Near Infrared Autofluorescence (NIRAF) Detection for Identifying Parathyroid Glands During Parathyroidectomy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Near Infrared Autofluorescence (NIRAF) Detection for Identifying Parathyroid Glands During Parathyroidectomy (NCT05152927), a randomized na study. The primary outcome is Median Number of Frozen Sections (or Parathyroid Aspirate) Sent for Analysis.

2. Clinical Question

The broader research question concerns whether a device used to locate parathyroid tissue during surgery changes procedural and postoperative outcomes. The registry summary describes possible aims such as reducing the time needed to locate glands, frozen-section testing, costs, and repeat surgery. Those aims are not themselves evidence of an effect. The primary outcome specifically captures the number of samples sent for confirmation; it does not directly measure all of those broader outcomes.

3. Trial Design

The registry identifies NCT05152927 as a completed, randomized, single-masked, parallel-group study sponsored by the University of California, San Francisco. The study compared two assigned approaches: intraoperative use of Parathyroid Eye (PTeye) and usual standard of care. The record lists enrollment of 79 participants. It does not report who was masked, how the random sequence was generated or concealed, or the allocation ratio as a protocol detail.

The registry lists the study start as 2022-01-10 and primary completion as 2024-11-30. These dates describe the study record; they do not establish when every participant was recruited or followed. The primary outcome was assessed at the end of parathyroidectomy, within a timeframe of up to 5 hours. Secondary outcomes include postoperative biochemical or clinical outcomes, gland identification, intraoperative testing, and time to identification, with follow-up windows varying by outcome.

The primary arm summaries include 38 participants in the PTeye group and 41 in usual care. Both groups had a reported median of 0 frozen sections or aspirate samples sent, with a full range of 0 to 1. A formal primary-outcome comparison, confidence interval, or p-value is not reported in the registry record. The registry also does not report the detailed protocol, eligibility criteria, sample-size justification, masking procedures, or a complete statistical analysis plan. Those omissions limit how fully the design and analysis can be evaluated from the record alone.

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 Median Number of Frozen Sections (or Parathyroid Aspirate) Sent for Analysis, measured over At the end of the parathyroidectomy, up to 5 hours.

The primary endpoint is the median number of frozen sections or parathyroid aspirate samples sent for analysis during parathyroidectomy to confirm potential parathyroid tissue. The timeframe is at the end of the operation, up to 5 hours. A sample sent for analysis represents an intraoperative confirmation step; the endpoint therefore describes how often and how extensively that step was used, rather than directly measuring gland identification accuracy or later patient outcomes.

A median is a measure of the middle of a distribution. It can be useful when an outcome is a count and observations may cluster at low values, because it is less influenced by unusually high counts than the mean. The full range gives the smallest and largest recorded values, but does not show how many participants had each value or how observations were distributed between the endpoints.

The reported median is 0 in both arms, and the full range is 0 to 1 in both arms. These summaries show that the central reported value and the observed endpoints were the same across arms. They do not establish that the underlying distributions were identical. The registry record does not report a formal between-arm estimate, uncertainty interval, or statistical test for this endpoint, so the precision of a treatment contrast cannot be assessed from the primary summaries alone.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the primary summary describe?

The primary outcome is a count summarized by its median and full range. The median gives a central location: half the observations are at or below it and half are at or above it, allowing for ties. The range reports the lowest and highest observed values. In this trial, the median is 0 and the range is 0 to 1 in both arms. Those summaries are easy to interpret, but they omit the number of participants at each count and do not provide an estimate of the difference between arms. The registry record does not report a test or interval for the primary comparison.

For count outcomes, a median can be informative when many participants have low or zero counts or when the distribution is skewed. That is a general statistical reason to report a median; the record does not report the observed frequency distribution or explain why this summary measure was chosen. The full range is sensitive to individual observations and does not show how common any value was. Equal medians and equal ranges do not imply identical distributions.

How should a risk difference be read?

A risk difference subtracts the event proportion in one group from the event proportion in the other. Negative values in the reported comparisons indicate a lower observed event proportion in the PTeye arm than in usual care, according to the comparison direction used in the registry. The estimate is a contrast in observed proportions, not a measure of causation by itself. Its uncertainty interval indicates a set of values compatible with the data under the method used to calculate it. The interval level and calculation method are not reported in the registry record.

When a risk-difference interval includes zero, the data do not rule out no difference at that interval level. Such an interval may also include effects in either direction. It should not be read as proof of equivalence or as evidence that a clinically meaningful difference is absent. Equivalence requires a prespecified margin and an appropriate analysis; those are not reported in the registry record.

What do the secondary p-values indicate?

The listed p-values are unadjusted. A p-value measures how surprising data at least as incompatible with a specified null model would be if that model and the test assumptions held. It is not the probability that the null hypothesis is true, nor does it measure the size or importance of an effect. The unadjusted values are 0.333, 0.345, and 0.447 for the secondary comparisons described in the results. The registry record does not provide the test method for these p-values or a prespecified threshold for interpreting them.

