Buzzy Versus Vapocoolant Spray: Pediatric Needle Pain Relief: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Buzzy Versus Vapocoolant Spray: Pediatric Needle Pain Relief (NCT00919100), a randomized na study. The primary outcome is Faces Pain Scale-Revised (FPS-R).

2. Clinical Question

This is a question about pain scores after a specific procedure, in the participants enrolled in this trial. It is not a general comparison of all methods for reducing needle pain, and the registry record does not establish whether the findings apply to other procedures, age groups, or clinical settings. Random allocation is relevant because it is intended to make groups comparable on average, but the registry record does not describe the allocation sequence or concealment procedures. The available record also does not provide enough detail to determine how the single masking was implemented.

3. Trial Design

The registry record describes a completed, randomized, single-masked, parallel-group trial sponsored by Georgia State University. Enrollment was 81, with 40 participants assigned to Standard Care and 41 assigned to Buzzy. The study start is recorded as 2008-04 and primary completion as 2008-08. The phase is listed as NA. More detailed information about the setting, eligibility criteria, age distribution, or participant flow is not reported in the registry record.

In a parallel design, participants are assigned to one group and outcomes are compared across groups. The registry record describes random allocation, which can support a fair comparison when implemented appropriately. However, the methods used to generate and conceal allocation are not reported in the registry record. “Single” masking is recorded, but the identity of the masked party and the procedures used to maintain masking are not reported. The descriptions of the two interventions make it important not to assume that participants, clinicians, or outcome assessors were masked in any particular way.

The standard-care arm received venipuncture with vapocoolant spray offered. The Buzzy arm received a vibrating device and cold pack positioned proximal to the venipuncture site, with optional distraction cards. The intervention descriptions indicate a combined approach; the registry record does not separate the effects of vibration, cold, or distraction. It also does not report whether treatment use or adherence varied among participants.

The posted primary result is the median Faces Pain Scale-Revised score for each arm, with full ranges. A secondary result concerns venipuncture success in one attempt. The registry record names OSBD-R observational pain/distress as another secondary outcome, but its outcome values are not reported in the registry record. The posted record contains no reported analysis for the primary endpoint and no reported adjusted analysis for the secondary comparison. Accordingly, the design supports a comparison in principle, while the available reporting limits conclusions about the analysis and its precision.

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

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 Faces Pain Scale-Revised (FPS-R), measured over 5 minute.

The primary endpoint is the Faces Pain Scale-Revised (FPS-R), a self-report measure intended to capture a participant’s pain experience. Its six faces range from a neutral expression to increasing expressions of pain. The recorded scoring range is 0-10, with lower scores representing lower pain and higher scores representing higher pain. A self-report measure is useful because pain is a subjective experience; an observational measure can describe visible behavior, but it does not directly substitute for the participant’s report.

The registry record gives a timeframe of 5 minute. Its description says that the FPS-R was conducted several minutes after venipuncture, typically between 2-5 minutes after completion, and that the exact time was not tracked. Thus, the label for the outcome timeframe should not be read as evidence that every assessment occurred at precisely the same minute. The absence of recorded timing may matter if pain reports change over the period following the procedure.

The posted primary results are medians with full ranges rather than means with standard deviations. A median describes the middle of the observed scores when ordered, while the full range gives the lowest and highest reported values. These summaries describe the observed distributions but do not, by themselves, quantify uncertainty in a between-group contrast. The registry record does not report a test, confidence interval, or adjusted analysis for the primary endpoint. The arm-level medians can therefore be described, but they should not be mistaken for a complete inferential comparison.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The following concepts are general explanations of how to read the statistics reported for this trial. They do not imply that the registry record documents every method described.

What does a median describe?

A median is the central value after observations are ordered. It is often useful when scores are ordinal, skewed, or not well summarized by an average. The FPS-R results are reported as medians and full ranges. A range describes the observed extremes, but it does not show how many participants had each score or how concentrated scores were between the extremes. Two groups can have different medians while still having overlapping individual values, and a range alone does not quantify the precision of a group comparison.

