This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Relieving Acute Pain (RAP) Study: A Pilot Study (NCT03426137), a randomized phase 2 study. The primary outcome is Pain Self-reports.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03426137 |
| Phase | Phase 2 |
| Condition | Trauma, Opioid Use, Spine Fusion |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 3 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Maryland, Baltimore |
| Results posted | Yes |
2. Clinical Question
Population
Adults with traumatic pain and opioid use were the intended population. The registry record lists Trauma, Opioid Use and Spine Fusion as conditions. All three participants gave written consent and signed the HIPAA form, but withdrew before starting any study procedures. Consequently, the record contains no outcome observations from participants who received a study intervention.
Intervention
The study planned three arms. The Full Dose (FD) arm was to receive NSAIDs and Oxycodone (5mg), dosed according to University of Maryland Shock Trauma Center guidelines. The Partial Reinforcement (PR) arm was to receive NSAIDs, Oxycodone (5mg), and placebo pills, with the stated aim of reaching a 50% reduction in total opioid intake. The Control arm was to receive NSAIDs and placebo pills.
Comparator
The planned comparisons were among Full Dose, Partial Reinforcement and Control. The registry record identifies randomized allocation and a parallel model, but does not report details of the allocation sequence or how participants were assigned. Since no participant started study procedures, there are no observed group outcomes to compare.
Primary question
The primary outcome was pain self-reports on a visual analogue scale, with 0 representing “no pain” and 100 representing “maximum pain tolerable.” The planned assessment times were Day 1-7, Week 2, Months 1, 3 and 6. The central question was whether pain reports differed among the planned medication and placebo strategies. The registry record contains no pain scores or comparison results.
3. Trial Design
This was a Phase 2, randomized, triple-masked, parallel pilot study sponsored by University of Maryland, Baltimore. The planned design had three arms: Full Dose (FD), Partial Reinforcement (PR), and Control. The registry lists Oxycodone and Ketorolac as drug interventions and Placebo as another intervention. The arm descriptions specify NSAIDs and Oxycodone (5mg) for FD; NSAIDs, Oxycodone (5mg), and placebo pills for PR; and NSAIDs and placebo pills for Control. The PR description states an intended 50% reduction of total opioid intake.
The recorded enrollment was 3. All three participants gave written consent and signed the HIPAA form, but withdrew before starting study procedures. The record says those withdrawals were handled per protocol and quotes the consent statement that participants were free to withdraw consent at any time. No participant exposure to the study interventions is reported. The trial status is TERMINATED.
The planned primary outcome was pain self-reports collected on a visual analogue scale at Day 1-7, Week 2, Months 1, 3 and 6. The scale anchors are described as 0 for “no pain” and 100 for “maximum pain tolerable.” The record identifies one outcome measure but reports no numerical pain results and no analyses. Specific procedures for randomization, masking, treatment adherence, and follow-up are not reported in the registry record. Nor is a planned sample-size justification reported. The available details therefore describe the intended design, but they do not permit evaluation of how the trial would have compared outcomes had participants begun the study.
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
| Stage | Full Dose (FD) | PR (Partial Reinforcement) | C (Control) |
|---|---|---|---|
| STARTED | 0 | 0 | 0 |
| COMPLETED | 0 | 0 | 0 |
| NOT COMPLETED | 0 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: All three participants gave written consent to participate in the study and signed the HIPAA form, but withdrew before starting any study procedures. These 3 withdrawals were handled per protocol. As is written in the consent, "You are free to withdraw your consent at any time." Therefore, there was no analyzable data collected.
