Effects of Broccoli Sprout Extract on Allergy Rhinitis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of Broccoli Sprout Extract on Allergy Rhinitis (NCT02885025), a randomized phase 2 study. The primary outcome is Total Nasal Symptom Score (TNSS) Change From Baseline to 3 Weeks of Randomly Assigned Treatment.

2. Clinical Question

The trial asked whether broccoli sprout extract was associated with a change in nasal symptoms over 3 weeks of randomly assigned treatment among people with allergic rhinitis to grass. It also compared treatment combinations that paired the extract or its placebo with nasal fluticasone or normal saline. The registry describes an intent-to-treat population consisting of participants assigned to one of the four groups.

The registry summary places the question in the context of allergic symptoms and possible exposure to grasses combined with pollution. That context motivates studying an antioxidant-containing supplement, but it does not establish what effect the trial would find. The posted results should be read as descriptive arm-level changes rather than a definitive estimate of the extract’s effect.

3. Trial Design

This was a randomized, triple-masked, parallel-group phase 2 trial. Participants were assigned among four combinations: broccoli sprout extract with nasal fluticasone; broccoli sprout extract with normal saline nasal spray; placebo pill with nasal fluticasone; and placebo pill with normal saline nasal spray. The registry lists total enrollment as 47. The primary outcome describes an intent-to-treat population made up of everyone assigned to one of the four groups.

The registry lists the trial status as completed, with a start date of 2016-10-01 and primary completion on 2019-03-12. It identifies the VA Office of Research and Development as sponsor. The masking designation is triple, but which specific trial roles were masked is not reported in the registry record. Details of the randomization sequence, allocation concealment, and implementation are also not reported in the registry record.

The factorial-looking arrangement of supplement and nasal spray combinations makes it possible to consider the extract alongside two nasal-spray regimens. However, the registry’s posted primary results are arm-level summaries, not estimates of a main effect for the supplement, an interaction between treatments, or pairwise contrasts. The exact planned comparison structure and the statistical model are not reported in the registry record. The record does not describe treatment duration beyond the primary outcome’s 3-week timeframe, nor does it explain the timing or adherence procedures for each intervention.

The listed arm counts for the primary outcome are 16, 12, 9, and 8, respectively. Those endpoint counts are not identical across all four groups, and the registry does not explain the difference between the listed enrollment total and the arm-level outcome counts. The reasons for any unavailable outcomes or exclusions are not reported in the registry record. These details matter when interpreting how representative the posted arm-level summaries may be of everyone randomized.

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: intent to treat population (all participants assigned to 1 of the 4 groups above).

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.

Population: A total of 47 subjects had a positive reaction to the up dose grass allergen challenge that began with 75 subjects.

6. Primary Endpoint

The registry lists the primary outcome as Total Nasal Symptom Score (TNSS) Change From Baseline to 3 Weeks of Randomly Assigned Treatment, measured over measures at various points following challenge at baseline and 21 days.

The primary endpoint is change in the Total Nasal Symptom Score (TNSS) from baseline to 3 weeks of randomly assigned treatment. The registry describes symptom assessment following challenge at baseline and 21 days. Participants rate four symptoms: nasal congestion or postnasal drainage, nasal pruritus, rhinorrhea, and sneezing. Each symptom is scored from 0 to 3, where 0 means no symptoms and 3 means severe symptoms that interfere with activity and nighttime sleep. The total score can range from 0 to 12, and a higher score corresponds to greater rhinitis activity.

A summed symptom score is useful because it combines several patient-reported features into one measure that can be followed over time. A change score expresses how the score at follow-up differs from the baseline score. In this trial, the registry reports the mean change and standard deviation for each arm. A negative change is consistent with a lower score at follow-up than at baseline on average; it does not, by itself, show that one treatment combination produced a different change from another.

The score is a symptom measure, not a direct measure of inflammation or a cytokine outcome. The registry also names six secondary outcomes involving interleukins, but those are distinct from the primary symptom endpoint. The timing and full measurement procedures beyond the registry’s description are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: it is a numerical score, and the registry specifies a mean as the summary measure with a standard deviation as its measure of spread. A mean describes the group’s average change. A standard deviation describes how much individual changes vary around that average; it is not a confidence interval and does not directly quantify how precisely the mean or a treatment contrast has been estimated.

For a randomized trial, the central statistical question is usually a contrast between groups, not whether each group changed from its own baseline. A contrast would estimate how much the average change differs between specified treatment groups. Its interpretation depends on which groups are compared and how the analysis handles the trial’s design. The registry record posts arm-level summaries but does not report an estimate or uncertainty interval for a primary between-group contrast.

What does a confidence interval add?

General statistical explanation: a confidence interval communicates the range of effect estimates compatible with the data and the statistical procedure used. Its width reflects precision: a wider interval indicates less precision than a narrower interval. An interval is most informative when paired with a clearly defined contrast and analysis plan. No confidence interval for the primary comparison is reported in the registry record, so the precision of a comparative treatment effect cannot be assessed from the posted primary results.

Why does the four-group structure matter?

