Compare Propofol to Fentanyl and Midazolam for Colonoscopy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Compare Propofol to Fentanyl and Midazolam for Colonoscopy (NCT01488045), a randomized na study. The primary outcome is Patient Satisfaction Scores (Absolute Value).

2. Clinical Question

3. Trial Design

The registry describes a randomized, single-masked, parallel-group trial comparing propofol sedation with fentanyl and midazolam sedation for colonoscopy. In a parallel-group design, participants are assigned to one of the study arms rather than receiving each regimen in sequence. Randomization is intended to support a fair comparison by assigning treatment without choosing an arm on the basis of observed participant characteristics. The registry does not state how the random sequence was generated or concealed.

The record labels the trial single-masked but does not specify who was masked. It therefore does not establish whether participants, clinicians, outcome assessors, or another group were unaware of assignment. Details about the conduct of masking are not reported in the registry record.

Overall enrollment is listed as 289. The brief summary describes a prospective randomized study of 262. These are different figures in the record, and the reason for the difference is not reported. The primary-outcome description says that all patients who completed the intervention were included in its analysis; this is not the same as confirming that every enrolled participant contributed an outcome.

The registry lists the study as completed and gives a start of 2011-06 and primary completion of 2015-03. It lists phase as NA. These registry entries describe the record, but do not provide further information about recruitment, follow-up completion, or the conduct of the trial. The full protocol and details of the statistical plan are not reported in the registry record.

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 patients who completed the intervention were included in the analysis

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 Patient Satisfaction Scores (Absolute Value), measured over Survey administered in the recovery room up to 30 minutes following procedure ("Recovery room"), and a follow-up patient survey was carried out by telephone between 1 and 5 days postprocedure ("1-5 d postprocedure").

The registered primary endpoint is Patient Satisfaction Scores, recorded as a mean with standard deviation. Patients used a 100-point Visual Analog Scale, shown in the record as [0-100%]. Higher scores indicate stronger agreement with the statement or question and are described as indicating higher satisfaction. The measure is intended to capture the patient’s own experience of colonoscopy sedation rather than a clinician’s impression alone.

The registry describes two assessment occasions: a survey in the recovery room up to 30 minutes following the procedure, and a telephone survey between 1 and 5 days postprocedure. These occasions can reflect different points in a patient’s experience, so results should be read with attention to which assessment they represent. The registry record does not report a single primary time point or reduce the listed occasions to one comparison.

As a general statistical point, a continuous score preserves differences across the scale rather than grouping responses into categories. A mean summarizes the average score, while a standard deviation describes the spread of individual scores around that mean. Neither measure alone shows how precisely the arm difference has been estimated. The registry information does not include the primary endpoint values or a confidence interval, so the size and precision of the patient-satisfaction comparison are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the mean summarize?

The registered primary endpoint is continuous and is summarized as a mean with standard deviation. In general, the mean represents the average score among the participants included in the analysis. The standard deviation describes how dispersed individual scores are around that average. These answer different questions: an arm mean describes its central score, while the standard deviation describes variation among participants. A difference between arm means, if reported, would summarize the average contrast on the scale. The registry record does not give those primary-outcome values.

What does the scale mean?

The endpoint uses a 100-point Visual Analog Scale, represented in the registry as [0-100%]. The record says that higher scores mean stronger agreement and that higher agreement indicates higher satisfaction. Interpretation therefore depends on that stated direction: a higher score corresponds to a more favorable satisfaction response. The endpoint is patient-reported, so it captures the participant’s account rather than an observer’s rating. The record does not describe the exact wording of each question or the method used to combine questions, if any.

Why do assessment occasions matter?

The registry identifies a recovery-room survey up to 30 minutes following the procedure and a telephone survey between 1 and 5 days postprocedure. These are not interchangeable measurement occasions. A score collected in recovery reflects the response at that point, while a later telephone response reflects a different time after the procedure. In general, repeated assessments can be analyzed as separate outcomes or with a method that models their relationship, but the method used is not reported in the registry record. The posted results should therefore be interpreted by the time point stated for each result, rather than treated as one undifferentiated score.

How should an estimate and confidence interval be read?

In general, an estimated difference summarizes the contrast observed in the analyzed participants. A confidence interval conveys uncertainty around that estimate and the precision of the comparison. An interval compatible with a wide range of differences provides less precise information than an interval spanning a narrower range. The clinical meaning of an interval depends on the scale and on a prespecified threshold for what difference matters. The registry information does not include a primary estimate or confidence interval, so no numerical interpretation of magnitude or precision is possible from this record alone.

A confidence interval is not a guarantee that the true effect lies within its endpoints. It is a statistical summary produced under an analysis model and its assumptions. Similarly, a p-value addresses compatibility with a specified null model; it does not quantify the size of an effect or prove that two treatments are equivalent. The registry record does not report a primary p-value or a detailed inferential result.

What is required for an equivalence claim?

