Effects of Neupro on Cardiovascular Observations in Patients With Restless Legs Syndrome: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of Neupro on Cardiovascular Observations in Patients With Restless Legs Syndrome (NCT01455012), a randomized phase 4 study. The primary outcome is Change From Baseline in the Number of Elevations of Systolic Blood Pressure (BP) During the Night That Are Associated With Periodic Limb Movements (PLMs) at the End of the 4-week Maintenance Period.

2. Clinical Question

The clinical rationale described in the registry is that periodic limb movements during sleep have been associated with elevations in blood pressure. The study set out to assess whether rotigotine treatment could reduce the number of nocturnal elevations associated with those movements. The results describe measurements recorded during the trial; they do not establish that a change in this measure leads to a particular health outcome.

3. Trial Design

This was a Phase 4, randomized, double-masked, placebo-controlled, two-arm parallel study. It was conducted at multiple centers and enrolled 81 participants with restless legs syndrome. The trial status is completed. The registry lists a start in 2011-09 and primary completion in 2012-05. The treatment groups were rotigotine and placebo, with an optimal rotigotine dose between 1 mg/24 h and 3 mg/24 h.

The primary endpoint was assessed from baseline to the end of a 4-week maintenance period. The registry describes polysomnography recordings before baseline and before the end-of-maintenance visit. Continuous blood pressure and a 12-lead electrocardiogram were recorded, and sleep measures were assessed using electroencephalogram readings. The stated recording plan used 2 consecutive nights at each assessment, for up to 8 hours per night. The first night was used for analysis only if the second-night recording was considered invalid for evaluation.

The primary efficacy analysis population was the Full Analysis Set: randomized participants with both a baseline and a post-baseline measurement for the primary variable. The registry reports that all 66 participants in this set were included in that outcome analysis. The arm-level primary summaries include 29 participants in the placebo group and 37 in the rotigotine group.

The record does not report the trial’s original sample-size justification, the full allocation procedure, the identities of the masked parties, or detailed rules for handling missing measurements. It also does not report a full statistical analysis plan in the information. Those omissions limit how much can be inferred about design choices beyond the elements explicitly recorded.

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.

Before assignment: Participant Flow refers to the Randomized Set (RS). RS consists of all subjects randomized into this study.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Full Analysis Set (FAS) includes all randomized subjects having both a Baseline and a post-Baseline measurement for the primary efficacy variable. All 66 subjects in the FAS are included in the analysis of this Outcome Measure.

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: Baseline Characteristics refer to the Full Analysis Set (FAS). FAS includes all randomized subjects having both a Baseline and a post-Baseline measurement for the primary efficacy variable.

6. Primary Endpoint

The registry lists the primary outcome as Change From Baseline in the Number of Elevations of Systolic Blood Pressure (BP) During the Night That Are Associated With Periodic Limb Movements (PLMs) at the End of the 4-week Maintenance Period, measured over Baseline to the end of the 4-week Maintenance Period.

The primary endpoint was change from baseline in the number of nocturnal systolic blood-pressure elevations associated with periodic limb movements, measured at the end of the 4-week maintenance period. It is a continuous outcome, summarized in the registry as least-squares means with 95% confidence intervals. The measurement focused on blood-pressure elevations linked to limb movements during sleep, not simply all elevations during the night.

The registry describes overnight polysomnography, including continuous blood-pressure recording, and explains that the Periodic Limb Movement-Related Arousal Index reflects the degree to which limb movements contribute to arousal from sleep. Sleep stages and time in each stage were assessed using electroencephalogram readings. These details situate the endpoint in a sleep-laboratory assessment, but the record does not give a complete operational definition of how an elevation was identified or linked to a limb movement.

The registry states that a negative change from baseline indicates improvement for this primary measure, and that a more negative value represents a greater improvement. This direction helps interpret the arm summaries: both groups had negative mean changes, with a more negative reported value in the rotigotine group. The measure is a physiological observation over recorded nights; by itself, it does not describe symptoms, daily functioning, or longer-term clinical consequences. Other outcomes in the record assess total nocturnal elevations, limb movements, symptom ratings, quality of life, and clinical global impressions.

