DESIVI: Dosing of Electrical Stimulation in Venous Insufficiency: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for DESIVI: Dosing of Electrical Stimulation in Venous Insufficiency (NCT03850496), a randomized na study. The primary outcome is Venous Haemodynamics - Percent Change in Time Averaged Mean Velocity TAMV.

2. Clinical Question

DESIVI concerns people with varicose veins, venous stasis, or venous insufficiency. Its clinical question is whether venous haemodynamics differ after 6 weeks among people assigned to no device use, daily use of a neuromuscular electrical stimulation device for 30 mins, or daily use for 60 mins. The primary outcome focuses on percentage change in Time Averaged Mean Velocity, a measure of venous flow.

The design therefore frames a comparison of device use with no device use, as well as a comparison between the two daily-use schedules. The registry record does not reduce the primary outcome to one comparison, and it does not report group-level primary-outcome results or a statistical test for these contrasts. The clinical question can be stated from the registered aims, but the direction and size of any observed differences cannot be determined from the registry record.

3. Trial Design

DESIVI is recorded as a randomized, single-masked, parallel-group study. The registry lists an enrollment of 76 and a status of completed. The phase is listed as not applicable. The intervention is the Revitive IX Neuromuscular Stimulation Device, with Group A assigned to no device use, Group B to use for 30 mins per day, and Group C to use for 60 mins per day. Each group description specifies a 6-week period.

Random allocation is intended, as a general design principle, to make assigned groups comparable on average with respect to both measured and unmeasured characteristics. It does not guarantee that the groups will be identical, especially in a study of limited size. The registry record does not report how the random sequence was generated, how allocation was concealed, or whether the groups were assigned in equal proportions.

The record describes masking as single, but does not identify who was masked or how masking was maintained. It also does not report whether participants, clinicians, outcome assessors, or analysts knew the assignments. This matters because perceived assignment can influence behavior, adherence, measurement, and interpretation, although the direction or extent of any such influence cannot be inferred.

The primary outcome is percentage change in Time Averaged Mean Velocity, with a timeframe of 0 and 6 weeks. The record also lists secondary outcomes involving venous flow parameters, microcirculatory blood flow, limb volume, venous clinical severity, compliance, and generic quality of life measured with EQ-5D-5L and SF-12. It records 11 outcome measures. Numerical results for these outcomes are not reported in the registry record. Details of recruitment, eligibility criteria, participant flow, and analysis populations are also not reported in the registry record.

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:

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 Venous Haemodynamics - Percent Change in Time Averaged Mean Velocity TAMV, measured over 0 and 6 weeks.

The primary endpoint is venous haemodynamics expressed as percentage change in Time Averaged Mean Velocity, abbreviated TAMV in the registry title. TAMV is measured in cm/s, while the endpoint is described as percentage change from baseline. Measurements are specified at 0 and 6 weeks. The registry identifies the summary measure as the median and the dispersion measure as the inter-quartile range.

As a general measurement concept, venous flow velocity describes blood movement through the veins. A change from baseline can summarize how a measured value differs over the intervention period while accounting for the starting measurement in the endpoint definition. The median describes the middle of an ordered set of measurements, and the inter-quartile range describes the spread of the central portion of those measurements. These summaries can be useful when values are skewed or when a small number of observations are far from the center, but the registry record does not state why these summaries were selected.

The outcome is relevant to the registered question because the intervention is intended to alter venous haemodynamics, and TAMV is a direct flow parameter. However, an outcome measure is not itself evidence of a treatment effect. To judge the observed pattern, readers would need the group-specific summaries, the uncertainty around contrasts, and information about the analysis. Those numerical results and details are not reported in the registry record, so the size, direction, and precision of any primary-outcome difference cannot be described.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes randomized allocation, a parallel-group model, and single masking. These terms describe features of the design, not the numerical analysis of the outcomes. The record does not report a statistical analysis plan or an analysis result for the primary endpoint. The explanations below are general statistical context; they should not be read as a description of analyses actually conducted for DESIVI unless the registry record explicitly states that detail.

