Comparative User Experiences With BD Nano™ PRO 32G Extra Thin Wall Pen Needle vs the Terumo Nanopass® 34G Pen Needle: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparative User Experiences With BD Nano™ PRO 32G Extra Thin Wall Pen Needle vs the Terumo Nanopass® 34G Pen Needle (NCT03878745), a non-randomized na study. The primary outcome is BD Nano™ PRO Pen Needle Compared to Terumo Nanopass® (Injection Pain).

2. Clinical Question

In practical terms, the registered question concerns participants’ immediate ratings after paired injections, rather than a long-term clinical outcome. The record says scores were collected immediately after each paired injection and pooled across pairs for an average relative rating. It describes adjustment for injection order using a linear model. Those details indicate the intended comparison, but they do not supply an outcome estimate or establish how participants’ ratings differed between devices.

The brief summary describes a single-visit, multi-center study and calls it subject single blinded and block randomized. In contrast, the registry’s design fields classify it as non-randomized, unmasked, and single group. This internal inconsistency affects how confidently the comparison can be characterized. The record does not provide enough detail to resolve it, and it does not report a result that would permit an estimate of the size or precision of any observed difference.

3. Trial Design

The registry describes a prospective, single-visit, multi-center study involving Japanese American participants with Type 1 or Type 2 diabetes. Enrollment is listed as 55. The recorded start date is 2019-02-11, the primary completion date is 2019-06-14, and the status is completed. The study is listed as phase NA.

The two devices are BD Nano™ PRO 32G and Terumo Nanopass® 34G pen needles. Each arm description states that participants are to perform 6 pairs of injections. The brief summary says that the study compares user experiences with the BD needle and the thinner commercially available Terumo needle. The registered secondary outcomes concern force, needle bending, and leakage. The record lists 7 outcome measures and 5 analyses, but detailed results for those secondary outcomes are not reported in the registry record.

There is an important design-description mismatch. The brief summary describes the study as subject single blinded and block randomized, while the formal design fields classify allocation as NON RANDOMIZED, masking as NONE, and the model as SINGLE GROUP. The record does not explain this discrepancy. Accordingly, the registry information does not support treating the two device groups as a confirmed randomized, blinded, like-for-like comparison. The record itself flags that the comparison is not randomized and that the arms are not a like-for-like control comparison.

The primary outcome is assigned to the per protocol population. The number included in that population, the reasons for any exclusions, and the definition of protocol adherence are not reported in the registry record. A sample-size justification, planned power, and the protocol’s full statistical analysis plan are also not reported in the registry record. A planning illustration based on an observed effect, where available, should not be read as a design justification or as observed power.

Thus, the design description establishes the devices, intended injection activity, timing of score collection, and broad study setting, but leaves important operational details unresolved. In particular, the registry record does not clarify the discrepancy about randomization and masking or provide participant flow and analysis-population counts.

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

Analysis population for the primary outcome, as defined in the registry: Per protocol population

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 BD Nano™ PRO Pen Needle Compared to Terumo Nanopass® (Injection Pain), measured over Scores were collected immediately after each paired injection.

The primary outcome is titled as a comparison of the devices for injection pain, measured in millimeters. Its description specifies a relative 150 mm VAS, with the BD Nano™ PRO pen needle labeled at +75 mm and the comparator labeled at -75 mm. Zero represents no preference; positive values indicate preference for BD Nano™ PRO and negative values indicate preference for Terumo Nanopass®. Scores were collected immediately after each paired injection.

This type of scale can capture a participant’s subjective experience on a continuum rather than forcing a simple choice between devices. A mean score can summarize the average direction and magnitude of ratings across the observations included in the analysis. A confidence interval can express the uncertainty around that average and show which values remain compatible with the data and the analysis assumptions.

There is a naming ambiguity in the registry description: the outcome title calls the measure injection pain, while the scale instructions describe a relative user-preference rating between the needles. Those are related but not identical concepts. The record does not clarify whether participants rated pain, preference informed by pain, or another combined judgment. Therefore, the scale’s direction can be described as registered, but the exact construct represented by the score should be interpreted cautiously.

