A 4-arm Clinical Trial of Fuse®, EndoCuff™, EndoRings™ and Standard Colonoscopy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A 4-arm Clinical Trial of Fuse®, EndoCuff™, EndoRings™ and Standard Colonoscopy (NCT02345889), a randomized na study. The primary outcome is Adenomas Per Colonoscopy.

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group trial with four arms: FUSE® colonoscopy, colonoscopy with EndoCuff™, colonoscopy with EndoRings™, and standard colonoscopy. The registry lists the masking as single, but does not identify who was masked. It does not report the allocation ratio, the method used to generate or conceal the random sequence, or whether any departures from the planned allocation occurred.

The registry lists an enrollment of 1262 and a status of completed. The recorded start was 2015-02, and primary completion was recorded as 2017-12. Indiana University is listed as the sponsor. The phase is listed as NA. These record details describe trial administration; they do not establish how many participants contributed to each outcome analysis.

The intervention descriptions distinguish the device configurations. FUSE® used a system with 3 HD monitors. EndoCuff™ and EndoRings™ were each described as distal attachments placed at the end of a standard colonoscope. The standard arm used a standard colonoscope to complete the procedure. The registry record does not report additional information about operator training, procedural standardization, or use of the devices across participating sites.

The primary outcome description says adenomas were counted overall for all three sites and then broken down by individual site. It also notes that the number of participants in each arm differed at each site, so the number analyzed varies by site and randomization. The sites are not identified in the record. This makes it important to distinguish the overall enrollment from the denominators used for a particular outcome or site-specific analysis; those denominators are not reported in the available outcome information.

4. Participant Flow and Accounting

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

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The number of adenomas was calculated overall for all three sites and then broken down into individual sites. The number of participants in each arm differed at each site, which is why the number analyzed differs depending on site and randomization.

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 Adenomas Per Colonoscopy, measured over During Procedure.

The primary endpoint was adenomas per colonoscopy, expressed as a mean with standard deviation. It measures the count of adenomas detected during a colonoscopy, with the trial record describing counts for all three sites overall and by individual site. Unlike an outcome that records only whether a participant had any adenoma detected, a count can reflect differences in the number detected per procedure.

The registry background describes adenoma detection rate as a validated marker relevant to reducing the risk of interval colorectal cancer after screening colonoscopy. That background explains why adenoma detection is of interest, but the primary endpoint named for this trial is the mean count of adenomas per colonoscopy, not the percentage of participants with an adenoma. The registry also lists participant-level adenoma detection among secondary outcomes.

A mean summarizes the average count in a group, while a standard deviation describes the spread of individual counts around that group average. Comparing means can describe how average counts differ across randomized groups, but interpretation requires the group estimates, denominators, and a measure of uncertainty or a statistical test. Those primary outcome results are not reported in the registry record. The endpoint description also notes site-specific differences in the number analyzed, so any overall or site-level interpretation needs to account for which participants contributed to each estimate.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a continuous summary of a count: adenomas per colonoscopy, analyzed as a mean with standard deviation. A mean is the arithmetic average of the observed values in a group. A standard deviation describes how dispersed those individual values are around the mean. Neither measure alone communicates the uncertainty in comparing randomized groups; that generally requires a standard error, confidence interval, or a statistical test. The registry record does not report those estimates or tests for the primary outcome.

What does a randomized parallel-group design mean?

In general, random allocation is intended to make assigned groups comparable, on average, with respect to characteristics measured and unmeasured before treatment assignment. It does not ensure identical groups in a particular trial, and it does not remove the need to report outcomes and the analysis used. In a parallel-group design, participants are assigned to a group and outcomes are compared across groups. Here, the registry identifies four groups, but does not describe the allocation ratio, sequence generation, allocation concealment, or the exact analysis contrasting them.

The registry labels masking as single. Masking can reduce the influence of expectations on care or outcome assessment, depending on who is unaware of group assignment. The record does not identify the masked party, so it is not possible to assess which potential sources of bias masking was intended to address. The word “single” alone does not establish that participants, clinicians, outcome assessors, or analysts were masked.

How should a mean count be interpreted?

Counts are whole-number observations, but their group mean can be fractional. The average count gives a concise comparison of adenoma burden per procedure, while the standard deviation describes individual variability. Count outcomes can have features such as many low counts, a long right tail, or variability greater than a simple model expects. In general, over-dispersion means that the observed variation exceeds the variation assumed by a model; if ignored, standard errors and tests may be poorly calibrated. The registry record does not identify a model for the count outcome, so it is not possible to determine whether or how such features were assessed.

A direct comparison of group means may use a model or test whose assumptions concern the distribution of the outcome and the independence of observations. Other count-data models may be suitable under different assumptions. This is general statistical context, not a description of the trial's chosen method. The statistical analysis plan and the method used for the primary outcome are not reported in the registry record.