7. Results Posted in the Registry

• Rotigotine: mean -239.95 versus -79.61 on control; difference -160.34 (95% CI -213.48 to -107.20), standardized effect d = -1.47; 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.

Change From Baseline in the Total Number of Elevations of Systolic Blood Pressure (BP) During the Night at the End of the 4-week Maintenance Period

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Rotigotine: mean -199.80 versus -34.30 on control; difference -165.50 (95% CI -288.05 to -42.95), standardized effect d = -0.65; z-test p = 0.008.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Rotigotine than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Change From Baseline in the Periodic Limb Movements Index (PLMI) at the End of the 4-week Maintenance Period

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Rotigotine: mean -50.10 versus -15.20 on control; difference -34.90 (95% CI -58.15 to -11.65), standardized effect d = -0.74; z-test p = 0.003.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Rotigotine than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Change From Baseline in the International Restless Legs Syndrome Rating Scale (IRLS) at the End of the 4-week Maintenance Period

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Rotigotine: mean -18.50 versus -12.50 on control; difference -6.00 (95% CI -10.17 to -1.83), standardized effect d = -0.71; z-test p = 0.005.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Rotigotine than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The registry lists 13 posted secondary outcomes, covering total nocturnal systolic blood-pressure elevations, periodic limb movements, restless legs symptom ratings, quality of life, and clinical global impressions. The numerical summaries in the results include three secondary measures: total nocturnal systolic blood-pressure elevations, periodic limb movements index, and the International Restless Legs Syndrome Rating Scale. Each of these has a more negative mean change in the rotigotine group than in the placebo group. These are descriptive patterns in the posted results, not a substitute for the primary endpoint analysis.

The secondary measures connect to the primary question in different ways. Total nocturnal elevations broadens the blood-pressure outcome beyond elevations associated with limb movements. The limb movement index measures the movement activity related to the proposed pathway, while the symptom rating scale concerns reported restless legs symptoms. Seeing changes across measures that relate to the study rationale can help readers understand the breadth of outcomes assessed, but this does not demonstrate that one measure caused a change in another.

Secondary results generally carry less inferential weight than the designated primary result, especially when many outcomes are examined. The registry lists multiple secondary endpoints, but the multiplicity strategy and any hierarchy among outcomes are not reported in the registry record. Without that information, nominal unadjusted comparisons may be more vulnerable to chance findings across repeated tests. The secondary results should therefore be read as supportive descriptions rather than as a set of independent confirmatory conclusions.

Results for the other listed secondary outcomes are not detailed in the numerical summaries. Their presence in the registry’s outcome list does not establish what those outcomes showed. In particular, readers should not infer unreported results for quality of life or clinical global impressions from the results for the three measures with numerical summaries.

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

• Change From Baseline in the Total Number of Elevations of Systolic Blood Pressure (BP) During the Night at the End of the 4-week Maintenance Period
• Change From Baseline in the Periodic Limb Movements Index (PLMI) at the End of the 4-week Maintenance Period
• Change From Baseline in the International Restless Legs Syndrome Rating Scale (IRLS) at the End of the 4-week Maintenance Period
• Change From Baseline in Restless Legs Syndrome-Quality of Life (RLS-QoL) at the End of the 4-week Maintenance Period
• Clinical Global Impressions (CGI) Item 2 (Change of Condition) at the End of the 4-week Maintenance Period
• Clinical Global Impressions (CGI) Item 1 (Severity of Illness) at the End of the 4-week Maintenance Period
• Clinical Global Impressions (CGI) Item 3 (Therapeutic Efficacy) at the End of the 4-week Maintenance Period
• Change From Baseline in Restless Legs Syndrome-6 Rating Scales (RLS-6) Item 1 at the End of the 4-week Maintenance Period

9. Statistical Interpretation

10. Statistical Methods Explained

The trial’s posted primary analysis used analysis of covariance (ANCOVA) and reported a mean difference in final values. ANCOVA is a general statistical approach for comparing groups on an outcome while accounting for a baseline measurement or other included covariates. The registry identifies the method as ANCOVA, but does not specify the covariates, model formula, assumptions checks, or every detail of the fitted model. It would therefore be inappropriate to infer precisely how baseline values or other variables entered the reported analysis.

