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 Feasibility Study to Improve AF Outcomes Using a Digital Application for CV Risk Reduction (NCT04050982), a randomized na study. The primary outcome is Percentage of Text Messages That Were Reviewed.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04050982 |
| Phase | NA |
| Condition | Atrial Fibrillation |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 11 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Stanford University |
| Results posted | Yes |
2. Clinical Question
Population
People with atrial fibrillation. The registry record lists an enrollment of 11. The pilot outcome was collected only among participants in the Pilot Testing group who interfaced with the AF CARE platform.
Intervention
AF CARE, a digital application intended to support lifestyle modification and cardiovascular risk reduction. The arm descriptions include participants interfacing with the application, including an AF CARE plus Usual Care group and a Usual Care then AF Care group.
Comparator
Usual care is named as a comparator in the planned study description. One arm description specifies usual care only for 6 months before participants interface with AF CARE. The primary outcome, however, was collected only in Pilot Testing, so it does not provide an outcome comparison between intervention and comparator groups.
Primary question
Among participants who used AF CARE in Pilot Testing, what was the mean percentage of text messages reviewed from baseline through month 6? The registry record identifies this as the primary outcome but does not report the observed mean or full range.
The registry record describes a pilot focused on the feasibility of using AF CARE to support lifestyle modification for people with atrial fibrillation. It also describes a prospective randomized study intended to compare cardiovascular risk factors, atrial fibrillation knowledge, symptom severity and burden, and quality of life between and within a wait-list group and an AF CARE group at baseline, 3, 6, and 12 months. Those planned comparisons are not the primary outcome reported in the record.
The distinction matters: the listed primary outcome is an engagement measure, not a direct measure of cardiovascular risk, symptoms, or quality of life. Its purpose can be understood as describing whether messages were reviewed by platform users. Whether the application changed clinical or patient-reported outcomes cannot be determined from this primary outcome, and those numerical results are not reported in the registry record.
3. Trial Design
The registry record identifies NCT04050982 as a randomized, parallel study with no masking. It lists the phase as NA and an enrollment of 11. Stanford University is named as the sponsor. The study started on 2019-10-01, reached primary completion on 2023-01-26, and has a status of TERMINATED. The reason for termination is not reported in the registry record.
The title and study description characterize the work as a feasibility study and a precursor to a multicenter randomized trial. The brief description distinguishes a pilot portion, intended to assess the feasibility of AF CARE, from a prospective randomized portion intended to assess cardiovascular risk factors and patient-reported measures over time. The planned assessments are described at baseline, 3, 6, and 12 months. The record does not report whether all parts of that plan were carried out.
The intervention list names AF CARE as a device and Usual Care as a behavioral intervention. The arm descriptions include Pilot Testing, AF CARE plus Usual Care, and Usual Care then AF Care. The last description specifies a 6 month period of usual care only before participants interface with the application. These descriptions indicate different study activities, but the registry record does not give a complete account of how many participants were assigned to each arm or which comparisons were ultimately analyzed.
Random allocation means assignment is intended to use a chance-based process; in general, this can help balance baseline characteristics across groups. A parallel design means groups are followed in separate arms rather than all participants necessarily receiving every condition in sequence. Those general design features do not establish that the planned randomized comparisons have reported results. The registry record lists zero analysis records, and the primary outcome is limited to the Pilot Testing group. Thus the primary outcome cannot answer the planned between-group question.
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 | Pilot Testing | AF CARE Plus Usual Care | Usual Care Then AF Care |
|---|---|---|---|
| STARTED | 9 | 2 | 0 |
| Interfaced With AF CARE Digital Platform | 7 | 1 | 0 |
| COMPLETED | 7 | 1 | 0 |
| NOT COMPLETED | 2 | 1 | 0 |
Reasons for not completing this period:
| Reason | Pilot Testing | AF CARE Plus Usual Care | Usual Care Then AF Care |
|---|---|---|---|
| Did not meet eligibility criteria | 0 | 1 | 0 |
| Withdrawal by Subject | 1 | 0 | 0 |
| Unable to enroll on platform | 1 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Data for this outcome measure were collected only in the Pilot Testing group. Only participants who interfaced with the AF CARE platform are included.
