Dermatome Electrical Stimulation on Individuals With Overweight and Class I Obesity: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Dermatome Electrical Stimulation on Individuals With Overweight and Class I Obesity (NCT03261531), a na na study. The primary outcome is Change in Body Weight.

2. Clinical Question

In broad terms, the study was intended to assess whether T6 stimulation was associated with changes in body weight and with several measures related to gastric function, appetite, satiation and satiety. That describes the research question, not a demonstrated effect. The registry record supplies no primary outcome values, change estimate, uncertainty interval or analysis result. It also does not report results for the listed secondary outcomes. The record is therefore informative about the intended question and the reason the study stopped, but it cannot show whether the intervention changed any measured outcome.

3. Trial Design

The registry record describes a single-group study of T6 dermatomal electrical stimulation delivered through a TENS device. The planned participants were healthy volunteers who were overweight or had class I obesity. Enrollment is listed as 7. The record does not describe random allocation, and masking is listed as none. It does not set out a concurrent control group, so the study was not designed as a randomized comparison of stimulation against a control condition.

The study was sponsored by Mayo Clinic. Its recorded start date is 2017-02-21, and its primary completion date is 2019-01-30. Its status is terminated. The primary outcome was change in body weight, with measurement planned at baseline and 3 months. The record explains the termination by stating that the device failed; despite efforts, the investigators were unable to collect data.

The registry lists 13 outcome measures and 0 analyses. Among the secondary outcomes are fasting and postprandial gastric volumes measured by 99mTc-SPECT imaging, change in gastric emptying percentage, satiation volumes, buffet-meal energy intake as a measure of appetite, appetite score, and fasting and peak postprandial plasma ghrelin at 3 months. Listing an outcome indicates that it was part of the registered study record; it does not mean that measurements were obtained or that results are available.

The record does not report a sample-size justification, a planned statistical analysis strategy, an interim analysis plan, or an analysis population. It does not state how long participants received stimulation or give enough detail to assess treatment adherence. These omissions limit reconstruction of how the study would have proceeded if data collection had been completed. The posted enrollment should not be treated as the number with observed primary outcome data: the record explicitly says those data could not be collected.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Study was terminated due to device failure. Sincere efforts were made but we were unable to collect data

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 Body Weight, measured over Baseline, 3 months.

The primary endpoint was change in body weight, measured from baseline to 3 months. Body weight is a direct measure of body mass and can be summarized as a change between measurements at different times. In a completed study, such an endpoint could describe whether participants' recorded weights shifted during the observation period. By itself, however, a change over time in a single group would not separate an intervention effect from other explanations for change, such as ordinary variation over time or other influences not controlled by the design.

The registry record says weight was to be measured in kilograms or pounds. It does not specify which unit was used, the exact calculation for the change, or whether the intended summary was a mean, median or another measure. Those details are not reported in the registry record. More importantly, the endpoint description states that the study was terminated due to device failure and that the investigators were unable to collect data. No baseline or 3-month body-weight values, change estimate, or analysis result are posted.

Consequently, the endpoint identifies what the study intended to measure, but it does not provide an observed estimate of change. The time points and measurement label should not be mistaken for evidence that measurements were successfully obtained. The registry record cannot show the direction, size or precision of any body-weight change.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies the study as single-group and reports no analyses. It does not describe a statistical analysis plan, a model for the primary endpoint, or a method for handling repeated measurements. A planned comparison of body weight across baseline and 3 months might ordinarily be summarized with a change estimate and a measure of uncertainty. That is a general description of how a longitudinal endpoint can be analyzed, not a claim about the methods used in this study. No such estimate or uncertainty measure is posted.

What an estimate and confidence interval would show

In general, an estimate summarizes the observed effect or change in a study, while a confidence interval communicates the uncertainty around that estimate under the assumptions of the analysis. A narrow interval indicates greater precision than a wide interval, although precision does not by itself establish that a result is unbiased or clinically important. For this record, there is no posted primary estimate or confidence interval to interpret. The missing data prevent readers from judging either the observed direction of change or its precision.

What a test result could and could not establish

In general, a statistical test assesses how compatible the observed data are with a specified null hypothesis under a statistical model. A p-value is not the probability that the null hypothesis is true, and it does not measure the size or importance of an effect. The registry record contains no reported primary analysis or test result. It is not possible to infer a p-value, statistical significance, or an effect from the enrollment count or the study status.