The description says paired-injection scores were pooled and an average relative rating was calculated, with a linear model used to adjust for order. The numerical average and its two-sided 95% confidence interval are not reported in the registry record. Without them, the endpoint’s observed direction, size, and precision cannot be assessed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome description combines a continuous rating scale, repeated paired injections, an average score, a confidence interval, and a linear-model adjustment for order. These elements can be explained as general statistical concepts, but the registry record does not provide the numerical results needed to judge the study’s findings.

What does the relative VAS represent?

A visual analog scale records a rating along a continuum. In this study’s description, the relative VAS is anchored so that zero means no preference, positive scores mean preference for BD Nano™ PRO, and negative scores mean preference for Terumo Nanopass®. The listed range is -75mm to 75mm. A mean of such ratings would describe the average score across observations included in the analysis. It would not show that every participant gave a similar rating; individual responses can vary around an average.

The outcome title refers to injection pain, but the scale instructions explicitly describe preference between the needles. This matters because statistical analysis can summarize a recorded score but cannot remove ambiguity about what participants were asked to judge. The registry record does not clarify the distinction. General interpretation should therefore distinguish the scale’s stated direction from the underlying concept it was intended to measure.

Why use a confidence interval?

A confidence interval gives a range of values compatible with the observed data under the statistical model and its assumptions. It conveys uncertainty about an estimated average, rather than only indicating whether a test crosses a decision threshold. A narrower interval generally reflects greater precision, while a wider interval indicates less precision. The interval’s location relative to zero can help describe the direction supported by the data, but its interpretation depends on the outcome definition and analysis design.

The registry states that a two-sided 95% confidence interval was calculated for the average relative rating. It does not report the average or either confidence limit. As a result, the interval’s width and position cannot be assessed. A confidence level does not mean that a particular interval has a 95% probability of containing the true value; in general, it describes the long-run coverage property of the interval procedure under its assumptions.

Why might injection order be included?

The outcome description says a linear model was used to adjust for order effect. In a paired experience comparison, the sequence in which devices or injections are encountered can potentially influence ratings. For example, a rating may reflect not only the device being assessed but also the participant’s earlier experience in the sequence. As a general matter, an order adjustment attempts to account for systematic differences associated with sequence when estimating the average comparison.

The registry does not report the exact model specification, the order variable’s coding, other model terms, or whether any other adjustments were made. It also does not report the adjusted estimate or its uncertainty. The phrase “adjust for the order effect” therefore identifies an intended feature of the analysis but is not enough to reproduce it or evaluate the adequacy of the adjustment.

What does pooling repeated scores imply?

The record says scores from paired injections were pooled and an average was calculated, and its description refers to 330 pairs for all participants. Repeated ratings from the same participant are generally correlated: one person’s scores may be more alike than scores from different people. General statistical methods need to account for that dependence if the goal is to estimate uncertainty correctly. Treating every repeated observation as independent when observations are clustered within people can make uncertainty appear smaller than it is. The record mentions a linear model but does not explain how within-participant dependence was handled.

The count of pairs in the outcome description does not by itself identify the number of participants included in the per protocol analysis or establish that every planned score was observed. The per protocol population is named, but its size and the flow of participants into the analysis are not reported in the registry record.

How should the decision thresholds be read?

The registry gives a non-inferiority rule requiring the lower confidence bound to be greater than -10cm and says a lower bound greater than 0 can also support superiority. In general, a non-inferiority analysis asks whether the data exclude a disadvantage larger than a prespecified margin, while a superiority analysis asks whether the estimate is sufficiently inconsistent with no difference in the favored direction. The margin and the decision rule must be interpreted in the outcome’s units and in light of the design and analysis.