Unadjusted analyses assess each comparison without accounting for the number of outcomes examined. When many outcomes are tested, the chance of obtaining one or more apparently unusual results by chance can increase. This is a general multiplicity concern. The registry record does not report a multiplicity adjustment or a hierarchy assigning confirmatory status to outcomes. Accordingly, secondary comparisons should be treated as descriptive or exploratory rather than as independent confirmation of a primary claim.

How do the other effect measures help?

For the utilization outcome, the registry also reports a risk ratio and an odds ratio. A risk ratio compares the event proportions between groups; a value of 1 represents equal proportions. An odds ratio compares event odds; a value of 1 represents equal odds. These measures use different scales and can look numerically different while describing the same underlying data. Their interpretation depends on the event definition and group ordering. The reported intervals for both measures include 1, and the risk-difference interval includes zero. This is consistent with considerable uncertainty rather than a precise estimate of a between-group association.

The outcome counts and group sizes should be considered alongside these effect measures. The registry reports 5 participants with visits or admissions in the PTeye arm and 8 in usual care, with group sizes of 38 and 41, respectively. These are observed counts, not adjusted estimates. The record does not report covariate adjustment, missing-data handling, or an analysis population definition for the comparisons.

What is the role of the sample-size illustration?

The posted planning illustration uses the observed effect for the utilization outcome as its starting point. It assumes a two-sided significance level of 0.05, equal allocation, and a normal approximation. For planning for 100% of the observed effect, it lists 531 participants per arm for 80% power and 710 participants per arm for 90% power. For planning for 75% of the observed effect, it lists 980 participants per arm for 80% power and 1,312 participants per arm for 90% power. For planning for 50% of the observed effect, it lists 2,287 participants per arm for 80% power and 3,061 participants per arm for 90% power.

These are planning illustrations, not observed power and not the trial's own design justification. They are conditional on the assumptions and effect sizes used; a smaller target effect requires a larger study under those assumptions. The registry record does not report the trial's sample-size justification, and the illustration does not establish what the trial was designed to detect. It also concerns the utilization outcome, not the primary count endpoint.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and multiple secondary outcomes, but a multiplicity strategy is not reported in the registry record. When several outcomes are examined, interpreting each unadjusted p-value as if it were the only test can overstate the strength of evidence. General approaches include prespecifying an outcome hierarchy, adjusting significance thresholds, or treating secondary analyses as exploratory. The record does not indicate that any of these approaches was used, so the secondary p-values should not be treated as multiplicity-controlled confirmatory evidence.

Missing-data methods and analysis populations are also not reported in the registry record. The posted arm sizes vary by outcome: the primary summaries include 38 and 41 participants, while the failed-parathyroidectomy outcome includes 29 and 33. The registry does not explain whether those differences reflect follow-up availability, eligibility for a particular measure, missing observations, or another reason. They should not be interpreted as evidence of a particular missing-data mechanism.

The record does not report whether the analyses followed intention-to-treat, per-protocol, or another population definition, nor does it describe imputation, sensitivity analyses, or reasons for absent outcome data. These omissions matter because estimates can depend on who is included and how missing observations are handled. Randomization supports comparison of assigned groups in principle, but it does not by itself resolve missing follow-up or deviations from assigned treatment.

The registry also does not report the primary comparison test, a primary-outcome uncertainty interval, the confidence-interval level for the secondary estimates, or a full prespecified analysis plan. Consequently, the posted statistics allow a descriptive account of the recorded outcomes but a limited assessment of analytic choices. These gaps do not establish that analyses were improperly conducted; they mean that those methods cannot be evaluated from the registry record.

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 5% reporting threshold.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: pleural effusion (2.6%), neoplasms benign, malignant and unspecified (incl cysts and polyps) - other, specify (2.6%), fracture (2.4%), pericardial effusion (2.4%), syncope (2.4%).

The registry reports serious adverse events in 2 of 38 participants in the PTeye group and 5 of 41 participants in usual care. It reports no other adverse events in either group and no deaths in either group. These are descriptive counts in the recorded groups. The registry record does not provide an adjusted comparison, an uncertainty interval, or a statistical test for the serious adverse-event figures.

The serious-event terms listed include pleural effusion and a neoplasm category at 2.6% each, and fracture, pericardial effusion, syncope, and another neoplasm-category entry at 2.4% each. The record's listing does not establish that these terms were caused by the device or by surgery, and it does not give enough detail to infer a comparative risk for individual event types. Terms and percentages should be read as registry safety reporting, not as causal conclusions.

With these group sizes and event counts, the figures are useful for describing what was recorded but provide limited information about uncommon harms or differences between groups. Absence of a reported event is not proof that no such event occurred outside the recorded information. Clinical interpretation requires context about event definitions, severity, relatedness, and follow-up; those details are not reported in the registry record.