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 | Pilot Testing | AF CARE Plus Usual Care | Total |
|---|---|---|---|---|
| Participants analysed | 9 | 2 | 11 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 5 | 1 | 6 |
| Age, Categorical: >=65 years | Participants | 4 | 1 | 5 |
| Sex: Female, Male: Female | Participants | 5 | 2 | 7 |
| Sex: Female, Male: Male | Participants | 4 | 0 | 4 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 9 | 2 | 11 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 1 | 0 | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 6 | 2 | 8 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 2 | 0 | 2 |
| Region of Enrollment: United States | Participants | 9 | 2 | 11 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Text Messages That Were Reviewed, measured over Baseline through month 6.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Full Range |
| Unit | percentage of texts |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is the percentage of text messages that were reviewed, measured from baseline through month 6. The registry record specifies the mean as the summary measure and the full range as the measure of dispersion. It says that data were collected only in the Pilot Testing group and that only participants who interfaced with the AF CARE platform are included.
In general, a percentage of messages reviewed describes engagement with messages: it relates the number reviewed to the number considered in the measure. The mean gives an average across the included participants or observations, while the full range describes the spread from the lowest to the highest recorded value. These summaries can help characterize whether the digital platform was being used, but the record does not state a threshold for acceptable engagement or explain how this outcome was intended to guide a feasibility decision.
The numerical mean and range are not reported in the registry record. Nor does the record provide a comparison group for this primary outcome: it was collected only in Pilot Testing. Consequently, the endpoint definition alone does not show how much message review occurred, how variable it was, or whether it differed from usual care. The record also does not report a primary-outcome analysis or a statistical test for this measure.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The most important interpretive point is that the registry record defines a primary outcome but does not report its numerical result. There is no posted mean percentage of text messages reviewed and no posted full range. Without those values, the degree of engagement and its variability cannot be described from the record. The listed outcome is confined to the Pilot Testing group, so it also cannot establish a contrast between AF CARE and usual care.
The record reports an enrollment of 11 and labels the study randomized and parallel. It describes a broader prospective randomized study comparing cardiovascular risk factors, knowledge, atrial fibrillation symptom severity and burden, and quality of life. It lists four secondary outcomes concerning changes in knowledge, quality of life, symptom severity, and symptom burden. Numerical results for those outcomes are not reported in the registry record. The record lists zero analysis records, so it does not present analytic estimates for these planned outcomes.
The status is TERMINATED. That status identifies the study’s recorded administrative state; it does not by itself explain why the study ended, whether the feasibility objectives were met, or whether the application had an effect. The reason for termination is not reported in the registry record. The study’s small enrollment and pilot framing are relevant context, but the record does not report a sample-size justification or enough outcome data to assess precision for an effect estimate.
For safety, the registry record lists 9 participants at risk in Pilot Testing and 2 in AF CARE Plus Usual Care. It records 0 serious adverse events and 0 deaths in each of those groups, as well as 0 other adverse events in each. These are the posted counts for the listed groups, not a comparison of treatment risks; no comparative safety analysis is reported. The absence of recorded events in these entries should not be interpreted as proof that an intervention is free of risk.
General statistical interpretation depends on both the estimated effect and its uncertainty. A confidence interval, when reported, describes a range of values compatible with the data and the analysis assumptions; it helps readers assess precision rather than merely whether a result crosses a significance threshold. No confidence interval or numerical effect estimate for the primary outcome is reported in the registry record. Accordingly, no conclusion about the size or precision of an engagement effect, or about differences in clinical or patient-reported outcomes, can be drawn from the posted results.