Here, the stated VAS range and unit are in millimeters, but the threshold is written in centimeters. The record does not explain the discrepancy, so it is not appropriate to recast the threshold or judge the criterion. Nor can either decision rule be applied without the lower confidence limit. The protocol rationale for the margin and the full analysis plan are not reported in the registry record.

General statistical interpretation also separates an estimate from a decision. An estimate describes the observed data under a model; a threshold-based conclusion depends on the prespecified rule, valid measurement, appropriate analysis, and adequate reporting. The registry’s design fields conflict with the brief summary’s randomization and masking description, which adds uncertainty about the comparison structure. No missing numerical outcome should be inferred from the stated methods or decision criteria.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 7 outcome measures and 5 analyses. It names secondary outcomes for force, needle bending, and leakage, in addition to the primary outcome comparing the devices for injection pain. The record does not report a multiplicity strategy, such as whether any adjustment was planned for examining several outcomes or analyses. It is therefore not possible to establish how the chance of false-positive findings across multiple statistical tests was addressed. The protocol’s full statistical analysis plan is not reported in the registry record.

The primary outcome is assigned to the per protocol population. The number of participants in that population, the number excluded, and the reasons for exclusion are not reported in the registry record. The registry enrollment is 55, but that figure does not establish how many participants contributed usable primary-outcome data or how many repeated ratings were analyzed.

Missing-data procedures are not reported in the registry record. It does not state whether incomplete injection pairs or missing ratings occurred, how any missing observations were handled, or whether sensitivity analyses were conducted. These details matter because conclusions based on complete cases can differ from conclusions under other assumptions about missing observations. This is a general concern, not evidence that missing data occurred in this study.

The record also does not state whether the analysis population, outcome definition, order adjustment, or decision thresholds were finalized before examining the results. The internal mismatch between the brief summary’s description of block randomization and single blinding and the formal non-randomized, unmasked, single-group fields makes a clear account of the analysis structure especially important. Those unresolved details limit assessment of multiplicity, missingness, and the population represented by any estimate.

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.

The registry reports serious adverse events in 0 of 55 participants for BD Nano™ PRO and 0 of 55 for Terumo Nanopass. It also reports other adverse events in 0 of 55 participants for each device group, and deaths in 0 participants in either group. These are the posted counts for the categories shown in the record.

A zero count means that no events in that category were recorded for the listed group in the registry results. It does not establish that the risk is zero, nor does it rule out events that were not collected, reported, or captured in the record. In general, safety counts are interpreted alongside the period and method of monitoring, the event definitions, and the number of participants observed. Those details are not reported in the registry record.

The two device groups should not automatically be treated as independent, randomized comparison arms. The registry classifies the allocation as non-randomized and the model as single group, while the brief summary describes block randomization. The record does not resolve this inconsistency. The safety figures are descriptive counts and do not establish a comparative safety effect.

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

The registry record establishes that the study was designed to compare user experiences with BD Nano™ PRO 32G and Terumo Nanopass® 34G pen needles in participants with diabetes. It describes repeated paired injections, immediate score collection, a relative VAS, and an analysis intended to adjust for order. It also lists secondary outcomes involving force, needle bending, and leakage.

It does not report the numerical primary outcome estimate or its 95% confidence interval. Consequently, the posted results do not establish the direction, size, or precision of the average rating. They also do not permit evaluation of the stated non-inferiority or superiority rules. The rule’s threshold is expressed in centimeters while the scale is described in millimeters; the record does not explain this mismatch.

The study design is not consistently described across the registry. The brief summary says subject single blinded and block randomized, whereas formal fields say non-randomized, no masking, and single group. A registry note explicitly cautions that the comparison is not randomized and the arms are not a like-for-like control comparison. Without clarification, the design should not be treated as a confirmed randomized trial.

The safety counts report no serious or other adverse events and no deaths in either listed device group. Those counts describe what was recorded; they do not prove that events are impossible or that the devices have equivalent safety. The record does not provide additional monitoring details or comparative analyses.