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: The three participants who gave written consent to participate in the study and signed the HIPAA form withdrew before randomization or starting any study procedures. Therefore there is no data available to report.
| Characteristic | Unit | Full Dose (FD) | PR (Partial Reinforcement) | C (Control) | Total |
|---|---|---|---|---|---|
| Participants analysed | 0 | 0 | 0 | 0 | |
| Sex: Female, Male: Female | — | — | — | — | |
| Sex: Female, Male: Male | — | — | — | — | |
| Race (NIH/OMB): American Indian or Alaska Native | — | — | — | — | |
| Race (NIH/OMB): Asian | — | — | — | — | |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | — | — | — | — | |
| Race (NIH/OMB): Black or African American | — | — | — | — | |
| Race (NIH/OMB): White | — | — | — | — | |
| Race (NIH/OMB): More than one race | — | — | — | — | |
| Race (NIH/OMB): Unknown or Not Reported | — | — | — | — |
6. Primary Endpoint
The registry lists the primary outcome as Pain Self-reports, measured over Day 1-7, Week 2, Months 1, 3 and 6.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was Pain Self-reports, measured on a visual analogue scale. Its stated anchors were 0 for “no pain” and 100 for “maximum pain tolerable.” The planned collection times were Day 1-7, Week 2, Months 1, 3 and 6. The record does not specify a single summary value across those times, such as an average, a change from baseline, or a value at a particular visit.
A self-reported pain scale is intended to capture the participant’s own assessment of pain, rather than relying only on an observer’s judgment. In general, a defined scale can make subjective reports easier to record consistently and compare across assessment times or groups. Interpretation still depends on knowing exactly how scores were collected, how repeated assessments were summarized, and how missing observations were handled. Those details are not reported in the registry record.
Here, the endpoint is described, but no pain scores are reported. All three participants withdrew before starting any study procedures, so the registry record supplies no observed endpoint values from treated participants. There is therefore no reported group estimate, measure of variability, or treatment comparison to interpret.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a planned randomized comparison of three strategies for managing acute pain, but it does not report outcome data. Although enrollment was 3, all three participants withdrew before starting study procedures. As a result, there are no recorded pain self-reports after treatment began, no group summaries, and no estimated differences among Full Dose, Partial Reinforcement and Control.
The primary outcome was intended to measure pain on a visual analogue scale from 0, “no pain,” to 100, “maximum pain tolerable,” at Day 1-7, Week 2, Months 1, 3 and 6. The outcome definition alone does not establish what the groups experienced. Without recorded scores, there is no effect estimate to describe as larger or smaller, and no confidence interval to indicate the precision of a comparison. The registry record reports 0 analyses.
The absence of observed outcomes must be distinguished from a finding of no difference. A comparison that cannot be estimated is not evidence that the interventions produced equivalent pain reports, nor is it evidence that one strategy performed better. The result is an absence of evaluable treatment outcome data in the registry record, rather than a treatment-effect estimate with uncertainty around it.
The adverse-event entries list 0 participants at risk and 0 affected in each of the three arms, with 0 deaths listed. Because all participants withdrew before study procedures, those entries do not provide an assessment of adverse events following exposure. A count of 0 among participants who were not exposed cannot establish the safety profile of the planned strategies.
The record includes no reported analysis method, no outcome estimates, and no treatment-effect uncertainty measures. Details of allocation, masking procedures, and the intended handling of repeated pain assessments are not reported in the registry record. The planned design gives context for the question, but it cannot replace the missing observations. Statistical conclusions about efficacy, comparative effects, or variability cannot be drawn from the registered outcome information.
The record’s sample-size assumptions describe a planning illustration using a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. Those are assumptions for a planning calculation, not results from participants. No observed effect is reported in the registry record, and no trial-specific sample-size justification is reported. Any planning illustration should therefore not be interpreted as observed power or as evidence about the intervention effects.
9. Statistical Methods Explained
Randomization is intended, in general, to allocate participants among study arms using a chance-based process. If implemented as planned, it can help make groups comparable with respect to measured and unmeasured characteristics, though it does not guarantee balance in a small study. The registry record identifies the trial as randomized, but details of the sequence generation, allocation concealment, and assignment process are not reported in the registry record. Since all three participants withdrew before study procedures, there are no assigned-group outcomes available for analysis.
What does the parallel design mean?
In a parallel design, participants are assigned to one study group and outcomes are compared across groups. The planned arms were Full Dose, Partial Reinforcement and Control. The registry describes their intended medication and placebo regimens, but does not report implementation or adherence. The outcome record therefore cannot support a comparison of the planned parallel groups.
