Wearable Technology and Alcohol-Facilitated Intimate Partner Violence: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Wearable Technology and Alcohol-Facilitated Intimate Partner Violence (NCT05374798), a na na study. The primary outcome is Heart Rate Variability During Alcohol-Facilitated Intimate Partner Violence (IPV).

2. Clinical Question

The project’s stated purpose was to examine the usability, feasibility, and acceptability of activity trackers and a smartphone application among couples, while also testing whether use of the device and application would affect alcohol use and couple conflict. The primary endpoint is narrower than those broader aims: it focuses on heart rate variability during periods classified by reported alcohol use and intimate partner violence or conflict. Those classifications came from participant assessments rather than an independently described event adjudication process.

Because the study has a single group and no listed comparator, the registry record does not support a treatment-versus-control estimate. Its structure is descriptive and observational over the evaluation period, even though participants used an intervention device. The primary endpoint could characterize physiological measurements in relation to reported events, but the posted record does not give enough results to determine the direction, size, or precision of any such pattern.

3. Trial Design

This completed study is registered as a single-group device intervention, with the intervention named Heart Rate Variability-Biofeedback via a smartwatch. The registry lists enrollment of 92 and identifies the sponsor as Medical University of South Carolina. The listed conditions are alcohol abuse, intimate partner violence, and couples. Phase is recorded as NA, allocation as NA, and masking as none.

The registry record lists a start date of 2023-01-27 and primary completion on 2024-05-28. The study status is completed. The study description includes screening followed by a 28-day observation period. During that period, participants were asked to wear a smartwatch, complete assessments, and provide feedback. The device is described as enabling continuous ambulatory physiological monitoring and geolocation. Smartphone assessments were scheduled four times daily, with optional event-triggered reports, covering alcohol use, couple conflict including intimate partner violence, and affect.

Although an intervention is named, the registry does not describe a separate control arm or a randomized allocation scheme. It would therefore be misleading to interpret the design as a randomized trial or to treat an unlisted group as a control. The record does not report a protocol-level account of how the biofeedback was delivered, whether participants received additional treatment, or whether device use was compared with usual care or another intervention.

The primary endpoint analysis population is described as N=83 participants with at least one valid heart rate variability measurement. The registry explains that N=9 participants were not included in that analysis, with reasons listed as loss to follow-up, withdrawal, withdrawal by the principal investigator, or no heart rate variability collection. These are analysis-population details and should not be treated as evidence that all remaining participants completed every assessment. The registry record does not report the number of usable observations per participant or the amount of missing data within participants.

The record lists four outcome measures and zero analyses. No detailed statistical analysis plan, sample-size justification, interim analysis plan, or prespecified handling of repeated observations is reported in the registry record. A planning illustration based on the observed effect is described as separate from the trial’s own design; the registry does not report a trial-specific design calculation.

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: Participants were N=46 couples (N=92 individuals) where at least one partner within each dyad must have 1) met Diagnostic and Statistical Manual of Mental Disorders (DSM-V) diagnostic criteria for current alcohol use disorder and current alcohol use, and 2) have reported at least one instance of physical intimate partner violence in the past two years.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Analysis completed on N=83 participants who had at least one valid Heart Rate Variability measurement. N=9 participant were not included in the sample. N=2 lost to follow up. N=2 withdrew from the study. N=2 withdrawn by principal investigator. N=3 heart rate variability was not collected. The means below represent instances where reports were generated in each condition (e.g. HRV diary report when responder indicated no alcohol and no IPV)

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: The full sample consists of N=92 participants. Outcome measures were collected and reported on N=86 participants (2 participants dropped out, 2 participants were lost to follow up and 2 participants were withdrawn by Principal Investigator).

6. Primary Endpoint

The registry lists the primary outcome as Heart Rate Variability During Alcohol-Facilitated Intimate Partner Violence (IPV), measured over From enrollment through end of evaluation period; 28 days..

The primary endpoint is mean heart rate variability, expressed in milliseconds and summarized with a standard deviation. It was measured using respiratory sinus arrhythmia data derived from a Garmin smartwatch. Respiratory sinus arrhythmia is described in the registry as a component of heart rate variability associated with changes in heart rate during normal breathing. The evaluation period ran from enrollment through the end of the 28-day evaluation period.

