Post Marketing Observational Study (PMOS) to Assess Quality of Life in Swedish Hidradenitis Suppurativa (HS) Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Post Marketing Observational Study (PMOS) to Assess Quality of Life in Swedish Hidradenitis Suppurativa (HS) Patients (NCT02739828), a registered phase not stated study. The primary outcome is Change From Baseline in DLQI at Week 12.

2. Clinical Question

The clinical question is about quality of life in patients with moderate or severe HS receiving adalimumab under usual care. DLQI is a patient-reported measure of symptoms and the impact of dermatologic disease on quality of life. Its score ranges from 0 to 30, with higher scores indicating more impaired quality of life. The primary outcome is framed as a change from baseline, rather than as a comparison between treatment groups.

The study also listed secondary measures involving DLQI, skin pain, and EQ-5D responses at different follow-up visits. Those additional measures broaden the description of patient experience, but they do not create a control group. Without a randomized comparator, observed change over time cannot by itself distinguish treatment-related change from other influences, including the natural course of HS and changes in care or circumstances.

3. Trial Design

This was a post-marketing observational study of adalimumab in Swedish patients with moderate or severe HS. The registry record describes treatment according to routine clinical practice and the Swedish Summary of Product Characteristics. Enrollment was 24. The study is marked completed, with a start date of 2016-04-07 and a primary completion date of 2018-03-28.

The listed treatment group consists of patients with HS prescribed adalimumab. The record does not describe a randomized allocation or a control group; it explicitly indicates that this is not a randomized comparison and that the listed groups are not a like-for-like control comparison. The primary question is consequently a within-cohort question about change in DLQI from baseline to Week 12, not an estimate of the difference between adalimumab and another treatment or no treatment.

The study objective included quality of life, skin pain, work productivity or activity, and health-related problems before and after treatment. The listed secondary outcomes include DLQI change at Week 4 and Week 24, skin-pain assessments at Week 4, Week 12, and Week 24, and EQ-5D responses at Week 4, Week 12, and Week 24. The title and objective describe follow-up over 6 months. The specific schedule and analytical details beyond the stated outcomes are not reported in the registry record.

Because treatment occurred in routine care rather than through a randomized comparison, the design can describe outcomes observed in the treated cohort but does not isolate the effect of treatment from other explanations for change. Details such as recruitment procedures, any prespecified analysis plan, and the method used to handle follow-up assessments are not reported in the registry record. The participant count and completed status describe the study record; they do not establish how many participants contributed to each outcome analysis.

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:

Analysis population for the primary outcome, as defined in the registry: Full Analysis Set (modified Intention-to-treat): All enrolled participants, with the exception of those who were enrolled and not treated with any dose of adalimumab, or who had no baseline or post baseline data collected for the primary analysis variable DLQI. Participants with an assessment at Week 12.

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 Change From Baseline in DLQI at Week 12, measured over Baseline, Week 12.

The primary endpoint is change from baseline in DLQI at Week 12. DLQI assesses symptoms and the impact of dermatologic diseases on quality of life. The score ranges from 0 to 30, and a higher score indicates more impaired quality of life. A change score expresses how a participant’s measured score differs from their baseline measurement; interpretation depends on the direction and size of the reported change and on the analysis used.

The registry record specifies the endpoint as a mean with standard deviation. A mean describes the average score change in the analysis population, while the standard deviation describes how variable individual score changes are around that average. These are complementary summaries: the mean conveys the cohort’s average change, and the standard deviation indicates the spread of participant-level changes. Neither alone describes the precision of the estimated mean as fully as a confidence interval would.

The endpoint is relevant to the stated objective because it captures the patient-reported effect of skin disease on quality of life, rather than relying only on clinical signs. However, the primary change estimate, its standard deviation, and a confidence interval or other inferential result are not reported in the registry record. The record therefore identifies what was intended to be measured, but does not permit assessment of the observed direction, magnitude, or precision of the Week 12 change.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the mean change represent?

The primary outcome is defined as change in DLQI from baseline to Week 12 and is summarized as a mean with standard deviation. In general, a change score is calculated for each participant by comparing the follow-up measurement with that participant’s baseline measurement, and the mean summarizes those participant-level changes. The direction of the change depends on the subtraction convention used. The registry record does not state that convention, and it does not report the mean change itself. The score interpretation is clear: higher DLQI scores indicate more impaired quality of life.

The standard deviation describes variability among individual measurements or changes. It is not the same as the uncertainty around the group mean. In general, a confidence interval for a mean uses information about both the observed spread and the number of observations included. Since the primary estimate, its standard deviation, analysis count, and confidence interval are not reported in the registry record, the observed variation and precision cannot be evaluated.

Why is the study design important?

This is an observational study in which participants were treated according to routine clinical practice. The record does not describe random assignment or a control group. A before-and-after comparison can show how measurements changed in the observed cohort, but the passage of time includes more than treatment exposure. In general, natural disease variation, concurrent care, changes in health or daily life, and regression to the mean can contribute to changes between assessments. A randomized comparison is one way to strengthen causal interpretation; this record does not describe one.