For these reasons, arm-level medians and ranges are descriptive summaries. A formal comparison might estimate a difference between groups and its uncertainty, using a method appropriate to the outcome and analysis plan. The registry record does not report such a primary-endpoint estimate or identify the method that would have been used. It is not possible to infer the intended test from the reported summaries alone.

What is a risk difference?

A risk difference expresses the difference between the proportions experiencing an event in two groups, on the absolute probability scale. In the secondary comparison, the event is success in one venipuncture attempt, and the contrast is reported for Buzzy relative to Standard Care. The posted estimate is 0.204. The confidence interval, from 0.021 to 0.387, represents uncertainty around that estimate under the assumptions of the calculation. It gives a range of values that are compatible with the observed data and method; it is not a guarantee that the true value lies in that range.

The record also reports a risk ratio of 1.313, with an interval from 1.012 to 1.704, and an odds ratio of 3.141, with an interval from 1.064 to 9.274. These measures use different scales and should not be treated as interchangeable. A risk ratio compares event probabilities, while an odds ratio compares event odds. An odds ratio can appear farther from its null value than a risk ratio when the outcome is common. The risk difference instead describes an absolute contrast. Each measure answers a related but distinct statistical question.

How should the p-value be read?

The unadjusted p-value for the secondary comparison is 0.034. In general, a p-value describes how unusual results at least as incompatible with a specified null model would be if that model and the test assumptions were correct. It is not the probability that the null hypothesis is true, nor is it a measure of clinical importance. The word “unadjusted” matters: the value does not account for the possibility that several outcomes or comparisons were examined. The registry record does not report a multiplicity adjustment or a plan establishing which outcome was primary for formal testing.

A p-value should be read alongside the effect estimate, its confidence interval, and the design and analysis details. The interval communicates uncertainty about the magnitude, while the p-value is a test statistic interpreted relative to a null hypothesis and specified method. Neither can correct for incomplete outcome reporting, unclear analysis choices, or limited generalizability.

Why do analysis populations and missing outcomes matter?

Randomized trials can be analyzed according to the group assigned, according to treatment actually received, or using other defined populations. These choices can affect the interpretation of a result. The registry record does not report the analysis population for the posted outcomes, participant exclusions after randomization, or the handling of missing scores. The arm counts in the results do not, by themselves, establish whether every randomized participant contributed to every outcome.

Missingness can be informative. For example, if participants with higher pain scores are less likely to complete a questionnaire, the observed scores may not represent all assigned participants. This is a general concern, not a claim about what occurred in this trial. The record does not describe missing-data rates or methods, so the effect of missing information cannot be assessed.

What do the planning illustrations mean?

The registry record includes sample-size illustrations based on the observed secondary effect, not the trial’s own design. They assume a two-sided significance level of 0.05, equal allocation, and a normal approximation. The listed scenarios plan for 100%, 75%, or 50% of the observed effect, with participants per arm for 80% and 90% power. These values are planning illustrations only. They are not the trial’s enrollment targets, do not establish the original rationale for enrollment, and are not observed power. The sample-size justification for the trial is not reported in the registry record.

Planning for a smaller effect than the observed estimate generally requires more participants, because smaller contrasts are harder to distinguish from random variation. This is a general statistical relationship, not evidence that any particular effect will occur in a future study. Observed effects from small trials can be imprecise, so a planning exercise that uses an observed estimate should be interpreted cautiously. The record does not report the protocol assumptions or design calculations that led to enrollment of 81.

