Parafilm to Prevent CLABSI in Pediatric Patients Undergoing HCT: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Parafilm to Prevent CLABSI in Pediatric Patients Undergoing HCT (NCT02575079), a non-randomized na study. The primary outcome is Rate of Central Line Associated Bloodstream Infections (CLABSI).

2. Clinical Question

The study also aimed to assess ease of use. Its listed secondary outcomes include antibiotic treatment courses and exposure duration, ICU admissions secondary to sepsis, death, and perception of parafilm. The record does not report results for these outcomes, so the clinical question cannot be answered from the available registry information alone.

3. Trial Design

This was a completed, parallel, non-randomized study sponsored by Emory University. The registry lists phase as not applicable and masking as none. Enrollment is recorded as 119. That figure is the study enrollment entry; the record does not specify in the information available how participants were distributed between the parafilm group and the historical cohort.

The intervention group consisted of pediatric HCT patients with CVCs who received parafilm at the catheter hub or connection. The comparison group was a historical cohort of pediatric HCT recipients from the 16 months preceding the intervention; their data were collected retrospectively from medical records. Because allocation was not randomized and the comparator came from an earlier period, differences between the groups could reflect factors beyond parafilm exposure. The record does not describe adjustment for such differences.

The primary outcome covered the period from CVC placement or HCT admission, whichever occurred later, to CVC removal or transfer back to the primary service, whichever occurred sooner. The stated average duration was 3 months. The precise intervention maintenance procedure is not fully described in the registry record.

The study began in 2015-03, had primary completion on 2018-03-29, and is marked completed. The registry lists 10 outcome measures and zero analyses. It does not report the protocol’s sample-size justification, detailed statistical analysis plan, interim analyses, or analysis populations. Those details should not be inferred from the design label or from planning calculations.

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: Fifty-one individuals consented to participate in the study. Prior to beginning any study interventions one was lost to follow up, one withdrew, and one did not begin the prep regimen, resulting in 48 participants who began the study intervention.

Overall Study

Reasons for not completing this period:

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 Rate of Central Line Associated Bloodstream Infections (CLABSI), measured over Baseline (at the time of placement of the CVC or admission for HCT, whichever occurs later) to end of study (CVC removal or transfer back to primary service, whichever occurs sooner, average of 3 months).

The primary endpoint is the rate of central line associated bloodstream infections (CLABSI), expressed as CLABSI per 1000 catheter-days. The registry definition describes CLABSI as identification of a bacterial infection from a blood culture drawn from a CVC, without a primary infection source from another body site. The endpoint is based on the number of infections relative to the time catheters are observed, rather than simply counting infections without accounting for catheter exposure.

As a general statistical explanation, an exposure-adjusted rate can help compare infection occurrence across groups whose observed catheter time may differ. The rate’s interpretation depends on both the event count and the catheter-days used as its denominator. The registry specifies a 95% confidence interval as the measure of dispersion, which is intended to convey uncertainty around an estimated rate. A wider interval indicates less precision; an interval alone does not establish that group differences are caused by the intervention.

The record describes comparing the rate in parafilm study participants with the rate in a historical pediatric HCT cohort. However, it does not report the event counts, catheter-days, rate estimates, or confidence intervals. The endpoint’s definition and intended comparison are therefore available, but the observed primary outcome is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as a count-based CLABSI rate per 1000 catheter-days, with a 95% confidence interval. It does not report the numerical rate or interval, nor does it describe the statistical method used to calculate or compare the rates. The explanations below are general statistical context and should not be read as a description of methods confirmed to have been used in this study.

What does a rate per catheter-days represent?

In general, a rate expresses event occurrence relative to time at risk or exposure. For this endpoint, catheter-days are the exposure measure: participants contribute time while their central lines are observed during the defined study period. This approach is useful when the amount of catheter observation differs across participants or groups. It does not make the groups comparable by itself, and it does not control for other differences between them.

The primary outcome description defines the observation window from CVC placement or HCT admission, whichever occurred later, until CVC removal or transfer back to the primary service, whichever occurred sooner. The registry gives an average duration of 3 months. It does not report how catheter-days were counted in practice, how multiple lines or events were handled, or whether any additional eligibility rules applied to the endpoint analysis.

What does a confidence interval add?

As a general explanation, a confidence interval describes the uncertainty associated with an estimate under the assumptions of the statistical method used. A point estimate gives a central summary, while the interval shows a range of values compatible with the observed data under that method. Greater precision is generally reflected by a narrower interval. A confidence interval is not a guarantee that the true value lies within its endpoints, and it does not by itself establish clinical importance or causation.

The registry specifies a 95% confidence interval for the primary rate but does not give its limits or the method used to obtain it. Without the rate estimate and interval, there is no basis for describing the primary result as precise or imprecise. The confidence level alone is not a result.

