Safety and Effectiveness of a New Pleural Catheter for Symptomatic, Recurrent, MPEs Versus Approved Pleural Catheter: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety and Effectiveness of a New Pleural Catheter for Symptomatic, Recurrent, MPEs Versus Approved Pleural Catheter (NCT02649894), a randomized na study. The primary outcome is The Proportion of Subjects Achieving Pleurodesis Without Recurrence..

2. Clinical Question

The clinical question combines an outcome of pleurodesis with the requirement that it occur without recurrence by the specified follow-up point. This is a binary endpoint: each participant either met the stated outcome or did not. It is not simply a measure of time until pleurodesis, nor does it capture all possible benefits or complications of catheter use.

The comparison is randomized and parallel-group, with the two catheter types assigned to separate groups. The registry describes the study as single-blinded, but does not report which parties were masked. The record describes the study purpose as evaluating safety and effectiveness; the posted primary result specifically addresses the proportion achieving pleurodesis without recurrence. The registry record does not report a more detailed clinical hypothesis or a prespecified threshold for a clinically important difference.

The result should therefore be read as a comparison of the recorded outcome in the stated population and timeframe. It does not, by itself, answer broader questions about longer-term outcomes, all aspects of safety, or patient experience. Those questions require other reported outcomes and fuller details of how the trial was conducted.

3. Trial Design

This was a randomized, parallel-group study comparing a silver nitrate coated indwelling pleural catheter with an approved uncoated PleurX indwelling pleural catheter. The registry lists the masking as single-blind, without identifying who was masked. The study is marked completed, and its phase is listed as not applicable. Enrollment is recorded as 119.

The registry lists malignant pleural effusion as the condition and describes the intended participants as having symptomatic, recurrent effusions. The primary outcome population is narrower in wording: all participants who successfully had the catheter placed. The posted primary endpoint results give arm denominators of 77 for the coated catheter and 37 for the uncoated catheter. The record does not explain the relationship between the enrollment entry and the endpoint denominators, or report how many participants were screened, randomized, excluded from the endpoint population, or lost to follow-up.

The study start is recorded as 2016-05 and primary completion as 2018-04-18. The sponsor is C. R. Bard. The official title describes the study as pivotal, multicenter, randomized, controlled, and single-blinded, and identifies the comparison as a silver nitrate coated catheter versus the uncoated PleurX catheter. The record does not provide site-level information in the registry record presented for this analysis.

Other design details are not reported in the registry record. These include the randomization method, allocation concealment, the identity of the blinded parties, the protocol’s full eligibility criteria, and the intended handling of deviations from assigned treatment. The trial’s original sample-size assumptions and justification are also not reported in the registry record. Planning illustrations based on the observed results are a separate exercise and should not be mistaken for the trial’s original design plan.

The registry lists eight outcome measures, while two secondary outcomes are posted in the information available for interpretation. It reports no statistical analyses for those secondary outcomes. This limits how completely the trial’s analysis strategy and the context of its outcome reporting can be assessed from the registry record alone.

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: All participants who successfully had the catheter placed.

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: All randomized participants

6. Primary Endpoint

The registry lists the primary outcome as The Proportion of Subjects Achieving Pleurodesis Without Recurrence., measured over 30 days post catheter insertion.

The primary endpoint is the proportion of participants who achieved pleurodesis without recurrence at 30 days after catheter insertion. The registry defines the analysis population as all participants who successfully had the catheter placed. Pleurodesis refers to the intended clinical outcome named in the endpoint; the combined wording requires that recurrence was not recorded by the specified assessment point.

This is a binary outcome, expressed as a count of participants meeting the endpoint relative to the number assessed in each group. Binary endpoints can be useful when a study is asking whether participants reached a clearly defined outcome within a stated timeframe. They make the group comparison directly interpretable as a difference in the chance of meeting that outcome, although they do not describe when the outcome occurred or how outcomes changed over time.

The registry reports 17 participants out of 77 in the coated-catheter group and 12 out of 37 in the uncoated-catheter group as achieving the primary outcome. The corresponding posted proportions are 0.221 and 0.324, respectively. The risk-difference estimate is 0.103, with a 95% confidence interval from -0.073 to 0.281. The posted unadjusted p-value is 0.235.

The timeframe matters: this endpoint concerns status 30 days after insertion, not a general measure of durable pleurodesis over an unspecified period. The registry also lists time to confirmed pleurodesis and time to recurrence as secondary outcomes. Those measures address related but distinct questions. The primary endpoint’s combined success definition gives a single summary at a fixed follow-up point, but it does not show the timing of events or provide a complete account of symptoms, complications, or later recurrence.

