Targeting Obesity to Optimize Health in Cardiac Rehab (TOPCARE): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Targeting Obesity to Optimize Health in Cardiac Rehab (TOPCARE) (NCT03423238), a randomized na study. The primary outcome is Compliance - Percentage of Sessions Attended.

2. Clinical Question

TOPCARE is registered as NCT03423238. Its stated aim focuses on feasibility, rather than a reported test of clinical benefit. This distinction matters when reading the record: the attendance endpoint can describe participation in the intervention, but it is not itself a measure of change in body weight, walking performance, strength, or mobility. Those measures appear among the listed secondary outcomes, without results in the registry record.

3. Trial Design

TOPCARE is registered as a randomized, double-masked, parallel-group trial with an enrollment of 38. The registry lists the phase as not applicable. The trial status is completed. Its recorded start date is 2018-03-21, and its primary completion date is 2020-04-10. These dates describe the registry timeline; they do not provide details about recruitment duration, follow-up completeness, or when individual participants completed study visits.

Participants were assigned to Rehab Only or Rehab+Weight Loss (WL). The registry describes randomization using blocking stratified by sex and obesity severity, with the obesity-severity categories defined using BMI below 30 versus BMI 30 or higher. Blocking and stratification describe features of the assignment procedure, but the registry record does not report the block sizes, sequence-generation method, allocation concealment procedures, or the people who were masked.

Both groups were described as receiving standard exercise-based cardiac rehabilitation. The Rehab+Weight Loss (WL) group was also assigned a weight-loss intervention. Listed intervention categories include exercise, health education, exercise compliance, calorie-restricted diet, behavioral modification, weight-loss compliance, and dietary counseling. The arm descriptions are incomplete, so specific schedules, contact frequency, and intervention fidelity procedures are not reported in the registry record.

The stated primary goal was to determine the feasibility of adding a 6-month behavioral weight-loss intervention to exercise-based cardiac rehabilitation. The primary endpoint was attendance at exercise or counseling sessions over 6 months. Body weight, a 6 Minute Walk (6MW) Test, grip strength, and mobility are among the listed secondary outcomes. The registry record does not provide a complete sequence of visits or outcome time points.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

5. Baseline Characteristics

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

6. Primary Endpoint

The registry lists the primary outcome as Compliance - Percentage of Sessions Attended, measured over 6 months.

The primary endpoint is the percentage of exercise or counseling sessions attended over 6 months. The record defines it as the number of sessions attended divided by the number prescribed, multiplied by 100. It is summarized as a mean with a standard deviation. The endpoint therefore expresses participation relative to each participant’s prescribed sessions, rather than an absolute count of visits.

Attendance is relevant to a feasibility question because it describes whether participants took part in the planned exercise or counseling activities. In general, a mean summarizes the average value in a group, while a standard deviation describes the spread of individual values around that mean. These statistics can characterize attendance, but they do not by themselves establish why attendance varied or whether the intervention changed a health outcome.

The registry record does not report group means, standard deviations, an estimated between-group contrast, or uncertainty intervals for this endpoint. It also does not report the number of sessions prescribed or attended. As a result, the endpoint’s definition and time frame are available, but its observed values and the precision of any comparison are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

TOPCARE is described as randomized, double-masked, and parallel-group. In general, random assignment is intended to make treatment groups comparable on average with respect to both measured and unmeasured baseline factors. It does not guarantee that groups will be identical, particularly in a small study. The registry states that randomization used blocking stratified by sex and obesity severity. In general, blocking can help maintain assignment balance as enrollment proceeds, while stratification defines categories within which the assignment process is organized. The block sizes and other technical details are not reported in the registry record.

Double masking is the registry’s classification of the trial. In general, masking can reduce the influence of expectations on participant behavior, care, or outcome assessment. The record does not specify which people were masked, how masking was maintained, or whether it was assessed. The allocation concealment process is also not reported in the registry record. These are distinct design details and should not be inferred from the masking label alone.

What does the primary summary measure tell the reader?

The primary endpoint is a continuous measure: percentage of prescribed exercise or counseling sessions attended over 6 months. The record specifies a mean and standard deviation. In general, the mean reports the group’s average, and the standard deviation describes variability among the observations. Neither statistic alone gives the uncertainty of a group comparison. A standard error or confidence interval for a contrast would address that uncertainty, but such results are not reported for the primary endpoint.

The endpoint’s denominator is the number of sessions prescribed. In general, a percentage based on a participant-specific denominator can reflect different prescribed amounts across participants. Interpretation therefore depends on how prescriptions were set and how attendance was recorded. The registry definition gives the calculation, but the number and scheduling of prescribed sessions and the handling of missed or unrecorded sessions are not reported in the registry record.

How should a group comparison be read?