Endpoint means were stratified according to alcohol and intimate partner violence status at the preceding report. The event classifications came from smartphone ecological momentary assessments, which asked about alcohol use, intimate partner violence or conflict, and affect. The measure is therefore intended to relate a physiological signal to recently reported context. The registry describes respiratory sinus arrhythmia as an autonomic biomarker of arousal relevant to alcohol use disorder pathophysiology.

In general, a mean describes the central level of a continuous measure across observations, while a standard deviation describes how dispersed those measurements are around the mean. Neither statistic alone establishes that a difference between event categories is meaningful or attributable to an intervention. Interpretation also depends on the number and timing of observations, their variability, and the analysis approach.

The registry describes higher heart rate variability or respiratory sinus arrhythmia as representing better autonomic balance and physiological reactivity, and lower levels as representing more maladaptive reactivity and autonomic imbalance. However, the numerical means and standard deviations for the endpoint are not reported in the registry record. Nor are confidence intervals, tests, or an estimated contrast between status categories reported. Thus, the endpoint’s measurement rationale is available, but its observed values and statistical precision cannot be assessed from the posted record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry characterizes the primary measure as a continuous outcome reported as a mean with a standard deviation. In general, continuous measurements can take a range of values, such as the milliseconds recorded for respiratory sinus arrhythmia. A mean condenses those observations into a central summary. A standard deviation describes how much observed values vary around that mean. These descriptive statistics are useful for understanding a measurement’s scale and spread, but do not on their own answer whether groups differ or how precisely an estimated contrast is known.

What would a confidence interval add?

In general, a confidence interval expresses uncertainty around an estimated quantity, such as a mean or difference. A narrower interval indicates greater precision under the assumptions of the analysis; a wider interval indicates less precision. The registry record does not report confidence intervals for the primary endpoint. Since it also does not report the endpoint’s means or an estimated contrast, there is no posted interval to interpret. The uncertainty around the observed relationship between prior reports and heart rate variability therefore cannot be quantified from the registry record.

Why does the structure of the observations matter?

Participants were asked to complete repeated smartphone assessments during a 28-day observation period, and the smartwatch collected continuous physiological monitoring. Repeated measurements from the same participant are generally correlated: readings from one person may be more alike than readings from different people. In general, a statistical analysis of repeated data should account for that dependence rather than treating every reading as an independent participant. Otherwise, the estimated uncertainty may not reflect the data structure. The registry record does not identify a repeated-measures model, a method for handling within-person correlation, or the number of usable readings per participant.

The endpoint groups readings by alcohol and intimate partner violence status at the prior report. The timing is important: a measurement is classified in relation to a preceding self-report, rather than by a classification independent of participants’ reports. The record does not specify the exact time window connecting a report to the heart rate variability reading, how conflicting reports were handled, or how optional event-triggered reports entered the endpoint analysis. These details can affect how the categories are interpreted and how many observations contribute to each summary.

How should the analysis population be read?

The endpoint analysis included N=83 participants who had at least one valid heart rate variability measurement. This is a participant-level inclusion description, not a count of readings. The reasons listed for N=9 participants not included are N=2 lost to follow up, N=2 study withdrawals, N=2 withdrawals by the principal investigator, and N=3 without heart rate variability collection. In general, excluding participants with no valid outcome data can affect the population represented by an analysis, especially if the reasons for missing data are related to participants’ characteristics or outcomes. The registry record does not report a missing-data method or compare included and excluded participants.

What can the inferential results establish?

No analysis is listed in the registry record. It therefore does not report a test statistic, a p-value, a confidence interval, or an adjusted estimate for the primary endpoint. Without these results, it is not possible to assess whether the reported data show a pattern that is distinguishable from sampling variation or to gauge the precision of an estimated association. Even with inferential results, statistical association would not by itself establish that the intervention caused an endpoint change, particularly in a single-group design without a listed control group.

In general, a p-value evaluates how compatible data are with a specified statistical model and null hypothesis; it is not a measure of effect size, clinical importance, or the probability that a hypothesis is true. A confidence interval is often more informative for judging the range of values consistent with an estimate, though it too depends on the model and its assumptions. Neither is reported for the primary endpoint in this record.

What does over-dispersion mean in general?

For outcomes analyzed as counts, over-dispersion means that the observed variability exceeds what a chosen probability model expects. It can make standard errors too small if ignored, and methods that accommodate extra variability may be needed. The listed primary endpoint is continuous and summarized by a mean and standard deviation; the registry record does not state that a count model or an over-dispersion adjustment was used. This general concept should not be mistaken for a feature reported in this study.

