Vascular Inflammation in Psoriasis-Ustekinumab (VIP-U): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Vascular Inflammation in Psoriasis-Ustekinumab (VIP-U) (NCT02187172), a randomized phase 4 study. The primary outcome is Change in Vascular Inflammation.

2. Clinical Question

3. Trial Design

VIP-U was a phase IV randomized, double-blind, placebo-controlled study with a parallel-group design. The registry lists quadruple masking. Enrollment was 43, and the study is marked completed. It was sponsored by the University of Pennsylvania. The record lists a start date of 2014-07 and primary completion on 2018-09-11.

The randomized placebo-controlled period ran through week 12. During that period, one group received ustekinumab and the other placebo. The placebo group then began ustekinumab, so the later active-treatment summary is not a continuing randomized comparison of ustekinumab against placebo. The record describes the active-treatment summary as baseline to week 52 for the original ustekinumab group and baseline to week 64 for the original placebo group.

The primary endpoint concerns total vascular inflammation across five aortic segments, assessed by FDG-PET/CT. The registry's primary result reports analyzed group sizes of 22.0 for ustekinumab and 19.0 for placebo in the randomized period. It also reports a composite active-treatment group of 38.0 for the end-of-study analysis. The record notes that analyzed numbers reflect participant dropouts and availability of analyzable samples; the full analysis-population definitions are not reported in the registry record.

The study also listed measures of psoriasis activity, patient-reported diet-related behavior and physical activity, and safety. The registry's overall enrollment should not be treated as the denominator for every endpoint: the analyzed populations differ by outcome and period.

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: The number of subjects analyzed reflect patient dropouts and availability of analyzable samples. The two arms in the RCT period are compared in Statistical Analysis 1. The composite "Total" group is used to assess 52 weeks of active treatment at end of study compared to baseline and is analyzed separately in Statistical Analysis 2.

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 in Vascular Inflammation, measured over Baseline - Week 12; Baseline - End of Study Visit (Week 52 or Week 64).

The primary endpoint measures change in vascular inflammation using FDG-PET/CT. The record describes measuring arterial uptake of FDG with a standardized uptake value, then dividing the maximum arterial value by the mean venous value to obtain a target-to-background ratio, or TBR. The measure combines information across five aortic segments, and the primary outcome is expressed as TBR max.

Imaging-based measures can capture activity in the vessel wall that is not directly represented by symptoms. In this study, that makes the endpoint a way to examine vascular inflammation alongside the participants' psoriasis. This is a general explanation of why imaging biomarkers can be used in clinical research; it does not establish that the measure predicts a clinical event or reflects every aspect of cardiovascular health.

The randomized comparison focuses on baseline to week 12, when one group received placebo and the other ustekinumab. A separate result covers baseline to the end of active treatment. Because the placebo group subsequently received ustekinumab, that later composite result describes change during active treatment rather than a concurrent placebo-controlled contrast. The record does not report further details on image reading, reproducibility, or the clinical interpretation of a particular TBR change.

7. Results Posted in the Registry

• Ustekinumab (RCT Period): mean -0.10 versus 0.14 on control; difference -0.25 (95% CI -0.34 to -0.15), standardized effect d = -1.49; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Number of Participants Achieving PASI75 (75% or Greater Reduction in PASI Score)

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Ustekinumab (RCT Period): 77.3% (17/22) versus 10.5% (2/19) on control; risk difference 66.7 percentage points (95% CI 44.5 to 89.0), risk ratio 7.34 (1.94–27.77); unadjusted two-proportion z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically higher for Ustekinumab (RCT Period) than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Number of Participants Achieving PASI90 (90% or Greater Reduction in PASI Score)

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Ustekinumab (RCT Period): 40.9% (9/22) versus 0.0% (0/19) on control; risk difference 40.9 percentage points (95% CI 20.4 to 61.5); unadjusted two-proportion z-test p = 0.002.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically higher for Ustekinumab (RCT Period) than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Number of Participants Achieving Physician Global Assessment (PGA) Clear/Almost Clear