How should a count rate be analyzed?

In general, count outcomes measured over exposure time may be analyzed with methods that account for the exposure denominator. Some count models make assumptions about how event counts vary around their expected values. If real-world counts vary more than a model assumes, an approach that accounts for over-dispersion may produce more appropriate uncertainty estimates. This is general background only: the registry record does not report a model, a dispersion assessment, or whether any such adjustment was used.

A rate comparison may also be presented as a contrast between groups, with uncertainty around that contrast. Its interpretation depends on the model, the underlying event and exposure data, and any adjustment for relevant differences. The registry record does not report a comparison estimate, model specification, covariates, or adjusted analysis. It therefore cannot support a claim about which group had a higher rate or how large any difference was.

What does the design imply for statistical interpretation?

Random allocation is not reported; the study is explicitly non-randomized, and its comparator is historical. In general, randomization can help balance measured and unmeasured characteristics between groups, while historical comparisons can be vulnerable to differences in patient characteristics, care, and measurement over time. The registry does not report whether these potential differences were assessed or addressed statistically. The concern is about what the design can establish, not evidence that any specific bias occurred.

The historical data were obtained retrospectively through medical records, while the intervention cohort received parafilm during the study. In general, data collection from different periods or sources can affect consistency of outcome ascertainment. The registry does not report whether CLABSI surveillance procedures were identical across cohorts, or how missing or unclear records were handled.

What do planning calculations mean?

The record characterizes sample-size assumptions as planning illustrations computed from the observed effect, using a two-sided significance level of 0.05, equal allocation, and a normal approximation. It also states that the effect to detect is a stated fraction of the observed effect; for time-to-event tables, the described quantity is total events, while other tables are described as participants per arm. These are planning assumptions, not results of the trial. They do not represent observed power.

The registry record does not report the observed primary effect or the numerical planning outputs in the registry record for interpretation. Therefore, those assumptions cannot be used to state a required sample size or to judge whether the completed study had adequate precision. The record also does not report the trial’s own sample-size justification, whether an interim analysis occurred, or a prespecified statistical analysis plan. A planning illustration should not be mistaken for evidence that a particular analysis was prespecified or performed.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 10 outcome measures, including the primary CLABSI rate and secondary outcomes concerning antibiotic treatment courses, duration of antibiotic exposure, ICU admissions secondary to sepsis, death, and perception of parafilm. Considering multiple outcomes can raise a multiplicity issue: in general, testing many hypotheses increases the chance of at least one apparently notable finding by chance if no adjustment or interpretation strategy is used. The registry record does not report a multiplicity adjustment, a hierarchy for secondary outcomes, or a plan for interpreting multiple comparisons. It also lists zero analyses, so no outcome-specific statistical results are available to assess.

The record does not describe missing-data handling, completeness of medical records, exclusions from analyses, or the population included in each analysis. These details matter because missing outcome or exposure information can affect rate estimates, and exclusions can change the group being described. No assumption about the extent or impact of missing data can be made from the registry record.

Analysis populations are also not reported. The record does not state whether all enrolled participants were included in outcome analyses, how participants with incomplete follow-up were handled, or whether any per-protocol or other restricted analysis was planned. The non-randomized, historical design makes a clear description of the analyzed groups particularly important, but the registry information does not supply it. These are reporting gaps; they do not establish that particular analyses or data problems occurred.

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 serious adverse event terms

Serious events with the highest arm-level rate: graft versus host disease (gvhd) (4.2%), acute hypoxemic respiratory failure (2.1%).

For the Parafilm group, the registry records 48 participants at risk of serious adverse events and 3 affected by serious adverse events. It records 0 participants at risk of other adverse events and 0 affected by other adverse events. The deaths entry is 3. The record does not establish whether the deaths overlap with the serious-adverse-event count, so the entries should not be added together or interpreted as separate groups of people.

The listed leading serious-event terms are graft versus host disease (GVHD), 4.2%, and acute hypoxemic respiratory failure, 2.1%. The registry does not report the denominators used for these percentages in the information, nor does it provide additional details about event timing, duration, or severity beyond the serious-event classification.

These figures describe reported events in the parafilm group; they do not establish that parafilm caused them. The record does not report an attribution assessment or corresponding safety figures for the historical cohort. It also does not explain how the serious-event listings relate to the death entry. They should therefore be read as registry safety entries, not as a causal comparison or as a complete account of clinical risk.

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

The record establishes that a completed, non-randomized study examined parafilm use around the CVC hub in pediatric HCT patients and planned to compare CLABSI rates with a historical cohort. It defines the primary outcome and reports an observation period. Those details clarify the question the study was designed to address, but they are not evidence of the observed effect.