The primary arm summaries are least-squares means. In general, a least-squares mean is a model-based group mean, often adjusted for covariates included in the analysis. It is not necessarily the same as a raw arithmetic average. In this record, the analysis set and outcome are specified, but the full model details are not reported in the registry record. The displayed arm estimates should be read as the registry’s reported summaries rather than reconstructed raw averages.

The between-group result is the contrast of interest: it compares the change or final outcome between the assigned groups, rather than asking only whether each group changed from baseline. A within-group decline does not by itself establish a difference between treatments. Here, the registry reports an ANCOVA contrast for rotigotine versus placebo, alongside an interval estimate and a p-value. The estimated contrast is negative, in keeping with the endpoint description that more negative change indicates a greater reduction.

The confidence interval is a range of values compatible with the observed data and the analysis under the model’s assumptions. General interpretation: a narrower interval indicates greater precision, while a wider interval indicates more uncertainty about the estimated contrast. The interval does not mean that a specified proportion of participants experienced an effect within its endpoints, nor does it describe the spread of individual outcomes. The primary arm-level intervals and the between-group interval answer related but different questions: one describes an estimate for each arm, and the other describes the contrast between arms.

The page also displays a recalculated unadjusted comparison based on the posted arm summaries. Such a recalculation is not the same as reproducing ANCOVA, because it does not use the trial’s fitted model or adjustment choices. It is useful as a simple descriptive check of the group contrast, but it should not replace the sponsor’s reported analysis. The two estimates are close in this record, while their small differences reflect that the calculation approaches are not identical. The registry’s own ANCOVA remains the primary reported inferential analysis.

The primary endpoint is continuous, and the record reports means and confidence intervals rather than event counts. General explanation: the mean summarizes the average outcome, while a standard deviation, when reported, describes variation among observations. A standard error instead describes the sampling uncertainty in an estimated mean. These quantities are not interchangeable. In the primary arm summaries, the registry presents least-squares means and confidence intervals; the recalculated comparison includes estimates based on the posted summaries. No claim about the underlying distribution or model diagnostics can be made from these numbers alone.

General explanation: over-dispersion matters when count data vary more than a model’s assumptions allow. If variability is understated, uncertainty estimates and tests can be misleading. The primary endpoint is a count-like measure of elevations, but the registry reports it as a continuous outcome analyzed using ANCOVA. The record does not report a count-data model, an assessment of over-dispersion, or a reason for choosing ANCOVA over another approach. It is not possible to say from the registry information whether over-dispersion was assessed or how it might have affected inference.

The reported p-value addresses how compatible the observed data are with a null hypothesis of no group difference under the analysis assumptions. General explanation: a small p-value is not the probability that the null hypothesis is true, and it does not quantify the size or clinical importance of an effect. The estimated difference and confidence interval are therefore essential complements. For this study, the interval indicates the direction and precision of the reported group contrast; the p-value alone cannot convey either the magnitude or the practical meaning of the result.

For continuous outcomes, the accompanying planning illustration uses the observed effect and stated assumptions to show hypothetical sample sizes for detecting specified fractions of that effect. This is not the original design calculation. General explanation: planning calculations depend on the target effect, variability, significance level, allocation, and statistical approximation. The registry’s original design assumptions and any original power calculation are not reported in the registry record, so the planning illustration should not be treated as a reconstruction of the study’s design process.

The analysis population also matters. The Full Analysis Set was defined as randomized participants with baseline and post-baseline measurements for the primary efficacy variable. This definition is explicit, but the record does not provide details about the disposition of all enrolled participants, reasons for missing assessments, or sensitivity analyses. General explanation: excluding participants without a post-baseline measurement can change the composition of the analysis set, particularly if missingness relates to outcomes or treatment. Without the relevant details, the direction or size of any such influence cannot be established.

