Ginger's Therapeutic Potential in Asthma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Ginger's Therapeutic Potential in Asthma (NCT03705832), a randomized early/phase 1 study. The primary outcome is Change in Tolerance to Inhaled Methacholine.

2. Clinical Question

The study was registered as an early phase 1, randomized, parallel-group trial. Its stated purpose was to study whether consuming ginger might have potential benefits for people with asthma. The primary measure was tolerance to inhaled methacholine, reported in mg/ml. Methacholine is used in a challenge test that provokes airway narrowing; the registry describes using the dose that produces a specified change in lung function to measure airway hyperresponsiveness.

The registry record also lists secondary outcomes involving serum cytokines, eosinophilia, asthma control, and asthma-specific quality of life. These outcomes address different aspects of asthma-related biology and reported health status. They do not replace the primary question, which concerns the methacholine measure at Day 28. No medical conclusion about ginger’s effects follows from the study description alone, and the primary posted results do not include an estimable between-group analysis.

3. Trial Design

This was a randomized, placebo-controlled, parallel-group study registered as early phase 1. The registry describes quadruple masking. It does not specify which groups of people were masked, so the masking label should not be expanded into assumptions about participants, clinicians, or assessors. Enrollment was 54. The study status is completed; the recorded start date is 2019-08-22 and the primary completion date is 2021-02-28.

Participants assigned to the active-drug arm were to receive 2 grams daily of Ginger Extract for 56 days. Participants assigned to placebo were to receive a matching placebo for the same period. The registry identifies Emily DiMango, MD as sponsor. It does not report additional details about how randomization was generated, whether allocation was concealed, or how adherence was assessed.

The primary endpoint was measured at baseline and Day 28. Listed secondary outcomes were assessed at baseline and Day 56, including changes in serum cytokines, eosinophilia, Asthma Control Test score, and Juniper Mini-Asthma Specific Quality of Life score. The available numerical secondary summaries cover serum cytokines, eosinophilia, and the Asthma Control Test. Numerical results for the Mini AQLQ-J are not reported in the registry record.

The primary endpoint analysis included nine active-drug participants and seven placebo participants. The record explains that methacholine testing was withheld for safety reasons when lung function was low at the study visit, and that testing was discontinued during the COVID-19 pandemic because it is an aerosol-generating procedure. The record does not describe a full participant flow or explain the analysis populations for every outcome.

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: 54 participants were enrolled and 12 participants were excluded due to: lost to follow-up, asthma controlled, lung function below threshold, on exclusionary medications, and not taking asthma medications. Eight participants were withdrawn due to an institutional COVID-19 research pause.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Nine active drug and seven placebo participants were analyzed due to: 1) low lung function at the time of the study visit (methacholine testing was withheld for safety reasons) and 2) during the COVID-19 pandemic, methacholine testing was discontinued, as it is an aerosol generating procedure.

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 Change in Tolerance to Inhaled Methacholine, measured over Baseline and Day 28.

The primary endpoint is change in tolerance to inhaled methacholine, measured in mg/ml, between baseline and Day 28. The registry describes a methacholine challenge: a participant inhales gradually increasing doses, and spirometry measures the resulting airway narrowing. The methacholine provocation dose, PD20, is used to measure change in airway hyperresponsiveness.

This measure is used because methacholine can provoke bronchoconstriction, allowing airway responsiveness to be assessed in a controlled test. It is a physiological measure, rather than a direct measure of symptoms or quality of life. The registry also lists symptom-related and biological measures among the secondary outcomes, so those outcomes address complementary questions.

The posted primary summaries report a mean of 5.3 mg/ml with a standard deviation of 15.1 for nine active-drug participants, and a mean of 24.2 mg/ml with a standard deviation of 55.9 for seven placebo participants. The registry does not provide an estimable between-group comparison for this endpoint. The posted means therefore describe the analyzed groups; they do not, on their own, establish the size or precision of a treatment contrast.

The primary analysis population was restricted because testing was withheld for safety reasons for some participants and stopped during the COVID-19 pandemic. The registry does not report the number excluded for each reason or further details about how the endpoint was derived from participant-level measurements.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What the group summaries mean. A mean is the average value within a group for a continuous outcome. A standard deviation describes how dispersed individual measurements are around that group mean. It does not show the precision of a comparison between groups. Precision for a mean difference is usually conveyed with a confidence interval, which describes the range of effects compatible with the data and the analysis assumptions. The primary endpoint has group means and standard deviations posted, but no estimable between-group interval or inferential result.

How to read the recalculated secondary comparisons. For the secondary outcomes with numerical data, the posted unadjusted recalculations compare the active-drug mean with the placebo mean. A mean difference is expressed in the outcome’s own units; its sign indicates which group has the higher mean under the stated subtraction order. The recalculated confidence interval shows uncertainty around that estimate. When an interval includes zero, the summaries do not rule out a zero difference under the calculation’s assumptions. That does not demonstrate equivalence, and it does not establish that any possible difference is clinically important.