What does triple masking indicate?
The record identifies masking as triple. Masking is a general design approach intended to limit the influence of knowledge about treatment assignment on study conduct, outcome assessment, or participant reporting. The identities of the parties masked and the procedures used to maintain masking are not reported in the registry record. No conclusion can be made from the label alone about whether masking was maintained.
How should repeated outcome times be understood?
Pain self-reports were planned for Day 1-7, Week 2, Months 1, 3 and 6. Repeated measurements can describe the course of an outcome over time, but they also require a prespecified strategy for defining the main comparison. General approaches may focus on a particular visit, change from an initial value, or a pattern across visits. The registry record does not report which summary or statistical model was planned. With no pain observations recorded, none of these approaches can be applied to estimate a treatment effect.
What would an estimate and confidence interval convey?
In general, an estimate summarizes the observed difference or relationship in a study, while a confidence interval expresses the uncertainty associated with that estimate under the model and assumptions used. A narrow interval indicates greater statistical precision than a wide interval, but neither an interval nor a point estimate establishes clinical importance by itself. The registry record reports no treatment-effect estimate or confidence interval. Precision therefore cannot be assessed for the planned comparisons.
Why do analysis assumptions matter?
Statistical methods rely on assumptions about how outcomes are distributed, how observations relate to one another, and how participants enter the analysis. For example, an analysis of repeated measurements must account for the fact that scores from the same participant may be related. The record does not report the planned model or its assumptions. Since there are no recorded outcome measurements, it is not possible to evaluate whether a particular model would fit the observed data.
The sample-size assumptions describe a planning illustration based on a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and a stated fraction of an observed effect. In general, sample-size planning asks how much information a study might need to detect a target effect under specified assumptions. Such a calculation is not an outcome analysis, and it is not observed power. The registry record does not report an observed effect or a trial-specific sample-size justification. The assumptions alone cannot establish that the planned enrollment was adequate.
The record identifies one primary outcome measure and 0 analyses. It does not report whether any interim analyses were planned, how multiple time points or comparisons would be handled, or whether the planned statistical approach changed after enrollment. Those details are not reported in the registry record. Without an analysis plan and observed outcomes, the intended inferential procedure cannot be reconstructed from the available information.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome was assessed at planned times spanning Day 1-7, Week 2, Months 1, 3 and 6, and the design included three arms. When a study has multiple outcome times or several group comparisons, statistical methods generally need to define which comparisons are primary and how the risk of chance findings across comparisons will be addressed. The registry record does not report a multiplicity strategy, a hierarchy of comparisons, or a single time point selected for the main treatment contrast.
The record lists one outcome measure but 0 analyses. It does not report an analysis population, such as whether the intended primary analysis would include all randomized participants or another defined group. The three consented participants withdrew before starting any study procedures, and the record says the withdrawals were handled per protocol. The specific missing-data method and details of the analysis population are not reported in the registry record.
In general, missing outcome values can affect the interpretation of a comparison, particularly when the reasons for missingness are related to treatment or outcome. Here, there are no post-procedure pain observations to analyze, so statistical methods for handling partially missing repeated measurements cannot recover a treatment comparison. The withdrawal information explains why no endpoint results are available, but it does not provide outcome data for participants who did not begin study procedures.
No interim analyses, imputation procedures, or sensitivity analyses are reported in the registry record. Without an analysis plan and observed outcomes, it is not possible to determine how multiplicity or missing data would have been addressed in an inferential analysis.
11. What the Result Does, and Does Not, Mean
The registry record documents an intended clinical question and a planned three-arm randomized study, but it does not contain an estimate of how the study regimens affected pain. All three participants withdrew before starting study procedures. Consequently, the primary outcome was not observed in participants after exposure to the planned interventions, and no group comparison is reported.
This does not mean that the groups had the same pain scores. It also does not show that one regimen led to lower or higher pain reports. There are no outcome values or treatment-effect estimates from which to draw either conclusion. The absence of an estimate is different from an estimate near no difference: the latter would require observed data and a defined comparison, neither of which is reported.
