A Smartphone-based Application Post-myocardial Infarction to Manage Cardiovascular Disease Risk: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Smartphone-based Application Post-myocardial Infarction to Manage Cardiovascular Disease Risk (NCT03416920), a na na study. The primary outcome is Number of Participants With Readmission at 30 Days.

2. Clinical Question

The study’s stated aims include evaluating the feasibility of onboarding patients to the application and the platform’s clinical efficacy. Those aims are not themselves outcome results. The named primary measure is a count of participants with a readmission, while the listed secondary outcomes concern readmission at 90 days and enrollment in clinic-based cardiac rehabilitation at 90 days. The registry record does not give results for these outcomes either.

3. Trial Design

The registry describes a completed, single-group study of Wellframe. The intervention description says that participants in the Wellframe arm would use the application for 90 days. The study is not presented as a randomized comparison: allocation is recorded as NA, masking as NONE, and the model as SINGLE GROUP. There is no control arm listed for a direct comparison.

The registry records enrollment of 167. This is the enrollment entry, not a reported analysis denominator for the primary outcome. The record does not state how many participants contributed data to each outcome, whether all enrolled participants began using the application, or whether follow-up was complete.

The recorded start date is 2018-02-12, and the primary completion date is 2019-08-20. The status is COMPLETED. These administrative details describe the study’s recorded timeline and status; they do not establish that outcome data were complete or analyzed.

The primary outcome is the number of participants with hospital readmission at 30 days. Two secondary outcomes are named: the number with readmission at 90 days and the number enrolled in clinic-based cardiac rehabilitation at 90 days. The record lists three outcome measures in total, but does not supply a result for the primary or secondary measures. A study protocol, detailed analysis plan, and sample-size justification are not reported in the registry record. The general planning assumptions attached to sample-size illustrations should not be read as the study’s actual design, particularly because those assumptions describe a two-arm allocation while the study is recorded as single-group.

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

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 Number of Participants With Readmission at 30 Days, measured over 30 Days.

The primary endpoint is the number of participants who were readmitted to hospital at 30 days. It is a participant count: it records whether participants experienced the specified event during the stated period, rather than describing the number of readmission episodes per participant. The registry does not give the observed count or a denominator for this endpoint.

Readmission is used as a clinical outcome that can describe hospital use after the procedure and intervention period. A count alone, however, does not show the proportion of participants readmitted unless the relevant denominator is also known. It also does not explain the circumstances of a readmission or establish why it occurred. The registry record does not report definitions for readmission, rules for confirming events, or details about how outcome status was obtained.

The application was intended for use over 90 days, whereas the primary endpoint’s stated timeframe is 30 days. These are distinct time periods in the record. The named secondary readmission outcome uses a 90-day timeframe, and the other secondary measure is enrollment in clinic-based cardiac rehabilitation at 90 days. No results for any of these measures are reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count describe?

The primary outcome is a count of participants with readmission at 30 days. In general, a binary outcome classifies each participant according to whether an event occurred; a group-level count then reports how many participants met the event definition. That count is not the same as a rate, a risk, or a comparison between groups. To interpret a proportion, the relevant denominator is needed, and to estimate a comparative effect, an appropriate comparator and a defined contrast are needed. The registry record reports neither a primary-outcome count nor its analysis denominator.

What does the single-group structure allow?

General statistical context: a single-group study can describe outcomes among participants enrolled in that group. It cannot, on its own, distinguish an intervention effect from other influences that may affect outcomes over time. A concurrent comparison group can help estimate what would have happened under an alternative condition, provided the design and analysis support a fair comparison. No such arm is listed in this record, and allocation is recorded as NA. The registry also does not report an adjusted or unadjusted effect estimate.

The registry labels masking as NONE. Masking concerns whether participants, investigators, or outcome assessors are kept unaware of assigned treatment or study status. In a single-group study, the meaning and practical consequences of masking differ from those in a blinded randomized comparison. The record does not give further details about who knew which information or whether outcome assessment was independent.

Why do counts need context?