The recalculated p-values are unadjusted. A p-value is a measure of how unusual the observed data, or data more extreme, would be under a specified null model. It is not the probability that the null hypothesis is true, nor a measure of the size or practical importance of an effect. Because these secondary comparisons are recalculated from summary statistics and are not analyses reported in the registry record, their role is descriptive and exploratory. The registry record lists no reported analyses.

Why variability matters

High variability makes group means less precise, particularly when the analyzed groups are small. The primary endpoint summaries have wide dispersion relative to their group means, and the analyzed sample counts are limited. A contrast based on a small number of highly variable observations can be uncertain. This is one reason the primary group summaries alone should not be treated as a precise estimate of the treatment contrast.

Over-dispersion, in general, means that observations vary more than a statistical model expects. Greater variability can widen uncertainty and make a study less able to distinguish a real contrast from random fluctuation. The registry record does not report a model-based assessment of over-dispersion or an analysis that adjusts for it. The reported standard deviations permit a basic description of spread, but they do not establish which statistical model is most appropriate.

Planning illustrations, not observed power

The sample-size planning illustration uses a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. It considers effects set at 100%, 75%, and 50% of the observed effect, and reports participants per arm for 80% and 90% power. These are planning scenarios based on observed effects, not the trial’s own design justification and not observed power. They should not be interpreted as evidence that the completed study had a particular probability of detecting an effect.

Planning calculations based on an observed effect can be especially uncertain when the estimate comes from a small sample. A different assumed effect leads to a different planning requirement, which is why the illustration includes several effect assumptions. The registry does not report its original sample-size justification, target power, or whether a formal sample-size calculation guided enrollment. The planning illustration cannot fill in those missing protocol details.

Analysis populations and missing measurements

The primary endpoint analysis includes nine active-drug participants and seven placebo participants. The registry attributes the limited methacholine data to safety-related withholding when lung function was low and discontinuation of testing during the COVID-19 pandemic. It does not report a missing-data method, an intention-to-treat analysis, a per-protocol definition, or sensitivity analyses. It also does not separate how many missing measurements arose for each stated reason.

Group counts differ across the available secondary outcomes. Such variation means that each endpoint’s summary describes its own analyzed participants; it should not be assumed that all outcomes used the same people. The registry does not report an explanation for every endpoint-specific count or enough information to reconstruct participant flow. No additional calculations can resolve those gaps from the posted aggregate summaries.

Finally, the registry does not report adjustment for multiple comparisons, a hierarchy among secondary endpoints, or a prespecified statistical analysis plan. The recalculated secondary p-values should therefore be understood as unadjusted. If the sponsor’s own analysis becomes available, it would take precedence over simple unadjusted recalculations when interpreting the sponsor’s analysis; the registry record currently lists no reported analyses.

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("Active Drug", "Placebo")
n   <- c(9, 7)
m   <- c(5.3, 24.2)
sp  <- c(15.1, 55.9)
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  Active Drug  9  5.300  15.100  -6.307  16.907
CARM  Placebo  7  24.200  55.900  -27.499  75.899

11. Multiplicity, Missing Data and Analysis Populations

The registry record does not report whether the study used a prespecified hierarchy for testing the primary and secondary outcomes, or whether it adjusted for multiplicity. It lists several secondary outcomes, but does not state how their results were intended to contribute to a single overall conclusion. The recalculated secondary p-values are unadjusted; interpreting each as though it were the only analysis would understate the uncertainty created by considering several outcomes.

Missingness is a notable issue for the primary methacholine endpoint. Only nine active-drug participants and seven placebo participants were analyzed. The registry explains that testing was withheld when lung function was low at the visit and that testing was discontinued during the COVID-19 pandemic because of aerosol-generation concerns. The record does not report how many participants were affected by each reason, whether missingness was related to outcome values, or how missing observations were handled statistically.

The available secondary outcomes also have different analyzed group counts. The registry does not report a complete participant flow, endpoint-specific reasons for missing data, or a common analysis-population definition. It is therefore not possible to establish from the record whether the analyses followed an intention-to-treat approach, used another defined population, or included sensitivity analyses.

The registry lists no reported analyses and does not report the statistical analysis plan. In particular, it does not describe how the primary contrast was to be estimated, how missing data or multiple outcomes were to be addressed, or whether interim analyses were planned. These items are not reported in the registry record; they should not be inferred from the descriptive summaries or the recalculated secondary comparisons.

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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: coronavirus disease 2019 (covid-19) (8.3%).

The safety summaries report serious adverse events in zero of 20 participants at risk in the active-drug group and one of 12 participants at risk in the placebo group. The record reports no deaths in either group. It also reports one other adverse event in each group, among the same respective counts at risk.

The registry lists Coronavirus Disease 2019 (COVID-19) as the top serious adverse event term, with a reported frequency of 8.3%. The record does not establish a causal relationship between the event and either study assignment. These counts describe what was recorded during the trial; they do not, by themselves, establish comparative safety.

