This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for A Randomized, Single Centre, Double-blind, Parallel, Sham-controlled Pilot Study Using gammaCore®-G (NCT02388269), a randomized na study. The primary outcome is Symptom Changes in Subjects With Functional Gastrointestinal Disorder (Functional Dyspepsia and Irritable Bowel Syndrome).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02388269 |
| Phase | NA |
| Condition | Dyspepsia, Irritable Bowel Syndrome |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 91 |
| Arms in the primary outcome | n/a |
| Lead sponsor | ElectroCore INC |
| Results posted | Yes |
2. Clinical Question
Population
People with functional dyspepsia or irritable bowel syndrome were eligible for the study. The primary outcome description identifies the intention-to-treat population. The registry record reports enrollment of 91 participants, but does not report the diagnostic breakdown of the enrolled population or further eligibility details in the information available for this trial.
Intervention
The active intervention was gammaCore®-G, a non-invasive vagus nerve stimulation device. The arm description says that the device was applied to the skin on both sides of the neck, with two stimulations performed on one side before stimulation on the other. Further details of the application description are incomplete in the registry record.
Comparator
The comparator was a sham device. The registry describes it as a hand-held portable device designed to resemble the active device in appearance, weight, feedback, application and controls. Its description says that it delivered a low-frequency signal that could be felt as tingling. The brief study summary characterizes the sham as inactive.
Primary question
The study asked whether symptom changes during the randomized period differed between the active-device and sham groups. The registry describes the primary outcome as symptom change for functional dyspepsia and irritable bowel syndrome, assessed over the last 2 weeks of the 4 week randomized period. It does not report a primary-outcome comparison or its uncertainty.
3. Trial Design
This was a randomized, single-centre, double-blind, parallel, sham-controlled pilot study of gammaCore®-G. The registry lists the allocation as randomized, the model as parallel, and masking as triple. The brief summary describes two parallel groups: active treatment and sham treatment. The study enrolled 91 participants with functional dyspepsia or irritable bowel syndrome and is marked completed. The registry dates the study start to 2014-06 and primary completion to 2015-05.
The intervention was a device rather than a drug. The active-device arm description concerns application to the right and left sides of the neck. The sham device was described as similar in look, weight, feedback, application and control, with a low-frequency signal that could be perceived as tingling. Those details help characterize the intended comparison, but the registry record does not report how well masking was maintained or whether participants or investigators correctly identified group assignment.
The primary outcome timeframe was the last 2 weeks in the 4 week randomized period. A secondary outcome refers to symptom change at 8 weeks compared with 4 weeks, but the registry record does not provide results for that comparison. It also lists quality of life, symptom frequency, concomitant medication use and adverse events among secondary outcomes. The study title calls the investigation a pilot study; the registry record does not report a protocol rationale for the pilot design or a sample-size justification.
The registry does not report the number randomized to each group for the primary analysis, participant flow, adherence, withdrawals or treatment exposure. Safety entries are presented for four groups divided by condition and active or sham assignment; those entries should not be treated as a substitute for an account of participant flow or the primary-outcome analysis.
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
| Stage | gammaCore®-G | gammaCore®-G Sham | Not Randomised |
|---|---|---|---|
| STARTED | 41 | 40 | 10 |
| Randomised Period | 41 | 40 | 0 |
| Open Label | 37 | 38 | 0 |
| COMPLETED | 32 | 38 | 0 |
| NOT COMPLETED | 9 | 2 | 10 |
Reasons for not completing this period:
| Reason | gammaCore®-G | gammaCore®-G Sham | Not Randomised |
|---|---|---|---|
| Adverse Event | 2 | 0 | 0 |
| Withdrawal by Subject | 1 | 2 | 0 |
| less than 50% stimulations | 1 | 0 | 0 |
| no diary data | 3 | 0 | 0 |
| Protocol Violation | 2 | 0 | 0 |
| Screen Failure | 0 | 0 | 10 |
Analysis population for the primary outcome, as defined in the registry: Intention To Treat population (ITT)
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.