9. Statistical Methods Explained
Randomized allocation and outcome analysis address different questions. In general, randomization assigns participants to groups by chance and can reduce systematic differences between groups at the outset. It does not ensure that every group will be similar in a small study, and it does not substitute for reporting outcome data. The registry record labels this study randomized, but it does not report the allocation procedure, the numbers assigned to each arm, or an analysis comparing the randomized groups.
What does a mean and full range describe?
The primary outcome is summarized by a mean and a full range. In general, a mean is an average, and the full range reports the lowest and highest observed values. Together, they offer a compact description of a measure’s central level and its observed spread. The range can be sensitive to extreme observations and does not show how observations are distributed between its endpoints. Other summaries, such as a standard deviation or confidence interval, answer different questions; they are not reported for this primary outcome in the registry record.
Here the measure is the percentage of text messages reviewed, with a timeframe from baseline through month 6. The record does not state how message review was operationalized, how repeated messages or repeated observations were handled, or whether the mean was calculated across participants or another unit. It also does not report the outcome values. These missing details prevent a more specific reconstruction of the calculation.
Why does the study structure matter?
The study is described as having a pilot portion and a prospective randomized portion. The listed primary outcome belongs only to Pilot Testing, and only participants who interfaced with AF CARE are included. Therefore, the primary outcome is descriptive of application users in that group rather than a randomized contrast against usual care. A comparison of outcomes between randomized arms would require outcomes recorded and analyzed in those arms using a stated comparison method. Such an analysis is not reported in the registry record.
The brief description names planned assessments at baseline, 3, 6, and 12 months for cardiovascular risk factors, knowledge, symptom severity and burden, and quality of life. Repeated measurements can be analyzed in several ways. In general, an analysis may compare groups at a follow-up time, compare changes from baseline, or model measurements over time while accounting for their within-person correlation. The record does not specify which approach was planned or used. It also does not report estimates for the listed secondary outcomes.
What can a confidence interval add?
General statistical explanation: a confidence interval conveys the uncertainty around an estimate under the assumptions of the analysis. A narrow interval indicates greater precision than a wide interval, but the interval’s meaning depends on the study design, measurement, and analysis. An interval can also show which effect sizes remain compatible with the data. No confidence interval for the primary outcome is reported in the registry record, so its precision cannot be assessed from a posted interval.
A p-value, when reported, is a measure of how compatible the observed data are with a specified null model under the analysis assumptions. It is not the probability that the null hypothesis is true, and it does not quantify the size or importance of an effect. The registry record does not report a p-value or analysis for the primary outcome. No claim about statistical significance can be made from the outcome definition alone.
What do planning illustrations mean?
General statistical explanation: a sample-size calculation depends on design assumptions, including the target effect, significance level, allocation, and statistical model. An illustration based on an observed effect is a planning exercise; it is not evidence that the study had a particular probability of detecting an effect. The registry record describes a planning illustration using a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a fraction of the observed effect. It specifies that non-time-to-event illustrations count participants per arm, while time-to-event illustrations count total events.
Those assumptions describe the illustration, not necessarily the trial’s own design. The record does not report the trial’s sample-size justification, and the primary outcome has no posted observed effect from which to assess precision. Any sample-size illustrations should therefore be read as planning scenarios rather than observed power or a statement about the study’s ability to detect an effect.
What can the adverse-event counts establish?
General statistical explanation: adverse-event counts are descriptive unless the record also provides a defined observation period, event ascertainment details, and an appropriate comparison analysis. Counts can indicate what was recorded in the listed groups, but zero events in a small group does not establish zero underlying risk. The safety entries report participants at risk and event counts for two named groups. The record does not provide event definitions, exposure-adjusted rates, confidence intervals, or comparative tests.