Finally, multiple endpoints create an interpretive issue. The record lists 14 outcome measures and 13 posted secondary outcomes, alongside the primary measure. General explanation: when many outcomes are tested, the chance of observing an apparently strong result by chance can rise if no adjustment or prespecified hierarchy is used. The multiplicity approach is not reported in the registry record. This makes the primary endpoint and the trial’s reported primary analysis central, while secondary findings are more exploratory in interpretation unless additional analysis-plan information is available.

11. Confidence Intervals and Precision

The primary arm-level estimates have 95% confidence intervals. For placebo, the reported least-squares mean change is -79.61, with an interval from -119.2 to -39.97. For rotigotine, the corresponding estimate is -239.9, with an interval from -275.3 to -204.6. These intervals describe uncertainty around each group estimate; they are not the uncertainty interval for the between-group difference.

For the treatment contrast, the registry’s ANCOVA analysis reports -160.34, with a 95% confidence interval from -213.23 to -107.45. The interval is entirely below zero. In general, this indicates that the reported data are more compatible with a negative contrast than with a zero contrast under the fitted analysis. The endpoint’s direction means a more negative change represents a larger reduction in the measure. The interval does not establish the effect for every participant or identify the mechanism behind the observed group difference.

The recalculated unadjusted contrast is -160.3, with a 95% confidence interval from -213.5 to -107.2. Its similarity to the ANCOVA estimate is reassuring as a descriptive cross-check, but the two intervals arise from different methods and should not be treated as interchangeable. The sponsor’s reported analysis is the trial analysis to prioritize when describing the posted result.

Precision is limited by the number of participants included in the primary analysis: the registry reports 66 participants in the Full Analysis Set. General explanation: more information often leads to narrower intervals, but precision also depends on outcome variability and analysis methods. The interval gives a more informative sense of uncertainty than the p-value alone. It still cannot capture uncertainty from unreported design choices, missing-data handling, model assumptions, or possible multiplicity across outcomes.

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 sample-size display is a planning illustration based on the observed primary effect, not a report of the trial’s original sample-size calculation. The figures are participants per arm, not total participants or total events. They assume a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Each row considers a target effect stated as a fraction of the observed effect.

The column for 80% power gives the number of participants per arm that the illustration estimates would be needed for an 80% chance of detecting the specified effect under those assumptions, if that effect were the true one. The 90% power column gives the corresponding planning figure for a 90% chance. These are planning probabilities conditional on the assumptions and target effect; they do not describe the probability that this completed trial found a real effect.

The table includes plans for detecting 100%, 75%, and 50% of the observed effect. The smaller target effects require more participants per arm in the displayed illustration. This is a general feature of study planning: distinguishing a smaller effect from random variation usually requires more information, all else equal.

These figures are not observed power. They should not be read as a retrospective score for the completed study, or as evidence that the trial’s original design used these assumptions. The original sample-size justification and design assumptions are not reported in the registry record. The curve and table are best used to understand how the hypothetical sample requirement changes with the target effect under the listed planning assumptions.

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 = -160.340; pooled standard deviation σ = 109.432.
2. n = 2 × (1.96 + 0.842)² × 109.432² / -160.340² = 7.3, 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 <- -160.34                      # observed difference in means
sigma <- 109.432049060862                     # 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(1455012)
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), 18 (90% power)
 50% of observed effect: n per arm = 30 (80% power), 40 (90% power)
power.t.test: 8.4 
Simulated power at n = 8 per arm: 0.776 (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 trial’s primary analysis as an ANCOVA comparison of final values. It gives a mean difference of -160.34 and a 95% confidence interval from -213.23 to -107.45. The reported p-value is below < 0.001. This is the sponsor’s reported analysis for the primary endpoint.

The simple recalculation from the posted summary statistics gives a difference of -160.3, a 95% confidence interval from -213.5 to -107.2, and p < 0.001. This recalculation is unadjusted and is not a reproduction of the ANCOVA model. It serves as a check using the displayed group summaries, not as a replacement for the analysis performed for the registry results.

