Garmin PACT (Physical Activity Tracking in Type 1 Diabetes Using Garmin Vivosmart): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Garmin PACT (Physical Activity Tracking in Type 1 Diabetes Using Garmin Vivosmart) (NCT05992350), a registered phase not stated study. The primary outcome is Moderate to Vigorous Physical Activity (MVPA) Amount.

2. Clinical Question

The clinical question is therefore best read as the intended subject of observation, not as a tested treatment effect. The record documents a plan to collect wearable-device and survey information over participation, but it does not report analyzed outcome data. It also does not establish that tracker use was compared with usual care, no tracker use, or another tracking device.

3. Trial Design

Garmin PACT (Physical Activity Tracking in Type 1 Diabetes Using Garmin Vivosmart) is registered as an observational study. The registry lists Children's Mercy Hospital Kansas City as sponsor and enrollment as 45. The listed study start is 2024-01-16, and the listed primary completion date is 2025-06-18. The current status is TERMINATED.

The study description says children and youth with type 1 diabetes and their parents would take part. Participants were to wear a Garmin Vivosmart (4 or higher) for a year and complete surveys at the beginning, middle and end of participation. The surveys were to ask about type 1 diabetes, diabetes management and physical activity. Parents of children were also to complete similar surveys about diabetes. The listed intervention is a Garmin physical activity tracker.

The record does not state how participants were allocated, and it does not describe a separate control group. It therefore does not support treating the listed arm as a randomized comparison or assuming that participants were assigned to contrasting conditions. The arm label “Primary Analysis Arm” does not by itself establish a comparator.

The registry describes 21 outcome measures, including the primary MVPA amount and secondary outcomes concerning self-reported physical activity and self-reported diabetes management. The primary outcome timeframe is “Up to 365 days +- 30 days.” The record states that the study was terminated before analysis because of slow enrollment and unexpected termination; the little data collected could not be analyzed, and there is no future plan to analyze it. The registry lists zero analyses. Thus, the design and intended measurements are described, but the record does not supply analyzed outcome estimates.

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: Only parent data was collected for Secondary Outcomes 16, 18, and 21. Parents only completed the Hypoglycemic Fear Scale II for Parents (HFS-P).

Overall Study

Analysis population for the primary outcome, as defined in the registry: Study terminated before analysis took place, due to slow enrollment and unexpected termination the little data collected could not be analyzed. There is no future plan to analyze the 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.

Population: Only parent data was collected for Secondary Outcomes 16, 18, and 21. Parents only completed the Hypoglycemic Fear Scale II for Parents (HFS-P).

6. Primary Endpoint

The registry lists the primary outcome as Moderate to Vigorous Physical Activity (MVPA) Amount, measured over Up to 365 days +- 30 days.

The primary endpoint is the amount of moderate to vigorous physical activity (MVPA), described as minutes per day. MVPA refers to activity at moderate or vigorous intensity; measuring its daily amount provides an outcome tied directly to the study’s stated question about physical activity. A wearable tracker is relevant to this question because the study planned for participants to wear a Garmin Vivosmart while taking part.

The timeframe is “Up to 365 days +- 30 days.” The registry does not specify a unit in the endpoint unit field, but its description identifies minutes per day. The record does not explain the precise calculation of daily MVPA, how device readings were converted into the endpoint, what minimum wear time would count as usable measurement, or how missing device readings would be handled. These details are not reported in the registry record.

The endpoint’s purpose is to quantify physical activity, not to establish by itself whether diabetes status or management changed. Those topics appear among the study’s questions and secondary outcomes, but the primary outcome is MVPA amount. Because the study ended before analysis, no endpoint estimate, uncertainty interval or comparison is reported. The endpoint can therefore be described as the planned measure, but not as an observed finding.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the study as observational and lists the intervention as a Garmin physical activity tracker. It does not report a statistical analysis plan. In particular, the record does not describe a model, a hypothesis-testing procedure, an adjustment strategy, or a plan for estimating change in MVPA. It also does not report how a comparator was defined or whether any formal comparison was planned. These omissions matter because the choice of analysis depends on the question, the measurement schedule, the structure of the data and the intended comparison.

What would an endpoint estimate represent?

In general, an endpoint estimate is a numerical summary of the outcome for a defined population and analysis. For MVPA, the planned outcome is described as minutes per day. Depending on the prespecified question, an analysis might summarize participants’ measurements at a particular time, describe change over time, or compare defined groups. Those are different estimands: each answers a different question. The registry does not specify which estimand was planned, and no estimate is reported.

Repeated measurements can require methods that account for the fact that measurements from the same participant are related. In general, treating repeated observations as independent can misrepresent uncertainty. A longitudinal analysis may model the pattern of measurements over time, while a simple summary at one time point addresses a narrower question. The planned beginning, middle and end surveys indicate repeated survey occasions, but the record does not give the statistical method for handling them. It also does not explain whether wearable measurements were continuous, summarized by day, or analyzed in another way.