Equivalence is a particular type of research question. In general, investigators define an acceptable range of differences before examining the trial results. The uncertainty interval for the treatment contrast must then be assessed against that range. Merely failing to find a statistically significant difference is not sufficient to demonstrate equivalence: an imprecise estimate may be consistent with both negligible and meaningful differences. The study summary states an aim to determine equivalence, but the equivalence margin, its justification, and the analysis used to assess it are not reported in the registry record.

The same principle applies to the word noninferiority, although that is not the stated primary aim in this record. A noninferiority analysis also requires a prespecified margin and an analysis designed for that question. No such details should be inferred from the randomized design or from the study’s stated equivalence objective.

Why can over-dispersion matter?

As a general concept, over-dispersion means that observed variability is greater than a statistical model expects. It matters for outcomes analyzed as counts or other non-continuous quantities because a model that underestimates variability can yield overly narrow uncertainty intervals. The registered primary outcome is a continuous score summarized by a mean and standard deviation, not a count outcome. The record does not report an over-dispersion assessment or a model for the primary endpoint, so there is no basis to say whether this issue was relevant to the actual analysis.

What do the planning illustrations show?

The sample-size section is described as a planning illustration computed from the observed effect, using a two-sided significance level of 0.05, equal allocation, and a normal approximation. It gives participants per arm for non-time-to-event outcomes and uses the stated fraction of the observed effect as the target effect. These are illustrations of the sample size associated with those assumptions. They are not observed power, do not establish that the trial was originally planned that way, and do not show the probability that the trial’s result is correct. The registry does not report its own sample-size justification or the planning assumptions used when the trial was designed. Any interpretation should keep the illustration separate from the actual randomized enrollment and observed analysis population.

For a continuous endpoint, a planning calculation depends on assumptions about the target difference and variability, among other design choices. Changing those assumptions changes the resulting planning requirement. A calculation based on an observed effect is especially conditional on the effect used in the calculation. It should be read as a hypothetical planning reference rather than evidence that the study had adequate power or that its result is conclusive.

What analysis details remain unknown?

The registry labels the endpoint as a mean and standard deviation, states that all patients who completed the intervention were included in the analysis, and lists one analysis. It does not describe the exact test or model, treatment of baseline values, missing-data method, confidence-interval procedure, or any adjustment for multiple comparisons. Those methods cannot be reconstructed from the design labels alone. The posted tables and plots may display calculated summaries, but their presence does not fill in unreported protocol decisions or analysis-plan details.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists three outcome measures and describes the primary satisfaction survey at more than one occasion: in the recovery room up to 30 minutes following the procedure and by telephone between 1 and 5 days postprocedure. The record also identifies patient pain and discomfort and physician perceptions as secondary outcomes. Testing or estimating several outcomes and occasions can create a multiplicity issue: when many comparisons are considered, the chance of finding an apparently notable result by chance may increase. As a general statistical approach, a study may define one primary comparison in advance, adjust for multiple tests, or treat additional analyses as exploratory. The registry record does not report which approach was used.

The record indicates one analysis and says the primary outcome has several categories or time points and was not reduced to one comparison. The exact analysis strategy, multiplicity adjustment, and hierarchy among outcomes and occasions are not reported in the registry record. This limits the ability to identify which comparison should be considered definitive.

The primary-outcome population is described as all patients who completed the intervention. The record does not explain how many participants lacked an outcome, why data might be missing, or how missing observations were handled. It also does not report whether any analyses used a different population definition. In general, excluding participants without completed intervention or outcome data can affect the interpretation if those participants differ systematically from those analyzed; whether that occurred cannot be determined from this record.

The safety section has its own group-specific at-risk denominators, while overall enrollment is also recorded. The registry does not explain the reasons for these differences or provide a participant flow description. Consequently, the available information does not establish how many randomized participants contributed to each primary-outcome time point.

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 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists safety groups for propofol and for midazolam/fentanyl. In the propofol group, 126 participants were at risk for the serious-event summary and 0 were affected; 126 were at risk for other adverse events and 18 were affected. In the midazolam/fentanyl group, 136 participants were at risk for the serious-event summary and 0 were affected; 136 were at risk for other adverse events and 19 were affected. Deaths are listed as 0 in each group. No top serious-event terms are listed.

These are descriptive figures from the registry record. The other-event counts should not be read as counts of serious events: the serious-event count is separately recorded as 0 in each group. The record does not describe the types of other events, their severity, timing, or how they were collected. It also does not give enough detail to determine whether each count represents people with at least one event or the total number of events beyond the registry’s group labels.

Comparing raw counts without accounting for definitions, observation time, and group denominators can be misleading. No event-rate calculation is presented. These safety figures do not establish the overall safety profile of either regimen, and they do not address the primary patient-satisfaction endpoint.

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

The record establishes that a randomized, parallel-group trial compared propofol sedation with fentanyl and midazolam sedation for colonoscopy. It identifies patient satisfaction scores as the primary outcome, describes a Visual Analog Scale and its direction, and lists assessments in recovery and by telephone after the procedure. It also describes patient pain and discomfort and physician perceptions as secondary outcomes. These details make the intended comparison and measurement approach understandable.