| Characteristic | Unit | gammaCore®-G Functional Dyspepsia | gammaCore®-G Sham Functional Dyspepsia | gammaCore®-G Irritable Bowel Syndrome | gammaCore®-G Sham Irritale Bowel Syndrome | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 20 | 20 | 21 | 20 | 81 | |
| Age, Continuous | years | 40.6 (SD 14.39) | 33.9 (SD 12.01) | 40.1 (SD 13.78) | 41.1 (SD 16.84) | 38.9 (SD 14.4) |
| Sex: Female, Male: Female | Participants | 13 | 12 | 16 | 15 | 56 |
| Sex: Female, Male: Male | Participants | 7 | 8 | 5 | 5 | 25 |
| Race/Ethnicity, Customized: white | Participants | 18 | 16 | 20 | 16 | 70 |
| Race/Ethnicity, Customized: black | Participants | 0 | 2 | 0 | 4 | 6 |
| Race/Ethnicity, Customized: asian | Participants | 2 | 1 | 1 | 0 | 4 |
| Race/Ethnicity, Customized: other | Participants | 0 | 1 | 0 | 0 | 1 |
| Region of Enrollment: United Kingdom | Participants | 20 | 20 | 21 | 20 | 81 |
6. Primary Endpoint
The registry lists the primary outcome as Symptom Changes in Subjects With Functional Gastrointestinal Disorder (Functional Dyspepsia and Irritable Bowel Syndrome), measured over Last 2 weeks in the 4 week Randomized period.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary outcome is described as symptom change in people with functional dyspepsia or irritable bowel syndrome. It is a patient-reported symptom measure, intended to capture how severe symptoms were over a retrospective period. For functional dyspepsia, the Global Overall Symptom scale uses a 7-point Likert scale, from 1 for no problem to 7 for very severe problem. It assesses 10 upper gastrointestinal symptoms, and the record states a total range from 10 to 70.
For irritable bowel syndrome, the registry describes a five-question severity score covering abdominal pain, days with pain, abdominal distension, satisfaction with bowel movements and interference with general life. Each question ranges from 0, not severe, to 100, severe; the stated total ranges from 0 to 500. These condition-specific measures use different content and scales, so their raw scores are not directly interchangeable.
Patient-reported symptom measures can capture experiences that may not be represented by a laboratory or clinical examination. However, the registry record does not explain how the two condition-specific measures were combined or compared for the primary analysis. It identifies the intention-to-treat population and specifies the last 2 weeks in the 4 week randomized period, but does not report group means, standard deviations, a treatment contrast or a result. The intended question is therefore identifiable, while the observed magnitude and precision of any difference are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies a randomized comparison of gammaCore®-G with a sham device and specifies symptom change as the primary outcome. It does not report numerical primary-outcome results. In particular, the registry record does not report group means, standard deviations, a between-group estimate, a confidence interval or a significance test for the primary outcome. The posted record therefore does not establish the direction, size or precision of a difference in symptom change between the groups.
The primary measure is not a single common score across both conditions: the registry describes one scale for functional dyspepsia and another for irritable bowel syndrome, with different score ranges and item content. It also notes that the primary outcome has several categories or time points and is not reduced to one comparison. Without the analysis details and the corresponding estimates, a reader cannot tell whether results were assessed separately by condition, combined in another way, or reported across multiple outcome categories. The registry record does not report that information.
General statistical interpretation: an estimated treatment contrast describes the observed difference between groups for a specified outcome and analysis. A confidence interval describes the range of values compatible with the estimate under the model and its assumptions; it communicates precision as well as direction. A significance test addresses compatibility with a specified null hypothesis, but a p-value alone would not convey the size or practical importance of an effect. None of these primary-outcome quantities is reported in the registry record, so no conclusion about the statistical evidence or its precision can be drawn from this record.
The word pilot describes the study as registered, but does not itself establish whether the study was intended to estimate an effect, assess procedures, or address another objective. The record does not report its design rationale, target effect, sample-size justification or prespecified decision criteria. Enrollment of 91 participants gives the recorded study size, but does not by itself show whether the primary comparison was adequately precise.
Safety entries report no serious adverse events in the four listed groups, alongside counts of participants with other adverse events. These are descriptive registry entries and do not supply a full comparative safety analysis. The record also does not report inferential comparisons for the secondary outcomes. Overall, it documents a randomized pilot design and planned symptom assessment, but not enough outcome data to interpret treatment effects statistically.
9. Statistical Methods Explained
What does a mean describe?
The primary outcome specifies a mean as its summary measure and standard deviation as its measure of dispersion. A mean represents the arithmetic average of the recorded scores within a group. It can provide a compact summary of a continuous measure, but does not show the full distribution of individual scores. The standard deviation describes how spread out scores are around the group mean. It is not the same as the uncertainty around the estimated mean or around a difference between groups.