How should uncertainty be understood?

In general, a confidence interval gives a range of values compatible with the data and the assumptions of the analysis. Its width conveys precision: wider intervals indicate less precise estimates than narrower intervals. A point estimate without an interval gives less information about uncertainty, while a p-value addresses a specific testing framework and does not describe the size of an effect. Here, the registry reports no analyzed primary outcome estimate, confidence interval or primary analysis p-value. There is therefore no reported inferential result to interpret.

Statistical precision depends not only on the enrollment listed in a registry but also on the amount and quality of outcome data that can be analyzed, the variability in those data, and the analysis design. The record says the little data collected could not be analyzed. It does not report how many participants had usable device readings or completed surveys, so enrollment alone cannot establish the precision that an analysis might have achieved.

What do planning assumptions mean?

In general, a sample-size planning illustration uses assumptions about a target effect, variability, allocation and statistical procedure to show the amount of information a future study might need. Such a calculation is not an outcome finding, and it is not observed power. The registry’s stated planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect expressed as a stated fraction of the observed effect. They are identified as planning illustrations computed from an observed effect, not as the trial’s own design. The record does not report the trial’s sample-size justification or establish that the observational study used equal allocation or two arms. In particular, an illustration based on an effect should not be read as a result of this terminated study.

For time-to-event outcomes, general planning methods may count events rather than participants, while other designs may express a planning requirement per arm. That distinction concerns how a calculation is expressed; it does not establish that this study had a time-to-event endpoint. The primary endpoint is MVPA amount, and no time-to-event outcome is identified among the registry entries about the primary endpoint.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variability is greater than a statistical model assumes. If a model underestimates variability, uncertainty intervals may be too narrow and tests may appear more decisive than warranted. Appropriate modeling can account for extra variability when the outcome and data structure call for it. The registry does not report a model for MVPA, a dispersion estimate, or an assessment of over-dispersion. It would therefore be speculative to say whether this issue applied or how it was handled.

More broadly, the registry does not report model diagnostics, covariate adjustment, assumptions about missingness, handling of repeated wearable readings, or a prespecified analysis population. These are not details that can be reconstructed from the endpoint name or study summary. Since the record states that analysis did not take place, statistical methods can be discussed only as general concepts, not as procedures used to produce study findings.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 21 outcome measures and zero analyses. The listed secondary outcome categories include self-reported physical activity and self-reported type 1 diabetes management. Repeated entries appear for those categories, but the record does not explain how each measure differs, which outcomes were intended for particular time points, or which comparisons were considered primary beyond the stated MVPA endpoint.

When a study tests multiple outcomes or comparisons, the chance of at least one apparently noteworthy result can increase. In general, multiplicity procedures may control the interpretation of several tests, or investigators may identify a small number of primary hypotheses in advance. The registry record does not report a multiplicity plan, an analysis hierarchy, or any completed tests. Because the study was terminated before analysis, there are no outcome test results from which to assess multiplicity in practice.

The record says the little data collected could not be analyzed, but does not report the amount or pattern of missing wearable or survey data. It does not state whether data were missing because of non-wear, missed surveys, withdrawal, or other reasons. No missing-data assumptions, imputation method, sensitivity analysis or complete-case approach is reported in the registry record.

Similarly, the analysis population is not reported in the registry record. The record does not specify who would have been included in an analysis of the primary endpoint or how participants with incomplete measurements would have been handled. Enrollment as listed in the registry should not be treated as the number contributing to an endpoint analysis. Since no analysis took place, there is no reported analysis population to evaluate.

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.

Most frequent non-serious adverse event terms

The registry lists one arm titled “Primary Analysis Arm.” For serious adverse events, it records 24 at risk and 0 affected. For other adverse events, it records 24 at risk and 3 affected. The death count is 0. These are the posted safety figures; they should not be converted into rates or read as an estimate of comparative risk.

The study is observational, allocation is not stated, and the record does not describe a like-for-like control comparison. The listed arm therefore does not establish a controlled safety contrast. The registry lists no top serious-event terms, so it does not identify a specific serious event category in that field. The record also does not explain the difference, if any, between the safety population and the enrollment listed for the study.

These entries describe the registry’s recorded adverse-event counts, not the primary MVPA outcome. They do not show whether tracker use caused or prevented an event. The study’s termination and lack of analysis also mean that the safety figures should not be treated as a comprehensive analysis of all collected data. No further detail about event timing, severity beyond the serious-event classification, or relationship to the tracker is reported in the registry record.

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

The record establishes that Garmin PACT was intended to examine wearable tracking, physical activity and aspects of type 1 diabetes among children and youth and their parents. It identifies daily MVPA as the primary endpoint and describes the planned use of surveys and a Garmin Vivosmart. It also records that the study was terminated before analysis took place.