The four groups combine two supplement assignments with two nasal-spray assignments. General statistical explanation: in a design with multiple treatment components, investigators may estimate component effects, compare particular combinations, or evaluate whether the effect of one component depends on the other. These are different questions and may require different contrasts or models. The registry does not report the planned primary contrast, an interaction analysis, or a model specification. It is therefore not possible to identify from the record which comparative estimand was intended.

The outcome is a change score, and the posted arm summaries give mean change and standard deviation. General statistical explanation: a change-score analysis compares the average changes between randomized groups. Other approaches, such as modeling follow-up scores while accounting for baseline scores, can answer a related question but may have different assumptions and precision. The registry does not report whether any such approach was used. No adjusted analysis is posted.

What does over-dispersion mean for these results?

General statistical explanation: over-dispersion occurs when observed variability is greater than a model assumes. It can make standard errors too small and statistical evidence appear stronger than warranted if the model does not account for the extra variability. This concept is especially relevant to outcomes modeled as counts or rates. TNSS is reported as a continuous score with a mean and standard deviation, and the registry does not describe a model or a finding of over-dispersion. It would not be appropriate to infer that over-dispersion occurred in this trial.

The registry’s planning description refers to sample-size illustrations based on the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes planning for a stated fraction of the observed effect. These are planning illustrations, not observed power and not evidence that the trial was designed around those assumptions. The registry does not report its original sample-size justification, the effect size used in the trial’s design, or whether the planning illustrations reflect the protocol’s assumptions. Because no two-arm primary estimate is posted, the comparative effect and its uncertainty cannot be reconstructed from the registry record.

The record lists no analyses for the outcome comparison and flags the continuous two-arm comparison as missing or not estimable. General statistical explanation: a non-estimable comparison may result when the necessary contrast data or analysis output is unavailable, but the reason cannot be determined without further information. The registry does not explain why the comparison is absent. The arm-level mean and spread remain descriptive summaries, but they cannot substitute for the missing comparative analysis.

Interpretation also depends on the analysis population and handling of missing measurements. The outcome description identifies an intent-to-treat population, but the registry does not explain whether every assigned participant contributed an endpoint value, how missing measurements were handled, or whether the posted arm counts reflect missing observations. These details affect which participants are represented in the summaries and the assumptions needed to interpret a treatment contrast.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("BSE + Nasal Fluticasone", "BSE + Normal Saline Nasal Spray", "Placebo Pill + Nasal Fluticasone", "Placebo Pill + Normal Saline Nasal Spray")
n   <- c(16, 12, 9, 8)
m   <- c(-0.5277, -0.5484, -0.8359, -0.181)
sp  <- c(0.1048, 0.0014, 0.3903, 0.0846)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  BSE + Nasal Fluticasone  16  -0.528  0.105  -0.584  -0.472
CARM  BSE + Normal Saline Nasal Spray  12  -0.548  0.001  -0.549  -0.548
CARM  Placebo Pill + Nasal Fluticasone  9  -0.836  0.390  -1.136  -0.536
CARM  Placebo Pill + Normal Saline Nasal Spray  8  -0.181  0.085  -0.252  -0.110

11. Multiplicity, Missing Data and Analysis Populations

The registry lists six secondary outcomes: interleukin 5, interleukin 4, interleukin 6, interleukin 8, interleukin 13, and interleukin 1 Beta. It also reports eight outcome measures overall. No secondary-outcome analysis results are posted in the record, and it does not describe a plan for controlling multiplicity across outcomes or treatment contrasts. When several outcomes or comparisons are examined, general statistical explanation: the chance of finding at least one apparently unusual result can increase unless the analysis plan addresses multiple testing. The record does not state whether any adjustment or hierarchy was planned.

The primary outcome description names the intent-to-treat population as all participants assigned to one of the four groups. However, the arm-level outcome counts are 16, 12, 9, and 8, and the registry does not explain why those counts differ from one another or from total enrollment. The record does not report how many endpoint measurements were missing, why they were missing, whether any imputation was used, or how missingness was handled in an analysis.

The statistical analysis plan, including any prespecified primary contrast, covariate adjustment, sensitivity analysis, or interim analysis, is not reported in the registry record. The record also does not explain whether the listed intent-to-treat definition was applied to the posted arm summaries. These omissions limit assessment of whether the reported summaries reflect the planned analysis and how robust a treatment comparison would be to missing data or multiple testing.

12. 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 registry reports serious adverse events for each group. The number affected by a serious adverse event is 0 in all four groups. The corresponding numbers at risk are 16, 14, 9, and 8. No deaths are reported in any group, and no serious adverse-event terms are listed.

These figures describe what the registry reports for the recorded groups; they do not establish that no serious events occurred beyond the trial’s recorded observation or reporting. The record does not give further details about safety surveillance, the observation period for these events, or how serious events were defined. The at-risk counts for the safety summary differ from some of the primary-outcome arm counts, and the registry does not explain the difference.

The registry also reports other adverse events affecting 3, 4, 0, and 2 participants across the four groups, respectively. These are counts, not comparative risk estimates. Without a stated analysis, uncertainty intervals, event descriptions, or information about follow-up and ascertainment, they should be read as descriptive safety counts rather than evidence of a difference between regimens. No medical conclusion about safety can be drawn from these counts alone.