7. Results Posted in the Registry

• Approved Uncoated PleurX Indwelling Pleural Catheter: 32.4% (12/37) versus 22.1% (17/77) on control; risk difference 10.4 percentage points (95% CI -7.3 to 28.1), risk ratio 1.47 (0.79–2.75); unadjusted two-proportion z-test p = 0.235.

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.

Time to Confirmed Pleurodesis

• 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:
  • Approved Uncoated PleurX Indwelling Pleural Catheter: mean 18.70 versus 11.40 on control; difference 7.30 (95% CI 0.29 to 14.31), standardized effect d = 0.45; z-test p = 0.041.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Approved Uncoated PleurX Indwelling Pleural Catheter than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Time to Recurrence

• 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:
  • Approved Uncoated PleurX Indwelling Pleural Catheter: 0.0% (0/37) versus 1.3% (1/77) on control; risk difference -1.3 percentage points (95% CI -3.8 to 1.2); unadjusted two-proportion z-test p = 0.486.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Approved Uncoated PleurX Indwelling Pleural Catheter and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes address related aspects of the treatment course but do not measure the same thing as the primary endpoint. Time to confirmed pleurodesis summarizes timing, while time to recurrence records participants with recurrence by a later stated follow-up point. The primary outcome instead captures whether pleurodesis occurred without recurrence at a fixed assessment point. Together, they offer context about timing and recurrence, but they cannot be combined into a single overall treatment conclusion from the registry results alone.

The posted secondary findings are not wholly aligned in the strength of their statistical signals. The time-to-confirmed-pleurodesis comparison has an unadjusted p-value of 0.041, whereas the time-to-recurrence comparison has an unadjusted p-value of 0.486. The primary endpoint’s unadjusted p-value is 0.235. These values should not be treated as a ranking of clinical importance: p-values depend on endpoint definition, observed information, and the analysis, and they do not measure effect size or importance.

Secondary results generally carry less confirmatory weight when there is no reported plan for controlling the chance of false-positive findings across multiple outcomes. The registry lists eight outcome measures, but the available result information includes two secondary outcomes, and no secondary analyses are reported. The registry record does not report whether the secondary outcomes were prespecified in a hierarchy, whether multiplicity was addressed, or whether any results were adjusted. Without that context, an isolated secondary p-value is best regarded as exploratory evidence.

The secondary outcomes can help identify questions for further study, but they do not override the primary comparison. Their definitions, follow-up windows, and statistical summaries differ, and the registry does not report a joint analysis linking them. The time-to-recurrence result also involves very few events, limiting the amount of information it can provide. Overall, these outcomes contribute context, not a definitive resolution of the primary uncertainty.

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

• Time to Confirmed Pleurodesis
• Time to Recurrence

9. Statistical Interpretation

10. Statistical Methods Explained

The primary endpoint is a binary outcome: participants are counted according to whether they achieved pleurodesis without recurrence at 30 days after catheter insertion. The registry reports arm-specific counts and denominators, then gives a risk-difference estimate, confidence interval, and unadjusted p-value. These statistics describe different aspects of the comparison and should be read together.

What does a risk difference represent?

A risk difference compares the proportions experiencing an outcome between groups by subtracting one group’s proportion from the other’s. Its zero value represents equal proportions. A positive or negative estimate indicates the direction of the contrast according to the order used for the comparison. Here, the posted proportions are 0.221 for the coated catheter and 0.324 for the uncoated catheter, with a reported risk difference of 0.103. The registry’s comparison lists the uncoated catheter as the comparator, but readers should rely on the displayed group labels and stated estimate rather than infer a different contrast convention.

A risk difference is an absolute-scale measure. It describes the gap between proportions, rather than the relative size of one group’s result compared with the other. Other measures, such as risk ratios and odds ratios, describe relative contrasts and can give a different perspective on the same binary data. The posted comparison also includes a risk ratio of 1.469, with a confidence interval from 0.785 to 2.748, and an odds ratio of 1.694, with a confidence interval from 0.707 to 4.06. These relative measures are also uncertain because their confidence intervals include the null value for those scales.

How should the p-value be understood?

The unadjusted p-value is 0.235 for the primary endpoint. In general, a p-value measures how unusual data at least as incompatible with a no-difference model would be if that model and the test assumptions were correct. It does not give the probability that the no-difference model is true, nor does it tell whether a difference would matter clinically. An unadjusted result means the calculation is not reported as adjusted for other factors or for examining multiple outcomes. The registry record does not report a primary adjusted analysis.

