Evaluation of the Value of Perianal Infiltration During Thermodestruction of Haemorrhoidal Disease by Radiofrequency: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of the Value of Perianal Infiltration During Thermodestruction of Haemorrhoidal Disease by Radiofrequency (NCT05519189), a randomized phase 4 study. The primary outcome is Visual Analogue Scale (VAS) of Pain.

2. Clinical Question

3. Trial Design

This completed Phase 4 study is recorded as a randomized, single-masked, parallel-group trial. It compares peri-anal infiltration of ropivacaine with no peri-anal ropivacaine infiltration during radiofrequency thermodestruction of haemorrhoidal disease. The record lists total enrollment as 134. It reports group sizes of 56 for infiltration and 57 for no infiltration for the primary outcome. The registry does not explain the difference between enrollment and the group sizes shown for that outcome, so the reasons for the reported numbers cannot be determined from this record.

The study start date is 2023-01-10, the primary completion date is 2025-12-16, and the status is completed. These dates describe the registry timeline; they do not establish how long each participant was followed. The primary endpoint is a pain score recorded at H6 post-op, 6 hours after the start of the operation. The outcome is summarized as a mean and standard deviation in each arm.

“Randomized” describes how participants were assigned, but the registry record does not report the randomization sequence method or allocation concealment procedures. “Single-masked” is recorded, but the record does not say which people were masked or how masking was maintained. The arm descriptions do not provide further procedural details. The record also does not report the original sample-size justification, the planned analysis populations, or the protocol’s statistical plan. These omissions limit what can be concluded about implementation and analysis beyond the posted design labels and results.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

5. Baseline Characteristics

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

Population: Baseline population contains 134 patients, but only 113 patients have a data for principal outcome

6. Primary Endpoint

The registry lists the primary outcome as Visual Analogue Scale (VAS) of Pain, measured over H6 post-op (6 hours after the start of the operation).

The primary endpoint is the Visual Analogue Scale (VAS) of Pain at H6 post-op, defined in the record as 6 hours after the start of the operation. The scale’s minimum value is 0 and its maximum value is 10. The registry summarizes this continuous measure using a mean and standard deviation for each group.

A pain score provides a way to represent participants’ reported pain on a numerical scale at a specified time. Comparing group averages describes the difference in mean scores at that time point. The mean is a useful summary of a continuous outcome, while the standard deviation describes how dispersed individual scores are around the group mean. Neither summary alone shows the full distribution of scores or how individual participants’ experiences varied.

This endpoint is specific to the recorded time point. It does not, by itself, describe pain at other times, longer-term outcomes, or other aspects of recovery. The registry does not report the endpoint population or further details about how VAS responses were collected, handled when absent, or incorporated into the analysis. The posted result should therefore be read as a comparison of the recorded group summaries at H6, not as a complete account of pain over time.

7. Results Posted in the Registry

• No Peri-anal Ropivacaine Infiltration: mean 1.90 versus 1.50 on control; difference 0.40 (95% CI -1.20 to 2.00), standardized effect d = 0.09; z-test p = 0.625.

8. Statistical Interpretation

9. Statistical Methods Explained

The registry posts descriptive summaries for a continuous outcome and a sponsor-reported regression analysis. A separate, simple unadjusted recalculation uses the posted group means and standard deviations to estimate a mean difference and its uncertainty. These are distinct analyses and should be kept distinct when reading the results.

What a mean difference represents

A mean difference expresses how far apart two group averages are, in the original units of the outcome. Here, the outcome is a pain score measured in units on a scale with a minimum of 0 and maximum of 10. For the unadjusted comparison, the stated direction is no infiltration minus infiltration: the posted means are 1.9 and 1.5, and the recalculated difference is 0.4. With this direction, a positive estimate means the no-infiltration group’s average score is higher; a negative estimate would mean the infiltration group’s average is higher. This direction is a convention for reading the contrast, not a separate clinical conclusion.

A mean summarizes the center of the observed values, while a standard deviation summarizes their spread around that mean. The posted standard deviations are 4.4 for infiltration and 4.3 for no infiltration. A group average does not reveal whether scores cluster near the mean, whether there are unusually high or low values, or whether the distribution has a particular shape. The registry does not post individual-level results or distribution plots in the registry record.

What the unadjusted recalculation adds

The recalculation is based on the posted summary statistics and is unadjusted. It reports a pooled standard deviation of 4.35, standard errors of 0.588 and 0.570 for the two group means, and a standardized effect size of 0.092. The standard error describes the sampling uncertainty of an estimate: in general, a smaller standard error means that repeated samples under the same assumptions would yield estimates less variable around the underlying quantity. It is not a measure of how variable individual pain scores are; that role belongs to the standard deviation.