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Ustekinumab (RCT Period): 63.6% (14/22) versus 10.5% (2/19) on control; risk difference 53.1 percentage points (95% CI 28.7 to 77.5), risk ratio 6.05 (1.57–23.28); unadjusted two-proportion z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically higher for Ustekinumab (RCT Period) than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The posted secondary outcomes include measures of psoriasis response and patient-reported behavior and activity. For the randomized period, the reported comparisons for PASI75, PASI90, and Physician Global Assessment clear or almost clear all point in the direction of more favorable observed psoriasis outcomes in the ustekinumab group. This broad pattern is relevant to the study's dermatologic outcomes, but it is separate from the primary vascular inflammation measure.

The secondary outcomes do not establish that changes in psoriasis activity correspond to changes in vascular inflammation. They measure different concepts, and the registry does not report an analysis linking individual skin responses with individual imaging changes. The later active-treatment summaries are also descriptive in context: the original placebo group began ustekinumab after week 12, so those summaries do not preserve the randomized placebo contrast.

The registry lists five secondary outcomes, while results for MEDFICTS and IPAQ are not reported in the registry record. The absence of those results means the complete pattern across all listed secondary measures cannot be assessed from the record.

Secondary findings generally carry less weight than a prespecified primary analysis, especially when many outcomes are examined. Multiple testing increases the chance that some comparisons appear noteworthy by chance. The registry record does not report a multiplicity adjustment or enough information to determine how these outcomes were prioritized in the original analysis plan. The secondary comparisons are therefore best viewed as supporting or exploratory context, not as independent confirmation of the primary result.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Number of Participants Achieving PASI75 (75% or Greater Reduction in PASI Score)
• Number of Participants Achieving PASI90 (90% or Greater Reduction in PASI Score)
• Number of Participants Achieving Physician Global Assessment (PGA) Clear/Almost Clear
• Change in Patient-Reported Outcomes: MEDFICTS
• Change in Patient-reported Physical Activity Assessments: IPAQ

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: it is a mean change in TBR max. A mean summarizes the average change in each group, while a mean difference compares the two group summaries. In the randomized comparison, the reported contrast is calculated as the ustekinumab group's mean minus the placebo group's mean. A negative value therefore indicates a lower mean change in the ustekinumab group on this scale; it does not, on its own, establish the clinical importance of that difference.

What does the confidence interval describe?

A confidence interval expresses the precision of an estimate under the statistical model used. A narrower interval indicates greater precision than a wider interval. An interval that includes zero is compatible with no group difference under the model; an interval that excludes zero is less compatible with that possibility. This general interpretation does not address bias, measurement quality, or whether the endpoint is clinically important.

The registry reports a linear regression analysis for the primary comparison, with a mean difference in final values. The registry record does not report the regression specification, covariates, or other model details. The recalculation displayed alongside the reported result is an unadjusted comparison derived from the posted group summaries. It is useful as a check on the direction and approximate size of the contrast, but it does not reproduce the sponsor's regression analysis.

Why are the reported and recalculated results different?

The registry analysis and the simple recalculation do not have identical confidence intervals or p-values. They may reflect different analysis approaches or inputs, but the details needed to identify the reason are not reported in the registry record. Since the record flags a discrepancy, the sponsor's own analysis takes precedence. The recalculation should be interpreted as a supplementary, unadjusted check rather than as a correction to the registry analysis.

What does the p-value add?

A p-value describes how unusual data at least this incompatible with a specified null model would be if that model and its assumptions were correct. It is not the probability that the null hypothesis is true, nor does it measure the size or clinical importance of an effect. The registry's primary randomized-period p-value is 0.001; the simple unadjusted recalculation reports p < 0.001. The registry's later composite result has p = 0.672. These values should be interpreted with their respective estimates, confidence intervals, analyses, and study limitations, rather than as standalone verdicts.

Why does over-dispersion matter for some outcomes?