The interval estimate provides information that a p-value alone cannot. A confidence interval gives a range of effect values that are reasonably compatible with the data under the statistical model used. In repeated use of the same method under its assumptions, intervals constructed this way would cover the underlying value at the stated confidence level at the corresponding long-run rate. It is not a statement that there is a particular probability that this one interval contains the true effect. For the primary risk difference, the interval ranges from -0.073 to 0.281 and includes zero, so the data do not exclude no difference at the interval’s confidence level.

Why are the secondary outcomes different?

Time to confirmed pleurodesis is recorded as a mean in days with standard deviations. A mean summarizes the average observed time, while a standard deviation describes the spread of observations around that mean. The posted means are 11.4 days for the coated catheter and 18.7 days for the uncoated catheter; the reported mean difference is 7.3, with a 95% confidence interval from 0.295 to 14.31 and an unadjusted p-value of 0.041. A mean-based summary does not by itself describe the full distribution, and the registry record does not report a time-to-event model or further distributional details.

Time to recurrence is posted as a count of participants by 90 days after insertion. It has only one event in the coated group and none in the uncoated group. With very few events, the estimate is necessarily sensitive to the observed counts. The risk-difference confidence interval, from -0.038 to 0.012, includes zero, and the unadjusted p-value is 0.486.

What does unadjusted mean?

In general, an unadjusted comparison uses the posted group data without accounting for other covariates or for the family of outcomes examined. Adjustment may be useful for prespecified reasons, but the registry record does not report whether any such model was planned for the trial. An unadjusted result is not inherently invalid; it simply has a narrower interpretation than a fully specified analysis that accounts for design features and other relevant factors.

The registry lists eight outcome measures, while the posted results include the primary outcome and two secondary outcomes. It reports zero analyses in the analysis listing and no reported analyses for the secondary outcomes. That gap means the statistical methods used for the posted comparisons, beyond the registry record statistics, are not fully described in the registry record. General explanations of confidence intervals, p-values, and effect measures describe statistical concepts; they do not fill in an unreported trial analysis plan.

11. Confidence Intervals and Precision

Precision concerns how narrowly the data estimate an effect. A point estimate gives one summary value, while its confidence interval shows the range of values reasonably compatible with the data under the method used. Narrower intervals generally indicate more precise estimates; wider intervals indicate greater uncertainty. Precision is distinct from whether an estimate is statistically significant or clinically important.

For the primary risk difference, the estimate is 0.103 and the 95% confidence interval is -0.073 to 0.281. Because the interval includes zero, the results are compatible with no difference as well as differences in either direction. Its breadth also indicates that the size and direction of the underlying contrast are not precisely resolved by these data. The interval should be considered alongside the group counts, 17 of 77 and 12 of 37, rather than interpreting the point estimate alone.

The posted relative-effect intervals also span their respective null values: the risk ratio is 1.469 with an interval from 0.785 to 2.748, and the odds ratio is 1.694 with an interval from 0.707 to 4.06. These measures use different scales from the risk difference, but all convey uncertainty about the size and direction of the comparison.

For time to confirmed pleurodesis, the mean difference is 7.3 days with an interval from 0.295 to 14.31. The time-to-recurrence risk difference is -0.013 with an interval from -0.038 to 0.012. These intervals relate to different endpoints and should not be treated as interchangeable evidence. In particular, the recurrence result is based on one event in one group and none in the other, so the limited event information is important context for its imprecision.

Confidence intervals do not account automatically for every source of uncertainty. Their interpretation depends on the analysis method and assumptions, and they do not address unreported missing-data procedures, outcome ascertainment, multiplicity, or possible deviations from the intended design. Those details are not reported in the registry record. Thus, the intervals quantify statistical uncertainty under the methods used, not uncertainty about every aspect of the study.

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 illustrations based on the observed effect, not the trial’s original design assumptions. The registry record does not report the original sample-size justification or assumptions. The illustrations use a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set as the stated fraction of the observed effect.

For the binary primary endpoint and the mean-based secondary endpoint, the entries are participants per arm. The 80% power column gives the planned participants per arm for a design that would have an 80% chance of detecting the stated effect under the listed assumptions, if that effect and the model assumptions were correct. The 90% power column gives the corresponding planning number for 90% power. These are design probabilities for a hypothetical study, not probabilities that the observed result is correct.

The rows distinguish planning for 100% of the observed effect, 75% of the observed effect, and 50% of the observed effect. A smaller target effect generally requires more participants to distinguish it from no effect with the same significance level and power. The figures should be read as planning illustrations, not recommendations for a future trial; an actual design would need justified assumptions about the outcome, meaningful effect, variability, allocation, follow-up, and analysis.