What does uncertainty add?

A confidence interval conveys the precision of an estimate by describing a range of values compatible with the observed data and the procedure's assumptions. A narrower interval usually indicates greater precision than a wider interval, but an interval must be interpreted in the context of the outcome and the comparison. A p-value, if reported, describes how incompatible the data are with a specified null model under the test assumptions; it does not measure the size or importance of an effect. Neither confidence intervals nor p-values are reported for the primary outcome.

For a four-arm trial, an overall test and pairwise contrasts answer different questions. An overall test can assess whether there is evidence that group means are not all alike, whereas pairwise contrasts address particular group comparisons. A planned contrast may also be relevant if the design specified a focused comparison. The record does not report which of these approaches was used, or whether adjustments were made for multiple comparisons. It therefore does not support a reconstruction of the inferential plan from the arm structure alone.

How should the planning illustration be read?

The record describes sample-size planning illustrations based on a fraction of the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Such calculations are planning illustrations: they show how a hypothetical target effect and assumptions relate to a planned sample size. They are not observed power, and they do not show the probability that the completed trial detected a true effect. The record does not provide the illustration's result values or the effect fractions used, and it does not report the trial's own sample-size justification. The illustration's assumptions should not be mistaken for the trial's statistical analysis plan.

The registry record's primary endpoint description says the number analyzed differs by site and randomization. For any estimate, the denominator and the set of participants included matter. A sample-size calculation cannot resolve questions about missing outcomes, site composition, or which participants entered the analysis. The analysis population definitions, missing-data methods, and handling of site in the statistical model are not reported in the registry record.

Overall, the methods information establishes the type of endpoint, broad design, and some planning assumptions. It does not establish the detailed model, contrast strategy, diagnostic checks, adjustment procedures, or uncertainty estimates used for the reported outcome. Those distinctions are essential when interpreting a trial's numerical results, and the primary numerical results themselves are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The trial has four arms and lists 15 outcome measures. The named secondary outcomes include adenoma detection, sessile serrated polyp measures, polyp detection, and cecal insertion time. Testing several outcomes or making several group comparisons can increase the chance of at least one apparently unusual result arising by chance. Statistical plans may address this through a prespecified hierarchy, adjustment, or a clearly defined focus on selected comparisons. The multiplicity strategy is not reported in the registry record.

The record notes that the primary outcome was calculated across all three sites and then broken down by individual site. It also notes that the number analyzed differs by site and randomization. This raises questions about whether the overall and site-specific estimates were prespecified, how site was incorporated, and how multiple results were interpreted. The registry record does not report the analysis plan or identify a primary contrast, so it is not possible to determine how these issues were handled.

Missing-data handling is also not reported in the registry record. The statement that numbers analyzed differed across sites does not establish that outcome data were missing; the record does not explain the reason for the differences. It does not describe whether all randomized participants were included, how incomplete procedures or unevaluable outcomes were treated, or whether any imputation or sensitivity analysis was used.

The registry lists enrollment as 1262, but does not provide outcome-specific analysis populations or participant flow by arm and site. The distinction between enrolled participants and those contributing to a particular endpoint is important. Without denominators and analysis-population definitions, the effect of exclusions or unavailable outcomes cannot be evaluated. No conclusion about attrition, missingness, or bias from exclusions can be drawn from the registry record alone.

11. 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.

The adverse-event entries list, for standard colonoscopy, 295 participants at risk for serious events and other events, with 0 affected in each category and 0 deaths. For colonoscopy with EndoCuff™, the corresponding at-risk count is 299, with 0 serious events, 0 other events, and 0 deaths. For colonoscopy with EndoRings™, 295 were at risk, with 0 serious events, 0 other events, and 0 deaths. For FUSE® colonoscopy, 299 were at risk, with 0 serious events, 0 other events, and 0 deaths.

These entries are reported counts, not proof that no adverse events could occur. A zero count means that no affected participants are recorded in the corresponding registry category for the listed at-risk group. The registry record does not list serious-event terms, and does not report additional information about event definitions, ascertainment, follow-up duration, or how the safety data were collected. Consequently, the counts should be read within the limits of the record rather than as a complete account of safety evidence.

The at-risk counts differ by arm, and the record does not explain the reasons for the difference. These figures do not provide comparative estimates with uncertainty, nor do they resolve whether every participant had the same opportunity for event detection. The safety entries also do not provide evidence about the primary adenoma-count outcome.

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

The registry record establishes that this was a randomized, parallel-group comparison of four colonoscopy approaches and that adenomas per colonoscopy was the primary endpoint. It gives descriptions of the device configurations, identifies the trial as completed, and lists an enrollment of 1262. It also reports the endpoint's mean-and-standard-deviation format and notes that the number analyzed varied by site and randomization.