For count or binary outcomes, statistical models often rely on assumptions about how much variation is expected. Over-dispersion means the observed variation exceeds what a model assumes. If it is ignored, standard errors can be too small and confidence intervals too narrow. This is a general statistical concern; the record does not report whether over-dispersion was assessed or whether a correction was used for any outcome.

For the binary secondary outcomes, the registry reports chi-squared analyses for some randomized comparisons, with differences of proportions and confidence intervals. Such comparisons describe differences in the observed proportions between groups. The registry does not report a multiplicity-adjusted analysis, and the recorded methods do not fully describe the analysis plan. As a result, the secondary p-values should be treated as exploratory rather than as a collection of independent confirmations.

The primary outcome's population description notes that analyzed numbers reflect dropouts and availability of analyzable samples. The exact handling of missing imaging measurements and the precise analysis population are not reported in the registry record. Those choices matter because a comparison based on participants with available measurements can differ from one based on all randomized participants if missingness is related to outcome or treatment. The record does not provide enough detail to assess that possibility.

11. Confidence Intervals and Precision

The primary randomized-period recalculation estimates a mean difference of -0.246 TBR max, with a 95% confidence interval from -0.341 to -0.151. This interval lies below zero and indicates that the observed estimate is not highly precise to a single value: values across the interval remain compatible with the posted data under the recalculation's assumptions. The interval is not a range that contains 95% of individual participants' changes.

The sponsor's regression analysis reports a mean difference of -0.246, with a 95% confidence interval from -0.387 to -0.104. Its interval is wider than the recalculated interval. Both analyses report an interval below zero, but the different widths show that the choice of analysis affects the stated precision. The record flags a discrepancy, so the sponsor's result is the principal reported analysis.

For the composite active-treatment result, the reported confidence interval runs from -0.087 to 0.057 around a mean difference of -0.015. Because the interval includes zero, the data are compatible with a range of average changes on either side of zero. This estimate is not a concurrent randomized comparison, and it should not be interpreted as evidence that the randomized treatments were equivalent.

Confidence intervals do not account automatically for every source of uncertainty. They do not resolve missing-data concerns, measurement limitations, unreported model choices, or the effects of examining multiple outcomes. The registry does not report enough analysis detail to determine how those considerations were handled.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm for the continuous primary comparison, not total events. The displayed illustrations use the observed effect as a starting point and consider planning for 100%, 75%, or 50% of that observed effect. The entries indicate participants per arm for 80% power and participants per arm for 90% power. The 80% column represents a design aiming for an 80% chance to detect the specified effect under the planning assumptions if that effect is real; the 90% column represents a higher target chance. These are design targets, not probabilities that the trial result is correct.

The listed assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is the stated fraction of the observed effect. The registry record's original design assumptions and sample-size justification are not reported in the registry record. These planning illustrations were not the trial's design calculation, and this is not observed power.

The planning figures rise as the assumed effect becomes smaller: detecting a less pronounced difference generally requires more participants under otherwise similar assumptions. The curve and entries should therefore be read as conditional planning examples based on this trial's observed effect, not as a retrospective measure of whether the completed trial was adequately powered. Actual requirements can differ if the planned population, outcome variability, analysis, missingness, or target effect differs from the illustration.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -0.246; pooled standard deviation σ = 0.165.
2. n = 2 × (1.96 + 0.842)² × 0.165² / -0.246² = 7.1, rounded up to 8 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -0.2457                      # observed difference in means
sigma <- 0.165106762662597                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(2187172)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 8 (80% power), 10 (90% power)
 75% of observed effect: n per arm = 13 (80% power), 17 (90% power)
 50% of observed effect: n per arm = 29 (80% power), 38 (90% power)
power.t.test: 8.2 
Simulated power at n = 8 per arm: 0.789 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The registry reports the sponsor's primary randomized-period analysis as linear regression: mean difference -0.246, 95% confidence interval -0.387 to -0.104, p = 0.001. A simple unadjusted recalculation from the posted summary statistics gives -0.246, 95% confidence interval -0.341 to -0.151, p < 0.001. These are close in estimated direction and magnitude, but their intervals and p-values are not identical.

