Comparing Peripherally Inserted Central Catheters to Long Peripheral Catheters in Pediatrics: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparing Peripherally Inserted Central Catheters to Long Peripheral Catheters in Pediatrics (NCT05346406), a randomized na study. The primary outcome is Average Dwell-time.

2. Clinical Question

The rationale in the registry record is that PICCs are commonly used for prolonged vascular access in hospitalized children, while concerns include central line associated blood stream infection and venous thromboembolism. The investigators propose that LPCs might be an alternative for selected patients needing medium-term non-central access. Those statements explain the research question; they are not findings from this trial. The stated primary objective is to test the feasibility of a full-scale effectiveness trial and to inform its design. The record also describes planned engagement of patients and families as advisors about device placement and maintenance. It does not report whether that engagement occurred or what participants or families said.

3. Trial Design

This was a completed, randomized, parallel-group pilot trial with no masking listed in the registry record. The phase is listed as NA, and total enrollment is 35. The sponsor is the Medical College of Wisconsin. The record gives a start date of 2022-08-10 and a primary completion date of 2023-08-10.

The design includes randomized and observational groups for both device types. The randomized PICC group has 4 participants, and the randomized midline group has 4. The observational PICC group has 6, and the observational midline group has 21. The non-randomized groups are explicitly described as observational only. They should not be treated as additional randomized comparison groups: clinicians' or participants' selection into those groups may differ in ways that also relate to dwell-time or other outcomes.

The midline device is described as also known as a long peripheral catheter. The registry record's randomized midline result label says “Midline Catheter, Randomized (PICC R),” while the arm description identifies the randomized midline group as MC R. This labeling inconsistency makes careful reading of group identity important. The other randomized group is labeled Peripherally Inserted Central Catheter, Randomized (PICC R).

The study is described as a clinical effectiveness pilot, with feasibility of a future full-scale trial as its primary objective. It also lists outcomes concerning therapy completion with the initial vascular access device, complications, sedation for placement, use for blood draws, and the need for additional devices. The registry record does not report detailed eligibility criteria, the randomization procedure, allocation concealment, or how the observational groups were assembled.

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.

Before assignment: We had an enrollment goal of 30 participants per each randomized arm. The RCT eligibility was not met.

Overall Study

Analysis population for the primary outcome, as defined in the registry: The primary outcome, a feasibility outcome, only applied to the randomized portion of the study (PICC R and MC R arms); and is the proportion of patients that agreed to participate in randomization out of all eligible patients. Therefore, the Overall Number of Participants Analyzed represents the number of participants eligible for the randomization part of the study prior to enrollment.

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 Average Dwell-time, measured over An average of 14 days.

The primary endpoint is titled Average Dwell-time, but its reported parameter is the median, with inter-quartile range as the stated dispersion measure. Dwell-time is defined as the time from device placement until removal for any reason. Removal may follow completion of therapy or occur because of a complication. The stated timeframe is “An average of 14 days.”

Time until removal is relevant to a device intended to remain in place during a course of treatment: it describes how long the device was used before removal, without restricting removal to a particular cause. Including all reasons for removal makes the endpoint a measure of overall time in place, not a direct measure of complication-free use. A device removed after planned therapy completion and one removed because of a complication both contribute to the endpoint, although those events have different clinical meanings.

For skewed time data, the median describes the middle of the observed distribution and is less sensitive to unusually short or long times than the arithmetic mean. The inter-quartile range describes the central spread of observations. These are general statistical interpretations; the registry record does not give a fuller endpoint analysis plan. Although the endpoint title uses “Average,” the reported statistic is the median. The registry record does not report an estimable two-arm comparison for this median time endpoint, so the arm-level summaries do not establish a comparative effect.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a median dwell-time describe?

For a set of observed dwell-times, the median is the middle value when observations are ordered. It describes a typical position in the distribution, rather than the arithmetic average. The registry record calls the endpoint “Average Dwell-time” but specifies MEDIAN as the reported statistic. Those terms are not interchangeable: the reported group summaries are medians. The inter-quartile range (IQR) describes the span from the lower to the upper quartile and gives information about the spread of the central part of the data. It does not describe every participant's dwell-time or the full range.

The endpoint is time to device removal for all reasons. In general, time-to-event outcomes track the time until a defined event; in this trial, the event is device removal. The definition includes removal after therapy completion as well as removal because of complications. A general feature of time-to-event methods is that they can account for participants whose event time is not observed during follow-up through censoring. The registry record does not state how censoring, incomplete follow-up, or other time-to-event details were handled in the analysis. No such approach should be inferred from the endpoint label alone.

Why distinguish a group summary from a treatment comparison?

A median calculated separately for each arm is descriptive. A comparative analysis estimates how outcomes differ between groups while accounting for the method of assignment and, where appropriate, other features of the data. For randomized groups, random assignment is intended to make comparison less vulnerable to systematic baseline differences, but it does not eliminate uncertainty, especially when groups are small. For observational groups, device selection was not randomized according to the arm descriptions. Differences in their summaries therefore cannot be attributed to the device alone without an appropriate design and analysis.

