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 The Predictive Value of Ureteral Jet Assessment With Ultrasound in Patients Presenting With Acute Renal Colic (NCT02577146), a na na study. The primary outcome is Time in Days From Diagnosis to Stone Passage..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02577146 |
| Phase | NA |
| Condition | Ureteral Calculi |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 74 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Washington University School of Medicine |
| Results posted | Yes |
2. Clinical Question
Population
Patients presenting with acute renal colic and diagnosed with a ureteral calculus by CT were the intended study population. The record describes a single-institution prospective study. It reports enrollment of 74, but also says 28 cases were not included in the primary analysis because of screen failures, subject non-compliance and missing data. The characteristics of the cases included in that analysis are not reported in the registry record.
Intervention
The study procedure was renal and bladder ultrasound with ureteral jet assessment. The ultrasound was obtained after CT diagnosis of ureteral calculus. Ureteral jet data were documented, and patients were followed prospectively for spontaneous stone passage or need for surgical intervention.
Comparator
There was no randomized comparator group. The registry describes a single-group study, and allocation is recorded as NA. CT was part of the diagnostic sequence and was also relevant to the secondary outcome concerning concordance of treatment recommendations; it was not described as a separate study arm.
Primary question
The primary endpoint was time in days from diagnosis to stone passage, reported as a median with a 95% confidence interval over a timeframe of 42 days. The study sought to evaluate the prognostic significance of ultrasound with ureteral jet assessment and its utility for evaluating spontaneous passage. The numerical median and confidence interval are not reported in the registry record, so the posted information does not establish the observed time to passage or its precision.
3. Trial Design
The registry describes a prospective, single-institution study of renal and bladder ultrasound with ureteral jet assessment in patients with ureteral calculi. Enrollment is recorded as 74. The study status is completed, and the phase is recorded as NA. The start is recorded as 2015-10 and primary completion as 2018-05-07.
This was a single-group study, not a randomized comparison. Allocation is recorded as NA, and masking is recorded as NONE. The ultrasound assessment followed CT diagnosis of ureteral calculus. The record describes prospective follow-up for spontaneous stone passage or need for surgical intervention, with a maximum observation time of 42 days. It does not report a parallel control arm or a treatment assignment process.
The primary outcome was time in days from diagnosis to stone passage, with the outcome description also referring to intervention by the maximum observation time. Its stated summary measure was the median with a 95% confidence interval. The registry also lists a secondary outcome concerning cases with concordant treatment recommendations based on ultrasound and CT. Numerical results for these outcomes are not reported in the registry record.
Enrollment should not be read as the number included in the primary analysis. The record states that 28 cases were not included in that analysis due to screen failures, subject non-compliance and missing data. It does not give a detailed accounting of the remaining participants or explain how the analysis population was defined. The sponsor was Washington University School of Medicine.
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 | Study Ultrasound |
|---|---|
| STARTED | 74 |
| COMPLETED | 46 |
| NOT COMPLETED | 28 |
Reasons for not completing this period:
| Reason | Study Ultrasound |
|---|---|
| Lost to Follow-up | 8 |
| Physician Decision | 3 |
| Screen Failure | 17 |
Analysis population for the primary outcome, as defined in the registry: 28 cases were not included in analysis due to screen failures, subject non-compliance and missing data.
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.
| Characteristic | Unit | Study Ultrasound |
|---|---|---|
| Participants analysed | 46 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 43 |
| Age, Categorical: >=65 years | Participants | 3 |
| Age, Continuous | years | 45.1 (SD 13.9) |
| Sex: Female, Male: Female | Participants | 16 |
| Sex: Female, Male: Male | Participants | 30 |
| Race and Ethnicity Not Collected | Participants | — |
| Region of Enrollment: United States | Participants | 46 |
6. Primary Endpoint
The registry lists the primary outcome as Time in Days From Diagnosis to Stone Passage., measured over 42 days.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | 95% Confidence Interval |
| Unit | Days |
| Endpoint classification | Time-to-Event Analysis |
The primary endpoint measures elapsed time from diagnosis to stone passage, expressed in days. The registry specifies a median and a 95% confidence interval, with observation limited to 42 days. The outcome description also refers to intervention by the maximum observation time. This makes the endpoint a time-to-event measure: it concerns both whether an event is observed during follow-up and how long it takes to occur.