The registry includes a planning illustration framework based on a fraction of the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It states that such values are planning illustrations, not the trial’s own design, and that they are based on the observed effect. The registry record does not report a trial-specific sample-size justification or the numerical planning results in the information available for this analysis. These planning values should not be interpreted as observed power or evidence about the study’s findings.

In general, statistical power is a design concept tied to an assumed effect, variability, sample size, and analysis. It does not describe the probability that a completed study has found a true effect. A post hoc calculation based on an observed effect cannot replace examination of the estimate and its uncertainty. Because the primary endpoint results and inferential analyses are not reported, no assessment of power or precision for the observed endpoint is possible.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures and zero analyses. It does not report how the outcomes were prioritized beyond identifying the primary endpoint, or whether any multiplicity adjustment was planned. In general, when multiple outcomes or multiple comparisons are tested, the chance of obtaining at least one apparently unusual result can increase. A prespecified approach can help distinguish confirmatory analyses from exploratory ones. The absence of analysis details means the handling of multiple outcomes and comparisons is not reported in the registry record.

The primary endpoint uses repeated measurements and status classifications based on prior ecological momentary assessments. The registry does not describe a statistical method for repeated observations, specify how many measurements contributed to the mean, or report whether observations with incomplete assessment information were excluded or classified in another way. It also does not describe a missing-data strategy, such as an imputation procedure or sensitivity analysis. These omissions limit assessment of the endpoint’s analytic handling.

At the participant level, the endpoint analysis included N=83 participants with at least one valid heart rate variability measurement. The record lists N=2 participants lost to follow up, N=2 who withdrew from the study, N=2 withdrawn by the principal investigator, and N=3 for whom heart rate variability was not collected. That accounting explains the stated participant inclusion count, but it does not show whether missingness was related to alcohol reports, conflict reports, physiology, or other factors. The record also does not report a comparison of participants included in the analysis with those excluded.

The number of analyses is listed as zero, and no inferential results or analysis population definitions for secondary outcomes are described. Thus, the multiplicity approach, missing-data assumptions, and any sensitivity analyses are not reported in the registry record. These gaps do not establish that no such procedures occurred outside the registry, but they cannot be evaluated from the posted record.

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 5% reporting threshold.

The registry’s adverse-event summary lists the total sample as the group at risk, with 92 participants at risk for serious adverse events and 92 at risk for other adverse events. It records zero serious adverse events, zero other adverse events, and zero deaths. These are the event counts posted for the completed study.

In general, a recorded count of zero means no events of that type were reported in the registry’s summary for the stated group. It is not proof that an event was impossible, nor does it establish that every possible harm was captured or assessed in the same way. Interpretation depends on the study’s event definitions, monitoring procedures, reporting period, and completeness of follow-up. Those details are not reported in the registry record.

The safety figures should be read separately from the primary endpoint. They do not show the level of heart rate variability, the frequency of alcohol use or intimate partner violence, or the effect of the intervention. The record lists no serious-event terms and no other-event terms for the summary. The registry record does not provide further event descriptions or a breakdown by time, participant characteristics, or intervention exposure. Therefore, the appropriate reading is limited to the event counts and risk denominators recorded in the total-sample summary, without extending them to unreported safety details.

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

The registry record establishes that the study evaluated a smartwatch-based heart rate variability biofeedback intervention in a single group, using wearable physiological monitoring and smartphone reports. It specifies respiratory sinus arrhythmia as the primary continuous measure and describes how measurement periods were classified according to alcohol and intimate partner violence status at the prior report. It also identifies the primary endpoint analysis population as N=83 participants with at least one valid measurement.

What the posted record does not establish is the numerical level of the endpoint or whether it differed across reported status categories. Means, standard deviations, contrasts, confidence intervals, and tests are not reported. The record lists zero analyses. Consequently, it does not support a conclusion about the direction, magnitude, or precision of an association between reported events and heart rate variability.

The single-group structure also limits causal interpretation. There is no separate control group or randomized comparison described, so the record does not provide a treatment-versus-control estimate. A change over time, or a difference across event classifications, cannot by itself distinguish an intervention effect from other explanations. This is a general limitation of interpreting observational patterns without a concurrent comparison, not a finding about what happened to participants.