Over-dispersion is a general issue in count or rate outcomes when variation exceeds what a simple model assumes. It can make standard errors too small if not accommodated. The posted primary endpoint is a bounded pain score, and the available secondary result is binary; the registry record does not identify an over-dispersion model or report count-rate analyses. Thus, over-dispersion should not be presumed to have been relevant to the analyses in this trial. More generally, statistical methods should match the outcome’s scale and distribution, but the primary analysis plan is not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry record identifies the FPS-R as the primary outcome and lists OSBD-R observational pain/distress and one-attempt venipuncture success among the secondary outcomes. It does not report a statistical analysis plan, a hierarchy for testing outcomes, or a method for controlling the overall risk of false-positive findings across multiple tests. The available secondary comparison is explicitly unadjusted. Its p-value should therefore be interpreted as a result for that comparison, not as a multiplicity-adjusted conclusion about the trial as a whole.

Multiplicity arises when investigators assess more than one outcome, time point, subgroup, or comparison. Even if each test is conducted appropriately on its own, considering many results can make at least one appear noteworthy by chance. Prespecification and adjustment strategies can help define how such results should be interpreted. Which outcomes were prespecified in a protocol, and whether any adjustment was planned, are not reported in the registry record. The registry record also does not report interim analyses or stopping rules; their presence or absence should not be inferred.

Missing-data details are similarly limited. Although the registry record gives arm sizes and outcome summaries, it does not describe the number of missing primary scores, the reasons for missingness, or the method used to handle missing observations. It does not report whether all randomized participants were included in each analysis or how post-randomization exclusions were addressed. These details matter because missing outcomes can affect both the representativeness of the summaries and the validity of a comparison.

The record also does not provide a full protocol or statistical analysis plan from which to assess deviations, endpoint definitions, or analysis choices. The count of posted outcome measures does not resolve whether every registered outcome is represented by a result. In particular, the OSBD-R result is not reported in the registry record. As a result, readers cannot assess the complete outcome pattern or determine whether the reported analyses correspond to the original planned analyses.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The serious adverse event figures report zero affected participants among 40 at risk in Standard Care and zero among 41 at risk in Buzzy. The record also reports zero participants with other adverse events in each arm. These are observations from the trial, not proof that the interventions carry no risk. An event not observed during a trial can still occur in other circumstances, and a small study may be unable to characterize uncommon events precisely.

The registry record does not provide serious adverse event terms, because none are listed, and does not report death counts. A blank death value should not be converted into a claim of zero deaths. The record also does not describe how adverse events were solicited, the observation period for safety, or the criteria used to classify events. Thus, the figures are best read as a narrow account of posted event counts rather than a comprehensive safety assessment.

These data do not support medical advice or a general conclusion about safety. They describe the events recorded for the trial groups and should be interpreted in light of the limited sample and reporting detail.

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

The primary outcome results show lower median FPS-R scores in the Buzzy group than in Standard Care, with the scale defined so that lower values represent lower pain. This is a descriptive pattern in the enrolled participants. Because the registry record does not report a primary comparison estimate, confidence interval, or p-value, the precision and statistical uncertainty of the difference between medians cannot be evaluated from the posted primary results alone.

The secondary result provides a separate estimate for one-attempt venipuncture success. Its confidence interval and unadjusted p-value describe uncertainty and evidence under the assumptions of that comparison, but they do not resolve the missing primary-endpoint analysis. Nor does a secondary procedural outcome establish a difference in reported pain. Different outcomes represent different experiences and processes, and their findings should be considered on their own terms.

The randomized design is an important feature, but it does not automatically guarantee that every practical source of bias is addressed. The record does not report allocation concealment, who was masked, the participant flow, missing-data handling, or the analysis population. The timing of the FPS-R assessment was not tracked precisely according to the outcome description. These factors limit how confidently the observed arm summaries can be interpreted.

The findings also do not establish that the results would be the same in other populations, procedures, settings, or versions of the intervention. The registry record describes a combined device, cold pack, and optional distraction approach, so any observed contrast cannot be attributed separately to vibration, cold, or distraction. It does not report subgroup or component analyses.

In short, the record supports describing the observed scores and the posted secondary comparison, while leaving important questions about inferential precision, completeness, and generalizability unresolved. It does not justify a claim that Buzzy definitively reduces pain, nor a claim that it does not. The appropriate interpretation is bounded by the data and analysis details actually recorded.