Those details do not reveal the observed primary outcome. The group means, standard deviations, uncertainty intervals, and statistical tests are not reported in the registry record. There is therefore no basis in this record for saying which group had a larger average adenoma count, how large any difference was, or how precise an estimate might be. Absence of a reported result is not evidence that groups had the same outcome.

The registry background describes adenoma detection rate as a validated marker relevant to interval colorectal cancer risk after screening colonoscopy. That rationale does not make the primary endpoint a direct measurement of interval cancer or long-term clinical outcomes. The primary measure is a count during a colonoscopy. Secondary outcomes include participant-level adenoma detection and other polyp-related measures, but results for them are not reported in the registry record.

Likewise, the safety entries show zero affected participants recorded for serious events and other events in each arm, and zero deaths. They should be interpreted as registry counts, not as proof of absence of risk or as a substitute for a fuller safety assessment. Follow-up and ascertainment details are not reported.

In general, a comparative conclusion requires the outcome estimates, analysis population, method of comparison, and uncertainty around the estimates. The registry record does not report those elements for the primary endpoint. It supports a description of what was studied and how the endpoint was defined, but not a judgment about comparative effects or their clinical importance.

13. Why This Trial Matters Statistically

This trial is statistically interesting because it places three device-based approaches alongside standard colonoscopy in a randomized, parallel-group design. A multi-arm comparison can address more than one question, but its interpretation depends on which contrasts were planned and how they were analyzed. The registry record identifies the four arms without reporting a particular contrast strategy or primary statistical test.

The endpoint is a mean count rather than simply the presence or absence of an adenoma. That choice describes the average number detected per procedure, while the listed secondary outcomes include participant-level detection measures. These outcomes capture different aspects of detection and should not be treated as interchangeable. The registry record does not report numerical results for either the primary or secondary measures.

The trial also describes an overall endpoint calculation across three sites and site-specific breakdowns, with differing numbers analyzed by site and randomization. That detail matters because pooled and site-specific estimates can reflect different participant sets. Without arm-by-site denominators, site identities, and results, the record cannot establish whether any pattern was consistent across sites or whether a pooled comparison obscured variation.

Finally, the distinction between design information and evidence is important. Randomization and an enrollment count describe the trial structure, but neither supplies an outcome estimate. The record includes safety counts, yet those do not answer the adenoma-count question. The statistical value of the trial's comparison cannot be judged from design details alone when the results and analysis methods are not reported.

14. 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 principal limitation of interpreting this registry record is that numerical primary outcome results are not reported. There are no group means, standard deviations, confidence intervals, p-values, or pairwise estimates in the record. The registry lists no analyses, and it indicates that the primary outcome was not reduced to one comparison because it has several categories or time points. This prevents a direct account of the comparative findings.

The endpoint description says analyses were conducted overall across three sites and by individual site, while the number analyzed in each arm differed by site. The record does not identify the sites or provide denominators for each arm and analysis. It is therefore not possible to evaluate the contribution of each site, the precision of site-specific estimates, or whether the overall results were consistent across sites.

Important design and analysis details are also absent. The record does not identify who was masked, describe the randomization procedure, report the allocation ratio, or specify the primary contrast or statistical model. It does not report how multiplicity was handled, how missing outcomes were addressed, or which analysis populations were used. The noted differences in numbers analyzed do not establish why those differences occurred.

The registry lists an enrollment of 1262, but that figure does not determine the denominator for the primary outcome. The sample-size information describes planning illustrations based on assumed comparisons and the observed effect, but the result values and the trial's own sample-size justification are not reported. The safety entries provide zero event counts in each category, but event definitions and ascertainment details are not reported. These limitations restrict interpretation of both efficacy and safety from the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A 4-arm Clinical Trial of Fuse®, EndoCuff™, EndoRings™ and Standard Colonoscopy — NCT02345889.
• Registry record last updated 2019-03-12; status last verified 2019-02.
• Results first posted 2019-03-12.
• 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.

18. Record Summary

NCT02345889 is listed as a completed, randomized, single-masked, parallel-group trial sponsored by Indiana University. The registry records enrollment of 1262, a start of 2015-02, and primary completion in 2017-12. The four arms were FUSE® colonoscopy, colonoscopy with EndoCuff™, colonoscopy with EndoRings™, and standard colonoscopy.

The primary endpoint was adenomas per colonoscopy, summarized as a mean and standard deviation during the procedure. The record describes an overall calculation across three sites and site-specific breakdowns, with differing numbers analyzed by site and randomization. It lists secondary outcomes concerning adenomas, sessile serrated polyps, polyps, and cecal insertion time.

Numerical primary outcome results, statistical comparisons, and detailed analysis methods are not reported in the registry record. The adverse-event entries list zero serious events, zero other events, and zero deaths in each arm.