Global Prospective Case Series Using a Single-Use Duodenoscope: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Global Prospective Case Series Using a Single-Use Duodenoscope (NCT04103749), a na na study. The primary outcome is Number of Participants With Successful ERCP Procedure.

2. Clinical Question

3. Trial Design

The registry identifies this investigation as a global prospective case series using a single-use duodenoscope. It is a single-group study, with no masking and allocation recorded as NA. The listed intervention is the Exalt Model D Single-Use Duodenoscope; participants were to undergo a clinically indicated ERCP or another duodenoscope-based procedure using the study device.

The registry reports enrollment of 551 and a completed status. The recorded study start date is 2021-03-22, and the primary completion date is 2022-11-23. The phase is listed as NA. Boston Scientific Corporation is named as sponsor.

This design describes procedural experience with the device rather than a randomized comparison between devices. The secondary outcomes include endoscopist rating, crossover from the single-use device to a reusable duodenoscope, and adverse events identified as serious and related to the device and/or procedure. The record does not report the number of participants who crossed over or the endoscopist-rating results.

Enrollment is not the same as the number included in every endpoint analysis. The registry record does not report the primary endpoint analysis population, exclusions from analysis, or the number with an evaluable primary outcome. It also does not report study locations or additional details about recruitment. Those omissions limit how fully the conduct of the case series can be reconstructed.

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

5. Baseline Characteristics

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

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Successful ERCP Procedure, measured over Procedure success is assessed at the end of the procedure (within 24 hours on study day 1)..

The primary endpoint is the number of participants with a successful ERCP procedure. Success is defined as completing the procedure for its intended indication or indications, with the outcome classified as success or failure. Assessment was specified at the end of the procedure, within 24 hours on study day 1.

The description gives examples of intended procedures, including biliary stent placement, pancreatic stent placement, sphincterotomy and clearance of bile duct stones. These are examples, not a report of which procedures participants actually received.

A binary endpoint such as success or failure provides a direct count of participants meeting a defined procedural criterion. To interpret that count as a rate, readers also need the number assessed for the endpoint and information about missing outcomes. The registry record does not report the success count, failure count, or endpoint denominator. Consequently, it does not establish the observed frequency of procedure success or the precision of an estimate of that frequency.

As a general statistical point, a clear endpoint definition helps distinguish the measured outcome from broader judgments about performance. It does not, by itself, show how consistently the criterion was applied or whether outcome assessment was independent. Those details are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a single-group case series estimate?

In general, a single-group study records outcomes among participants receiving an intervention without assigning a concurrent control treatment. For a binary outcome, the basic descriptive result is a count of participants in each category and, when the denominator is known, the proportion in each category. Such a result describes the study participants and setting. Without a control group, it does not isolate the effect of the intervention from other influences, such as participant characteristics, procedure context, or clinical practice.

For this study, the primary outcome is classified as success or failure, and the record defines success as completion for the intended indication or indications. The registry reports enrollment of 551, but not the number with a recorded primary outcome. Enrollment should therefore not be substituted for the endpoint denominator. Neither a success proportion nor its uncertainty can be recovered from the listed enrollment alone.

Why does the endpoint definition matter?

As a general principle, a binary endpoint depends on a rule that assigns each observed case to a category. The registry description supplies the intended rule and examples of procedures, but it does not report how often each type of procedure occurred, how missing or incomplete procedures were classified, or whether outcome assessment was reviewed by an independent assessor. These details affect how readers understand the consistency and scope of the outcome measure.

What can a confidence interval tell readers?

In general, a confidence interval expresses uncertainty around an estimate under the assumptions of the statistical method used. A narrow interval indicates greater precision than a wide interval, but it does not correct limitations in study design or establish causation. The registry record does not report a confidence interval for the primary endpoint, and it does not provide the endpoint count needed to interpret one. No interval should be inferred from enrollment alone.

Why is a randomized comparison different?

In general, random allocation can help create groups that are comparable in expectation, allowing a treatment contrast to be estimated with fewer concerns about baseline differences. This study is registered as single-group, with allocation listed as NA and masking listed as NONE. It therefore has no randomized control group in the registered design. The record does not report a controlled comparison or an adjusted estimate of differences between devices.