The record does not, in the information, report the primary arm means, the numerical contrast, an uncertainty interval, or the equivalence margin. Therefore, it does not support a conclusion about how large or precise the satisfaction difference was, or whether the trial formally demonstrated equivalence. The study’s stated aim should not be treated as a result. Likewise, absence of a reported significant difference would not by itself establish equivalence; equivalence depends on a prespecified margin and sufficiently precise results.

The planning illustrations are not observed power and should not be used as a retrospective verdict on trial adequacy. They are calculations based on the observed effect and stated assumptions. The registry record does not report the trial’s own design justification. The difference between overall enrollment of 289 and the brief summary’s description of a prospective study of 262 is also unexplained, so those figures should not be treated as interchangeable without additional information.

The safety listing reports 0 serious events and 0 deaths in each group, alongside other adverse-event counts. This is a limited description, not a comprehensive account of event types or a basis for broad claims about comparative safety. Overall, the record describes the trial question and selected outcomes, but the information is insufficient to make a definitive statistical statement about the primary comparison.

13. Why This Trial Matters Statistically

This trial is statistically interesting because its stated objective is equivalence, while the registered primary measure is a continuous patient-reported score observed at more than one occasion. Equivalence questions require a different interpretive standard from simply asking whether a conventional test detects a difference. The acceptable range must be specified, and the uncertainty around the estimated contrast must be evaluated against it. Without a reported margin and primary estimate, a reader cannot determine whether the stated objective was met.

The record also illustrates why outcome timing matters. A recovery-room response and a telephone response between 1 and 5 days postprocedure refer to different assessment occasions. They may be useful for describing patient experience at different points, but they should not be collapsed into a single result unless the analysis plan justifies that choice. The registry states that multiple categories or time points were not reduced to one comparison, highlighting the need to know which comparison was prioritized.

The primary endpoint is a patient-reported score, whereas one secondary measure concerns physician perceptions. Keeping those perspectives distinct is important: they are different constructs and should not be treated as interchangeable evidence. The mean and standard deviation describe the continuous score, but an estimate of the between-arm contrast and its precision are needed to interpret the comparison.

Finally, the record distinguishes overall enrollment from the population described for primary analysis and from the safety denominators. These numbers serve different purposes and cannot be assumed to represent the same participants. The trial is a useful example of how design labels and outcome descriptions provide context, while missing analysis details and numerical estimates limit what can be concluded from a registry summary.

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 registry record does not include detailed eligibility criteria, participant characteristics, or a flow description showing how participants moved from enrollment through intervention and outcome assessment. Overall enrollment is 289, while the brief summary describes a prospective randomized study of 262; the reason for the difference is not reported in the registry record. The primary outcome is described for patients who completed the intervention, but the record does not give the number contributing to each assessment occasion.

Important intervention details are absent. The arm descriptions identify propofol and fentanyl with midazolam, but dose, administration, and other procedural details are not reported in the registry record. Although masking is listed as single, the identity of the masked group and the procedures used to preserve masking are not stated.

The primary measure is described, but the exact question wording and the relation between satisfaction and discomfort are not fully specified. The record gives two assessment occasions and does not reduce them to one comparison. The specific primary contrast, equivalence margin, statistical model, confidence-interval method, and multiplicity strategy are not reported. Nor are missing-data methods or sensitivity analyses described.

The safety summary lists serious events, other adverse events, and deaths, but does not identify the other events or explain their ascertainment and follow-up. The registry record also does not provide its own sample-size justification. The planning illustrations are based on the observed effect and should not be mistaken for a prospective design calculation. These limitations constrain interpretation of both efficacy-related outcomes and safety beyond what is explicitly recorded.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Compare Propofol to Fentanyl and Midazolam for Colonoscopy — NCT01488045.
• Registry record last updated 2023-05-23; status last verified 2023-04.
• Results first posted 2023-05-23.
• 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

This completed, randomized, single-masked, parallel-group trial compared propofol sedation with fentanyl and midazolam sedation for colonoscopy. Overall enrollment is listed as 289; the brief summary describes a prospective randomized study of 262, and the reason for the difference is not reported in the registry record.

The primary endpoint is patient satisfaction measured on a 100-point Visual Analog Scale, with higher scores indicating higher satisfaction. The registry describes a recovery-room assessment up to 30 minutes following the procedure and a telephone assessment between 1 and 5 days postprocedure. The primary analysis population is described as patients who completed the intervention. Numerical primary-outcome estimates and an equivalence margin are not reported in the registry information.

The record lists patient pain and discomfort and physician perceptions as secondary outcomes. It records 0 serious events and 0 deaths in each safety group, along with other adverse-event counts. Analysis details, missing-data methods, multiplicity handling, and the trial’s own sample-size justification are not reported in the registry record.