The study should therefore be understood as an assessment of outcomes among treated patients, rather than as a randomized estimate of the difference caused by adalimumab. Even if a numerical within-cohort change were available, it would not by itself show what would have happened to comparable patients without treatment. The registry record does not report an adjusted or comparative estimate that addresses this issue.

What can be inferred from a planning calculation?

The record describes sample-size calculations as planning illustrations based on the observed effect, not as the study’s own design. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a stated fraction of the observed effect. These assumptions describe a hypothetical planning exercise; they do not establish that the observational study used two randomized arms or was designed using those assumptions. The record does not report the numerical planning outputs or a stated effect fraction.

In general, a sample-size calculation asks how much information a proposed design might need to detect a specified effect under chosen assumptions. Its output depends on those assumptions, including the target effect and variability. A planning illustration is not observed power, and it cannot repair the absence of the primary outcome result. It should not be interpreted as evidence that the completed study had a particular probability of detecting an effect. The record’s planning assumptions are also distinct from the actual allocation, which is not reported as randomized.

Why does variability matter?

For continuous outcomes, variability affects how precisely a mean can be estimated and how readily a comparison can distinguish a signal from random fluctuation. The standard deviation is one summary of that variability. General statistical methods may also need to account for non-normal distributions or over-dispersion, meaning greater variability than a model expects. If a model assumes less variability than the data contain, its uncertainty estimates can be too small and its conclusions too confident. The registry record does not report a model choice, a distributional assessment, or an over-dispersion adjustment for the primary outcome.

These are general considerations, not descriptions of methods confirmed for this study. The registry record identifies the primary outcome as a mean with standard deviation but does not state the inferential test, model, confidence-interval method, covariate adjustment, or diagnostics. It is therefore not possible to say whether or how these statistical issues were addressed.

What is not reported about the analysis?

The primary analysis population is described as a modified Intention-to-treat set comprising enrolled participants except those who received no dose of adalimumab or had no baseline or post-baseline data for DLQI. The population description ends with an incomplete reference to participants with an assessment at “Wee”; the remainder of that detail is not reported in the registry record. The actual number analyzed for the primary endpoint is also not reported.

The record lists 31 outcome measures and 27 analyses. It does not report which inferential procedures were used for each analysis, whether outcomes were adjusted for baseline characteristics, how repeated measurements were modeled, or whether any results were prespecified. Such details matter because analysis choices can affect estimates and uncertainty. Without them and without the numerical primary result, statistical interpretation must remain limited to the stated endpoint and design.

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("Participants With Hidradenitis Suppurativa")
n   <- c(18)
m   <- c(-7.8)
sp  <- c(6.79)
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  Participants With Hidradenitis Suppurativa  18  -7.800  6.790  -11.177  -4.423

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 31 outcome measures and 27 analyses. The outcomes include the primary DLQI change at Week 12, additional DLQI assessments, skin-pain assessments, and EQ-5D responses at specified visits. Considering multiple outcomes or analyses can increase the chance that at least one result appears notable by chance when many statistical tests are performed. In general, multiplicity methods can control or otherwise address this issue, but the choice depends on the analysis goals and the relationships among outcomes.

Whether any adjustment for multiple comparisons was planned or used is not reported in the registry record. The record also does not identify a hierarchy of secondary outcomes or say which results were treated as confirmatory versus exploratory. Without that information, the listed number of outcomes and analyses should be understood as scope, not as evidence that any particular multiplicity approach was applied.

The primary analysis population is described as a modified Intention-to-treat set: enrolled participants are excluded if they received no dose of adalimumab or had no baseline or post-baseline data for the primary DLQI variable. The population description is incomplete after a reference to participants with an assessment at “Wee”; the remaining wording is not reported in the registry record. The number included in the primary analysis is not reported.

Missing-data procedures, including whether incomplete follow-up was imputed, modeled, or handled through another method, are not reported in the registry record. This matters because participants with unavailable follow-up data may differ from those with observed measurements. The amount and pattern of missing DLQI data are also not reported, so the possible influence of missingness on the primary result cannot be assessed.

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 5% reporting threshold.

For the listed group of patients with HS, the registry record reports 24 at risk for serious adverse events and 0 affected. It also reports 24 at risk for other adverse events and 0 affected, with 0 deaths. The registry record lists no top serious-event terms. These are reported counts, not estimates of an underlying event rate.

A zero count means that no event was recorded in the specified category for this group in the registry record. It does not establish that the treatment has no safety risks or that an event could not occur in other patients or settings. In general, a small observational cohort can provide limited information about uncommon events, and routine-care reporting may differ from event collection under a dedicated safety protocol.

The registry record does not report the safety observation window, event definitions, or further detail about ascertainment. The counts should therefore be read as the available descriptive safety information, not as a complete characterization of safety. They are separate from the unreported primary DLQI result and do not determine how quality of life changed.