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

The primary summaries establish that both arms had a reported median of 0 frozen sections or aspirate samples sent for analysis, and both had a full range of 0 to 1. They do not establish that the distributions were identical, that the device reduced sample use, or that the groups were equivalent. A formal primary comparison and its uncertainty are not reported in the registry record. Without them, the size and precision of a primary between-arm difference cannot be assessed.

The secondary comparisons show observed differences in event proportions, but their intervals include the null values for the corresponding effect measures. The estimates therefore remain compatible with no difference as well as with differences in either direction. They do not establish that PTeye improves or worsens postoperative outcomes or healthcare use. The unadjusted analyses and unreported multiplicity plan further limit confirmatory interpretation.

Nor do these results directly answer every aim in the registry summary. The primary endpoint concerns samples sent for analysis, not operating time, costs, accuracy of gland identification, or repeat surgery. Some related secondary outcomes are listed, but detailed results for many are not reported in the registry record. A result for one endpoint cannot be assumed to apply to another.

In general, a randomized comparison can help assess effects of assigned strategies when allocation, follow-up, and analysis are suitably implemented. The record identifies randomized allocation but does not report enough detail to evaluate sequence generation, concealment, masking roles, missing-data methods, or analysis populations. These results should therefore be read as registry-reported descriptive evidence with substantial uncertainties and reporting gaps, rather than as a definitive conclusion about clinical benefit, harm, or equivalence.

13. Why This Trial Matters Statistically

This trial is statistically interesting because its primary endpoint is a low-range count summarized by a median and full range, while the reported summaries are identical across the two randomized groups. That combination illustrates an important distinction: similar descriptive summaries do not, by themselves, quantify the uncertainty around an arm contrast. A formal estimate and interval would help show which differences remain compatible with the data, but those are not reported for the primary outcome.

The study also illustrates why outcome choice matters. Sending a frozen section or aspirate for analysis is a process measure that may be relevant to intraoperative decision-making, but it is not interchangeable with clinical outcomes, procedure duration, cost, or gland identification. A trial can address several related questions, yet each outcome needs its own clear definition and analysis. The registry lists a range of secondary outcomes, but results are not available in detail for many of them.

Another statistical issue is the interpretation of secondary findings. The available comparisons have unadjusted p-values and intervals that include the null values. Those results are not proof of no difference, and they are not strong evidence of a difference. With multiple outcomes and no reported multiplicity plan, the distinction between exploratory and confirmatory evidence is especially important.

Finally, registry reporting is part of the evidence record. Missing details about the analysis plan, participant flow, missing data, and the primary contrast limit independent assessment. These are not merely technical omissions: they shape how precisely readers can interpret the estimates and how readily the findings can inform the design of future studies.

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 trial-specific limitation is that the primary outcome has arm summaries but no reported between-group estimate, uncertainty interval, or test. The matching medians and ranges are descriptive and do not quantify the precision of a treatment contrast. The distribution of individual counts is not reported, so the summaries cannot show how often participants had 0 versus 1 sample.

Several design and conduct details are not reported in the registry record, including eligibility criteria, the masking role, allocation concealment, and the trial's sample-size justification. The record does not explain the differing numbers of participants contributing to some secondary outcomes, or specify the analysis population and missing-data approach. Those gaps make it difficult to assess potential effects of incomplete follow-up or deviations from assignment.

The available secondary comparisons are unadjusted, and multiplicity handling is not reported. The outcome list spans different domains and timeframes, but detailed results are not reported in the record for many listed outcomes. The utilization comparison also has a broad uncertainty interval, which limits precision. The planning illustration is based on the observed effect for that secondary outcome; it is not evidence of the study's original design assumptions or observed power.

Finally, the safety summary provides group counts and selected event terms but does not report causal attribution, event-level clinical context, or a formal comparative analysis. These limitations do not invalidate the reported summaries. They define what can and cannot be concluded from the registry record alone.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Near Infrared Autofluorescence (NIRAF) Detection for Identifying Parathyroid Glands During Parathyroidectomy — NCT05152927.
• Registry record last updated 2025-12-15; status last verified 2025-11.
• Results first posted 2025-12-15.
• 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

NCT05152927 is a completed, randomized, single-masked, parallel-group study sponsored by the University of California, San Francisco. It enrolled 79 participants and compared intraoperative PTeye use with usual standard of care during parathyroidectomy. The primary outcome was the median number of frozen sections or aspirate samples sent for analysis, assessed by the end of surgery, up to 5 hours.

The primary median was 0 in each arm, with a full range of 0 to 1 in each. The registry record does not report a formal primary comparison. Available secondary comparisons report unadjusted estimates with intervals spanning their null values. The record does not report the multiplicity strategy, analysis populations, or missing-data methods. Findings are therefore best interpreted as descriptive, with important uncertainty and reporting gaps.