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 Ultrasound Guided Catheter Length Survivability (NCT03655106), a randomized na study. The primary outcome is Duration of IV Survival.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03655106 |
| Phase | NA |
| Condition | Catheter Complications |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 270 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Corewell Health East |
| Results posted | Yes |
2. Clinical Question
Population
Patients with difficult IV access who received ultrasound-guided peripheral IV catheter insertion. The study summary describes daily monitoring during the patient’s hospital course. The registry does not give a more detailed description of the endpoint population.
Intervention
An ultra-long 6.35 cm 20 g IV catheter, placed under ultrasound guidance and monitored for function.
Comparator
A standard-length 4.78 cm 20 g IV catheter, also placed under ultrasound guidance and monitored for function.
Primary question
How long does an IV catheter remain functional, as measured by duration of IV survival, in each randomized group? The study was designed to compare catheter lengths. The registry reports a median and 95% confidence interval for each group, but does not report a statistical test or effect estimate for the between-group comparison. The posted summaries therefore describe survival in the two groups separately; they do not establish whether the difference between the group results is statistically distinguishable from chance.
3. Trial Design
This was a randomized, parallel-group trial comparing two peripheral IV catheter lengths in patients with difficult IV access. The registry records the study as completed, with enrollment of 270. Allocation is listed as randomized, masking as none, and the study model as parallel. The sponsor is Corewell Health East. The record lists the study start as 2018-10-29 and primary completion as 2019-07-15.
Participants were assigned to a standard-length 4.78 cm 20 g catheter or an ultra-long 6.35 cm 20 g catheter. Both interventions were ultrasound-guided catheter placements. According to the study summary, research staff assessed catheter function daily during the patient’s hospital course. The primary outcome was duration of IV survival, with a 30 days timeframe.
The registry reports primary-outcome summaries for 126.0 participants in the standard-length group and 131.0 in the ultra-long group. It does not explain how these outcome counts relate to the listed enrollment of 270, or whether any participants were excluded from the endpoint summaries. The record does not describe the randomization sequence, allocation concealment, or procedures used to maintain group assignments. It lists no masking, so the study was not masked as recorded.
Thrombosis and infection are listed as secondary outcomes. The record includes three outcome measures and two posted secondary outcomes, but lists zero analyses. No detailed protocol, analysis plan, recruitment flow, or explanation of the endpoint-analysis population is reported in the registry record. The study is classified as “other” rather than assigned a phase.
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 | Standard Long IV 4.78 cm 20 g Catheter | Ultra-Long IV 6.35 cm 20 g Catheter |
|---|---|---|
| STARTED | 135 | 135 |
| COMPLETED | 126 | 131 |
| NOT COMPLETED | 9 | 4 |
Reasons for not completing this period:
| Reason | Standard Long IV 4.78 cm 20 g Catheter | Ultra-Long IV 6.35 cm 20 g Catheter |
|---|---|---|
| Withdrawal by Subject | 3 | 2 |
| Lost to Follow-up | 2 | 1 |
| Duplicate Enrollment | 1 | 1 |
| Protocol Violation | 3 | 0 |
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 | Standard Long IV 4.78 cm 20 g Catheter | Ultra-Long IV 6.35 cm 20 g Catheter | Total |
|---|---|---|---|---|
| Participants analysed | 126 | 131 | 257 | |
| Age, Continuous | years | 58.2 (SD 18.6) | 60.2 (SD 18.2) | 59.2 (SD 17.8) |
| Sex: Female, Male: Female | Participants | 92 | 92 | 184 |
| Sex: Female, Male: Male | Participants | 34 | 39 | 73 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
| Region of Enrollment: United States | participants | 126 | 131 | 257 |
6. Primary Endpoint
The registry lists the primary outcome as Duration of IV Survival, measured over 30 days.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | 95% Confidence Interval |
| Unit | hours |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is duration of IV survival, measured in hours, with a stated timeframe of 30 days. The registry defines catheter function as the ability to draw back 5 ml of blood, flush with 5 ml normal saline without resistance, or support continuously infusing IV fluids or medication. Research staff assessed function daily.
This endpoint is intended to capture how long the catheter remains usable under the study’s functional definition. It focuses on catheter function over time rather than simply whether a catheter was placed. A duration measure can represent both the time a device remains functional and the point at which it no longer meets the specified criteria. The registry summaries use the median, which describes the middle of the observed duration distribution, alongside a 95% confidence interval.