What does randomization contribute?

As a general principle, randomization assigns participants by chance rather than by a rule chosen according to their health status or expected outcome. It can reduce systematic differences between assigned groups, including differences that investigators did not measure. In any particular randomized study, chance imbalances may still occur. Randomization supports a fair comparison of assigned strategies, but it does not fix problems such as missing outcome data, incomplete adherence, measurement error, or selective reporting.

The registry does not report the sequence-generation method, allocation concealment, or allocation ratio. Those details help readers assess whether assignment could have been predicted or influenced. The record states single masking but does not say who was masked. Masking can reduce the opportunity for knowledge of assignment to affect behavior or measurement; its relevance depends on who is masked and which aspects of the study they can influence. Those implementation details are not reported in the registry record.

Why report a median and inter-quartile range?

The primary outcome is summarized using a median and an inter-quartile range. In general, the median is the central observation after measurements are ordered. The inter-quartile range gives the span covering the central half of the observations. These summaries are less influenced by extreme values than the mean and standard deviation. They can therefore be informative when a distribution is asymmetric or contains outliers. The registry does not report the outcome distributions or explain the choice of summary, so it is not possible to assess from the record whether the summaries match the data shape.

A median and inter-quartile range describe each group’s data, but they do not alone quantify the uncertainty in a between-group contrast. To evaluate a comparison, readers would ordinarily look for a defined contrast, an estimate, and an uncertainty measure such as a confidence interval. A confidence interval is a range of values compatible with the data under the method’s assumptions; its width conveys statistical precision. No primary-outcome confidence interval or comparison estimate is reported in the registry record.

What does percentage change from baseline represent?

Percentage change expresses a follow-up measurement relative to a baseline measurement according to the endpoint definition. In general, this can make change easier to compare across people who begin at different measurement levels. It can also be sensitive to the baseline value and to measurement variability. The registry describes the endpoint as percentage change from baseline, with assessment at 0 and 6 weeks, but it does not provide the calculation details, participant-level observations, or group summaries. No additional calculation can therefore be reconstructed from the record.

The registry title names TAMV and gives cm/s as the measurement unit, while the endpoint unit is percentage change from device off. The description refers to percentage change from baseline. The record does not further explain the relationship between the device-off reference and the baseline assessment. It is appropriate to retain the registered endpoint wording rather than infer a more detailed measurement protocol.

How should the sample-size illustrations be understood?

The registry description characterizes sample-size values as planning illustrations computed from an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. For time-to-event tables, the described quantity is total events; for other outcomes, it is participants per arm. These are planning conventions, not observed trial results. A planned sample size under assumptions is not observed power and does not demonstrate that an analysis had a particular probability of detecting an effect.

The registry record does not report the study’s own sample-size justification. The primary outcome is not reduced to one comparison, and the numerical primary results needed to understand an observed-effect-based illustration are not reported in the registry record. No sample-size or power conclusion about the trial can be drawn from those descriptions alone. The planning assumptions should not be mistaken for evidence that the trial was designed around a prespecified effect or that a particular statistical analysis was carried out.

What remains unknown about the analysis?

The registry does not report the statistical test or model for TAMV, any adjustment for baseline values, handling of repeated measurements, covariates, or a rule for choosing among the registered groups and time points. It does not report whether the primary analysis followed randomized assignment or was restricted to participants who completed treatment. It also does not report how missing outcome values were handled. These are not minor details: they determine the population represented by an estimate and the assumptions underlying its uncertainty.