Overall, the registry record contains design descriptions and outcome definitions, but it does not report enough statistical output to reproduce or assess an outcome analysis. Details such as the analysis population, handling of missing observations, model specification, covariate adjustment, and multiplicity procedure are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one primary outcome and four secondary outcomes: change from baseline in knowledge related to atrial fibrillation, atrial fibrillation quality of life score, symptom severity, and symptom burden. It also describes planned assessment of cardiovascular risk factors and these patient-related measures at baseline, 3, 6, and 12 months. Testing multiple outcomes, time points, or within-group and between-group contrasts can increase the chance of at least one apparently notable finding by chance. General statistical practice may address this through a prespecified hierarchy or multiplicity adjustment, but the record does not report whether either was planned or used.
The record lists zero analysis records and does not report numerical results for the primary or secondary outcomes. The analysis populations and analysis methods are not reported in the registry record. In particular, it does not state whether analyses were based on assigned groups, participants who completed follow-up, or another population. It also does not report how missing outcome measurements were handled, whether any participants withdrew, or how incomplete follow-up affected the results.
These omissions matter because missingness can affect both the amount of information available and the interpretation of an estimate. In general, complete-case analysis uses participants with observed data for the relevant outcome, while other methods may use additional assumptions to account for missing measurements. No approach can be attributed to this study from the registry record. The outcome description’s restriction to participants who interfaced with AF CARE defines the group included for that measure, but it does not explain missing data within that group or establish a broader analysis population.
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 |
|---|---|---|---|
| Pilot Testing | 0 | 9 | 0.0% |
| AF CARE Plus Usual Care | 0 | 2 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Pilot Testing | 0 of 9 |
| AF CARE Plus Usual Care | 0 of 2 |
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 |
|---|---|
| Pilot Testing | 0 of 9 |
| AF CARE Plus Usual Care | 0 of 2 |
The registry record lists safety counts for Pilot Testing and AF CARE Plus Usual Care. Pilot Testing has 9 participants at risk, 0 serious adverse events, 0 other adverse events, and 0 deaths. AF CARE Plus Usual Care has 2 participants at risk, 0 serious adverse events, 0 other adverse events, and 0 deaths. No serious adverse-event terms are listed.
These entries describe what was recorded for the named groups; they do not establish that no adverse events could occur. General statistical interpretation: zero recorded events in a group is compatible with uncertainty about the underlying event risk, particularly when the group is small. A comparative safety conclusion would require an appropriate comparison and information about event definitions, ascertainment, and observation time. Those details and a comparative analysis are not reported in the registry record.
The record does not give a complete accounting of safety outcomes across every arm description, nor does it report event rates or uncertainty intervals. The counts should therefore be read as descriptive registry entries, not as evidence that AF CARE is safer or less safe than usual care.
12. What the Result Does, and Does Not, Mean
The registry record establishes that NCT04050982 was a randomized, parallel feasibility study of AF CARE for people with atrial fibrillation, with an enrollment of 11 and a status of TERMINATED. It describes a pilot focused on feasibility and a prospective randomized component intended to compare cardiovascular risk factors, knowledge, symptoms, and quality of life. It also defines the primary outcome as the mean percentage of text messages reviewed from baseline through month 6 among Pilot Testing participants who interfaced with the application.
However, the record does not report the numerical primary-outcome result, its full range, or estimates for the listed secondary outcomes. It therefore does not show the observed level of message review, the variability of that measure, or whether the intended clinical and patient-reported measures changed. Because the primary outcome was collected only in Pilot Testing, it does not provide a randomized comparison of AF CARE with usual care.
The record’s description of randomization and planned groups should not be mistaken for reported evidence of a treatment effect. The registry record lists zero analysis records, and it does not report confidence intervals, p-values, or a statistical analysis plan. It also does not state why the study was terminated. Those gaps limit conclusions about feasibility, comparative outcomes, and precision.