A count’s interpretation depends on how the event was defined, how follow-up was handled, and how missing outcome information was treated. For readmission, useful details would include the source used to identify events, the operational definition, and whether multiple admissions were counted as one participant with an event or as separate episodes. The registry identifies the endpoint as a participant count but does not report those procedural details. The measure should therefore be read according to its stated description, without assuming a more detailed definition.

General statistical context: when outcome data are missing, a complete-case count can describe only participants with observed outcome status. Other approaches may make different assumptions about participants whose status is unknown. The appropriate choice depends on the study question and missingness pattern. The analysis population, missing-data strategy, and amount of missing outcome information are not reported in the registry record.

How should uncertainty be understood?

General statistical context: estimates from a sample have uncertainty because the observed participants are not necessarily identical to all people of interest. A confidence interval communicates uncertainty around an estimate under stated assumptions. It is not a guarantee that the true value lies within that interval, and it does not address every source of bias. No confidence interval or primary-outcome estimate is reported in the registry record, so neither the direction nor the precision of the result can be evaluated.

For an event count, uncertainty and meaning depend on the denominator and the analysis target. A count without a denominator cannot establish the frequency of the event in the population of interest. In a single-group study, even a well-estimated frequency would remain a description of the observed group rather than a controlled estimate of the application’s effect relative to another strategy.

What do the planning assumptions mean?

The registry’s sample-size planning description refers to a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also says that the effect to detect is a stated fraction of the observed effect. These are assumptions for planning illustrations, not evidence that the study used that design or analysis. The record describes this trial as single-group, so the two-arm assumptions do not constitute its protocol.

General statistical context: a sample-size illustration estimates the number of participants or events that a hypothetical design might require under specified assumptions. Such a calculation depends on the target effect, variability or event frequency, analysis method, and desired power. It is not an observed result and is not “observed power.” The trial’s own sample-size rationale and analysis plan are not reported in the registry record. No numerical planning result is reported in the registry record for this analysis.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Wellframe")
n      <- c(118)
events <- c(10)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Wellframe  118  10  8.5  4.1  15.0  4.7  14.9  4.7  14.9

11. Multiplicity, Missing Data and Analysis Populations

The registry names a primary outcome and two secondary outcomes. Considering several outcomes can raise multiplicity concerns: when many statistical tests are conducted, the chance of at least one apparently notable result may increase. General approaches include specifying a primary hypothesis in advance, adjusting testing procedures, or treating secondary findings as exploratory. The registry record does not report a multiplicity strategy, planned hypothesis tests, or an analysis plan. It also lists no analyses, so there is no reported set of outcome tests to assess for multiplicity.

Missing-data handling is not reported in the registry record. The record does not give the number with known readmission status, the number with unknown status, reasons for missingness, or any method used to handle incomplete follow-up. It does not say whether analyses included all enrolled participants, only participants who began the application, or another defined group. These analysis populations are not reported in the registry record.

General statistical context: the treatment of missing outcomes can affect both the estimate and its uncertainty, especially if outcome availability is related to participants’ health or engagement. A reader cannot determine the direction or extent of any such influence without information on missingness and the analysis approach. The enrollment entry alone does not answer these questions.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

The registry’s adverse-event entry lists the Wellframe group with 118 participants at risk for serious events and 0 affected. It also lists 118 at risk for other events and 0 affected, with 0 deaths. These are the adverse-event figures recorded for the group; they are not a substitute for the missing primary readmission result.

The registry record does not provide further detail about the adverse-event collection period, event definitions, ascertainment process, or the relationship between the participants at risk and the endpoint analysis population. The enrollment entry is 167, while the adverse-event entry lists 118 at risk; the record does not explain this difference. The listed zeros therefore should be read as the recorded counts in the adverse-event entry, not as proof that no unrecorded events occurred or that the application has no safety risks.

General statistical context: an observed count of zero does not by itself establish that an event is impossible. How much can be inferred depends on the number monitored, completeness of follow-up, and how events were sought and defined. Those details are not reported in the registry record.

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

The registry record establishes that a completed, single-group study evaluated the Wellframe platform in a post-PCI context, with intended application use over 90 days. It identifies hospital readmission at 30 days as the primary outcome and names two secondary outcomes at 90 days. It also describes the platform’s educational, tracking, reminder, and communication features.