As a general statistical point, a median is useful when observed durations are unevenly distributed or include relatively long observations, because it is not pulled as strongly by extreme values as a mean can be. The registry does not report why the median was selected, how loss of observation was handled, or the precise event definition used to determine the end of survival. Although the record specifies daily function assessments, it does not describe how the time of failure was assigned between assessments. Those details matter when interpreting the precision and meaning of a time-based endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The standard-length group had a reported median IV survival of 92.0 hours, with a 95% confidence interval from 71.0 to 120.0 hours. The ultra-long group had a reported median of 136.0 hours, with a 95% confidence interval from 116.0 to 311.0 hours. These are group-specific summaries of duration under the registry’s definition of catheter function.
The median reported for the ultra-long group is greater than the median reported for the standard-length group. That descriptive contrast is not, by itself, a formal comparison of the randomized groups. The registry record reports no analysis for the primary outcome, no test statistic, no p-value, and no confidence interval for a between-group effect. It is therefore not possible to determine from the posted results whether the observed separation in medians is compatible with a range of chance variation under a specified comparison model.
A confidence interval describes uncertainty around an estimated quantity under the method used to construct it. It is not a guarantee that the true value lies within the interval, and it does not directly provide the uncertainty in the difference between two group estimates. The registry does not report the method used to calculate these intervals. The intervals should therefore be read as uncertainty estimates attached to each arm’s median, not as a substitute for a direct randomized comparison.
The interval for the ultra-long group is notably broad in its reported range, while the standard-length group’s interval is narrower. A broader interval indicates less precision in the corresponding estimate under the method used. It does not identify the reason for that imprecision. The registry does not report the distribution of individual survival times, the number of failures, censoring information, or the interval-construction procedure, so the sources of uncertainty cannot be separated from the posted summaries.
The primary endpoint concerns duration of function, not every aspect of catheter performance or patient experience. Thrombosis and infection are listed as secondary outcomes, but results for those outcomes are not included in the record information. The adverse-event figures report zero affected participants for the listed serious and other categories in both groups; they do not supply a detailed account of how those events were collected or classified.
The appropriate reading is descriptive: the registry posts different median survival estimates for the two catheter groups, with uncertainty intervals, but does not report the inferential comparison needed to quantify the evidence for a group difference. No conclusion about clinical benefit or treatment effectiveness follows from these summaries alone.
9. Statistical Methods Explained
The registry presents the primary endpoint as a median duration with a 95% confidence interval for each randomized group. It does not report the statistical method used to estimate either the median or its interval, and it lists zero analyses. The concepts below explain how such summaries are generally interpreted; they do not identify methods used in this trial when those methods are not documented.
What does a median describe?
As a general statistical concept, the median is the central value in an ordered distribution: half of the observations fall on either side when the observations can be ordered. For a duration endpoint, it offers a summary of the time distribution that is less sensitive to especially long or short observations than an arithmetic mean. A median does not describe the full shape of the distribution. Two groups can have similar medians but different patterns of early and late events, or different amounts of variability.
The reported medians are 92.0 hours for the standard-length group and 136.0 hours for the ultra-long group. Those estimates describe the groups separately. A randomized trial’s comparative question is usually addressed by estimating a contrast between assigned groups, with uncertainty around that contrast. No such comparative estimate is reported in the registry record.
How should a confidence interval be read?
In general, a confidence interval expresses the statistical uncertainty around an estimate under a particular model and procedure. A narrower interval indicates greater precision under that procedure; a wider interval indicates less precision. The 95% label describes a property of the interval-generating method over repeated applications under its assumptions. It does not mean that there is a 95% probability that this particular interval contains the true value.
The record reports a 95% confidence interval for each group’s median: 71.0 to 120.0 hours for the standard-length group and 116.0 to 311.0 hours for the ultra-long group. It does not identify the construction method or assumptions. Separate intervals for group-specific medians do not directly answer whether the medians differ. A direct effect estimate and its uncertainty would more directly address the randomized comparison.
Why does time-to-event analysis require extra detail?
As a general point, time-to-event data can include participants whose event time is not observed during follow-up. For example, observation may end while a device is still functional. Such an observation is often described as censored: the exact event time is unknown, though it is known to extend beyond the observed period. Methods for time-to-event outcomes can use this partial information, but their interpretation depends on assumptions and on how censoring and follow-up are handled.
The registry specifies a 30 days timeframe and daily assessments, but does not describe censoring, withdrawals, hospital discharge, or how the end of follow-up was handled. It also does not say how a failure time was assigned when a catheter’s status changed between daily assessments. These details could affect estimated durations and their precision. No particular survival-analysis method should be attributed to this trial based on the posted record.
What can be inferred from the displayed arm summaries?