General statistical explanation: a treatment comparison would usually require a defined contrast between groups, such as a difference in mean change, together with an uncertainty estimate. The outcome description names symptom changes, but the registry record does not report the numerical group summaries, the contrast, or the method used to estimate it. It is therefore not possible to establish from the record whether the comparison used change from baseline, an endpoint score, an adjusted model or another approach.
Why does the outcome scale matter?
The functional dyspepsia and irritable bowel syndrome measures do not use the same items or score ranges. The former is described as a 10-symptom total from 10 to 70, while the latter is a five-question total from 0 to 500. A score difference has meaning only in relation to the instrument and condition being measured. A one-unit change on one measure should not be assumed to carry the same interpretation as a one-unit change on the other. The registry record does not report a method for combining the measures or a common clinical interpretation of change.
General statistical explanation: if a continuous outcome is analyzed with a model that assumes a particular distribution or error structure, the quality of the estimate depends in part on whether those assumptions are reasonable. The registry record does not report the model, diagnostics, transformations, or handling of unusual values for the primary outcome. No specific assumption check can therefore be assessed.
What does randomization contribute?
Random allocation is intended to make treatment groups comparable on average at the start of a study, including for characteristics that are measured and those that are not. It supports a causal comparison when the allocation is implemented as planned and participants are analyzed appropriately. Randomization does not guarantee that the realized groups are identical, especially in a pilot study, and it does not remove the need to report participant flow, baseline characteristics, adherence and outcome data.
The registry reports randomized allocation and an intention-to-treat population for the primary outcome. The record does not report the allocation procedure, concealment details, baseline balance, the number analyzed for each outcome, or the precise intention-to-treat definition. It also does not report how missing outcome observations were handled. These omissions limit assessment of how the randomized comparison was carried out.
How should the planned power illustrations be read?
General statistical explanation: power is the probability that a specified analysis will detect an effect of a specified size, under the assumptions used for planning. It is not a measure of whether a result is true, and it is not a post-study probability that the observed result is meaningful. A sample-size calculation is a planning exercise, not evidence that an observed effect was present.
The registry’s planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation. They describe effects to detect as stated fractions of an observed effect. These assumptions are planning illustrations, not the trial’s own documented design justification. The registry record does not report a sample-size justification from the investigators. Such calculations should not be called observed power, and the assumptions alone cannot substitute for the missing primary-outcome estimate and its uncertainty.
For a continuous endpoint, the amount of information depends on the number of participants with usable outcome data and the variability of the measure. General statistical explanation: more variable outcomes typically make a group contrast less precise when other design features are held constant. The registry record does not report the primary-outcome standard deviations or analysis sample sizes, so precision cannot be evaluated from those components.
What can be inferred from the record?
The record supports description of the randomized, parallel, sham-controlled design and the stated outcome instruments and timeframe. It does not report a statistical analysis plan, a primary-outcome estimate, a confidence interval, a p-value, or details of model specification. The record lists 7 outcome measures, but it does not report how multiplicity was addressed. No statistical test or adjustment should be inferred from the mean and standard deviation summary labels alone.
General statistical explanation: when multiple outcomes, time points or subgroups are examined, the chance of finding at least one apparently notable result can increase if all are treated as independent confirmatory tests. Prespecifying a primary analysis and describing any adjustment or hierarchy can help readers interpret a family of results. The registry record does not provide such a plan or a complete set of results with which to assess it. As a result, the statistical evidence for the primary question remains unquantified.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 7 outcome measures, including quality of life, symptom frequency, concomitant medication use, symptom change at 8 weeks compared with 4 weeks, and adverse events. The Short-Form Leeds Dyspepsia Questionnaire outcome appears twice in the listed entries. The primary outcome description also encompasses condition-specific symptom measures and several outcome categories or time points; the registry notes that it was not reduced to one comparison. These features make it important to know which comparisons were planned as primary and how secondary comparisons were to be interpreted.
The registry record does not report a multiplicity strategy, such as a hierarchy of tests or an adjustment for multiple comparisons. It also does not report an analysis plan that would clarify the role of each outcome or time point. Without a full set of estimates and a stated strategy, the risk of selective emphasis across multiple results cannot be evaluated from the record.