The study’s stated broader aims include usability, feasibility, acceptability, alcohol use, and couple conflict, but results for these aims are not reported in the registry record available for this analysis. The serious adverse-event summary reports zero serious adverse events, zero other adverse events, and zero deaths among the total sample, but these counts do not answer the endpoint or intervention-effect questions.

Accordingly, the record is informative about the study’s intended measurement, monitoring approach, and analysis population, while leaving its primary numerical findings unavailable. The absence of posted results is not evidence of no effect, no association, or no change. It means those quantities cannot be assessed from the registry record.

13. Why This Trial Matters Statistically

This study is statistically notable for combining continuous wearable monitoring with repeated reports about alcohol use and couple conflict. Such data can provide fine-grained measurements of physiology and context, but they also create analysis challenges. Measurements collected repeatedly from the same participant are not generally independent, and event reports and physiological readings need a clearly described temporal relationship. The registry record does not report how these features were modeled.

The endpoint also illustrates the difference between a biomarker and a clinical outcome. Respiratory sinus arrhythmia is described as a physiological marker related to autonomic arousal. Its measurement can be informative about physiological patterns, but the registry’s description does not establish that a particular value corresponds to a specific change in alcohol use or intimate partner violence. The clinical meaning of a biomarker depends on evidence connecting it to outcomes and decisions, which is not reported in the record.

A single-group design can be useful for studying feasibility and measurement procedures, but it cannot provide a randomized comparison with an untreated or alternative-treatment group when no such comparator is listed. Keeping the design in view helps prevent descriptive patterns from being framed as causal effects. The registry’s aims include usability and acceptability, yet those results are not reported in the endpoint information; nor does the record include inferential results for the primary measure.

Finally, reporting the participant inclusion count and reasons for exclusion is useful for understanding who contributed data to the endpoint. However, a valid measurement from a participant does not necessarily mean complete data across the observation period. The absence of information about repeated-observation counts and missing-data handling makes it difficult to assess the representativeness and precision of the endpoint summaries. These considerations make transparent analysis reporting especially important for wearable studies with frequent, potentially incomplete measurements.

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 principal limitation for interpreting the primary endpoint is that the registry record describes the measure but does not report its numerical results. No endpoint means, standard deviations, effect estimates, confidence intervals, or hypothesis tests are available. Although the record lists four outcome measures, it lists zero analyses. The size and precision of any observed endpoint pattern therefore cannot be assessed.

The study is recorded as a single-group model, without a listed randomized comparison or separate control group. This precludes a direct intervention-versus-control estimate from the registered design as described. In addition, the endpoint categories rely on self-reported alcohol and intimate partner violence or conflict at the prior report. The record does not give details about the time window linking those reports to physiological measurements or about the handling of optional event-triggered reports.

Repeated wearable readings and smartphone assessments may produce data that vary in number and completeness across participants. The registry record does not report observation counts per participant, the statistical approach for within-participant correlation, or the method for handling incomplete observations. The endpoint population includes N=83 participants with at least one valid heart rate variability measurement, while the registry lists N=9 participants excluded from that analysis for specified reasons. It does not report whether missingness within the included participants affected the analysis.

The record also does not report a detailed statistical analysis plan, a trial-specific sample-size justification, interim analyses, multiplicity procedures, or sensitivity analyses. Results for the broader aims of usability, feasibility, acceptability, alcohol use, and couple conflict are not reported in the endpoint information. These reporting limits do not establish that unreported procedures or results do not exist outside the registry; they restrict what can be concluded from the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Wearable Technology and Alcohol-Facilitated Intimate Partner Violence — NCT05374798.
• Registry record last updated 2025-07-14; status last verified 2025-07.
• Results first posted 2025-07-14.
• 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 describes a completed, single-group smartwatch intervention study sponsored by Medical University of South Carolina, with enrollment of 92. Its start date is 2023-01-27 and its primary completion date is 2024-05-28. The intervention uses smartwatch monitoring and smartphone ecological momentary assessments during a 28-day observation period.

The primary endpoint is mean respiratory sinus arrhythmia, in milliseconds, summarized with a standard deviation and classified by alcohol and intimate partner violence status at the prior report. The endpoint analysis included N=83 participants with at least one valid heart rate variability measurement. The registry lists four outcome measures and zero analyses; numerical primary endpoint results are not reported in the registry record.

The total-sample adverse-event summary records zero serious adverse events, zero other adverse events, and zero deaths, with 92 participants at risk for each listed category. The registry record does not describe a randomized control comparison or report inferential results for the primary endpoint.