The recalculated mean difference is 0.4, with a confidence interval from -1.204 to 2.004 and an unadjusted p-value of 0.625. A p-value assesses how unusual results at least as far from a null value would be under a specified statistical model if the null value were true. It does not measure the probability that the null hypothesis is true, nor does it measure the probability that a treatment works. The registry’s recalculated p-value is not the sponsor’s p-value and does not replace the sponsor’s analysis.

How the sponsor’s analysis differs

The sponsor reports “Regression, Linear” with the parameter described as “Mean Difference (Final Values).” It is labelled “NON INFERIORITY” and gives an estimate of 0.3, an interval from -0.2 to 0.9, and p = 0.05. A regression analysis can estimate a group contrast while accounting for variables included in the model, but the record does not report which variables, if any, were included. It also does not state the non-inferiority margin or provide enough detail to reconstruct the analysis. The registry record labels the confidence-interval percentage as 5; that entry does not permit a clear interpretation of the interval’s confidence level. The sponsor’s own analysis takes precedence over the recalculation, while these missing details limit independent assessment.

Why dispersion and model assumptions matter

In general, over-dispersion means that observed variability is greater than a model expects. When a model underestimates variability, standard errors can be too small and intervals can be too narrow, making results appear more precise than they are. The registry’s posted standard deviations are large relative to the group means, but that fact alone does not establish over-dispersion or a model violation. Assessing distributional shape, outliers, or model fit would require information not reported in the registry record. The score is also bounded between 0 and 10, while common statistical approximations may use an unbounded distribution; whether that matters for this analysis cannot be judged from the posted summaries alone.

General statistical interpretation also depends on how missing observations, protocol deviations, and analysis populations are handled. The registry does not report these details for the primary endpoint. Nor does it report the original sample-size justification, interim analyses, or a fuller analysis plan. These are uncertainties about the available record, not evidence that any particular method was or was not used.

10. Confidence Intervals and Precision

The unadjusted recalculated confidence interval for the mean difference is -1.204 to 2.004, with the contrast defined as no infiltration minus infiltration. A confidence interval gives a range of estimates compatible with the observed data under the assumptions of the method. In general, the interval reflects both the observed estimate and its sampling uncertainty; it is not a range containing a fixed proportion of individual participants’ scores.

This interval includes zero and extends to values on either side of zero. The data therefore do not locate the unadjusted mean difference precisely enough to establish its direction. The interval’s width is important: the point estimate of 0.4 is only one estimate, and the interval indicates that materially different contrasts remain compatible with the summaries and calculation. The unadjusted p-value of 0.625 is consistent with the interval’s inclusion of zero, but neither statistic establishes equivalence or absence of a meaningful difference.

The sponsor’s reported interval is -0.2 to 0.9 around a reported estimate of 0.3. It belongs to the sponsor’s regression-based non-inferiority analysis, not to the unadjusted recalculation. The registry records the interval percentage as 5, so its confidence level cannot be confidently characterized from this entry. The registry also does not report the non-inferiority margin, which is essential context for judging whether an interval supports non-inferiority.

Precision should be considered alongside design and reporting limitations. The record gives group sizes for the primary outcome but does not explain their relationship to total enrollment or report how missing outcome data were handled. It also does not provide the score distributions or analysis-population details. These omissions make it difficult to evaluate whether the stated uncertainty captures all relevant sources of uncertainty.

11. 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 table and its curve are planning illustrations based on the observed effect, not the trial’s original design justification. For this continuous outcome, the table reports participants per arm, rather than total events. The listed planning 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 set to the stated fraction of the observed effect. The trial’s own original sample-size assumptions are not reported in the registry record.

The 80% power column gives the number of participants per arm that the planning calculation indicates would be needed to have an 80% chance of detecting the specified effect under those assumptions. The 90% power column gives the corresponding number per arm for a 90% chance. These are conditional planning quantities: they depend on the assumed effect size and the calculation’s assumptions. They are not estimates of the probability that the completed trial found a real effect, and this is not observed power.

The table includes planning for 100% of the observed effect, 75% of the observed effect, and 50% of the observed effect. For 100% of the observed effect, it lists 1,857 participants per arm for 80% power and 2,486 for 90% power. For 75% of the observed effect, it lists 3,301 and 4,419 participants per arm, respectively. For 50% of the observed effect, it lists 7,426 and 9,941 participants per arm, respectively. The curve presents the same planning relationship visually; it should be read as an illustration, not as an additional trial result.

The pattern reflects a general statistical principle: smaller effects are harder to distinguish from random variation, so detecting them at a chosen power generally requires more participants. These values should not be interpreted as recommended enrollment targets without considering whether the observed effect is a suitable planning assumption, whether the model assumptions are appropriate, and what effect is important for the research question.