The registry record reports arm-level medians and IQRs but says a two-arm comparison for the median-time endpoint was missing or not estimable. It lists no analyses. No hazard ratio, confidence interval, p-value, or other comparative estimate is included in the posted results. A hazard ratio is a relative comparison of event rates over time under a specified model; it is not the difference between two medians. The statistical meaning of any hazard ratio depends on the analysis and its assumptions. No hazard ratio is reported for this endpoint in the registry record, so none can be interpreted.

What does uncertainty mean in this setting?

In general, a confidence interval expresses the range of estimates compatible with the observed data under a statistical procedure and its assumptions. It communicates precision as well as direction. The registry record does not report confidence intervals for the arm-level median dwell-times or a comparative confidence interval. The IQRs are descriptive measures of observed spread, not confidence intervals for the medians and not uncertainty intervals for a device comparison. This distinction matters: an IQR can be wide or narrow because participants differ, while a confidence interval reflects uncertainty about an estimated quantity.

Small groups tend to yield imprecise estimates because each participant can have a sizable influence on the summary. General statistical reasoning therefore advises caution in interpreting the randomized medians, which are based on 4 participants in each arm. No precise uncertainty measure for the contrast is reported, and the unavailable comparison cannot be reconstructed from the arm medians and IQRs alone. No new effect estimate or significance test is calculated from those summaries.

How should planning calculations be understood?

Sample-size planning uses assumptions about the effect a future study is intended to detect, the significance level, allocation, and statistical method. The registry record describes planning illustrations based on a fraction of the observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. It specifies that time-to-event planning totals events, while other planning results are participants per arm. These are planning assumptions, not a report of the original trial's design justification. The registry record does not report its own sample-size justification.

In general, a planning calculation is conditional on its assumptions: changing the target effect, variability, event frequency, or analysis method can change the required study size. Any planning illustration based on this pilot's observed effect should be treated cautiously because the randomized groups are small and the primary comparison is not estimable in the registry record. Such a calculation is not observed power. Observed power is not a substitute for a confidence interval or a direct account of the uncertainty in an estimated effect.

Why can over-dispersion matter?

Over-dispersion is a general statistical issue in count data: variation can exceed what a simple model assumes. When present, standard errors from an overly restrictive model may be too small, making results appear more precise than warranted. The primary endpoint is time to removal, not a count outcome, and the registry record does not report an over-dispersion analysis. This general concept should not be mistaken for a method used in this trial.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 7 outcome measures and identifies 5 secondary outcomes. These include completion of therapy with the initial vascular access device, participants with at least one complication, sedation for placement, successful use for blood draws, and need for additional devices to complete therapy. The record does not report a multiplicity strategy, such as a prespecified hierarchy or adjustment for multiple statistical tests. Without that information, the status of any nominal statistical findings across several outcomes cannot be assessed. No inference about statistical significance across the outcomes is available from the listed outcome names alone.

The registry record reports no analyses. It does not specify how missing outcome data were handled, how participants with incomplete follow-up were treated, or whether any imputation or sensitivity analysis was planned or conducted. The primary endpoint comparison is identified as missing or not estimable. That statement does not explain why it was unavailable, and the reason is not reported in the registry record.

The record does not define analysis populations, such as whether the randomized comparison followed an intention-to-treat approach or another population rule. It also does not describe exclusions from analyses or the handling of protocol deviations. The randomized and observational arms are distinct; the record does not report an analysis combining them or an adjustment approach for observational comparisons. These omissions limit assessment of how participants entered each analysis and how missingness or group membership could affect estimates. They should be understood as reporting gaps, not evidence that a particular method was or was not used.

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 serious adverse event figures report zero affected participants in each of the four groups: PICC R, MC R, PICC NR, and MC NR. The corresponding numbers at risk are 4, 4, 6, and 21. The record also reports zero deaths in each group. These are counts observed in the recorded groups over the period captured by the registry; they are not proof that serious events cannot occur.

For other adverse events, the record reports zero affected participants in PICC R, 2 in MC R, zero in PICC NR, and 5 in MC NR. The numbers at risk are 4, 4, 6, and 21, respectively. These counts should not be interpreted as directly comparable risks: the randomized groups are very small, and the observational groups were not randomized. The registry record does not provide event descriptions for these “other” adverse events in the information, so their nature and severity cannot be characterized from these figures.

Zero serious events in a small group is compatible with substantial uncertainty about uncommon harms. The counts do not establish equal safety between devices, and they do not show that an event rate is zero in the broader population. The record lists no serious adverse event terms.

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

The posted results describe dwell-time and adverse-event counts in randomized and observational groups of a pediatric pilot. The randomized groups each contain 4 participants. Their reported median dwell-times are 11 days for PICC R and 4.7 days for MC R, with the corresponding IQRs reported in the registry record. The two-arm primary-endpoint comparison is not estimable in the record. Thus, the summaries do not constitute a formal estimate of a randomized treatment effect.