In general, time-to-event outcomes are useful when the timing of an event is clinically and scientifically relevant, and when participants may have different lengths of observation. A median is the time by which half of the relevant event-time distribution has occurred, if that point can be estimated. A confidence interval expresses uncertainty around an estimate; it is not a range containing a specified proportion of individual participants' times. The width of the interval is informative about precision.
The registry record does not report the primary median or its confidence interval. It also does not report the number of stone-passage events, the number of interventions, or how observations without an event by the end of follow-up were handled. Those details matter for interpreting a time-to-event endpoint. Without the estimate and its uncertainty, the endpoint definition alone cannot show the observed time pattern or how precisely it was estimated.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The study question concerns the prognostic information associated with renal and bladder ultrasound with ureteral jet assessment after CT diagnosis of ureteral calculus. Its design is prospective and single-group. Therefore, the record does not describe a randomized comparison that could directly estimate a difference between ultrasound and a control strategy. CT appears in the diagnostic sequence and in the secondary outcome about concordance of treatment recommendations, but the record does not define CT as a separate arm.
The primary endpoint is time in days from diagnosis to stone passage, summarized by a median and 95% confidence interval over 42 days. However, the registry record does not report the median, confidence interval, event count, or a statistical analysis for that endpoint. No hazard ratio is reported in the record. The listed secondary outcome concerns concordant treatment recommendations based on ultrasound and CT, but a numerical result for it is also not reported. Thus, the posted information does not quantify the observed passage timing, the degree of agreement in recommendations, or the uncertainty around either finding.
The enrollment entry is 74, while the primary outcome description says 28 cases were not included in analysis due to screen failures, subject non-compliance and missing data. These figures describe different parts of the study record and should not be treated as interchangeable measures of the analyzed group. The record does not provide an analysis-population count or participant flow detailed enough to determine who contributed to each outcome.
In general, a 95% confidence interval conveys the uncertainty of an estimate under the assumptions of the analysis. Because the interval itself is not reported, the precision of the primary estimate cannot be assessed. Likewise, without the event counts and handling of observations without an event, the influence of incomplete follow-up cannot be evaluated from the posted information.
The appropriate interpretation is limited to the study's design, endpoint definition and reported exclusions. There is no numerical result in the registry record from which to describe the observed magnitude or direction of the primary outcome. Absence of a posted estimate is not evidence of either a favorable or unfavorable result; it means the result cannot be assessed from this registry record. No conclusion about treatment effectiveness or clinical utility follows from these details alone.
9. Statistical Methods Explained
What does the median describe?
The registry specifies the median time from diagnosis to stone passage as the primary summary measure. In general, a median describes the midpoint of an observed or estimated distribution: half of the distribution lies on either side of it. For a time-to-event outcome, the median is interpreted as the time by which half of the relevant population is estimated to have experienced the event, when the data support such an estimate. It is not the same as the average time, and it does not describe every participant's experience.
The record's outcome description mentions stone passage or intervention through the maximum observation time. It does not make clear in the posted information whether these were analyzed as a combined event, as separate events, or according to another prespecified rule. That distinction affects what the median represents. The analysis details and the resulting median are not reported in the registry record.
What does the confidence interval add?
A confidence interval describes statistical uncertainty around an estimate under a method's assumptions. In general, a narrower interval indicates greater precision than a wider interval, while neither an interval nor its midpoint guarantees that the estimate equals the underlying value. The record specifies a 95% confidence interval for the median, but does not report its bounds. Consequently, the precision of the primary estimate cannot be evaluated from the posted information.
Why does follow-up matter?
Time-to-event analyses must account for participants whose event is not observed during their available follow-up. In general, such observations may be censored: their event time is known to extend beyond the last observed time, but the eventual event time is unknown. Appropriate handling depends on the endpoint definition and analysis method. The stated maximum observation time is 42 days, but the registry record does not report the number of participants with observed passage, intervention, or no recorded event by the end of follow-up, nor does it describe censoring procedures.
Time-to-event methods can use incomplete follow-up without simply treating all participants as if they had identical observation. However, their interpretation depends on assumptions about how follow-up ends and whether censoring is related to the event. These are general methodological considerations, not descriptions of methods documented for this study. The specific statistical method is not reported in the registry record.
