual measurements are around that mean. Neither statistic is reported numerically for the treatment groups in the registry record.

Using a measured area allows investigators to describe change in the size of plaques over the treatment period. Photographic measurement may support quantification of visible area, but interpretation depends on consistent image capture and measurement procedures. The record describes the camera distance and software, but does not report details such as assessor blinding, repeatability, or measurement reliability. Although measurements were scheduled at several time points, the record does not report the numerical group results at any time point or a single comparison that can be interpreted as the primary treatment effect.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean with standard deviation describe?

The primary outcome is continuous, and the registry says it was summarized using a mean and standard deviation. In general, the mean is an average that conveys the center of the observed measurements. The standard deviation describes their spread around that average. A mean can be useful for comparing groups, but it does not show the full distribution of measurements. It may be influenced by extreme values, and the same mean can arise from data with different shapes or patterns.

The registry record does not report the group means or standard deviations for percentage change in plaque area. It also does not give a numerical contrast between groups. Consequently, the planned summary type can be described, but the actual treatment estimates and variability cannot be interpreted. A standard deviation is not a confidence interval: it describes variation among observations, while a confidence interval expresses uncertainty around an estimated quantity under a specified analysis.

Why is the analysis unit important?

The trial description reports 14 participants and 58 plaques, with plaques divided among four groups. Participants, rather than plaques, are people enrolled in the study; plaques are measurements within people. In general, measurements from one person may be more alike than measurements from different people. This dependence is called clustering. If it is present, an analysis that treats every plaque as independent may produce uncertainty estimates that are too small. Statistical methods can account for clustering, but the registry record does not report whether this was done.

The record also does not state whether randomization was at the participant or plaque level. If treatment was assigned to participants, the person may be the natural unit of assignment even when several plaques are measured. If plaques were assigned separately, within-person dependence would still need consideration. Without the assignment unit, group counts, and analysis method, readers cannot determine how the 58 plaque measurements contributed to the reported comparisons.

What can repeated assessments show?

Plaque area was assessed before the first session and after the sixth and twelfth sessions. Repeated measurements can describe the course of an outcome over time, rather than only its value at one endpoint. In general, analyses of repeated measurements need to account for the fact that observations from the same plaque or participant are related. They also need to specify whether the target is change from baseline, a difference between groups at a particular time, or a difference in change over time.

The registry record provides the assessment schedule and describes a percentage decrease after twelve sessions, but it does not report how repeated observations were analyzed. It does not identify a single time point or contrast as the sole primary comparison. The registry’s stated reason for not reducing the primary outcome to one comparison is that it has several categories or time points. Numerical results at the scheduled assessments are not reported in the record.

What do confidence intervals and p-values contribute?

In general, a confidence interval communicates the precision of an estimate by giving a range of values compatible with the observed data and the method’s assumptions. A narrower interval indicates greater precision than a wider interval, all else being equal. A p-value assesses how unusual the observed data would be under a stated null hypothesis and analysis model. It does not measure the probability that a treatment is effective, and it does not convey the size or practical importance of a difference.

The registry record does not report confidence intervals or p-values for the primary endpoint. The absence of these quantities means that neither the precision of an estimate nor evidence against a specified null hypothesis can be assessed from the posted primary-outcome information. A numerical p-value alone would not resolve questions about the analysis unit, multiplicity, or bias; those require information about the design and methods as well.

How should planning calculations be distinguished from trial results?

The record 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 says that the effect to detect is a stated fraction of the observed effect. Such calculations are planning scenarios: they express how many participants per arm might be needed under specified assumptions. They are not observed trial outcomes and do not show the probability that this completed study detected an effect.

The record does not report the trial’s own sample-size justification. The planning assumptions concern two-arm comparisons, while this study describes four groups; readers should not treat the illustration as a description of the original design or as evidence of observed power. Sample-size calculations depend on their assumed effect, variability, allocation, significance level, and analysis. The registry record does not report a protocol rationale that can be used to evaluate whether the enrolled sample was selected for adequate precision.

In general, over-dispersion means that observed variation is greater than a model assumes. When a model underestimates variability, its uncertainty estimates may be too optimistic. For clustered plaque measurements, dependence within participants is a related concern because it can make the effective information lower than a count of separate plaques might suggest. These are general statistical considerations; the registry record does not report an over-dispersion assessment or a specific model for the primary outcome.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists five outcome measures and ten analyses. The primary outcome is described at multiple assessment times, and the record says it was not reduced to one comparison. It does not report which comparisons were designated as primary among the treatment groups and time points, or whether any adjustment for multiple testing was planned or used. In general, when several hypotheses are tested, the chance of at least one apparently notable result can increase; prespecified comparisons and appropriate methods help readers interpret a collection of results. No correction method is reported in the registry record.

The brief summary says all 14 participants completed the twelve sessions. Completion of treatment does not show whether all scheduled endpoint measurements were obtained. The record does not report missing measurement counts, reasons for missingness, imputation methods, or sensitivity analyses. It also does not specify whether the analysis included everyone as randomized or only participants with available measurements. The analysis population and handling of missing data are therefore not reported in the registry record.