The estimates are close, and the record does not flag a discrepancy. Their slight differences are compatible with the fact that an adjusted model-based analysis and a simple summary-statistic calculation need not produce identical values. When describing the trial’s own inferential result, the ANCOVA estimate and interval take precedence; the recalculation can be mentioned as a supplementary descriptive comparison. Neither analysis, by itself, answers questions about outcomes or populations not measured in this trial.

15. Multiplicity, Missing Data and Analysis Populations

The record identifies a primary endpoint and lists 14 outcome measures, with 13 posted secondary outcomes. This creates a multiplicity question: when several outcomes are assessed, the chance of at least one apparently notable result can increase if each is tested independently without adjustment. General explanation: prespecifying a hierarchy or using a multiplicity adjustment can help control interpretation across multiple tests. The registry record does not report whether either approach was used.

The primary analysis is reported as ANCOVA, but the record does not provide the full statistical analysis plan. It does not report the covariates in the model, detailed model diagnostics, any interim analyses, or a complete account of which analyses were prespecified. The original sample-size justification is also not reported in the registry record. These absences do not invalidate the reported results, but they limit independent assessment of how analysis decisions were made.

The stated primary analysis population includes randomized participants with both baseline and post-baseline measurements for the primary efficacy variable. The record reports 66 participants in this Full Analysis Set. It does not provide a detailed account of missing primary measurements, reasons for missingness, or the methods used to address missing data. It also does not describe sensitivity analyses examining alternative assumptions about missing outcomes. General explanation: missing-data methods can matter if the probability of an outcome being missing is related to the outcome itself or to treatment assignment. The available record does not establish whether such a relationship existed.

The enrolled total was 81, while the primary analysis set contained 66 participants. The arm-level primary summaries include 29 placebo participants and 37 rotigotine participants. These figures should be interpreted according to their stated roles; the record does not explain the difference between enrollment and the primary analysis set in enough detail to assign reasons to particular participants.

There is also a separate distinction in the safety reporting: the adverse-event table lists 40 participants at risk in each group, while the primary efficacy analysis uses the Full Analysis Set. The registry does not explain the relationship between these denominators. Readers should avoid assuming that the safety and efficacy populations are identical or that the difference reflects a specific event or exclusion reason.

16. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent non-serious adverse event terms

The adverse-event summary reports 0 participants with serious adverse events among 40 at risk in the placebo group and 0 among 40 at risk in the rotigotine group. For other, non-serious adverse events, the record lists 19 affected participants in the placebo group and 23 in the rotigotine group, again with 40 at risk in each group. The displayed serious-event terms list is empty.

These counts describe the safety information posted in the registry; they do not provide a complete characterization of event type, timing, severity, or relationship to study treatment. Deaths are recorded as null for both groups, which is not the same as a reported count of zero. The record does not clarify the safety observation period or explain how the safety denominators relate to the primary analysis population.

The absence of serious events in this summary should not be interpreted as proof that serious events cannot occur, or that the groups are equivalent in safety. The counts come from a study with a limited number of participants, and the registry information does not supply the detail needed for broader safety conclusions.

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

The result describes a difference between randomized groups in the change in nocturnal systolic blood-pressure elevations associated with periodic limb movements over the period assessed. The posted ANCOVA estimate is -160.34, with a 95% confidence interval from -213.23 to -107.45. The endpoint description says that a negative change indicates improvement and a more negative change represents a larger reduction. The interval is entirely below zero, indicating a group contrast in the negative direction under the reported analysis.

This is evidence about a specific sleep-laboratory measure in the studied population and time frame. It is not a direct measure of cardiovascular events, long-term blood pressure, or the participants’ health over a longer period. The record does not report whether the measured difference translated into a clinically important benefit, nor does it establish a mechanism linking changes in limb movements, sleep arousal, and blood pressure.

The result also does not show that every participant had a reduction, or that the average estimate predicts an individual response. Group means and confidence intervals summarize aggregate data. They do not provide the distribution of individual changes or identify which participants may have had different outcomes.