It does not establish whether physical activity increased, decreased or stayed the same. No analyzed MVPA result is reported, and the record says the collected data could not be analyzed. The absence of an estimate is not evidence that the tracker had no effect; it means the record cannot quantify an effect. Likewise, no reported outcome establishes whether diabetes status or management changed.

The record also does not establish a causal effect. The study is observational, allocation is not stated, and no control comparison is described. A comparison of outcomes, even if available, would need to be interpreted in light of the study design and any factors that differed between participants. The registry does not report an analysis addressing such factors.

The enrollment entry does not reveal how much usable outcome information was available. The registry does not report endpoint-specific participation, device adherence, survey completion, or missing-data patterns. Without those details and without an analysis, neither the magnitude nor precision of an outcome association can be assessed.

Thus, the appropriate conclusion is limited: the registry describes the intended questions and measurements, but it reports no analyzed primary or secondary outcome findings. The listed adverse-event figures are safety entries for the registry arm, not evidence of an effect on physical activity or diabetes outcomes. Any claim that the tracker did or did not change an outcome would go beyond what the record reports.

13. Why This Trial Matters Statistically

This record illustrates why a registered research question and an analyzed result are not the same thing. The study names a clinically relevant outcome—daily MVPA—and describes a plan to collect wearable and survey information. But it was terminated before analysis, and the registry says the collected data could not be analyzed. Consequently, the clinical question remains unanswered by the posted results.

Statistically, the distinction prevents an important interpretive error: treating a lack of reported findings as evidence of no effect. Without an endpoint estimate, there is no direction or magnitude to assess, and without an uncertainty interval there is no basis for judging precision. The record’s enrollment entry cannot replace those quantities or reveal how much analyzable data existed.

The observational design also makes clarity about the intended comparison important. The record does not state allocation or identify a like-for-like control group. That limits what could be inferred about causal effects, even apart from the lack of an analysis. A well-described question, population, outcome and comparison are necessary for readers to understand what an estimate would mean.

Finally, the entry is a reminder that outcomes, missing data, analysis populations and multiplicity plans are part of the evidence, not administrative details. The registry does not report these methods, and its statement that analysis did not occur makes those omissions consequential. Readers can identify what the study set out to examine, but should distinguish that intent from evidence about whether the tracker changed physical activity or diabetes-related 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 important limitation is stated directly in the registry: the study was terminated before analysis, the little data collected could not be analyzed, and there is no future plan to analyze it. As a result, the record contains no primary endpoint estimate and no analyzed secondary outcome results. The reason given is slow enrollment and unexpected termination.

The record offers limited detail about the data that were collected. It does not report the number of participants with usable wearable measurements, the completeness of device wear, the number completing surveys, or the pattern of missing measurements. The enrollment entry alone cannot indicate the quantity or quality of data available for any specific endpoint.

The registry does not describe allocation, a comparator group, or the intended statistical analysis. It also does not report a sample-size justification, analysis population, method for handling repeated measurements, missing-data approach, or plan for multiple outcomes. These details are not reported in the registry record, so neither the intended inferential framework nor the achievable precision can be assessed.

The endpoint description identifies MVPA in minutes per day and a timeframe of “Up to 365 days +- 30 days,” but the record does not explain how device readings were processed into the daily measure. Nor does it specify how incomplete wear or survey data would affect endpoint construction. The secondary outcomes are named in broad self-reported categories without further analytic results.

Finally, the safety entries do not supply a controlled comparison and are not linked in the record to an analysis of tracker-related risk. These limitations mean the registry documents the study’s intent and termination, but cannot support conclusions about outcome effects, precision or causality.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Garmin PACT (Physical Activity Tracking in Type 1 Diabetes Using Garmin Vivosmart) — NCT05992350.
• Registry record last updated 2025-10-20; status last verified 2025-09.
• Results first posted 2025-10-20.
• 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

Garmin PACT is an observational study of Garmin Vivosmart use among children and youth aged 8-21 with type 1 diabetes and their parents. The registry lists Children's Mercy Hospital Kansas City as sponsor and enrollment as 45. Participants were to wear a Garmin Vivosmart (4 or higher) for a year and complete surveys at the beginning, middle and end of participation.

The primary endpoint is the amount of moderate to vigorous physical activity, described as minutes per day, over “Up to 365 days +- 30 days.” The study status is TERMINATED. The registry states that slow enrollment and unexpected termination left little data, which could not be analyzed, and that there is no future plan to analyze it. No primary outcome result or analysis is reported.

The registry lists 21 outcome measures and zero analyses. Its safety entries list 0 serious adverse events, 3 other adverse events and 0 deaths for the named arm. Allocation and a like-for-like control comparison are not reported.