How should planning illustrations be understood?

General sample-size calculations ask how many participants might be needed under stated assumptions to detect a specified effect with a chosen statistical procedure. The planning assumptions associated with this record describe an illustration based on the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is expressed as a stated fraction of the observed effect. These are planning assumptions, not evidence that the study used a two-arm design or that its enrollment was determined by those calculations.

The illustration is distinct from the registered case series, which has one group. It should not be interpreted as observed power, as an analysis of the study participants, or as the study's own sample-size justification. The registry record does not report the original sample-size justification. In general, planning values depend on assumptions about the effect, outcome variability or event frequency, significance level, and analysis method; changing assumptions can change the resulting planning estimate.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variation is greater than a statistical model expects. A model that understates variability can make uncertainty appear smaller than it is. This concept is relevant to some count-data analyses, but the primary endpoint is a participant count classified as success or failure, and the registry does not report a fitted model or an analysis that addresses over-dispersion. It would be inappropriate to claim that such a method was used.

What is reported about analyses?

The record lists four outcome measures and zero analyses. It does not report the statistical methods used to analyze the primary outcome, how missing outcomes were handled, or whether any adjusted analyses were performed. General explanations of statistical methods cannot replace those unreported details. Any interpretation should separate the registered endpoint definition and design from results or methods that the registry record does not provide.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Exalt DScope 02")
n      <- c(551)
events <- c(529)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Exalt DScope 02  551  529  96.0  94.0  97.5  94.0  97.3  94.0  97.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures: the primary procedure-success measure and three secondary outcomes concerning endoscopist rating, crossover to a reusable duodenoscope, and serious adverse events related to the device and/or procedure. It lists zero analyses. The record does not report a statistical plan for handling multiple outcomes, a hierarchy among secondary outcomes, or any adjustment for multiple testing.

In general, testing multiple outcomes can increase the chance that at least one result appears statistically notable by chance. A prespecified hierarchy or multiplicity adjustment can address that issue, but the registry record does not say whether either was planned or used. With no registered analyses or outcome results, there is no basis to assess how multiplicity was handled in practice.

The record does not report missing primary outcome data, the number of participants with evaluable outcomes, or methods for handling missingness. It also does not describe an intention-to-treat, per-protocol, or other analysis population. These omissions matter because the enrolled total is not necessarily the denominator for an endpoint analysis. As a general point, conclusions from an outcome count depend on knowing who was included and how unavailable measurements were treated.

No assumptions about missing-data mechanisms or participant exclusions can be made from the registry record. The primary result and its precision remain uninterpretable without these details and the actual endpoint counts.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: pancreatitis (3.4%), cholangitis (1.1%), sepsis (0.9%), procedural pain (0.9%), abdominal pain (0.7%).

The registry reports 85 serious adverse events and 75 other adverse events, with 551 participants at risk for each category. It also reports 17 deaths. The record does not provide enough detail to determine from these aggregate figures whether the counts represent participants or individual event occurrences, or how events were distributed among participants. It does not give timing, severity breakdowns beyond the serious/non-serious categories, or participant-level overlap.

The listed serious adverse-event terms and percentages are pancreatitis, 3.4%; cholangitis, 1.1%; sepsis, 0.9%; procedural pain, 0.9%; abdominal pain, 0.7%; and gastrointestinal haemorrhage, 0.7%. These are reported terms, not a complete account of every event in the record.

A serious event and an event judged related to a device or procedure are not interchangeable concepts. Although a secondary outcome refers to serious events related to the device and/or procedure, the aggregate figures do not state how many events were attributed to the device, the procedure, both, or neither. The counts alone therefore do not establish causality. The registry record does not report further detail needed to interpret the deaths in relation to the intervention or procedure.

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

The registered study describes prospective experience with the Exalt Model D Single-Use Duodenoscope in clinically indicated ERCP and other duodenoscope-based procedures. Its primary endpoint has a defined procedural criterion: completion for the intended indication or indications, assessed at the end of the procedure within 24 hours on study day 1. The study reports 551 enrolled participants and a completed status.