The primary outcome identifies the intention-to-treat population, but does not report a detailed definition of that population or the number of participants contributing data to each analysis. The registry record does not report missing-data counts, reasons for missingness, imputation, sensitivity analyses, or how participants who discontinued treatment were handled. It also does not report whether all randomized participants were included in each outcome analysis. These details matter because an analysis based only on participants with observed outcomes may differ from an analysis that accounts for missing observations.
Consequently, the population label alone is not enough to reconstruct the analysis. The registry record does not report the analysis populations for the secondary outcomes or the methods used to handle incomplete data.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| gammaCore®-G FD | 0 | 20 | 0.0% |
| gammaCore®-G Sham FD | 0 | 20 | 0.0% |
| gammaCore®-G IBS | 0 | 21 | 0.0% |
| gammaCore®-G Sham IBS | 0 | 20 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| gammaCore®-G FD | 0 of 20 |
| gammaCore®-G Sham FD | 0 of 20 |
| gammaCore®-G IBS | 0 of 21 |
| gammaCore®-G Sham IBS | 0 of 20 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| gammaCore®-G FD | 15 of 20 |
| gammaCore®-G Sham FD | 13 of 20 |
| gammaCore®-G IBS | 16 of 21 |
| gammaCore®-G Sham IBS | 16 of 20 |
Most frequent non-serious adverse event terms
| Event term | Organ system | gammaCore®-G FD | gammaCore®-G Sham FD | gammaCore®-G IBS | gammaCore®-G Sham IBS |
|---|---|---|---|---|---|
| Headache | Nervous system disorders | 5 of 20 | 4 of 20 | 5 of 21 | 5 of 20 |
| Skin Irritation | Skin and subcutaneous tissue disorders | 1 of 20 | 3 of 20 | 3 of 21 | 4 of 20 |
| Dizziness | Nervous system disorders | 1 of 20 | 5 of 20 | 2 of 21 | 2 of 20 |
| Influenza | Infections and infestations | 1 of 20 | 2 of 20 | 3 of 21 | 3 of 20 |
| Back Pain | Musculoskeletal and connective tissue disorders | 2 of 20 | 2 of 20 | 2 of 21 | 1 of 20 |
| MuscleTwitching | Musculoskeletal and connective tissue disorders | 0 of 20 | 2 of 20 | 1 of 21 | 2 of 20 |
| Neck pain | Musculoskeletal and connective tissue disorders | 1 of 20 | 1 of 20 | 2 of 21 | 1 of 20 |
| Rash | Skin and subcutaneous tissue disorders | 1 of 20 | 2 of 20 | 1 of 21 | 1 of 20 |
| Toothache | Gastrointestinal disorders | 1 of 20 | 0 of 20 | 2 of 21 | 1 of 20 |
| Myalgia | Musculoskeletal and connective tissue disorders | 1 of 20 | 2 of 20 | 0 of 21 | 1 of 20 |
The registry reports safety figures in four groups: gammaCore®-G FD, gammaCore®-G Sham FD, gammaCore®-G IBS and gammaCore®-G Sham IBS. For each group, it lists participants at risk and participants affected by serious and other adverse events. The serious-event counts are 0 in each listed group, and the death count is 0 in each listed group. The number of participants at risk is listed separately for every group.
These entries are counts, not estimates of comparative risk. The registry record does not report a statistical comparison of serious events between active and sham groups, nor does it provide a confidence interval for those counts. A zero count in a study group means that no serious event was recorded for that group in the posted safety data; it does not establish that an event is impossible or that rare events have been ruled out.
The record also lists participants affected by other adverse events in each group. Those counts do not identify event severity, timing, duration, relationship to the device or whether participants experienced more than one event. The listed adverse-event terms do not include serious-event terms. The registry record does not report the additional detail needed to characterize the nature or clinical course of these events.
Safety interpretation should therefore remain descriptive: the posted record gives group-specific counts, but does not provide a comprehensive comparative analysis or enough detail to assess event patterns.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized, parallel, sham-controlled pilot study of gammaCore®-G was conducted in people with functional dyspepsia or irritable bowel syndrome. It documents a planned patient-reported symptom outcome over the last 2 weeks of the 4 week randomized period and identifies an intention-to-treat population. It also describes the sham device and lists secondary outcomes and safety counts.
Those design details do not establish whether symptoms changed more in one group than the other. The registry record does not report primary-outcome group summaries, a between-group estimate, a confidence interval or a p-value. It also does not report how the two condition-specific scales were analyzed together or separately. The result, its direction, size and precision are therefore not reported in the registry record.