The secondary time-to-event endpoint is treated differently: its planning figures represent total events, not participants per arm. This distinction matters because event-driven planning depends on the number of outcome events, rather than only on the number enrolled. The time-to-confirmed-pleurodesis planning display uses participants per arm, as do the binary-outcome planning figures. These planning calculations are not observed power.

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, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.221; treatment proportion p₁ = 0.324; average p̄ = 0.273.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.6297 = 1.2342.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.6254 = 0.5264.
4. n = (1.2342 + 0.5264)² / (0.1035)² = 289.1, rounded up to 290 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
p0 <- 0.220779220779221                          # control proportion
p1 <- 0.324324324324324                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^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 (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(2649894)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 290 (80% power), 387 (90% power)
 75% of observed effect: n per arm = 500 (80% power), 668 (90% power)
 50% of observed effect: n per arm = 1,088 (80% power), 1,455 (90% power)
power.prop.test: 289.1 
Simulated power at n = 290 per arm: 0.804 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-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. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when a study examines multiple outcomes, comparisons, time points, or analyses. Even when each individual test uses a conventional significance threshold, conducting many tests can increase the chance that at least one result appears statistically notable by chance. Statistical approaches can address this, but their appropriateness depends on a prespecified analysis strategy and the questions the trial was designed to answer.

The registry lists eight outcome measures. The primary outcome is identified, and two secondary outcomes have posted results. The registry record does not report whether the trial used a testing hierarchy, adjusted significance thresholds, or another method to account for multiplicity. It also does not report whether additional analyses were conducted but not posted. The secondary p-values should therefore be read as unadjusted findings, not as multiplicity-controlled evidence.

Important analysis details are also absent. The registry record does not report the statistical analysis plan, the method used to handle missing endpoint data, the extent of missingness, or sensitivity analyses addressing missing outcomes. It does not report whether participants were analyzed according to randomized assignment, according to treatment received, or under another analysis population. The primary endpoint population is described as all participants who successfully had the catheter placed, but the record does not explain how that population relates to all randomized participants.

These omissions matter because exclusions, missing outcomes, and analysis-population choices can affect estimates and their interpretation. Randomization supports a fair comparison when the intended groups and analysis are preserved, but the registry record alone does not establish how every participant was handled after allocation. No specific approach should be inferred in the absence of reporting.

The registry also reports no analyses in its analysis listing and no reported analyses for the secondary outcomes. The posted summary comparisons can still be described, but the lack of a documented analysis plan limits assessment of whether the reported tests were prespecified, how assumptions were checked, or whether any adjusted analyses were intended. Consequently, the primary result is best read as the posted unadjusted comparison, while secondary results warrant additional caution.

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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: pleural effusion (13.0%), pneumonia (11.7%), dyspnea (6.5%), breast cancer metastatic (5.4%), acute kidney injury (5.4%).

The registry reports serious adverse events for 56 of 77 participants in the silver nitrate coated catheter group and 20 of 37 participants in the approved uncoated PleurX group. It reports other adverse events for 48 of 77 and 25 of 37 participants, respectively. Deaths are recorded for 30 participants in the coated-catheter group and 7 in the uncoated group.

These are counts within the registry’s adverse-event reporting, not adjusted comparisons of risk. The record does not provide event timing, causal attribution, severity breakdown beyond the serious-event category, or a statistical comparison of the groups. The posted figures alone do not establish that an event was caused by a catheter or that the groups differ in safety. The registry lists pleural effusion, pneumonia, dyspnea, metastatic breast cancer, acute kidney injury, and sepsis among the leading serious-event terms, with percentages reported in the record. Those terms should be interpreted in the context of the participants’ underlying illness and the record’s limited detail, not as device-specific effects.

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

The primary result describes the observed proportion of participants who achieved pleurodesis without recurrence by 30 days after catheter insertion. The groups had posted proportions of 0.221 and 0.324, and the risk-difference estimate was 0.103. Its 95% confidence interval, from -0.073 to 0.281, includes zero and spans effects in either direction. The unadjusted p-value is 0.235. Taken together, these results do not precisely establish the direction or size of a difference between the catheter groups on this endpoint.

This does not mean that the two catheters are equivalent. Equivalence requires a defined margin and a design and analysis intended to assess whether the difference is sufficiently small. The registry record does not report an equivalence or non-inferiority objective or margin. Nor does a result that does not resolve a difference show that the treatments have no effect. It describes the limits of the comparison and the uncertainty in the posted estimate.