The record flags a discrepancy between the recalculation and the registry analysis. The sponsor's own analysis takes precedence. The recalculation is not a reproduction of the regression model: the registry record does not report enough detail about that model to reproduce it. The recalculated result is best treated as a check based on the posted group summaries, not a competing primary analysis.

For the later composite active-treatment result, the registry reports a mean difference of -0.015, with a 95% confidence interval from -0.087 to 0.057 and p = 0.672. This is a distinct analysis from the randomized-period contrast and should not be used to replace it. In particular, the post-week-12 treatment sequence means the later result does not preserve a placebo comparison.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists many outcome measures and analyses, including the primary imaging endpoint, several psoriasis outcomes, and patient-reported measures. When many statistical comparisons are made, the chance of at least one apparently notable result due to random variation can increase. A multiplicity strategy can address this issue by controlling error rates or by defining a hierarchy of tests. The multiplicity plan is not reported in the registry record, so it is not possible to determine whether the secondary p-values were adjusted or how the outcomes were ordered for interpretation.

Missing data are relevant to the primary endpoint. The record says that analyzed numbers reflect participant dropouts and the availability of analyzable samples. It does not report the reasons for missing measurements, the timing of dropouts, or the methods used to handle missing data. It also does not report whether sensitivity analyses tested how assumptions about missing measurements could affect results. These details matter because an analysis restricted to available samples can be biased if missingness is related to treatment or to the outcome.

The registry's population description is truncated, and the exact analysis-population definition is not reported in the registry record. The displayed analyzed numbers differ among the randomized primary analysis and the composite active-treatment analysis. Without fuller definitions, it is not possible to determine precisely who was included in each analysis or how protocol deviations were handled.

The randomized comparison is most directly interpretable through week 12. After that point, the placebo group received ustekinumab, so the later active-treatment summary cannot estimate a continued randomized contrast. The record does not report an interim-analysis plan, a detailed statistical analysis plan, or the original sample-size justification. Those omissions limit assessment of prespecification and analytic choices.

16. 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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: endometritis (5.3%), hypotension (5.3%), stroke (5.3%), vasovagal reaction (5.3%).

The adverse-event record reports serious adverse events affecting none of the 22 participants at risk in the ustekinumab group during the randomized treatment period, and none of the 21 participants at risk in the placebo randomized-period group. In the placebo active-treatment-period group, serious adverse events affected 3 of 19 participants at risk. The record also reports no deaths in any of the three listed groups.

Other adverse events affected 14 of 22 participants in the ustekinumab group, 3 of 21 in the placebo randomized-period group, and 16 of 19 in the placebo active-treatment-period group. These categories and periods should be read as reported; the groups do not represent identical treatment exposures throughout follow-up. The later placebo group received active treatment after week 12.

The registry lists Endometritis, Hypotension, Stroke, and Vasovagal reaction among the top serious adverse-event terms, each reported as 5.3%. The record does not provide enough context in this listing to assign each term to a specific treatment group or interpret the percentage as a comparative risk. These counts are descriptive and, given the analyzed group sizes and treatment sequence, do not establish whether an event was caused by a treatment.

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

The primary randomized-period result describes a difference between groups in change in an imaging measure of vascular inflammation over baseline to week 12. The sponsor's analysis estimates a negative mean difference and reports a confidence interval that excludes zero. The estimate therefore provides evidence of a group difference in this measured endpoint under the reported analysis, with uncertainty reflected by the interval.

That finding does not establish an effect on heart attacks, stroke risk, or other cardiovascular events. The endpoint is a PET/CT-derived biomarker, and the registry does not report a clinical-event outcome as the primary measure. A change in a biomarker is not automatically equivalent to a change in a patient's future health outcomes.

The result also does not determine whether the estimated difference is clinically important. The registry does not report a threshold for a meaningful TBR max change or a clinical interpretation linking the scale to patient benefit. The trial's small analyzed groups and missing-data details further limit how precisely the result can be generalized.