The results do not show that either device is superior, equivalent, or safer. A numerical difference between two descriptive medians, without an estimable comparison and appropriate uncertainty information, is not sufficient to establish a population-level effect. Nor does the dwell-time endpoint separate removals after planned therapy from removals due to complications. The adverse-event counts add descriptive safety information, but the small group sizes and lack of event detail limit what can be inferred from them.

The observational arms offer additional experience with each device, but they do not preserve the protection against selection differences that random assignment is intended to provide. Their dwell-time summaries should not be treated as a second randomized comparison. Combining randomized and observational participants would require a clearly reported analytic strategy; the registry record does not report one.

The stated purpose is to test feasibility and inform a larger effectiveness study, not to establish a definitive comparative effect. The posted data are therefore most useful as pilot observations and as a record of which outcomes were considered. They do not quantify the uncertainty around a device contrast, resolve the cause of the non-estimable endpoint comparison, or demonstrate that a future full-scale trial is feasible. Those matters are not reported in the registry record. The proposed safety rationale and anticipated benefits in the study description remain motivations and hypotheses, rather than conclusions established by these results.

13. Why This Trial Matters Statistically

Pilot trials can contribute information about whether a larger study can be designed and carried out, while also collecting preliminary outcome data. This study explicitly identifies feasibility of a full-scale effectiveness trial as its primary objective. That context is statistically important: a small pilot's arm-level outcome summaries are not automatically reliable estimates of the effect a later trial should expect to detect.

The randomized comparison has 4 participants in each group, and the primary dwell-time comparison is not estimable in the registry record. This means the posted summaries cannot answer the comparative question with a formal effect estimate. The distinction between a pilot's descriptive results and a confirmatory comparison helps prevent over-interpretation of the medians. It also emphasizes why reporting the analysis, uncertainty, and handling of missing data matters alongside the point summaries.

The inclusion of observational groups makes the design's structure especially important. Those groups provide separate descriptive information, but their device allocation was not randomized. Statistical interpretation must preserve that distinction rather than treating all four groups as interchangeable evidence about device effects.

The outcomes extend beyond dwell-time to complications, treatment completion, sedation, blood-draw use, and additional device requirements. Together, these reflect the practical questions the investigators identified for a future effectiveness study. The registry record does not provide analyses for those outcomes, so their statistical results cannot be assessed. The study description also emphasizes intended patient and family input, but does not report the results of that engagement.

Overall, the record illustrates a central issue in clinical biostatistics: a clinically motivated comparison can be well-defined while the posted data remain insufficient for a precise comparative conclusion. Clear labeling of randomized and observational groups, explicit endpoint definitions, and complete reporting of analysis methods are necessary for readers to distinguish preliminary description from evidence of an effect.

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 randomized groups are small, with 4 participants each, limiting precision and making group summaries sensitive to individual observations. The registry record does not report confidence intervals or an estimable two-arm comparison for the primary endpoint. As a result, the degree of uncertainty around the comparative dwell-time is not quantified in the posted results.

The endpoint title says “Average Dwell-time,” while the specified summary statistic is the median. The record defines dwell-time as time to removal for all reasons, combining removal after therapy completion with removal related to complications. That endpoint does not isolate complication-free use or distinguish the reasons for removal in the reported median.

The randomized midline arm's result label includes “PICC R,” while its arm description identifies it as MC R. This inconsistency can cause ambiguity when matching group labels to device type. The observational arms are explicitly non-randomized and should be interpreted separately from randomized groups. The registry record does not report detailed criteria for assigning participants to those observational arms.

Important analytic details are not reported in the registry record: eligibility criteria, randomization procedures, analysis populations, missing-data handling, censoring methods, and a multiplicity approach. The record lists no analyses, and the reason the primary comparison is not estimable is not stated. The other adverse-event counts lack event descriptions in the information. These reporting limitations constrain both reproducibility and assessment of the findings.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Comparing Peripherally Inserted Central Catheters to Long Peripheral Catheters in Pediatrics — NCT05346406.
• Registry record last updated 2025-06-17; status last verified 2025-05.
• Results first posted 2025-06-17.
• 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

NCT05346406 is a completed, randomized, parallel-group pediatric pilot trial comparing PICCs with midline catheters, also described as long peripheral catheters, for non-central vascular access indications. The record lists no masking, phase NA, enrollment of 35, and the Medical College of Wisconsin as sponsor. The recorded start date is 2022-08-10 and primary completion date is 2023-08-10.

The primary endpoint is titled Average Dwell-time, with median and inter-quartile range specified, measured to device removal for any reason. Randomized and observational groups are reported for both device types. The record lists 7 outcome measures, 5 secondary outcomes, and no analyses. A two-arm comparison of the primary median-time endpoint is not estimable in the posted results. Serious adverse events and deaths are reported as zero in each group; other adverse-event counts are also listed. The record does not provide a comparative estimate establishing a device effect.