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

The posted primary results show that the mean TNSS change was negative in each randomized group. This describes lower follow-up scores on average relative to baseline in all four arms. The registry does not report a two-arm comparison, confidence interval, or p-value for the primary outcome, so it does not establish how the observed changes differed between treatment combinations or how precisely any comparative effect was estimated.

The results do not isolate the effect of broccoli sprout extract from the effect of the nasal spray. The four treatment combinations could support several distinct comparisons, but the registry does not identify a primary contrast or report a model that separates the treatment components. Within-group changes alone cannot answer whether a change was caused by an assigned intervention.

The outcome is a symptom score, not a direct measurement of the interleukins listed as secondary outcomes. Those secondary outcomes are not accompanied by posted analyses in the registry record. The primary findings therefore do not establish a biological mechanism, and the record does not permit conclusions about the secondary measures.

The registry’s reported enrollment and endpoint counts also leave uncertainty about who contributed to the arm summaries. It does not explain the differences in counts or describe missing-data methods. This limits assessment of how representative the means are of all randomized participants.

In short, the record supports a descriptive account of arm-level symptom-score changes and adverse-event counts. It does not supply the comparative statistical evidence needed to determine the direction, magnitude, or precision of a treatment effect. The findings should not be interpreted as showing that broccoli sprout extract does or does not improve allergic rhinitis.

14. Why This Trial Matters Statistically

This trial is statistically interesting because it combines a supplement assignment and a nasal-spray assignment in four randomized groups. That structure can distinguish several questions, but each requires a clearly defined comparison. A contrast of extract with placebo under one nasal-spray regimen is not the same question as a contrast under the other regimen, and neither is identical to an overall estimate across regimens. The registry does not report which contrast was intended as primary.

The posted primary outcome is a patient-rated symptom score measured over time. Reporting mean change and standard deviation gives a useful descriptive view of each group, but the central randomized-trial inference concerns between-group differences and their uncertainty. The absence of a posted comparison highlights why arm-level summaries alone are not enough to assess a treatment effect.

The registry also illustrates the importance of linking the stated analysis population to the actual endpoint counts. The primary outcome description identifies an intent-to-treat population, while the listed arm counts differ. Without reasons for those counts or a missing-data description, readers cannot fully assess which randomized participants are represented in the outcome summaries.

Finally, the presence of multiple secondary cytokine outcomes makes a prespecified multiplicity plan relevant to interpretation. The registry does not report such a plan or analyses for those outcomes. These are not merely reporting details: they determine which statistical question is being answered, how much uncertainty surrounds the answer, and how broadly results can be interpreted.

15. 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 registry record does not report the primary between-group estimate, its confidence interval, or a p-value. As a result, the comparative effect and its precision cannot be assessed from the posted primary results. The record also does not report which of the possible comparisons across the four treatment combinations was prespecified as primary.

Although the endpoint description defines an intent-to-treat population, the arm-level outcome counts are 16, 12, 9, and 8. The registry does not explain the difference between these counts and total enrollment or describe missing outcome data, exclusions, or imputation. It also does not provide baseline TNSS summaries by arm, which would help characterize the groups’ starting scores.

Details of the analysis model, covariate adjustment, treatment-by-treatment interaction assessment, sensitivity analyses, and any interim analyses are not reported in the registry record. The record does not provide the original sample-size justification. Its planning description refers to illustrations based on the observed effect, but those illustrations do not replace a documented design rationale or a comparative result.

The masking designation is triple, but the roles that were masked and the procedures used to maintain masking are not reported. The randomization method and allocation concealment are also not described. The record names secondary cytokine outcomes but does not post their analyses or a multiplicity plan. Safety details beyond the event counts, including the observation period and event definitions, are not reported.

These limitations concern what can be learned from the registry record; they do not establish that the underlying trial lacked procedures or analyses. They mean that those procedures and comparative results cannot be evaluated from the information recorded there.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Effects of Broccoli Sprout Extract on Allergy Rhinitis — NCT02885025.
• Registry record last updated 2020-06-19; status last verified 2020-05.
• Results first posted 2020-06-19.
• 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.

19. Record Summary

The registry identifies NCT02885025 as a completed randomized, triple-masked, parallel-group phase 2 trial sponsored by the VA Office of Research and Development. Total enrollment is 47. The four groups paired broccoli sprout extract or placebo with nasal fluticasone or normal saline nasal spray.

The primary endpoint was change in TNSS from baseline to 3 weeks of randomly assigned treatment. The registry posts arm-level means and standard deviations, with negative mean changes in all four groups, but no two-arm primary comparison. Six secondary interleukin outcomes are listed, without posted analyses. Serious adverse events and deaths are reported as 0 in every group; other adverse-event counts are reported by group.

The registry does not report the comparative analysis, missing-data handling, multiplicity plan, or several details needed to evaluate the design and analysis. The posted results therefore support descriptive interpretation of arm summaries, not a precise comparative conclusion.