The adverse-event entries list 0 affected participants and 0 deaths in each arm, but also list 0 participants at risk. With withdrawals before study procedures, these entries should not be read as evidence that participants received the interventions without adverse events. They do not characterize risks after treatment exposure.
The study’s planned pain scale and assessment schedule describe what was intended to be measured, not what participants experienced. The registry record does not report a final analysis, a confidence interval, or a clinically interpretable contrast. It also does not report the analysis population or detailed methods for handling missing data. As a result, neither statistical precision nor the clinical importance of a treatment effect can be assessed.
The record can still be read as documentation of a pilot study’s planned design, interventions, outcome, and withdrawals. It cannot support a conclusion about comparative effectiveness or safety. Planning assumptions are not a substitute for observed trial outcomes, and no sample-size illustration should be treated as observed power.
12. Why This Trial Matters Statistically
This trial is statistically notable because its registry record makes the distinction between a planned comparison and an estimable result especially clear. The study was designed as a randomized, triple-masked, parallel pilot with three intended treatment strategies, but all three enrolled participants withdrew before starting any study procedures. There are therefore no observed pain outcomes to compare.
For clinical researchers, this matters because a well-defined outcome and randomized design do not by themselves produce evidence about a treatment effect. Statistical estimation requires outcome observations. Without those observations, there is no group contrast, no measure of uncertainty, and no basis for assessing whether any apparent difference would be compatible with chance or clinically meaningful.
The record also illustrates why withdrawal and exposure information are essential when reading adverse-event entries. Counts of 0 affected participants alongside 0 participants at risk do not describe adverse events among exposed participants. Understanding the denominator and whether participants received the intervention is necessary for interpreting event counts.
Finally, a planning illustration should remain separate from trial results. The registry describes assumptions for a sample-size calculation, but reports no observed effect and no trial-specific sample-size justification. Those assumptions cannot establish the study’s power or resolve the absence of outcome data. The statistical contribution of the record is therefore mainly descriptive: it identifies the intended question and clarifies why no treatment comparison can be estimated.
13. 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 main limitation is that all three participants withdrew before starting any study procedures. The registry record consequently contains no observed pain scores, no treatment-effect estimates, and no analysis results. The small recorded enrollment and absence of participant exposure mean that the planned comparison cannot be evaluated from the posted outcome information.
The registry record does not report the details of randomization, including sequence generation or allocation concealment. Although masking is labeled triple, the masked parties and procedures are not specified. The treatment descriptions state the intended regimens, but implementation, adherence, and receipt of study medication are not reported.
The primary endpoint is defined by its scale anchors and planned assessment times, but the record does not specify how repeated scores would be combined into a primary comparison. It does not report an analysis model, a prespecified primary contrast, or an analysis population. The approach to missing outcomes, multiplicity across treatment arms and assessment times, and sensitivity analyses is not reported in the registry record.
The status is TERMINATED, but the reason for termination is not reported in the registry record. The record also does not report a trial-specific sample-size justification. Its sample-size assumptions describe a planning illustration, while no observed effect is available to inform interpretation. These limitations mean that the registry entry describes the intended study more fully than it documents any realized treatment comparison.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: Relieving Acute Pain (RAP) Study: A Pilot Study — NCT03426137.
- Registry record last updated 2021-04-27; status last verified 2021-04.
- Results first posted 2020-03-16.
- 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.
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17. Record Summary
The Relieving Acute Pain (RAP) Study: A Pilot Study (NCT03426137) was a Phase 2 randomized, triple-masked, parallel study sponsored by University of Maryland, Baltimore. The registry lists Trauma, Opioid Use and Spine Fusion as conditions and records enrollment of 3. The trial status is TERMINATED.
Three arms were planned: Full Dose, Partial Reinforcement and Control. The primary outcome was pain self-reports on a visual analogue scale, with assessments planned for Day 1-7, Week 2, Months 1, 3 and 6. All three participants gave written consent and signed the HIPAA form, but withdrew before starting any study procedures. The record reports 0 analyses and no pain outcome results. The reason for termination and detailed statistical analysis plan are not reported in the registry record.