The record does not report the primary or secondary outcome results. It therefore does not show how many participants were readmitted at 30 days, how many were readmitted at 90 days, or how many enrolled in clinic-based cardiac rehabilitation at 90 days. It also does not report an estimate of intervention effect or its precision. No conclusion about clinical efficacy can be drawn from outcome results that are absent from the registry record.

The design further limits causal interpretation: there is no concurrent comparison arm listed. Even if an outcome count were available, a single-group observation would not by itself show what would have happened without the application or under another approach. The intended intervention and the study’s stated aims are not evidence of an effect.

The adverse-event entry records zero serious events, zero other events, and zero deaths among the listed group entries, with 118 participants at risk for each event category. These figures need to be interpreted in light of the record’s limited reporting about follow-up and event ascertainment. They cannot establish the absence of risk.

Thus, the record describes the intervention, design, and planned outcome questions, but offers insufficient outcome and analysis information to judge the application’s clinical effect or the precision of any effect estimate.

14. Why This Trial Matters Statistically

This study illustrates why a registry’s design description and outcome reporting need to be read together. The intervention is described in concrete terms, and the primary question is identifiable, but the record does not report the primary outcome count or an analysis. A stated aim to assess clinical efficacy is not equivalent to a reported estimate of efficacy.

The single-group structure is also central. An outcome observed in one group can describe that group, but a treatment effect is inherently comparative: it depends on what happened under the intervention relative to an appropriate alternative. Without a concurrent control arm, the record cannot provide that direct comparison. This distinction remains important even when the outcome itself is clinically relevant.

The difference between intervention duration and endpoint timeframe matters for interpretation as well. The application was intended for 90 days, while the primary outcome is specified at 30 days and the secondary outcomes at 90 days. Those timeframes identify different questions. Complete results and clear follow-up definitions would be needed to understand how each outcome was assessed.

Finally, the record’s planning assumptions should not be mistaken for the actual study design. The planning description assumes two-arm allocation, while the trial is recorded as single-group. Keeping planning illustrations separate from the protocol and observed findings is essential for sound statistical interpretation.

15. 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.

Several trial-specific reporting limitations restrict interpretation. Most importantly, the registry record does not report the observed primary readmission count, its denominator, an effect estimate, or uncertainty. The named secondary outcomes also lack reported results. The record lists three outcome measures but provides no outcome analysis, and it lists no analyses.

The single-group design has no listed concurrent comparator. It therefore does not support a direct controlled estimate of the application’s effect. Allocation is recorded as NA, masking as NONE, and the model as SINGLE GROUP; details that might clarify implementation or assessment are not reported in the registry record.

The record does not report eligibility criteria beyond the post-PCI context, participant characteristics, application uptake, completeness of follow-up, or the analysis population. It does not explain the difference between the enrollment entry of 167 and the adverse-event entry’s 118 participants at risk. This difference cannot be resolved from the record.

Readmission and rehabilitation outcome definitions, outcome ascertainment methods, missing-data procedures, multiplicity handling, and the statistical analysis plan are not reported in the registry record. Nor is the trial’s own sample-size justification reported. The listed planning assumptions describe a two-arm illustration rather than the recorded single-group design, so they should not be treated as protocol details.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Smartphone-based Application Post-myocardial Infarction to Manage Cardiovascular Disease Risk — NCT03416920.
• Registry record last updated 2023-07-17; status last verified 2022-08.
• Results first posted 2023-07-17.
• 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.

19. Record Summary

The registry record describes a completed, single-group study of the Wellframe application for people after PCI. Enrollment is listed as 167; intended application use was 90 days. The primary outcome is the number of participants with hospital readmission at 30 days. Secondary outcomes concern readmission and clinic-based cardiac rehabilitation enrollment at 90 days.

No primary or secondary outcome results, estimates, confidence intervals, or analyses are reported in the registry record. No concurrent comparator is listed, and the record does not report a detailed analysis plan, missing-data approach, or sample-size justification. The adverse-event entry lists 0 serious events, 0 other events, and 0 deaths, with 118 participants at risk for each event category.