For outcomes measured at more than one time point, general analytical approaches may account for within-person correlation. The suitable approach depends on the data structure and the prespecified question. The registry’s mention of 0 and 6 weeks does not establish that a repeated-measures model was used. Likewise, the registered use of medians and inter-quartile ranges does not establish which inferential method, if any, was applied. Without an analysis description and numerical estimates, statistical significance, precision, and robustness cannot be assessed.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 11 outcome measures and the primary endpoint is described at 0 and 6 weeks. It also specifies three assigned groups. Considering several outcomes, time points, or pairwise contrasts can create multiplicity: as the number of statistical questions grows, the chance of at least one apparently unusual result can increase if each is assessed separately. General approaches include prespecifying a hierarchy of questions, adjusting inference across selected comparisons, or clearly treating additional analyses as exploratory.

The registry record does not report a multiplicity strategy, a prespecified hierarchy among contrasts, or which comparisons were intended for confirmatory inference. The primary outcome is not reduced to one comparison, so the record does not identify a single contrast to interpret. It would be inappropriate to assume that a particular adjustment was or was not applied beyond what is reported. Numerical results and analysis details are not reported in the registry record.

Missing-data handling and analysis populations are also not reported in the registry record. The record does not state whether all randomized participants were included in the primary analysis, whether participants were excluded, how incomplete follow-up was addressed, or how missing measurements were treated. As a general principle, missingness can affect both the representativeness of an estimate and its uncertainty, particularly if the chance of missing a measurement is related to the participant’s outcome or assigned group. No direction or magnitude of such an effect can be inferred.

The enrollment entry does not establish outcome-specific denominators or completion rates. Nor does the adverse-event reporting denominator determine the number with primary-endpoint data. Without participant flow and outcome-specific analysis counts, readers cannot assess whether the reported analysis, if any, retained the randomized comparison or how much information was available for each outcome.

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 adverse-event entries report zero serious events in Group A, Group B, and Group C. For serious-event reporting, the record lists 26 at risk in Group A, 25 in Group B, and 25 in Group C. The other-event entries also report zero in each group, with the same group-specific at-risk counts. Deaths are listed as zero in all groups, and no top serious-event terms are listed.

These figures describe what is entered in the registry record; they do not establish that no adverse experiences occurred in every sense. The record does not provide further detail on how events were collected, the observation period used for safety reporting, event definitions, severity categories beyond the serious-versus-other distinction, or whether reporting was complete. The at-risk counts attached to these entries should not be treated as denominators for the primary endpoint or as evidence of full follow-up for every outcome.

Zero recorded events in a group is not proof that the intervention is free of risk. In general, an absence of recorded events can reflect the observed experience during the reporting period, while the ability to detect uncommon events depends on the amount and duration of observation and the completeness of ascertainment. Those details are not reported in the registry record. The safety entries therefore support only a narrow description of the recorded serious events, other events, and deaths; they do not support a broader safety conclusion.

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

The registry record establishes the question DESIVI was designed to address: whether venous haemodynamic outcomes differ across no device use and two schedules of neuromuscular electrical stimulation over 6 weeks. It identifies percentage change in TAMV as the primary endpoint and lists several secondary outcomes. It also records randomized allocation, single masking, a parallel-group model, enrollment of 76, and completed status.

Those design details do not reveal the result. Numerical group summaries, between-group estimates, confidence intervals, and statistical tests for the primary endpoint are not reported in the registry record. As a result, the posted record does not show whether TAMV changed in any group, whether groups differed, or how precisely any difference was estimated. It cannot support a conclusion that device use did or did not alter venous flow.

Nor does the record establish whether any measured difference, if one was observed, would be clinically important. Statistical evidence and clinical importance are distinct: the first concerns how compatible the observed data are with a specified comparison, while the second requires context about the meaning of the measured change. The registry does not give numerical outcome findings or a threshold for interpreting the importance of a TAMV change.

The same restraint applies to secondary outcomes and safety. Outcomes are named, but numerical findings are not reported. The adverse-event entries record zero serious events, other events, and deaths within the reported group entries, but do not establish that the device is free of risk. Missing-data methods, analysis populations, and multiplicity handling are not reported either. The most defensible reading is therefore descriptive: the registry records a randomized study with specified intervention schedules and outcomes, but it does not provide enough numerical results to assess effectiveness, precision, or the overall balance of outcomes.