What can a single-group design establish?
In general, a prospective single-group study can describe outcomes observed after a study procedure and can examine whether measurements are associated with later events. It does not by itself provide a randomized estimate of what would have happened under a different assessment strategy. Differences between patients, clinical decisions, follow-up and other factors can affect observed outcomes. The registry describes the aim as evaluating prognostic significance and utility, but does not report a statistical model or adjusted association estimate.
The record identifies a secondary outcome about concordance of treatment recommendations based on ultrasound and CT. Agreement or concordance is a distinct question from whether one approach improves outcomes. Its interpretation depends on how recommendations were defined and compared. Those definitions, the result, and the method of analysis are not reported in the registry record.
Are planning calculations the trial's analysis?
Planning illustrations based on the observed effect are not observed power and are not the study's original design justification. The stated assumptions for those illustrations include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. For time-to-event illustrations, the stated quantity is a total number of events. These are planning assumptions, not evidence that the single-group study used two arms or had that allocation.
The registry record does not report the study's sample-size justification or statistical analysis plan. It also lists no analysis entries. General statistical descriptions above explain concepts relevant to the endpoint; they should not be read as confirmation that a particular method was used in this study.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary time-to-stone-passage outcome and a secondary outcome concerning concordant treatment recommendations based on ultrasound and CT. It reports two outcome measures and no analysis entries. The numerical results and statistical tests for these outcomes are not reported in the registry record.
When a study examines multiple outcomes or multiple statistical comparisons, multiplicity can increase the chance of at least one apparently unusual finding. In general, researchers may address this through a prespecified hierarchy, adjusted significance thresholds, or by treating some analyses as exploratory. The registry record does not report a multiplicity plan, a hierarchy for the outcomes, or whether any adjustment was used. It would therefore be inappropriate to assume that the outcome analyses were adjusted or that they were all confirmatory.
The primary outcome description states that 28 cases were not included in analysis due to screen failures, subject non-compliance and missing data. The record does not describe the timing or type of missingness, identify which reason applied to each case, or explain how missing observations were handled. It does not report whether sensitivity analyses were performed. In general, the effects of missing data depend on why values are absent and on the analysis approach; exclusion can affect both the estimate and its uncertainty.
The registry does not report a detailed analysis population, participant flow by outcome, or a statistical plan for inclusion and exclusion. Enrollment of 74 should not be treated as the number analyzed, and the record does not justify inferring an analysis denominator by subtracting the reported exclusions. These omissions limit assessment of selection, missing-data bias and the reliability of any outcome estimate. No estimate is available in the registry record to evaluate those issues empirically.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Study Ultrasound | 0 | 46 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Study Ultrasound | 0 of 46 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Study Ultrasound | 0 of 46 |
For the Study Ultrasound group, the adverse-event record lists 46 participants at risk for serious adverse events and zero participants with a serious adverse event. It also lists 46 at risk for other adverse events and zero with other adverse events, and reports zero deaths. No serious adverse-event terms are listed.
These entries describe what was recorded in the registry, not proof that no adverse events occurred outside the scope or ascertainment of the reported record. The number at risk is the denominator associated with the safety entries; it should not be assumed to match the enrollment figure or the analysis population for the primary outcome. The record does not explain that relationship.
In general, observing zero reported events does not establish that the underlying event risk is zero. Interpretation depends on the number followed, duration and completeness of safety monitoring, event definitions, and the way events were collected. The record describes follow-up for stone passage or surgical intervention through 42 days, but does not give further details about safety-monitoring procedures or the completeness of adverse-event reporting. The safety figures should therefore be read as registry-reported counts, not as a comprehensive estimate of risk.
12. What the Result Does, and Does Not, Mean
The record establishes that a prospective, single-group study evaluated renal and bladder ultrasound with ureteral jet assessment after CT diagnosis of ureteral calculus. It defines a primary time-to-event endpoint, reports a 42-day maximum observation period, and notes that 28 cases were not included in the primary analysis due to screen failures, subject non-compliance and missing data. It also records adverse-event counts for the Study Ultrasound group.
These registry entries do not reveal the observed median time to stone passage or its 95% confidence interval. The registry record does not report the number of stone-passage events, the number of interventions, or the numerical result for the secondary outcome about concordant treatment recommendations. Without those results, the magnitude and precision of the outcomes cannot be assessed from the posted record.