13. Why This Trial Matters Statistically

This trial is statistically interesting because it places a patient-reported pain measure alongside a procedural outcome. Those outcomes capture different dimensions of a venipuncture experience. Keeping them distinct helps prevent a procedural measure from being treated as a direct substitute for a participant’s report of pain. It also illustrates why a clearly defined primary endpoint and a transparent analysis plan matter: the primary score summaries are available, but the registry record does not report an inferential comparison for them.

The report also shows how much interpretation depends on more than a p-value. The secondary comparison includes an effect estimate and confidence interval, allowing readers to consider both the direction and uncertainty of the result. Its unadjusted status and secondary role remain important. A statistically unusual result on a secondary endpoint cannot automatically answer the primary question, particularly when the approach to multiple outcomes is not reported.

Another lesson is that a trial’s numerical summaries do not reveal every design choice. The record does not report the primary analysis method, missing-data procedures, or details of masking and allocation concealment. Without those elements, readers cannot fully judge whether the analysis was prespecified, how robust it might be, or whether the posted results include all participants and outcomes. Transparent registration and reporting of these methods are essential for interpreting both positive and inconclusive findings.

Finally, sample-size illustrations based on an observed effect are not a substitute for a prospective design rationale. They can help explain how planned enrollment varies with an assumed effect size, but they do not establish what the original trial was designed to detect. The trial’s own sample-size justification is not reported in the registry record. Taken together, these points make the record useful for statistical reading while underscoring the limits of drawing firm conclusions from sparse reporting.

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.

Several limitations specific to this trial affect interpretation. The main limitation is that the primary FPS-R outcome is reported by arm as a median and full range, but no between-group analysis is reported. The descriptive scores show a difference in medians, yet the record offers no confidence interval or test for that contrast. A reader cannot infer the precision of the primary result from the ranges alone.

The endpoint description states that assessment timing was typically between 2-5 minutes following completion of venipuncture, while the exact time was not tracked. The timeframe is recorded as 5 minute, so the assessment label and the narrative description do not establish a uniform measurement time. If reports vary over time after a procedure, unrecorded timing can complicate comparisons.

The intervention is a combination of vibration and cold, with optional distraction cards. The record does not allow the contributions of those components to be separated. Nor does it report how consistently the device was applied or how often optional cards were used. The comparator is described as vapocoolant spray offered, which does not specify whether every participant received it.

Important trial conduct and analysis details are not reported in the registry record, including eligibility criteria, participant characteristics, allocation concealment, the identity of the masked party, participant flow, missing-data handling, and the analysis population. The OSBD-R outcome is listed but its values are not reported. The registry also does not provide a primary statistical analysis or an approach to multiplicity. These limitations leave uncertainty about completeness, potential bias, and the scope of the results, beyond the statistical uncertainty in the posted secondary comparison.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Buzzy Versus Vapocoolant Spray: Pediatric Needle Pain Relief — NCT00919100.
• Registry record last updated 2018-11-21; status last verified 2018-11.
• Results first posted 2018-09-18.
• 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

NCT00919100 is a completed randomized, single-masked, parallel-group trial sponsored by Georgia State University. Enrollment was 81, with 40 participants in Standard Care and 41 in Buzzy. The study start is recorded as 2008-04 and primary completion as 2008-08.

The primary outcome was FPS-R pain score, reported as a median and full range for each arm. The registry record does not report a primary between-group analysis. A secondary comparison for one-attempt venipuncture success includes an unadjusted estimate, confidence interval, and p-value. OSBD-R is listed as a secondary outcome, but its results are not reported in the registry record.

Zero serious adverse events and zero other adverse events are recorded in both groups; death counts are not reported. The record does not report the trial’s sample-size justification, analysis plan, missing-data methods, or multiplicity approach. Consequently, the posted results permit descriptive interpretation but leave important uncertainties about inferential analysis and completeness.