The secondary outcomes contribute different information, but they do not provide a definitive answer to the primary question. Their results are unadjusted, and the registry does not report a multiplicity plan or full analysis strategy. They should not be used in isolation to claim a confirmed benefit or harm. The safety counts likewise describe reported events without establishing causation or a comparative safety effect.

The results apply to the recorded trial population, endpoints, and follow-up windows. They do not establish outcomes outside those definitions, and the registry record does not provide enough information to assess all aspects of generalizability, missing data, or analysis choices. The trial’s enrollment entry is 119, while the primary outcome uses the population who successfully had catheter placement; the record does not fully explain the relationship between these counts.

In general, a clinical trial result is strongest when the endpoint, analysis, uncertainty, and conduct are all transparently reported. Here, the posted statistics permit a clear description of the observed primary comparison, but the missing analysis details and broad interval limit the strength of conclusions. No treatment recommendation follows from these registry results alone.

17. Why This Trial Matters Statistically

This trial is statistically informative because it asks a focused comparative question using random allocation and a defined primary outcome. The primary endpoint combines pleurodesis with absence of recurrence at a specified follow-up point, making the target of the comparison explicit. The posted group counts, proportions, risk difference, confidence interval, and p-value allow readers to assess both the observed contrast and its uncertainty.

The key statistical lesson is that an observed difference is not the same as a precise or decisive result. The primary estimate is positive, but its confidence interval includes zero and extends across a broad range. The unadjusted p-value does not establish a difference, while the interval shows why the estimate should not be reduced to a yes-or-no statement. Reading the point estimate together with its uncertainty is more informative than focusing on a single threshold.

The record also illustrates why outcome definitions matter. A fixed-time measure of pleurodesis without recurrence differs from the mean time to confirmed pleurodesis and from a recurrence count at a later time point. Each captures a different feature of the clinical course. Secondary findings require particular care when the registry does not report a multiplicity strategy or a complete statistical analysis plan.

Finally, the distinction between observed results and planning calculations is important. The sample-size illustrations use effects observed in this trial and stated assumptions; they are not the trial’s original sample-size justification and are not observed power. The record’s missing details about analysis populations, missing data, and masking also show why transparent registry reporting is essential for evaluating a trial beyond its headline estimates.

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.

Several limitations specific to this trial affect interpretation. The primary endpoint is defined among participants who successfully had catheter placement, but the registry record does not explain how that population relates to everyone randomized or to the enrollment entry of 119. The posted arm denominators are 77 and 37. Without participant-flow information, it is not possible to determine from this record how exclusions, placement failures, or missing outcome assessments were handled.

The registry describes the study as single-blinded but does not identify who was masked or how masking was maintained. It does not report the randomization procedure, allocation concealment, or details of outcome assessment. These omissions prevent a full appraisal of potential bias in treatment assignment or measurement.

The primary risk-difference interval is broad and includes zero, leaving substantial uncertainty about the comparison. The secondary time-to-recurrence outcome has very few recorded events. The secondary analyses are unadjusted, and the registry does not report a plan for handling multiple outcomes. The record lists eight outcome measures, but only two secondary results are available in the information presented for interpretation.

Other unreported details include the trial’s original sample-size justification, missing-data procedures, analysis populations, protocol deviations, and any sensitivity analyses. The registry record does not provide enough information to judge how these factors may have influenced the posted estimates. These are limitations of the available record; they should not be replaced with assumptions about what the protocol or investigators may have specified.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Safety and Effectiveness of a New Pleural Catheter for Symptomatic, Recurrent, MPEs Versus Approved Pleural Catheter — NCT02649894.
• Registry record last updated 2025-12-11; status last verified 2025-11.
• Results first posted 2020-08-13.
• 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

The registry record describes a completed, randomized, parallel-group comparison of a silver nitrate coated indwelling pleural catheter and an approved uncoated PleurX catheter for malignant pleural effusion. It lists single masking, enrollment of 119, a study start of 2016-05, and primary completion on 2018-04-18. The primary endpoint is pleurodesis without recurrence at 30 days after catheter insertion among participants who successfully had the catheter placed.

The primary comparison reports proportions of 0.221 and 0.324, a risk difference of 0.103 with a 95% confidence interval from -0.073 to 0.281, and an unadjusted p-value of 0.235. Two secondary outcomes and adverse-event counts are also posted. The registry record does not report the full statistical analysis plan, multiplicity handling, missing-data methods, or the original sample-size assumptions.