In general, a comparison of group means estimates the difference in average endpoint values between randomized groups. A confidence interval describes the precision of that estimate, conditional on the model and assumptions used. A p-value is not an estimate of effect size and does not indicate the probability that a treatment is effective. For TOPCARE’s primary outcome, the registry does not report a comparison estimate, confidence interval, or p-value, so no numerical inference about a group difference is available.

The sample-size planning description specifies a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It describes planning illustrations based on fractions of an observed effect, rather than the trial’s own design. In general, such illustrations show the sample size associated with stated assumptions; they are not observed power and cannot replace the trial’s actual outcome estimate and uncertainty. The record does not include the numerical planning illustrations in the registry record for this analysis.

Why can over-dispersion matter?

General statistical explanation: over-dispersion occurs when the variability in data is greater than a model assumes. If a model underestimates variability, standard errors may be too small and confidence intervals too narrow. That can make evidence appear more precise than it is. Attendance percentages may have features that require careful modeling, but the registry record does not report a model for the primary endpoint or any assessment of over-dispersion. It is therefore not possible to say whether this issue applied to the trial’s analysis.

What analysis details are available?

The record identifies the primary endpoint, its time frame, and its descriptive summary as a mean with standard deviation. It does not report the analysis model, covariate adjustment, handling of repeated observations, or procedures for missing data. It also does not report whether the primary analysis followed intention-to-treat, per-protocol, or another population definition. Those choices can affect how an estimate should be understood, and none should be assumed from the randomized design alone.

The record lists 31 outcome measures and 42 analyses. In general, testing or estimating many outcomes raises questions about which outcomes were designated as primary and whether multiplicity was addressed. The primary endpoint is identified by name, but an analysis hierarchy and multiplicity procedure are not reported in the registry record. Numerical results and analysis-specific model details are likewise not reported.

10. Multiplicity, Missing Data and Analysis Populations

The registry identifies one primary endpoint: percentage of exercise or counseling sessions attended over 6 months. It also lists secondary outcomes including body weight, the 6 Minute Walk (6MW) Test, grip strength, and mobility measured with MAT-sf. Overall, the record lists 31 outcome measures and 42 analyses. The list of measures and analyses does not by itself explain which comparisons were confirmatory, which were exploratory, or how any repeated measures were organized.

Multiplicity refers, in general, to the statistical issue created when several outcomes, time points, or comparisons are examined. Without an adjustment or a prespecified hierarchy, the chance of finding at least one apparently notable result can increase as the number of tests grows. The registry record does not report a multiplicity adjustment, a testing hierarchy, or the planned approach to interpreting multiple analyses. It also does not provide the results needed to assess how those issues affected interpretation.

Missing-data methods are not reported in the registry record. The record does not state how participants with incomplete attendance records or missing secondary-outcome measurements were handled, whether imputation was used, or what assumptions underlay any such method. Analysis populations are also not reported: it is not stated whether the primary analysis included all randomized participants or a defined subset. Although the recorded enrollment is 38, enrollment alone does not identify the number included in each outcome analysis. These omissions limit assessment of attrition, analysis-set selection, and the robustness of any estimate.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: angina/percutaneous coronary intervention procedure (5.3%), left basilar pneumonia (5.3%).

The registry lists safety figures for 19 participants in Rehab Only and 19 in Rehab+Weight Loss (WL). Serious adverse events are recorded for 2 participants in Rehab Only and 0 in Rehab+Weight Loss (WL). Other adverse events are recorded for 10 participants in each group. Deaths are recorded as 0 in both groups. These are the posted counts; the registry record does not report additional detail about event timing, duration, severity beyond the serious/non-serious classification, or relatedness to study interventions.

The listed serious adverse event terms are “Angina/Percutaneous coronary intervention procedure” and “Left basilar pneumonia,” each reported as 5.3%. The record does not specify an arm for either term in the information, so they should not be assigned to a group. The percentages are registry entries and are not recalculated.

General interpretation: adverse-event counts describe events recorded during the study, but a difference in counts does not establish that an intervention caused or prevented an event. Causal interpretation depends on the full safety definitions, observation period, event adjudication, and analysis context. Those details are not reported in the registry record. The figures should therefore be read as descriptive safety information rather than as a standalone causal comparison.

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

TOPCARE addresses a practical research question: whether a behavioral weight-loss intervention can be added to exercise-based cardiac rehabilitation, with feasibility assessed primarily through session attendance. The randomized, parallel-group design provides a framework for comparing Rehab Only with Rehab+Weight Loss (WL). The registry record also identifies several secondary measures, including body weight, walking performance, grip strength, and mobility.

The record does not report the observed primary endpoint results or the secondary-outcome results. It therefore does not establish the extent of attendance in either group, whether attendance differed between groups, or the precision of any such difference. It also does not show whether body weight, walking performance, strength, or mobility changed or differed. No treatment-effect conclusion should be drawn from outcome names, study completion, or the presence of an intervention.