The record does not report a detailed statistical analysis plan, the randomization unit, or whether the analysis accounted for multiple plaques within a participant. These omissions limit evaluation of multiplicity, missing-data assumptions, and uncertainty. The absence of a reported method should not be interpreted as evidence that no such method was used; the registry record does not establish the issue either way.

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

The trial record describes a randomized comparison of three active approaches and an untreated control, with plaque area as the primary outcome. However, it does not report numerical primary-outcome results. No direction or size of difference among the groups can therefore be stated, and the record does not support a conclusion about whether the groups differed statistically. It also does not provide confidence intervals with which to judge precision.

The study included 14 participants and 58 plaques in total. These figures describe the scope of the study, not the number of independent observations for every comparison. The record does not show how participants or plaques were distributed across groups or how within-participant dependence was handled. The small total participant count makes careful attention to uncertainty especially important, but the record does not provide estimates from which that uncertainty can be quantified.

The listed adverse-event entries show zero at risk and zero affected participants in the groups, while death counts are null. Because the number at risk is recorded as zero, these entries cannot be read as confirmation that no serious or other events occurred. Further safety information is not reported in the registry record.

These limitations mean the registry record supports a description of the trial’s design, treatment schedules, and intended outcome measurement, but not a conclusion about comparative effect, precision, or safety. The results should not be framed as evidence that an approach does or does not work. Such judgments would require numerical outcome results and a clear account of the analysis, including its handling of repeated measurements and plaques from the same participant.

12. Why This Trial Matters Statistically

This trial illustrates why counts at different levels of a study should be kept distinct. The record reports 14 participants and 58 plaques. A plaque-level outcome may yield many measurements, but multiple plaques from one person can share features. Statistical interpretation depends on whether randomization and analysis are based on participants, plaques, or a model that accounts for both levels. The registry record does not report these details, making the unit of analysis an important unresolved issue.

The study also has four groups and assessments at several times. A trial with multiple groups and repeated outcomes can generate several possible comparisons. In general, readers need to know which contrast and time point were prespecified and how multiplicity was handled to interpret a set of findings without overemphasizing a selected result. The registry record identifies ten analyses but does not describe their allocation across comparisons or any multiplicity procedure.

Finally, a defined measurement procedure does not substitute for reported results. The record describes photography and image analysis for plaque area, but gives no numerical group estimates or uncertainty measures for that endpoint. Without those, the central statistical questions—how large the observed differences were, how precise they were, and how they were analyzed—remain unanswered. This is a useful reminder that a trial’s design and its result reporting are separate parts of the evidence available for interpretation.

13. 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 total enrollment was 14 participants across four groups, and the registry record does not report group-specific participant or plaque counts. This prevents assessment of how the sample was distributed or how much information each comparison contained. The 58 plaques are nested within the participants; the record does not report whether this dependence was addressed in the analysis.

The primary outcome is described at three assessment points, but the record does not provide numerical results or a single primary contrast. It does not report the statistical model, treatment-effect estimates, confidence intervals, or p-values. Nor does it report the original sample-size justification or a detailed analysis plan. The planning illustration described in the record is based on specified assumptions and is not a substitute for the trial’s design rationale or observed results.

The registry’s masking field says none, while the study summary calls the trial single-blind. The record does not resolve the discrepancy or say who was blinded. The image-assessment description does not state whether the person quantifying plaque area was blinded to group or time point. This leaves the potential for measurement influence difficult to evaluate.

The record states that all participants completed the sessions but does not report completeness of outcome measurements, missing-data methods, or analysis populations. It also does not explain how the untreated control condition was applied alongside treatment of plaques. Finally, safety entries list zero participants at risk, and deaths are not reported; these entries do not establish the extent of safety monitoring or the absence of events.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: Effectiveness of Artificial Balneotherapy, Phototherapy and Artificial Balneophototherapy in the Treatment of Psoriasis — NCT02713711.
• Registry record last updated 2021-02-15; status last verified 2021-01.
• Results first posted 2021-02-15.
• 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.

17. Record Summary

This completed randomized, parallel-group trial compared phototherapy, balneotherapy, and balneophototherapy with an untreated control for psoriasis. The brief summary reports 14 participants, all of whom completed twelve sessions; the primary-outcome description reports 58 plaques across four groups. Assessments were scheduled before treatment and after the sixth and twelfth sessions.

The primary endpoint was percentage change in psoriatic plaque area, measured from photographs and summarized as a mean with standard deviation. Secondary outcomes concerned plaque erythema, PASI, quality of life, and psoriasis disability. The record identifies five outcome measures and ten analyses but does not report numerical primary-outcome results, group estimates, or uncertainty measures. It also does not report the analysis plan, group allocation counts, missing-data handling, or whether plaque clustering was addressed. The record’s masking field and study summary differ on whether masking was used.