General interpretation: a study’s design indicates what it was intended to assess, while reported outcome estimates indicate what the observed data show. An outcome definition or planned comparison is not itself a result. The safety entries record zero serious adverse events, other adverse events, and deaths in the two listed groups, but these descriptive counts do not establish absence of risk or comparative safety. The record supports describing the study and its reporting, but it does not support a conclusion about whether AF CARE changed health outcomes or was effective.
13. Why This Trial Matters Statistically
This study is statistically important as an example of the difference between a feasibility question and an outcome-effect question. The title and description frame AF CARE as a digital application intended to support lifestyle modification and cardiovascular risk reduction. The listed primary outcome, however, measures text-message review in the Pilot Testing group. That measure can describe engagement with the application, but it is not itself a measure of cardiovascular risk or a comparison of clinical outcomes.
The record also describes a prospective randomized component with outcomes intended to be assessed over time. This makes reporting the boundary between planned work and analyzed results especially important. Randomization can support a comparative design, but the primary outcome’s restriction to Pilot Testing means that outcome cannot serve as a randomized comparison. The record does not report numerical outcomes for the broader planned comparisons, so design intent and observed evidence must remain distinct.
From a biostatistical perspective, the record highlights why an outcome’s summary measure, population, timeframe, and analysis all matter. A mean and full range could describe message-review behavior, but without the actual values readers cannot assess its level or spread. Without reported estimates and uncertainty, readers also cannot judge precision. The absence of analysis details leaves questions about missing data, multiplicity, and analysis populations unanswered.
These limitations do not erase the descriptive value of a feasibility study. They do constrain what can be concluded from its registry record. For researchers planning digital interventions, the distinction between implementation measures and health outcomes is central to choosing endpoints and interpreting them. In this case, the record defines both a feasibility context and broader planned outcomes, while leaving numerical evidence for those outcomes unreported.
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 registry record provides limited outcome evidence. Although the primary endpoint is defined as the mean percentage of text messages reviewed, its observed mean and full range are not reported. The record also does not provide numerical results for the listed secondary outcomes, despite describing planned assessments of cardiovascular risk factors, knowledge, symptom severity and burden, and quality of life.
The primary endpoint is restricted to the Pilot Testing group and to participants who interfaced with AF CARE. That restriction makes the measure descriptive of platform users rather than a comparison between randomized groups. The record does not explain the precise calculation of message review or the unit over which the mean was calculated. It also does not report how many participants contributed primary-outcome data.
The study is marked TERMINATED, but the reason is not reported in the registry record. The record gives an enrollment of 11 but does not report a sample-size justification or explain whether the planned randomized component was completed. It lists arm descriptions but does not provide a complete account of assignment and outcome availability across all described groups.
Statistical methods are also insufficiently described for evaluating outcome estimates: the analysis populations, missing-data methods, multiplicity approach, and model specifications are not reported. The safety entries provide counts for two groups but do not describe event definitions, ascertainment, or comparative analyses. These limitations are specific to what the registry record reports and leave both the study’s feasibility findings and its planned comparative outcomes difficult to assess.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Feasibility Study to Improve AF Outcomes Using a Digital Application for CV Risk Reduction — NCT04050982.
- Registry record last updated 2023-09-22; status last verified 2023-08.
- Results first posted 2023-09-22.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT04050982 is listed as a randomized, parallel, unmasked study sponsored by Stanford University, with phase NA and enrollment of 11. It began on 2019-10-01, had primary completion on 2023-01-26, and is marked TERMINATED. Its title and description identify a feasibility study of AF CARE, a digital application for cardiovascular risk reduction in people with atrial fibrillation.
The primary outcome is the mean percentage of text messages reviewed from baseline through month 6, with a full range specified. It was collected only in Pilot Testing among participants who interfaced with AF CARE. The numerical result is not reported in the registry record. Four secondary outcomes concern changes in atrial fibrillation knowledge, quality of life, symptom severity, and symptom burden; their numerical results are also not reported. The registry record lists zero analysis records and does not state the reason for termination.