The record’s safety data include zero serious adverse events and zero deaths in each listed group. Those counts are useful descriptive information, but they do not establish an absence of risk or support a precise comparison of safety between groups. Other adverse-event counts are listed, while event-level details and a statistical safety analysis are not reported.
General statistical explanation: a randomized design can support a fair comparison, but interpretation also depends on outcome reporting, analysis methods, completeness of follow-up and uncertainty estimates. A pilot designation alone does not specify the study’s intended level of evidence or the precision sought. Without the primary result and analysis details, the registry record cannot support a conclusion about the magnitude or reliability of a treatment effect. This statistical description is not medical advice and does not determine what treatment is appropriate for any individual.
13. Why This Trial Matters Statistically
This trial is statistically notable for combining two clinical conditions with different symptom measures in one randomized pilot study. The registry describes a functional dyspepsia scale based on upper gastrointestinal symptoms and a separate irritable bowel syndrome score based on a different set of questions. Their ranges and content differ, making the choice of analysis and interpretation important. The registry record does not report whether these outcomes were analyzed separately or combined.
The randomized sham-controlled design sets up a comparative question rather than relying only on change within the active-treatment group. A sham device intended to resemble the active device can help make the comparison more informative, although the registry record does not report whether masking was successful. Nor does it report a statistical analysis plan or the primary-outcome estimates needed to judge the comparison.
The record also illustrates why outcome definitions and analysis populations are not enough on their own. The primary outcome is described, and the intention-to-treat population is named, but the observed group summaries, treatment contrast, uncertainty and missing-data handling are not reported. Readers cannot assess whether the estimated difference is small or large, precise or imprecise, or robust to analysis choices.
Finally, the registry includes several secondary outcome areas and safety counts. Their presence makes transparent reporting of prespecified analyses and multiplicity methods especially relevant. The record does not report those methods or outcome results. The central statistical lesson is that a clearly described design can frame a question, but outcome estimates and analysis details are needed to answer it.
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 limitation for interpreting this trial from the registry record is the absence of a reported primary-outcome result. The record does not provide group means, standard deviations, a treatment contrast, a confidence interval or a p-value. It therefore does not allow assessment of the direction, size or precision of symptom change between the active and sham groups.
The primary outcome covers two different conditions and two distinct symptom instruments. The registry does not report whether results were separated by condition, combined, or analyzed through another method. It also states that the primary outcome has several categories or time points and was not reduced to one comparison. The exact primary analysis is consequently unclear.
Other trial details needed to assess validity are not reported in the registry record, including participant flow, group sizes for the primary analysis, baseline characteristics, allocation concealment, adherence, withdrawals, missing-data handling and the analysis model. The record lists an intention-to-treat population but does not define it in detail. It also does not report how masking was assessed.
The study is described as a pilot, but its sample-size justification and statistical analysis plan are not reported. The registry lists multiple secondary outcomes without a reported multiplicity strategy, and it does not provide the results needed to assess those outcomes. Safety reporting is limited to group counts; event details and comparative safety estimates are not reported. These limitations concern interpretation of the registry record and do not establish what may appear in other study documents.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Randomized, Single Centre, Double-blind, Parallel, Sham-controlled Pilot Study Using gammaCore®-G — NCT02388269.
- Registry record last updated 2018-03-07; status last verified 2018-02.
- Results first posted 2018-02-06.
- 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.
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18. Record Summary
NCT02388269 is a completed, randomized, single-centre, double-blind, parallel, sham-controlled pilot study of gammaCore®-G. It enrolled 91 participants with functional dyspepsia or irritable bowel syndrome. The registry lists the study start as 2014-06 and primary completion as 2015-05.
The primary outcome concerns symptom change, measured with condition-specific patient-reported scales during the last 2 weeks of the 4 week randomized period. The registry identifies the intention-to-treat population but does not report a primary-outcome estimate, uncertainty interval or significance test. It lists secondary outcomes involving quality of life, symptom frequency, medication use, symptom change and adverse events.
Safety entries show zero serious adverse events and zero deaths in each of four listed groups. The registry record does not report a detailed statistical analysis plan, multiplicity strategy or missing-data methods. The posted record therefore describes the study design and planned outcomes, but does not provide the numerical primary result needed to interpret the treatment comparison.