The groups are small, and the event counts are sparse. With so few events, the summaries provide limited information about how event rates might compare beyond the participants observed. The registry record does not provide additional detail about event timing, severity beyond the serious classification, or relatedness assessments. The adverse-event figures should therefore be read descriptively and in the context of the limited study size.

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

The registry record establishes that this randomized, placebo-controlled study was completed and that descriptive results were posted for a subset of participants. It does not establish a precise between-group effect on the primary methacholine endpoint: the record includes group means and standard deviations, but no estimable primary comparison. The primary results therefore cannot answer how large or how certain a difference between groups may have been.

The recalculated secondary estimates provide additional, but limited, information. Their confidence intervals include zero, and the calculations are unadjusted. They neither prove the absence of effects nor establish a reliable benefit or harm. Numerical results are not reported in the registry record for every listed secondary outcome.

The findings do not show that ginger extract works or does not work for asthma. They also do not establish that the groups are equivalent. A failure to report an estimable primary comparison is not the same as demonstrating no difference. A small analyzed sample and substantial variability make precise conclusions especially difficult.

The appropriate reading is bounded by the record: it describes a completed early phase 1 study, its treatment schedules, its limited primary analysis population, and some secondary summaries. It does not report the original statistical plan, the handling of missing data, or a sponsor-reported analysis. These omissions prevent a fuller assessment of how the analyses were planned and whether the posted summaries capture all intended comparisons.

14. Why This Trial Matters Statistically

This trial illustrates why enrollment and endpoint-specific analysis counts must be distinguished. Enrollment was 54, while the primary methacholine summaries involve nine active-drug participants and seven placebo participants. Those different counts affect how much information is available for the primary question. The registry explains why methacholine measurements were unavailable for some participants, but does not provide a complete accounting of missing measurements.

It also demonstrates the difference between descriptive group summaries and an inferential comparison. Means and standard deviations characterize the observed groups, but they do not supply a confidence interval for the contrast. Without an estimable primary comparison, readers cannot assess the precision of the treatment contrast from the registry record. This is a central distinction when interpreting clinical trial results.

The secondary outcomes show another important statistical issue: a set of unadjusted comparisons does not automatically provide confirmatory evidence. Multiple outcomes create multiple opportunities to observe apparent differences, and the record does not report a multiplicity strategy. The recalculated comparisons are useful as exploratory descriptions, but they cannot substitute for a reported prespecified analysis.

Finally, the sample-size illustration is a planning aid, not evidence about the trial’s observed power or original design. By presenting several assumed effect sizes, it emphasizes that planning depends on what effect a future study aims to detect. The registry does not report its original sample-size justification. Taken together, the record makes clear why transparent analysis plans, complete outcome reporting, and explicit missing-data methods matter for interpreting small clinical trials.

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 primary endpoint has no estimable between-group analysis in the registry record. The reported means and standard deviations describe the analyzed groups but do not provide a confidence interval or inferential result for the primary contrast. This prevents a direct assessment of its magnitude and precision.

The primary analyzed population is limited to nine active-drug and seven placebo participants, compared with enrollment of 54. The registry attributes missing methacholine testing to safety-related withholding when lung function was low and to discontinuation during the COVID-19 pandemic. It does not report counts for each reason, a complete participant flow, or methods for addressing missing data. The resulting analyzed groups may not represent all enrolled participants.

Endpoint-specific group counts vary among the secondary summaries. The record does not explain every difference in those counts, and numerical results are not reported for the listed Mini AQLQ-J outcome. The available secondary comparisons are recalculated and unadjusted; the record lists no reported analyses and does not report a multiplicity approach.

Other design and analysis details are not reported in the registry record, including the statistical analysis plan, original sample-size justification, randomization-generation method, allocation concealment, and adherence assessment. Although the registry labels masking as quadruple, it does not specify who was masked. The study’s small analyzed groups and variability further limit precision. These gaps should be treated as limits on interpretation rather than filled by assumptions about the protocol.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Ginger's Therapeutic Potential in Asthma — NCT03705832.
• Registry record last updated 2023-03-27; status last verified 2023-03.
• Results first posted 2023-03-27.
• 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

NCT03705832, titled Ginger's Therapeutic Potential in Asthma, is registered as a completed early phase 1 randomized, quadruple-masked, parallel-group study. Enrollment was 54. The recorded start date is 2019-08-22, and primary completion was 2021-02-28. The sponsor is Emily DiMango, MD.

The active-drug group was assigned Ginger Extract at 2 grams daily for 56 days; the comparator group received matching placebo for 56 days. The primary outcome was change in tolerance to inhaled methacholine from baseline to Day 28. The primary summaries include nine active-drug and seven placebo participants, with testing unavailable for safety-related and pandemic-related reasons described in the record.

The registry lists secondary outcomes involving cytokines, eosinophilia, asthma control, and asthma-specific quality of life. Numerical summaries are available for three of these outcomes. No registry-reported analyses are listed, and an estimable between-group comparison is not reported for the primary endpoint.