Those details do not establish the primary outcome result. The registry record does not report how many participants had a successful procedure, how many had a failure, or how many were assessed. It also does not report a confidence interval or other measure of uncertainty. Thus, the record does not support a numerical estimate of the observed success frequency or its precision.

The case-series design also does not provide a concurrent randomized control group. A description of outcomes in one group cannot, by itself, establish what would have happened under a different device or estimate a causal difference between devices. The crossover outcome is listed as secondary and does not change the single-group design.

Safety entries describe counts and reported event terms, but the record does not provide enough detail to assign causation or fully characterize the events. Counts should not be interpreted as rates unless the event unit and relevant denominator are clear, and a report of an adverse event does not by itself establish that the device caused it.

In general, statistical evidence is strongest when the endpoint result, denominator, uncertainty, analysis population, and study design can be considered together. Several of these elements are not reported in the registry record. The appropriate reading is therefore limited to the registered study design, endpoint definition, enrollment, and the safety information actually reported—not a conclusion about comparative performance or causation.

14. Why This Trial Matters Statistically

This study illustrates an important statistical distinction between describing procedural outcomes and estimating a comparative effect. A prospective single-group case series can record how often a defined outcome occurs among participants treated in the study. It cannot supply a randomized contrast when there is no concurrent control group. Recognizing that distinction prevents descriptive experience from being read as a controlled treatment comparison.

The endpoint is also a useful example of why a definition and a result are separate pieces of evidence. The registry defines success in terms of completing the procedure for its intended indication or indications, but does not report the number meeting that definition. A clearly described endpoint does not substitute for the numerator, denominator, and uncertainty needed to interpret an observed frequency.

Safety reporting raises a related issue: event counts, participant counts, and attribution are different concepts. The record includes aggregate figures and serious-event terms, while the secondary outcome refers to events related to the device and/or procedure. Without further detail, readers should not equate an event occurring during a study with an event caused by the intervention.

Finally, planning calculations and trial design answer different questions. The planning assumptions describe a hypothetical two-arm illustration, whereas the registered study is single-group. Keeping those contexts separate is essential: a planning illustration is not a description of the study's allocation, a result, or observed power. The registry record does not report the study's own sample-size justification or statistical analysis plan.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The primary limitation for statistical interpretation is that the registry record does not report the primary outcome count, denominator, or an estimate of uncertainty. Although 551 participants were enrolled, the record does not establish how many had an evaluable primary endpoint. This prevents assessment of the observed frequency of successful procedures and the precision of that result.

The single-group design has no concurrent control arm, so the registered study cannot estimate a randomized contrast with reusable duodenoscopes or another device. The crossover outcome does not provide a like-for-like comparison, and its result is not reported. No adjusted comparative analysis is reported.

The record does not report participant characteristics, procedure mix, study locations, detailed eligibility criteria, missing outcome handling, or analysis populations. Without those details, readers cannot assess how the enrolled participants or procedures relate to other clinical settings, or how incomplete outcome information may affect the results.

Safety interpretation is also limited by the aggregate reporting. The record lists serious and other adverse-event counts, deaths, and selected serious-event terms, but does not clarify event-level attribution, timing, overlap among participants, or the relationship of deaths to the device or procedure. The record does not provide the primary outcome result or a statistical analysis plan, and the completed status alone does not fill those gaps.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Global Prospective Case Series Using a Single-Use Duodenoscope — NCT04103749.
• Registry record last updated 2023-12-12; status last verified 2023-11.
• Results first posted 2023-12-12.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

The registry record describes a completed, prospective, single-group case series of the Exalt Model D Single-Use Duodenoscope for clinically indicated ERCP and other duodenoscope-based procedures. It reports enrollment of 551, a study start date of 2021-03-22, and a primary completion date of 2022-11-23. The sponsor is Boston Scientific Corporation.

The primary endpoint is the number of participants with successful ERCP procedure completion for the intended indication or indications, assessed within 24 hours on study day 1. The registry record does not report the primary outcome count, analysis denominator, or statistical analyses. Safety reporting includes 85 serious adverse events, 75 other adverse events, and 17 deaths; attribution and further event-level details are not reported in the registry record.