Why the study structure matters

A single-group study can describe what happened to participants over time, if those measurements are available. It does not provide a concurrent control outcome against which to compare that change. In general, a comparator helps distinguish changes associated with an intervention from changes that might also occur without it. Here there is no control group listed, and the registry does not describe random allocation or masking. Even if the intended weight measurements had been collected, those design features would constrain causal interpretation. Because data were not collected, there is no observed change to assess in the first place.

What the planning illustration means

The page includes a sample-size planning illustration based on a stated effect fraction, with a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation. Such calculations are general planning tools: they estimate the participants per arm that would be needed under their assumptions to detect a specified effect with a chosen power. They are not the number enrolled, a result of this study, or observed power. In particular, the illustration's equal-allocation, two-arm setup differs from this registry record's single-group design. The registry does not report that those assumptions were used to plan this trial.

More fundamentally, the record says the primary outcome data could not be collected and lists 0 analyses. No observed primary effect is available in the registry record for readers to evaluate. Therefore a planning illustration cannot be used to infer the study's actual effect, the probability that it would have detected an effect, or the reason for termination. It does not overcome the absence of observed outcome data.

What remains unspecified

The registry does not report the planned summary statistic for body-weight change, a statistical model, assumptions about the distribution of the outcome, a missing-data method, or a strategy for multiple outcomes. These items are not reported in the registry record. Without them, readers cannot reconstruct a prespecified analysis or determine how the investigators intended to account for the several outcome measures. The record's 13 listed outcome measures and 0 analyses describe the breadth of registered measurement intentions and the absence of posted analyses; they do not identify which outcomes, if any, were successfully measured.

General statistical methods can clarify what results would mean if they were reported, but they cannot fill in missing results or recover an analysis plan that is not documented. The appropriate conclusion is limited: the study had a registered primary endpoint and a set of secondary outcomes, but the registry record does not provide the data or analysis needed to estimate effects.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 13 outcome measures, including the primary body-weight endpoint and secondary measures of gastric function, appetite, satiation, satiety and ghrelin. When a study examines multiple outcomes, general statistical practice considers multiplicity: testing many outcomes can increase the chance that at least one result appears notable by chance. Possible approaches include specifying a primary outcome, defining a testing hierarchy, or adjusting inference across a family of tests. The registry record does not report a multiplicity strategy or a prespecified hierarchy beyond identifying the primary outcome.

There are no posted analysis results to assess for multiplicity. The record lists 0 analyses and states that data could not be collected after device failure. It is therefore not possible to determine whether any secondary endpoint was measured, whether any comparisons were planned or conducted, or whether an adjustment would have been applied.

The record also does not report a missing-data analysis or an analysis population. It does not specify whether all enrolled participants were intended to contribute to each outcome, or how incomplete measurements would have been handled had data collection proceeded. The stated inability to collect data is not the same as a reported statistical method for handling missing observations. Nor does enrollment of 7 establish the number with usable outcome data. These details are not reported in the registry record.

In general, missing data can affect both the amount of information available and the conclusions drawn from an analysis, depending on why observations are missing and how they are handled. Here, the registry gives device failure as the reason the primary data could not be collected. It does not supply outcome observations or an analysis that would allow the impact of missingness to be quantified.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry lists the TENS group with 7 participants at risk for serious adverse events and 0 serious adverse events. It also lists 7 at risk for other adverse events and 0 other adverse events, with 0 deaths. These are the posted safety counts for the group. They should be reported as recorded, without implying that the figures establish the absence of risk.

In general, an adverse-event count is interpreted in relation to the participants observed, the period of observation, and the completeness of event collection. The registry record does not provide detailed follow-up duration for safety, event definitions, or further information about how adverse events were monitored. It also says the study was terminated because the device failed and that the investigators could not collect data for the primary outcome. The safety counts do not resolve what exposure or observation was achieved for each participant.

Thus, the appropriate description is that the registry reports 0 serious adverse events, 0 other adverse events and 0 deaths among the listed group, with 7 participants at risk in each adverse-event category. These figures are a record of reported events, not proof that no events occurred outside the recorded observation or that the device is generally safe. They should also be kept separate from the unavailable efficacy outcomes: safety counts do not answer the question about body-weight change.

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

This registry record documents a study intended to examine T6 dermatome electrical stimulation delivered by TENS in people who were overweight or had class I obesity. It identifies change in body weight from baseline to 3 months as the primary outcome and lists several secondary measures related to gastric function, appetite, satiation, satiety and ghrelin. It also records enrollment of 7 and reports that the study was terminated because of device failure.