As a general statistical point, group-specific descriptive summaries can show the direction and scale of observed outcomes, but they do not by themselves establish a treatment contrast. The observed difference between group estimates can reflect a real group effect, sampling variation, or both. A comparative analysis would need to define an effect measure and account for the study design and any relevant features of the outcome data. The registry record does not report such an analysis, so a p-value or direct confidence interval for the group contrast is not available.
The sample-size calculations associated with this analysis are planning illustrations based on an observed effect and stated assumptions, rather than the trial’s documented design justification. Such calculations describe hypothetical planning requirements under their assumptions; they are not observed power and do not show the probability that the trial detected an effect. The registry does not report its own sample-size justification or protocol assumptions.
Why can over-dispersion matter?
As a general statistical concept, over-dispersion occurs when variation in the observed data exceeds what a statistical model expects. When present, a model that assumes less variation than the data contain can give uncertainty estimates that are too small and can make evidence appear more precise than it is. The registry does not report a model for this endpoint or evidence about over-dispersion. This is a general consideration rather than a claim that over-dispersion occurred in this trial.
Overall, the posted primary-outcome information supports reading the medians and their intervals as arm-specific descriptive estimates. It does not provide enough detail to reconstruct the analysis, assess its assumptions, or infer a formal comparison between catheter lengths.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists thrombosis and infection as secondary outcomes, alongside the primary outcome of duration of IV survival. It reports three outcome measures and zero analyses. No statistical plan describing which outcomes were confirmatory, how outcomes were ordered, or how multiple comparisons were handled is reported in the registry record.
As a general statistical issue, testing several outcomes or making several comparisons can increase the chance of finding an apparently unusual result by chance if each is interpreted independently. Prespecified approaches to multiplicity can control how evidence is evaluated across a family of tests. The record does not report whether any such approach was planned or used. Since no secondary-outcome analyses are listed, the posted record does not support a conclusion about thrombosis or infection.
The registry provides endpoint counts for the two groups, but does not state the analysis population, explain the difference between listed enrollment and the participants represented in the endpoint summaries, or describe how missing outcome data were treated. It does not report withdrawals, exclusions, protocol deviations, or the handling of participants whose catheters were still functional at the end of observation. These omissions prevent assessment of whether the endpoint summaries include all randomized participants or a subset.
In general, missing-data handling matters when the probability of an unobserved outcome is related to participant characteristics or outcomes. Different assumptions can affect estimates and uncertainty. No missing-data assumptions or sensitivity analyses are reported in the registry record. The posted information also does not identify an intention-to-treat or per-protocol analysis population. These are unknown features of the reporting, not evidence that data were necessarily missing or that a particular analysis population was used.
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 |
|---|---|---|---|
| Standard Long IV 4.78 cm 20 g Catheter | 0 | 126 | 0.0% |
| Ultra-Long IV 6.35 cm 20 g Catheter | 0 | 131 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Standard Long IV 4.78 cm 20 g Catheter | 0 of 126 |
| Ultra-Long IV 6.35 cm 20 g Catheter | 0 of 131 |
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 |
|---|---|
| Standard Long IV 4.78 cm 20 g Catheter | 0 of 126 |
| Ultra-Long IV 6.35 cm 20 g Catheter | 0 of 131 |
The adverse-event information lists 126 participants at risk in the standard-length group and 131 in the ultra-long group. For both groups, the record lists zero participants affected in the serious adverse-event category, zero in the other adverse-event category, and zero deaths. These figures are counts as recorded, not rates or comparative risk estimates.
Zero affected participants in these categories means that the registry reports no events in the listed categories for the participants at risk. It does not establish that the devices have no safety risks, nor does it show that every possible complication was assessed or reported. The record does not provide event definitions, collection procedures, follow-up detail, or a statistical comparison of safety between groups.
Thrombosis and infection are also listed as secondary outcomes, but outcome results for them are not reported in the registry record. Their presence in the outcome list should not be mistaken for evidence that no events occurred. The posted adverse-event counts and the absence of reported secondary-outcome results are distinct pieces of information. They should be interpreted only within the categories and scope that the record describes.
12. What the Result Does, and Does Not, Mean
The results describe duration of IV survival in two randomized groups. The reported median is 92.0 hours for the standard-length catheter and 136.0 hours for the ultra-long catheter. Each median is accompanied by a 95% confidence interval, which communicates uncertainty in the arm-specific estimate under an unreported calculation method. The ultra-long group’s reported median is greater, but the registry does not report a direct statistical comparison.