The end-of-study composite result answers a different question from the randomized comparison. The original placebo group received ustekinumab after week 12, and the active-treatment summaries use different end-of-study visits. The composite estimate should not be understood as a continuing comparison of active treatment with placebo or as a direct confirmation of the randomized result.

Finally, the findings are specific to the population, treatment schedule, endpoint, and follow-up recorded in VIP-U. The registry record does not provide enough information to infer what would happen in other patient groups, under other treatment schedules, or for outcomes not measured in the study. These data support statistical interpretation of the posted trial results, not medical advice.

18. Why This Trial Matters Statistically

This trial illustrates why endpoint definition matters. Vascular inflammation was operationalized through FDG-PET/CT uptake and a target-to-background ratio across aortic segments. The statistical result is therefore about a particular imaging measure, not a broad or interchangeable concept of cardiovascular health. Interpreting the estimate requires keeping the measurement and its clinical limits in view.

It also shows the difference between a randomized contrast and a within-group or composite follow-up summary. Randomization supports comparison during the placebo-controlled period. Once the original placebo group begins active treatment, the end-of-study summary no longer supplies a concurrent untreated comparison. The labels and timing of each analysis are essential to understanding what it can answer.

The record gives an example of a recalculated estimate alongside the sponsor's own regression analysis. Small differences in estimates or intervals can arise when methods or inputs differ, and a summary-statistic recalculation is not a substitute for the reported model. Here, the record flags a discrepancy, so the sponsor analysis takes precedence while the unadjusted calculation serves as a transparent cross-check.

Finally, the primary results are accompanied by missing-data and multiplicity questions. Analyzed sample sizes reflect dropouts and available imaging samples, while the handling of missingness and the multiplicity plan are not reported. These omissions show why statistical interpretation depends not only on an estimate and p-value, but also on analysis populations, model specification, precision, and the study's full analysis plan.

19. 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 analyzed populations are limited in size, and the primary result is based on participants with available analyzable samples rather than a clearly described complete randomized population. The registry notes dropout and sample availability but does not report the reasons, timing, or method used to address missing imaging data. The potential impact of missingness therefore cannot be assessed from the record.

The full eligibility criteria and detailed participant characteristics are not reported in the record summary. Although psoriasis and cardiovascular disease are listed as conditions, this does not establish that every participant had cardiovascular disease. Generalizability beyond the enrolled study population cannot be determined from the available information.

The later active-treatment analysis is a composite summary after the placebo group crossed to ustekinumab. It has no concurrent placebo comparison and uses different end-of-study visits for the original groups. It therefore cannot be interpreted as a long-term randomized treatment contrast.

The statistical analysis plan, regression specification, handling of missing observations, and multiplicity strategy are not reported in the registry record. The primary outcome description concerns change from baseline, while the sponsor's reported parameter is described as a mean difference in final values; the record does not provide enough detail to reconcile that terminology fully. The record also does not report a threshold for clinical importance of the imaging measure or link its change to cardiovascular events.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Vascular Inflammation in Psoriasis-Ustekinumab (VIP-U) — NCT02187172.
• Registry record last updated 2019-08-15; status last verified 2019-08.
• Results first posted 2019-08-15.
• 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.

23. Record Summary

VIP-U was a completed phase IV, randomized, double-blind, placebo-controlled parallel-group trial sponsored by the University of Pennsylvania. Enrollment was 43, and the registry lists quadruple masking. The randomized comparison assessed change in TBR max from baseline to week 12, with ustekinumab compared with placebo.

The sponsor's regression analysis reports a mean difference of -0.246, with a 95% confidence interval from -0.387 to -0.104 and p = 0.001. The record also reports a later composite active-treatment result of -0.015, with a 95% confidence interval from -0.087 to 0.057 and p = 0.672. After week 12, the original placebo group received ustekinumab, so the later result is not a randomized placebo comparison.

The registry notes that analyzed numbers reflect dropouts and availability of analyzable samples. The analysis plan, missing-data approach, and multiplicity strategy are not reported in the registry record.