What the record does not show is an observed change in body weight or an analyzed effect on any of the secondary outcomes. The primary outcome description states that investigators were unable to collect data, and the registry lists 0 analyses. There are no reported estimates, confidence intervals, test results or outcome distributions from which to judge direction, magnitude or precision. The study therefore cannot be interpreted as showing either benefit or lack of benefit. Missing results are not equivalent to a null result.

The single-group design also matters to the interpretation of any hypothetical before-and-after data. Without a comparator, changes over time would not by themselves establish that stimulation caused those changes. The registry also records no masking and no randomized allocation. These design characteristics would need consideration alongside measured outcomes, but they cannot be used to manufacture an outcome conclusion where no results are posted.

The adverse-event listing reports 0 serious events, 0 other events and 0 deaths in the TENS group, with 7 participants at risk in each event category. Those registry counts should not be stretched into a broad claim about safety, especially since details of observation and event ascertainment are not reported. The most accurate overall conclusion is narrower: the study's planned questions are described, but the posted record does not contain collected primary outcome data or analyses capable of answering them.

13. Why This Trial Matters Statistically

This trial is statistically notable because it illustrates the distinction between a registered research question and an answer supported by data. A registry can describe the intended population, intervention, endpoint and follow-up even when the study does not reach a stage at which outcomes can be analyzed. Here, the record identifies body-weight change from baseline to 3 months as the primary endpoint, but states that device failure prevented collection of data.

That distinction matters when reading outcome lists and summary displays. A registered endpoint is not itself a result, and an enrollment count is not an analyzed sample size. The record lists 13 outcome measures but 0 analyses. This makes it important to separate what investigators planned to measure from what the record says was actually observed and analyzed.

The study also highlights how design and data availability are separate issues. Its single-group structure, with no randomized allocation or masking, would limit causal conclusions even if the planned measurements were available. The device failure and lack of collected data create a more fundamental limitation: there is no estimate to interpret at all. Statistical methods cannot compensate for the absence of observed outcomes.

Finally, planning calculations and safety counts need careful context. A sample-size illustration based on assumptions is not observed power and does not reveal an unreported effect. The recorded adverse-event counts describe what appears in the registry, but do not establish the completeness or duration of observation. These distinctions help readers avoid treating registration, planning, enrollment or event counts as substitutes for analyzed clinical outcomes.

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 most consequential limitation is that the registry record says the study was terminated due to device failure and that investigators were unable to collect data. No primary body-weight result is posted, and the record lists 0 analyses. The study therefore provides no reported estimate of change and no precision measure. The enrollment count of 7 cannot be assumed to be the number with usable outcome measurements.

The design was single-group, without a reported control group, random allocation or masking. In a completed study, a change from baseline could be described, but the design would not provide a concurrent comparison to help distinguish intervention-related change from other influences over time. In this record, that concern is secondary to the absence of outcome data, but it would still matter to any causal interpretation.

The registry record does not report the sample-size justification, a detailed statistical analysis plan, an analysis population, a missing-data method, or a multiplicity strategy. It also does not specify the statistical summary intended for body-weight change or provide details sufficient to assess the planned duration and adherence to stimulation. These items are not reported in the registry record. The listed secondary outcomes do not have posted results, so their measurement and analysis cannot be evaluated.

The safety listing reports no recorded serious adverse events, other adverse events or deaths, but the registry does not provide detailed event definitions or follow-up information. The figures should be treated as registry counts rather than a complete characterization of safety. Together, the termination, missing outcome data and limited methodological detail mean that the record is useful for understanding what was intended, but not for estimating an intervention effect.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Dermatome Electrical Stimulation on Individuals With Overweight and Class I Obesity — NCT03261531.
• Registry record last updated 2020-02-05; status last verified 2020-01.
• Results first posted 2020-02-05.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry record describes a Mayo Clinic study of T6 dermatomal electrical stimulation delivered through a TENS device to healthy volunteers who were overweight or had class I obesity. It is recorded as a single-group study with no masking, enrollment of 7, and status terminated. The primary outcome was change in body weight from baseline to 3 months.

The record states that device failure led to termination and that investigators were unable to collect data. It lists 13 outcome measures and 0 analyses, with no posted primary or secondary outcome estimates. The registry lists 0 serious adverse events, 0 other adverse events and 0 deaths in the TENS group, with 7 at risk in each adverse-event category. The record describes the planned research question but does not provide results that answer it.