13. Why This Trial Matters Statistically

DESIVI is statistically interesting because its registered question compares a no-device group with two daily-use schedules. This makes the scientific question more than a simple device-versus-control contrast: readers may also want to know whether the outcome differs between the 30 mins and 60 mins schedules. A study with multiple groups can therefore involve several possible contrasts, and a clearly stated primary comparison helps define which estimate should carry the main inferential emphasis. The registry record does not reduce the primary endpoint to one comparison.

The endpoint is expressed as percentage change from baseline and is summarized by the median and inter-quartile range. That combination raises useful analytical questions about the distribution of change, the handling of baseline measurements, and the method used to compare groups. These are general considerations, not evidence that any particular analysis was performed in DESIVI. The registry does not report the analysis method or numerical results needed to evaluate them.

The study also lists outcomes spanning venous flow, microcirculatory blood flow, limb volume, clinical severity, compliance, and quality of life. Such breadth can offer a broader view of what a study measures, while also making prespecification and multiplicity important for interpretation. Without a reported hierarchy or analysis plan, readers cannot distinguish a primary confirmatory comparison from other potential analyses.

Finally, the record illustrates the difference between a completed study entry and an interpretable results record. Design information identifies what was intended, but conclusions depend on estimates, uncertainty, denominators, and analysis details. Those results are not reported in the registry record. The statistical importance of the record is therefore primarily in its documented design and in the questions that remain unanswered, rather than in evidence for a particular outcome pattern.

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.

Important limitations for interpreting this trial arise from the information absent from the registry record. Although the study is marked completed, numerical results for the primary outcome are not reported. The primary endpoint has several categories or time points and is not reduced to one comparison. No group-level medians or inter-quartile ranges, contrast estimates, confidence intervals, or test results are available in the record. The direction, magnitude, and precision of any difference therefore remain unknown.

The design description is also limited. Masking is recorded as single, but the masked party and masking procedures are not reported. The randomization method, allocation concealment, and allocation ratio are not reported. Eligibility criteria, recruitment details, participant flow, outcome-specific denominators, and analysis populations are not reported in the registry record. Enrollment of 76 does not by itself establish how many participants contributed to each outcome analysis.

The registry names multiple outcomes but does not report a statistical analysis plan, a hierarchy of comparisons, or a multiplicity approach. It does not describe handling of missing measurements, deviations from assigned schedules, baseline adjustment, or the method used to compare groups. These gaps limit assessment of bias, precision, and the assumptions underpinning any result.

The record reports no serious events, other events, or deaths in the group entries, but does not describe event ascertainment or the duration and completeness of safety monitoring. Those entries should not be used to infer absence of risk. Finally, the registry does not report its own sample-size justification. The described sample-size calculations are planning illustrations, not observed power. Together, these omissions mean that the study’s registered question and design can be described, but its outcome evidence cannot be appraised from this record alone.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: DESIVI: Dosing of Electrical Stimulation in Venous Insufficiency — NCT03850496.
• Registry record last updated 2020-07-31; status last verified 2020-07.
• Results first posted 2019-09-04.
• 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

DESIVI is a completed randomized, single-masked, parallel-group study of the Revitive IX Neuromuscular Stimulation Device in venous insufficiency-related conditions. Group A used no device for 6 weeks; Group B used the device for 30 mins per day; Group C used it for 60 mins per day. The registry lists enrollment of 76.

The primary endpoint is percentage change in Time Averaged Mean Velocity, assessed at 0 and 6 weeks and summarized using the median and inter-quartile range. Secondary outcomes include venous flow parameters, microcirculatory blood flow, limb volume, venous clinical severity, compliance, and generic quality of life. The record lists 11 outcome measures.

Numerical primary and secondary outcome results, the analysis plan, missing-data methods, and analysis populations are not reported in the registry record. Adverse-event entries list zero serious events, other events, and deaths in each group. These entries do not establish an absence of risk.