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

The study addresses an important descriptive question: how quality of life and other patient-reported measures changed among Swedish patients with moderate or severe HS receiving adalimumab in routine care. The registry record identifies DLQI change from baseline to Week 12 as the primary outcome and explains how to interpret the score’s direction. It does not report the numerical primary result, so the observed direction, magnitude, and precision of change cannot be stated.

The study design also determines what a result could mean. Because the registry record does not describe randomization or a control group, a before-and-after change would not by itself establish that treatment caused the change. Other influences over time could contribute. A causal treatment comparison would require a credible comparator and suitable analysis, neither of which is described in this record.

The outcome is patient-reported and therefore offers a perspective on daily impact that is not interchangeable with a clinical assessment of disease signs. At the same time, the registry record does not provide participant-level results, a complete analysis population count, or uncertainty estimates. It is not possible to assess the consistency of changes across participants or the precision of the average.

The safety record reports zero serious adverse events, zero other adverse events, and zero deaths among the listed group at risk of 24. These descriptive counts do not prove absence of risk. The record does not provide the event observation window or additional ascertainment detail.

Any planning calculations described for sample size are illustrations under stated assumptions, not observed power and not evidence that a specific effect was detected. In short, the registry record defines the clinical question and some methods and safety information, but it does not support a numerical conclusion about the primary quality-of-life result or a causal claim about adalimumab.

14. Why This Trial Matters Statistically

This study is statistically instructive because it separates a clinically relevant question from the evidence needed to answer it precisely. DLQI is intended to capture symptoms and the impact of dermatologic disease on quality of life, and the registry record specifies a baseline-to-Week 12 change as the primary endpoint. Yet the endpoint definition alone is not enough to evaluate the result: the mean change, variability, analysis count, and uncertainty are not reported in the registry record.

The observational, routine-care setting is also important. Such a design describes outcomes in the context in which patients are treated, but a cohort’s change over time is not equivalent to a randomized treatment contrast. Statistical interpretation must account for design before considering significance or size. Here, the record does not describe a control group or randomized allocation, so a causal effect cannot be isolated from the posted study description.

The record lists multiple outcome measures and analyses, raising a general question about how multiplicity was handled. It also defines a modified analysis population while leaving some wording incomplete and does not state how missing outcomes were addressed. These are not minor reporting details: they affect which participants contribute information and how uncertainty should be understood.

Finally, the registry’s planning illustrations are explicitly distinguished from the study’s own design. This prevents a planning calculation from being mistaken for observed power or an outcome finding. The study therefore illustrates why clear reporting of estimates, uncertainty, analysis populations, missing-data methods, and design is essential for readers to judge what clinical data can support.

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 most consequential limitation of the available registry record is that it does not report the numerical result for the primary DLQI change at Week 12. The mean change, its standard deviation, and an uncertainty interval are not reported in the registry record. Consequently, the primary outcome’s direction, magnitude, and precision cannot be assessed.

The observational design provides no randomized comparison in the posted description. Patients were treated in routine clinical practice, and the record does not describe a control group. Changes over time may therefore have explanations other than treatment. The registry record does not report an adjusted comparative analysis that could address this limitation.

Although enrollment is listed as 24, the number contributing to the primary analysis is not reported. The modified Intention-to-treat definition excludes participants who received no adalimumab or lacked baseline or post-baseline DLQI data. The available population wording is incomplete, and missing-data methods and the pattern of missing assessments are not reported. These gaps limit assessment of selection and potential bias in the analyzed group.

The record lists 31 outcome measures and 27 analyses but does not report whether multiplicity was addressed, how secondary analyses were prioritized, or which statistical procedures were used. Details about model specification, baseline adjustment, and repeated-measure analysis are not reported in the registry record. Safety reporting also lacks the observation window and further event-ascertainment details. Together, these reporting and design limitations restrict interpretation to the study’s stated objectives and descriptive information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Post Marketing Observational Study (PMOS) to Assess Quality of Life in Swedish Hidradenitis Suppurativa (HS) Patients — NCT02739828.
• Registry record last updated 2019-08-09; status last verified 2018-05.
• Results first posted 2019-08-09.
• 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

NCT02739828 is a completed post-marketing observational study of adalimumab in Swedish patients with moderate or severe hidradenitis suppurativa. The record lists enrollment of 24 and dates of 2016-04-07 for study start and 2018-03-28 for primary completion. Treatment was prescribed in routine clinical practice.

The primary outcome was change from baseline in DLQI at Week 12, measured as a mean with standard deviation. The primary numerical result and its uncertainty are not reported in the registry record. Secondary outcomes included DLQI, skin pain, and EQ-5D measures at listed follow-up visits.

The record reports 0 serious adverse events, 0 other adverse events, and 0 deaths among the group with 24 at risk. It does not describe a randomized control comparison. Details of multiplicity handling, missing-data methods, and the complete primary analysis population are not reported in the registry record.