That distinction is important. A difference between descriptive estimates does not alone establish that the groups differ beyond what might arise from sampling variation. A comparative effect estimate, together with its uncertainty and analysis method, would be needed to assess the randomized contrast statistically. No p-value or direct confidence interval for that contrast is reported. No formal result should be inferred from the separate intervals.
The findings also do not answer every question about catheter performance. The primary endpoint uses a specific functional definition, assessed daily, and the record does not explain how failure times were assigned between assessments. It does not report the distribution of individual durations or how observations that ended before a catheter failed were handled. Those details limit the ability to interpret the estimates as a complete account of catheter survival.
The registry lists thrombosis and infection as secondary outcomes but does not report their results. The adverse-event record lists zero affected participants in each of the serious and other categories and zero deaths in both groups. These counts do not provide a full safety comparison or establish the absence of unreported complications.
Accordingly, the posted data show arm-specific median durations and associated confidence intervals, with a numerically greater median in the ultra-long group. They do not establish whether the catheter lengths differ statistically or clinically, and they do not support a claim that either device is effective or ineffective. The interpretation is constrained by the absence of a reported comparative analysis and by limited methodological and outcome-reporting detail.
13. Why This Trial Matters Statistically
This trial illustrates a key distinction in clinical-trial interpretation: reporting outcomes separately by randomized group is not the same as reporting the effect of random assignment. The medians describe observed durations within each arm. The trial’s comparative question requires a direct estimate of how the groups differ, together with uncertainty and a clearly described analysis. That comparison is not reported in the registry record.
Duration outcomes also raise methodological questions that are not always visible in a single summary statistic. Daily function assessments, the endpoint’s functional definition, the 30 days timeframe, and the handling of observations without an observed failure can all influence how a duration estimate is interpreted. The registry gives the assessment schedule and functional criteria, but not the analysis details needed to evaluate their impact.
The record further demonstrates why endpoint lists and outcome results must be distinguished. Thrombosis and infection appear as secondary outcomes, but their results are not reported. Similarly, zero adverse-event counts in listed categories are informative only within the categories and reporting methods documented; they do not substitute for detailed results on every safety outcome.
Finally, planning illustrations based on an observed effect are not a report of the study’s original design justification and are not observed power. Keeping these concepts separate helps prevent a post hoc planning calculation from being mistaken for a prespecified design feature or evidence that a trial could reliably detect a particular effect. The registry does not report its own sample-size justification, detailed analysis plan, or multiplicity strategy. These gaps limit statistical appraisal even though the primary outcome summaries are available.
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 main limitation for statistical interpretation is that the registry reports arm-specific medians and confidence intervals but no primary-outcome comparison. It lists zero analyses and does not provide a test, comparative effect estimate, or confidence interval for the difference between groups. The method used to estimate the medians and their intervals is not reported.
The record gives a 30 days timeframe and describes daily function assessments, but does not explain how time to catheter failure was assigned between assessments. It does not describe censoring, loss to follow-up, discharge, or the handling of catheters that remained functional at the end of observation. The relationship between the listed enrollment of 270 and the primary-outcome counts of 126.0 and 131.0 is also not explained.
There is no detailed account of randomization procedures, allocation concealment, adherence, participant flow, or analysis population. Masking is listed as none. The record does not report a statistical analysis plan, sample-size justification, missing-data procedures, or multiplicity approach. Thrombosis and infection are named as secondary outcomes, but their results are not reported.
These reporting gaps do not demonstrate that the study lacked appropriate procedures; they mean those procedures cannot be assessed from the registry record. In particular, the posted summaries are not enough to reconstruct the analysis or assess whether its assumptions were appropriate. The adverse-event counts are also limited by the absence of definitions and collection details.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Ultrasound Guided Catheter Length Survivability — NCT03655106.
- Registry record last updated 2020-03-11; status last verified 2020-02.
- Results first posted 2020-03-11.
- 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
The registry record describes a completed randomized, parallel-group study sponsored by Corewell Health East. It compared standard-length 4.78 cm 20 g IV catheters with ultra-long 6.35 cm 20 g IV catheters in patients with difficult IV access. Masking is listed as none, and enrollment is 270.
The primary outcome was duration of IV survival in hours, assessed daily using the stated catheter-function criteria, with a 30 days timeframe. The standard-length group had a reported median of 92.0 hours (95% CI 71.0 to 120.0), with 126.0 participants represented. The ultra-long group had a reported median of 136.0 hours (95% CI 116.0 to 311.0), with 131.0 participants represented.
Thrombosis and infection are listed as secondary outcomes, but their results are not reported in the registry record. The record lists zero analyses and provides no formal comparison of the primary outcome between groups.