Overall, the registry record supports a description of the question and planned measurement approach, but not a conclusion about which device received more favorable ratings or whether any difference was meaningful. Missing outcome results, unclear analysis-population details, and unresolved design and unit inconsistencies constrain interpretation. These limitations are about what can be concluded from the registry record, not evidence for a particular result.

13. Why This Trial Matters Statistically

This study is statistically interesting because it uses a within-experience rating scale and repeated paired injections to examine users’ immediate responses to two devices. A relative scale can represent both direction and degree of preference, rather than reducing responses to a simple choice. Repeated observations also raise a central analysis issue: ratings from one participant may be related, so the method used to calculate uncertainty should reflect the data structure.

The registry says scores were pooled and a mean was calculated, with a linear model to adjust for order. Those details identify potentially important analytic choices. However, the record does not explain how dependence among repeated scores was handled, give the full model specification, or report the resulting estimate and confidence interval. This illustrates why an analysis description and an outcome result are both needed for statistical interpretation.

The entry also illustrates the importance of consistent registry information. Its brief summary describes block randomization and single blinding, while formal fields identify a non-randomized, unmasked, single-group design. These are not interchangeable descriptions: the study structure affects how a comparison should be interpreted. The registry itself warns against treating the arms as a like-for-like control comparison.

Finally, the endpoint is framed as injection pain in its title but described as relative preference in its scale instructions, and the decision threshold uses a unit different from the scale’s stated unit. These details show how clear outcome definitions and internally consistent units are necessary for readers to assess a statistical claim. In this record, the numerical primary result is not reported, so the methods and design can be discussed, but the empirical comparison cannot be judged.

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 trial-specific limitations arise from the registry information. First, the primary outcome estimate and its confidence interval are not reported in the registry record. The central comparison therefore cannot be assessed for direction, magnitude, or precision. The record also does not report numerical results for the listed secondary outcomes.

Second, the design description is internally inconsistent. The brief summary refers to a single-blinded, block-randomized study, while the formal fields report non-randomized allocation, no masking, and a single-group model. The registry does not explain how these statements relate to one another. Its note that the comparison is not randomized and the arms are not like-for-like reinforces the need for caution about comparative interpretation.

Third, the primary outcome is described both as injection pain and as relative preference. The scale anchors indicate preference between devices, but the record does not clarify precisely what participants were asked to rate. In addition, the non-inferiority threshold is written as -10cm while the scale is stated in millimeters. The record does not resolve this unit inconsistency.

Fourth, the registry names the per protocol population without reporting its size or defining protocol adherence. Participant flow, missing-score handling, the full model specification, and the method for accounting for repeated observations are not reported in the registry record. These omissions limit reproducibility and assessment of uncertainty. The record also does not report a sample-size justification, multiplicity approach, or full statistical analysis plan. These are reporting limitations; they do not establish that any particular methodological problem occurred.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Comparative User Experiences With BD Nano™ PRO 32G Extra Thin Wall Pen Needle vs the Terumo Nanopass® 34G Pen Needle — NCT03878745.
• Registry record last updated 2020-05-19; status last verified 2020-05.
• Results first posted 2020-05-19.
• 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

The registry record describes a completed, prospective, single-visit, multi-center study of BD Nano™ PRO 32G and Terumo Nanopass® 34G pen needles in Japanese American participants with Type 1 or Type 2 diabetes. Enrollment is listed as 55. Participants were to perform 6 pairs of injections with each device, and immediate relative VAS scores were intended to capture injection pain or user preference.

The primary analysis is described as an average score with a two-sided 95% confidence interval and a linear-model adjustment for order. The primary population is identified as per protocol. The record also lists outcomes concerning force, needle bending, and leakage.

The primary numerical result is not reported in the registry record. The design fields conflict with the brief summary about randomization and masking, and the endpoint description contains a pain-versus-preference ambiguity and a threshold-unit inconsistency. Reported safety counts are zero for serious adverse events, other adverse events, and deaths in both listed device groups.