The findings should be considered alongside the trial’s limitations: the primary analysis included 66 participants, missing-data details are not reported, and the registry does not describe the multiplicity approach for numerous secondary outcomes. The trial was randomized and double-masked, which are relevant design features, but the record does not provide enough methodological detail to evaluate every potential source of bias or uncertainty.

In short, the posted primary result shows a more negative estimated change for rotigotine than placebo on the specified endpoint, with an interval that does not include zero. It does not, on its own, establish broader clinical benefit, long-term effects, comparative safety, or applicability beyond the population and measurement period represented in this study.

18. Why This Trial Matters Statistically

This trial is statistically informative because it separates a mechanistically specific blood-pressure measure from a broader count of nocturnal elevations. The primary endpoint concerns elevations associated with periodic limb movements, while a secondary endpoint concerns the total number of systolic blood-pressure elevations. That distinction matters: similar-sounding outcomes can answer different questions, and conclusions should remain tied to the outcome actually analyzed.

The results also illustrate why a between-group contrast matters more than noting change within one group. Both primary arm estimates were negative, but the key trial question is whether the groups differed. The ANCOVA comparison and its confidence interval directly address that contrast. Reporting the estimate alongside its interval conveys both direction and uncertainty, while the p-value alone would not describe the size or precision of the estimated difference.

Another statistical lesson is the importance of distinguishing model-based results from simple recalculations. The registry’s ANCOVA estimate is the trial’s reported analysis; the unadjusted calculation from summary statistics is a useful check but does not reproduce the fitted model. Readers can use both to understand the result while keeping their roles clear.

Finally, this record highlights the need to read primary and secondary findings differently. The many listed secondary outcomes offer context, but the multiplicity approach is not reported. Nor is the original sample-size rationale. Those omissions reinforce why estimates, analysis populations, and uncertainty should be considered together rather than treating a nominal significance result as a complete account of evidence.

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 primary outcome depends on overnight polysomnography and a definition of blood-pressure elevations associated with periodic limb movements. Although the registry describes recording procedures and the related arousal index, it does not provide the complete operational criteria for identifying each elevation or linking it to a movement. This limits independent appraisal of endpoint construction.

The primary analysis population consisted of 66 participants, compared with 81 enrolled. The registry does not explain why participants were not included in the primary analysis set, describe missing outcomes in detail, or report sensitivity analyses for missing data. This leaves uncertainty about how the analysis population may differ from all enrolled participants.

The registry reports ANCOVA but does not provide the full model specification, including the covariates used or diagnostic assessments. It also does not report the original sample-size justification, detailed allocation procedures, or the identities of the people masked. The absence of these details limits assessment of the model and trial conduct, although it does not by itself show that a problem occurred.

The record lists many secondary outcomes, while the multiplicity strategy is not reported. Numerical results are available for only three secondary measures; results for other listed outcomes should not be inferred. Safety counts are reported with 40 participants at risk per group, but the relationship between that population and the efficacy set is not explained. Finally, the reported endpoint is a sleep-laboratory measure assessed through the end of a 4-week maintenance period. The record does not establish longer-term effects or effects on broader clinical outcomes.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Effects of Neupro on Cardiovascular Observations in Patients With Restless Legs Syndrome — NCT01455012.
• Registry record last updated 2013-07-26; status last verified 2013-07.
• Results first posted 2013-07-18.
• 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

This completed Phase 4 trial was a randomized, double-masked, parallel comparison of rotigotine and placebo in people with restless legs syndrome. The registry reports 81 enrolled participants and a primary efficacy Full Analysis Set of 66. Rotigotine dosing ranged from 1 mg/24 h to 3 mg/24 h, and the primary endpoint was change from baseline in nocturnal systolic blood-pressure elevations associated with periodic limb movements at the end of a 4-week maintenance period.

The reported ANCOVA estimate was -160.34, with a 95% confidence interval from -213.23 to -107.45. Both groups had negative estimated changes, and the rotigotine group had the more negative estimate. The registry also lists secondary outcomes and safety counts, but multiplicity handling, detailed missing-data methods, the original sample-size rationale, and several model details are not reported in the registry record.