The single-group design also places limits on causal interpretation. In general, observed outcomes after an assessment procedure do not establish what would have occurred under another assessment strategy. The record does not describe random allocation to a comparison group, and CT is described as part of diagnosis and the concordance outcome rather than as a separate randomized arm. A prognostic association, if reported, would also differ from evidence that a procedure itself changes outcomes.
The reported zero adverse events and zero deaths are registry counts, not proof of zero risk. They should be interpreted with the stated at-risk figures and the limited safety details in mind. Overall, the record permits description of the study question and design, but it does not provide the primary or secondary numerical findings needed to assess the observed results. Missing results should not be interpreted as a null result or as evidence for either benefit or harm.
13. Why This Trial Matters Statistically
This study illustrates why the design and the result need to be read together. A prospective study can define a clear sequence of assessment and follow-up, and a time-to-event endpoint can capture not only whether stone passage is observed but also its timing. The registry describes ultrasound with ureteral jet assessment after CT diagnosis and follow-up for spontaneous passage or surgical intervention, with a maximum observation time of 42 days.
At the same time, the study is recorded as single-group, with no randomized comparator. That matters statistically because an observed outcome pattern does not directly estimate a contrast between assessment strategies. The secondary question about concordance between ultrasound- and CT-based treatment recommendations is distinct from a randomized treatment comparison and from a patient outcome.
The record also shows why analysis populations and missing data require attention. Enrollment is 74, while the primary outcome description excludes 28 cases for screen failures, subject non-compliance and missing data. Without a participant flow, outcome denominators and missing-data methods, readers cannot judge how those exclusions relate to the estimate or its precision.
Most importantly, a well-defined endpoint does not substitute for a reported estimate. The registry specifies a median and 95% confidence interval, but does not report either. This prevents assessment of the observed time pattern and uncertainty. Statistically, distinguishing a missing result from a result that indicates little or no association is essential. The record supports consideration of the research question and its methodological limits, but not a quantitative conclusion about the endpoint.
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 primary limitation for interpreting the registry record is that it does not report the numerical primary outcome. Although the endpoint is defined as time from diagnosis to stone passage and is to be summarized by a median with a 95% confidence interval, neither the estimate nor its interval is reported. Event counts and the number of observations without an event are also not reported.
The outcome description refers to stone passage or intervention by the maximum observation time, but the registry record does not explain how intervention was handled analytically or whether it was combined with passage. The method for handling incomplete follow-up is not reported. These details are important for understanding what a time-to-event estimate would represent.
The design is single-group, without randomized allocation to a comparator. The record therefore does not describe a randomized contrast in outcomes between ultrasound assessment and another strategy. Although CT is used to diagnose ureteral calculus and appears in the secondary outcome about concordant treatment recommendations, the record does not describe CT as a control arm.
The primary outcome description notes that 28 cases were excluded for screen failures, subject non-compliance and missing data. The registry does not specify the analysis population, participant flow by outcome, or methods for addressing missing observations. It also does not report a statistical analysis plan, multiplicity approach, or numerical secondary-outcome findings. These gaps limit evaluation of precision, selection and analytic choices. They do not establish that the study was conducted incorrectly, but they restrict what can be concluded from the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: The Predictive Value of Ureteral Jet Assessment With Ultrasound in Patients Presenting With Acute Renal Colic — NCT02577146.
- Registry record last updated 2019-12-10; status last verified 2019-12.
- Results first posted 2019-05-31.
- 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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18. Record Summary
NCT02577146 is a completed, prospective, single-institution study sponsored by Washington University School of Medicine. It evaluated renal and bladder ultrasound with ureteral jet assessment after CT diagnosis of ureteral calculus. Enrollment is recorded as 74; the primary outcome description says 28 cases were not included in analysis due to screen failures, subject non-compliance and missing data.
The primary endpoint was time in days from diagnosis to stone passage, summarized as a median with a 95% confidence interval over 42 days. The registry also lists a secondary outcome concerning concordant treatment recommendations based on ultrasound and CT. Numerical results for these outcomes are not reported in the registry record. The safety entries list zero serious adverse events, zero other adverse events and zero deaths among the reported at-risk group.