General statistical explanation: a feasibility measure and a health outcome answer different questions. Attendance can describe participation in planned sessions; it does not by itself quantify a change in health. Likewise, a numerical contrast, if reported, would need to be read with its uncertainty and analysis assumptions. In this record, the primary estimate and its uncertainty are not reported, so neither the size nor reliability of a group difference can be assessed.

The safety figures are descriptive counts among 19 participants in each group. They include serious adverse events recorded for 2 participants in Rehab Only and 0 in Rehab+Weight Loss (WL), other adverse events for 10 participants in each group, and no deaths recorded in either group. These counts do not, on their own, establish a causal safety difference. Event attribution and further safety-analysis details are not reported in the registry record.

The most defensible reading is therefore limited: the record documents the trial’s design, stated feasibility aim, endpoint definition, listed outcomes, and selected safety counts. It does not provide the outcome results necessary to judge the primary comparison or the secondary measures.

13. Why This Trial Matters Statistically

This trial is statistically relevant because it distinguishes a feasibility question from an outcome-effect question. The primary endpoint is session attendance, a measure of participation in exercise or counseling rather than a direct measure of body weight or functional performance. Keeping that distinction clear prevents an attendance measure from being interpreted as evidence about a separate health outcome.

The randomized design and stated stratification by sex and obesity severity identify important features of the planned comparison. At the same time, an enrollment of 38 means that estimates, if reported, would need to be read with close attention to their precision. General statistical explanation: small studies can produce uncertain estimates, and observed group differences can be sensitive to a small number of observations. This is a reason to examine confidence intervals and analysis methods, not a basis for assuming a particular result.

The record lists 31 outcome measures and 42 analyses, making transparency about outcome selection and multiplicity particularly relevant. The registry record does not report a multiplicity strategy, missing-data procedures, or analysis populations. Those omissions prevent readers from evaluating how the full set of analyses was planned and interpreted.

Finally, TOPCARE’s stated aim concerns adding a weight-loss intervention to cardiac rehabilitation, while the primary outcome is attendance over 6 months. That pairing makes endpoint interpretation central: session participation can inform feasibility, but cannot stand in for clinical outcomes. Because numerical results are not reported in the registry record, the trial’s statistical importance lies in the questions its design raises and the limits on conclusions from the available information, rather than in a demonstrated effect.

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 for interpreting the registry record is that it describes the primary endpoint without reporting its observed values. Group means, standard deviations, an estimated comparison, and uncertainty measures are not reported. Secondary-outcome results are also not reported. As a result, the record supports description of the design and planned measure, but not an assessment of the size or precision of outcome differences.

The available arm descriptions are incomplete. They identify standard exercise-based cardiac rehabilitation and, for Rehab+Weight Loss (WL), an added weight-loss intervention, but do not provide full details of delivery, contact frequency, or adherence support. The eligibility criteria and a detailed account of the enrolled population are not reported in the registry record. Masking is labeled double, but who was masked and how the procedures operated are not specified.

Analysis methods are not reported in enough detail to evaluate the primary comparison. The record does not state the model, covariate adjustments, analysis population, or approach to missing data. It also does not report procedures for handling multiple outcomes or analyses. These omissions make it difficult to assess potential sensitivity to analysis choices, incomplete observations, or selective emphasis among outcomes.

The safety information is limited to participant counts, deaths, and two listed serious adverse event terms with percentages. Further information about event timing, attribution, follow-up duration, and ascertainment is not reported in the registry record. Finally, the enrollment of 38 and the completed status do not establish how many participants contributed to each analysis or how broadly findings would apply. Since outcome estimates are absent, no conclusion about generalizability based on observed effects is available.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Targeting Obesity to Optimize Health in Cardiac Rehab (TOPCARE) — NCT03423238.
• Registry record last updated 2021-11-23; status last verified 2021-09.
• Results first posted 2021-11-23.
• 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

TOPCARE (NCT03423238) is a completed, randomized, double-masked, parallel-group study sponsored by Wake Forest University Health Sciences. The registry lists an enrollment of 38, a start date of 2018-03-21, and a primary completion date of 2020-04-10.

The comparison was Rehab Only versus Rehab+Weight Loss (WL). The stated goal was to assess the feasibility of adding a 6-month behavioral weight-loss intervention to exercise-based cardiac rehabilitation. The primary endpoint was the percentage of prescribed exercise or counseling sessions attended over 6 months, summarized as a mean with standard deviation.

Listed secondary outcomes include body weight, the 6 Minute Walk (6MW) Test, grip strength, and mobility. The record lists 31 outcome measures and 42 analyses. Numerical primary and secondary outcome results, detailed analysis methods, missing-data procedures, and analysis populations are not reported in the registry record. Safety counts are listed for 19 participants per group, with no deaths recorded.