12. 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 = 0.400; pooled standard deviation σ = 4.350.
2. n = 2 × (1.96 + 0.842)² × 4.350² / 0.400² = 1,856.4, rounded up to 1,857 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 <- 0.4                      # observed difference in means
sigma <- 4.34983690281384                     # 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(5519189)
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 = 1,857 (80% power), 2,486 (90% power)
 75% of observed effect: n per arm = 3,301 (80% power), 4,419 (90% power)
 50% of observed effect: n per arm = 7,426 (80% power), 9,941 (90% power)
power.t.test: 1857.3 
Simulated power at n = 1,857 per arm: 0.797 (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.

13. Analyses Reported by the Sponsor

The registry reports the sponsor’s own analysis as a linear regression of final values, with a mean difference of 0.3, a confidence interval from -0.2 to 0.9, and p = 0.05. It labels the analysis as non-inferiority. This is the sponsor’s analysis and takes precedence over the simple unadjusted recalculation, which gives a difference of 0.4, a confidence interval from -1.204 to 2.004, and p = 0.625.

The two results differ, but the record does not explain why. The recalculation is unadjusted and based on posted summary statistics; the sponsor’s result is described as regression-based. The registry does not specify the regression covariates, the handling of missing values, the analysis population, or other details that could clarify the difference. It would be speculation to assign a cause.

The non-inferiority label alone is insufficient to assess the sponsor’s conclusion. The registry record does not report the non-inferiority margin or its rationale. It also records the confidence-interval percentage as 5, leaving the interval’s confidence level unclear. Readers can report the sponsor’s estimate, interval, and p-value as posted, but should not infer a complete non-inferiority argument from the label alone.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome measure and one reported analysis. It lists no secondary outcome results. This means the posted results offer a limited view of the trial’s measured outcomes; it does not establish that no other outcomes were collected or considered. The registry record does not report whether multiple analyses, time points, or subgroups were planned, or whether any multiplicity adjustment was used. The extent of multiplicity and its handling are therefore not reported in the registry record.

The primary endpoint is identified as the VAS of Pain at H6 post-op, and the record gives group means and standard deviations. However, the endpoint population field is blank. The record does not say whether the analysis included all randomized participants, participants who received the assigned procedure, or another analysis population. It also does not describe how protocol deviations or incomplete outcome measurements were treated.

Missing-data handling is not reported in the registry record. In general, missing outcome values can affect an estimated group contrast if their occurrence or reasons differ between groups. Statistical methods for addressing missingness rely on assumptions, and interpretation depends on what was missing and how the method was applied. The posted summary does not permit assessment of these issues.

The registry gives total enrollment as 134 and reports primary-outcome group sizes of 56 and 57. It does not explain the relationship between these figures. That absence is not enough to infer how many participants had missing outcomes or why the reported group sizes differ from enrollment. Participant flow, exclusions, and reasons for any unavailable observations are not reported in the registry record.

The record also does not report interim analyses, stopping rules, or the full statistical analysis plan. It is therefore not possible to determine from this record whether any unreported analyses or decision procedures affected the posted result. These are reporting limitations; they should not be taken as evidence that a particular practice occurred.

15. 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 non-serious adverse event terms

The registry reports zero serious adverse events affecting participants in the peri-anal infiltration group, among 56 at risk, and zero in the no-infiltration group, among 57 at risk. It also reports zero deaths in each group. The serious adverse event terms list is empty.

The record separately lists 6 other adverse events in the infiltration group and 4 in the group labelled “Failure to Perform Peri-anal Ropivacaine Infiltration.” These are not the serious adverse event counts. The registry does not provide event descriptions in the registry record, so their nature and clinical importance cannot be characterized from this summary.

Zero serious events recorded in these groups means that the registry reports none for the listed participants; it does not demonstrate that the risk of a serious event is absent. Safety interpretation depends on the types of events captured, follow-up duration, completeness of reporting, and how events were defined and assessed. Those details are not reported in the registry record. The posted figures should therefore be read as counts in this trial record, not as a broad guarantee about safety.

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

The posted primary-outcome summaries show mean pain scores of 1.5 with peri-anal ropivacaine infiltration and 1.9 without infiltration at H6 post-op. The simple unadjusted recalculation estimates a mean difference of 0.4 for no infiltration minus infiltration, with a confidence interval from -1.204 to 2.004 and p = 0.625. The interval includes zero and allows for differences in either direction. This is a description of the posted data and uncertainty, not proof of equivalence or of no effect.

The sponsor’s analysis is reported separately: a linear-regression mean difference of 0.3, interval -0.2 to 0.9, and p = 0.05, labelled as non-inferiority. The non-inferiority margin is not reported in the registry record, and the interval’s confidence level is unclear because the record lists its percentage as 5. The label and result cannot be fully evaluated without that context. The sponsor’s own analysis takes precedence over the unadjusted recalculation, but the missing information limits interpretation.