The numerical primary findings are not reported in the registry record. Without group-specific CLABSI rates, catheter-day denominators, event counts, and confidence intervals, the size and precision of the comparison cannot be assessed. The registry also lists zero analyses. Consequently, the available record does not show whether the parafilm group had a higher or lower rate, or whether any observed difference was substantial.

Even if a rate comparison were available, the historical, non-randomized design would require cautious interpretation. As a general matter, differences between intervention and historical cohorts can reflect changes in patients, care, or measurement over time. The registry does not report enough information to determine whether such differences were present or adjusted for. The design alone cannot establish that an outcome difference was caused by the intervention.

The safety entries provide reported counts and serious-event terms for the parafilm group, but they do not establish causality or offer a comparable historical safety analysis. The record does not report results for the listed secondary outcomes, including ease-of-use perception. The clinical and statistical meaning of those outcomes therefore cannot be assessed from the registry information.

In short, the registry record documents the study’s objective and basic design, but not the numerical results needed to answer its primary comparative question. It supports describing what was evaluated, not claiming that parafilm did or did not change CLABSI rates.

13. Why This Trial Matters Statistically

This trial is statistically instructive because its primary outcome is a rate tied to exposure time. Counting infections alone can be misleading when groups contribute different amounts of catheter observation; expressing CLABSI per catheter-days makes the exposure denominator part of the endpoint. Interpreting such a rate requires attention to both the event count and the time at risk, as well as uncertainty around the estimate.

The study also illustrates the limits of a historical comparison. A concurrent randomized comparison is not described: the intervention group was compared with pediatric HCT recipients from the 16 months before the intervention. As a general principle, differences across time can complicate causal interpretation, even when an outcome is carefully defined. Statistical adjustment can address only factors measured and appropriately included; the registry does not report whether adjustment was performed.

Precision matters alongside the point estimate. The registry specifies a 95% confidence interval for the primary rate, but does not report its estimate or interval. Without those values, neither the magnitude nor the uncertainty of the primary comparison can be evaluated. A planning illustration based on an observed effect is also conceptually distinct from an observed trial result and from observed power.

Finally, the record lists multiple secondary outcomes and safety entries, while giving no analyses or numerical primary results. This underscores why clear outcome reporting, analysis populations, missing-data methods, and a multiplicity strategy are important for interpreting clinical studies. The statistical value of the record is therefore principally in its stated design and endpoint, along with the limits imposed by missing results and non-random allocation.

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 interpretation is that the registry record does not report the numerical CLABSI rates, catheter-day denominators, event counts, or confidence intervals. Without these results, the main comparison cannot be quantified. The record lists zero analyses, and no outcome-specific analysis details are available.

The comparator is historical, drawn from pediatric HCT recipients in the 16 months before the parafilm intervention, and allocation is non-randomized. The record does not report whether cohort characteristics, care practices, or infection ascertainment were comparable across periods, or whether statistical adjustment addressed possible differences. These are design-related interpretive limitations; the registry does not establish that any particular imbalance occurred.

The intervention description is incomplete in the registry record: the text describing how parafilm was maintained on the CVC is truncated. The record therefore does not fully document the intervention procedure. It also does not report adherence, missing-data handling, analysis populations, or detailed criteria and procedures for collecting the outcomes.

Although secondary outcomes and safety entries are listed, numerical results for the secondary outcomes are not reported. Safety information is presented for the parafilm group without a reported historical comparison or attribution details. The record also does not provide a statistical analysis plan, multiplicity approach, interim-analysis information, or sample-size justification for the trial. These omissions limit assessment of how outcomes were analyzed and how complete or robust the reported findings would be; they do not by themselves indicate that a particular method was or was not used.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Parafilm to Prevent CLABSI in Pediatric Patients Undergoing HCT — NCT02575079.
• Registry record last updated 2019-06-25; status last verified 2019-06.
• Results first posted 2019-06-25.
• 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

NCT02575079, titled Parafilm to Prevent CLABSI in Pediatric Patients Undergoing HCT, is listed as completed and sponsored by Emory University. It was a parallel, non-randomized study with no masking, an enrollment entry of 119, and phase listed as not applicable.

The study evaluated parafilm applied around the CVC hub in pediatric HCT patients. Its primary endpoint was CLABSI per 1000 catheter-days, compared with a historical cohort of pediatric HCT recipients from the 16 months before the intervention. The registry specifies a 95% confidence interval and an average observation period of 3 months.

The record lists 10 outcome measures and zero analyses. It does not report the primary rate estimates or confidence intervals, so the comparative result cannot be quantified from the registry record. Listed safety entries include 3 serious adverse-event affected participants, 3 deaths, and serious-event terms of graft versus host disease (GVHD), 4.2%, and acute hypoxemic respiratory failure, 2.1%.