The result is confined to the registry’s primary pain measure at H6 post-op. It does not describe pain at other time points, other outcomes, or how individual participants experienced the procedure. No secondary outcome results are posted. The registry also does not report the endpoint analysis population, missing-data approach, or detailed masking procedures. These gaps constrain how confidently the posted comparison can be generalized or independently assessed.

In general, statistical evidence should be distinguished from a clinical decision. A point estimate is not the same as certainty, and a p-value does not state the probability that a treatment is effective. Likewise, a non-inferiority label needs to be interpreted against a prespecified margin and analysis plan. The record supports describing the reported estimates and their precision; it does not, on its own, support medical advice or a definitive treatment recommendation.

17. Why This Trial Matters Statistically

This trial raises a focused statistical question: how to interpret a modest difference in group averages when the estimate is uncertain and the registry presents two analyses with different methods and results. The distinction between the sponsor’s regression-based non-inferiority analysis and the unadjusted recalculation matters. They answer related but not necessarily identical statistical questions, and the record does not explain the differences between them.

Non-inferiority is particularly dependent on design and interpretation details. The margin defines how much difference is acceptable for the research question; without it, readers cannot assess the sponsor’s reported result against the intended criterion. The registry also does not clearly identify the confidence level attached to the sponsor’s interval. These omissions show why a result label, estimate, and p-value are not enough on their own to evaluate a non-inferiority claim.

The precision of an estimate is also central. The unadjusted interval spans values on both sides of zero, illustrating that uncertainty can be more informative than the point estimate alone. The planning table further demonstrates, under its stated assumptions, how detecting smaller fractions of an observed effect calls for more participants per arm. Those calculations are illustrations rather than evidence about the original design or the probability that this completed study detected an effect.

Finally, the registry’s limited reporting on analysis populations, missing observations, masking, and secondary outcomes makes transparent interpretation harder. These are not merely technical details: they affect what the posted estimates can represent and how readers judge their reliability. The trial is therefore a useful example of reading estimates, intervals, and analysis labels alongside the completeness of the record.

18. 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 is reported at a single specified time point, H6 post-op. The registry does not provide other time-point results or secondary outcome results, so this record cannot describe the broader course of pain or other dimensions of outcome. The endpoint population field is blank, and the analysis population is not otherwise described.

The record reports enrollment of 134 and primary-outcome group sizes of 56 and 57, without explaining their relationship. It does not provide participant flow, reasons for unavailable outcome data, or the missing-data method. These omissions prevent assessment of how complete the primary endpoint data were and how the reported estimates relate to all enrolled participants.

The sponsor’s analysis is labelled non-inferiority, but its margin and rationale are not reported. The registry describes a linear regression but does not list model covariates or other specifications. Its confidence-interval percentage is recorded as 5, which leaves the confidence level unclear. The unadjusted recalculation differs from the sponsor’s result, and the registry does not explain the discrepancy.

Design details are also limited. The record says randomized and single-masked but does not state the randomization or concealment method, who was masked, or how masking was maintained. It does not report the original sample-size justification, interim analyses, or a full statistical plan. The VAS score distributions are not shown in the registry record, so the shape of the data and potential influence of extreme scores cannot be evaluated. These are limitations of what the registry record reports; they do not establish that any particular procedure or analysis was absent.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Evaluation of the Value of Perianal Infiltration During Thermodestruction of Haemorrhoidal Disease by Radiofrequency — NCT05519189.
• Registry record last updated 2026-11-04; status last verified 2026-10.
• Results first posted 2026-11-04.
• 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.

22. Record Summary

NCT05519189 is a completed Phase 4 randomized, single-masked, parallel-group trial sponsored by Centre Hospitalier Departemental Vendee. It compares peri-anal infiltration of ropivacaine with no peri-anal ropivacaine infiltration during radiofrequency thermodestruction for haemorrhoidal disease. The registry lists enrollment of 134, a study start date of 2023-01-10, and a primary completion date of 2025-12-16.

The primary outcome is the mean VAS pain score at H6 post-op, 6 hours after the start of the operation, on a scale from 0 to 10. The posted means are 1.5 and 1.9, with standard deviations of 4.4 and 4.3, in groups of 56 and 57. The sponsor reports a regression-based non-inferiority analysis; the unadjusted recalculation is presented separately and does not replace that analysis.

The registry reports no serious adverse events and no deaths in either group. It does not post secondary outcome results. Important details—including the non-inferiority margin, analysis populations, missing-data handling, and original sample-size justification—are not reported in the registry record.