Effects of Cardiac Rehabilitation (CR) on Functional Capacity and Cardiovascular Risk Factors: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of Cardiac Rehabilitation (CR) on Functional Capacity and Cardiovascular Risk Factors (NCT02575976), a randomized na study. The primary outcome is Functional Capacity Assessed by Changes in Total Distance Walked in the Incremental Shuttle Walk Test.

2. Clinical Question

The trial’s broader purpose was to investigate whether a comprehensive program of exercise and education differed from exercise-only rehabilitation or wait-list control across functional capacity, cardiovascular risk factors, health behavior, disease-related knowledge, depressive symptoms, and mortality. The registry record does not provide posted results for every outcome named in that purpose. Interpretation of the primary question therefore rests on the 6-month walking-distance summaries and the two comparisons with wait-list control. These results describe the analyzed participants; they do not by themselves establish what would occur in all eligible patients or in other health-care settings.

3. Trial Design

The registry record describes a randomized, parallel-group trial with single masking. It lists three groups: comprehensive cardiac rehabilitation, exercise-based cardiac rehabilitation, and wait-list control. The comprehensive program included education and exercise-based rehabilitation; the exercise-based group received exercise-based rehabilitation; and the wait-list group received no cardiac rehabilitation. The sponsor was the Federal University of Minas Gerais. The recorded enrollment was 115, and the trial status is completed.

The trial began in 2015-03, with primary completion in 2017-10. The phase is listed as not applicable. The record identifies Brazilian patients assisted by public health care as the setting of interest and lists cardiovascular disease and coronary disease as conditions. These features help define the context to which the findings may be relevant. The registry record does not report additional details about the setting, recruitment procedures, or the extent to which participants reflected the wider population with these conditions.

The primary outcome was functional capacity measured as total distance walked in the Incremental Shuttle Walk Test at 6 months. The posted comparisons use wait-list control as the reference for each rehabilitation arm. They do not provide a direct primary-outcome comparison between comprehensive and exercise-based rehabilitation. The record describes the analyzed primary results as per protocol, using thresholds of a minimum of 24 exercise sessions and 16 education classes. Thus, the analyzed population was defined partly by participation after assignment, rather than simply by initial allocation.

The registry record does not report the original sample-size justification, planned analysis model, handling of missing outcome data, or any interim analyses. It lists no reported analyses. The posted comparison statistics should therefore be read as unadjusted recalculations from the group summaries, not as a substitute for an unreported sponsor analysis plan. The record’s description of randomization and masking does not supply further details about sequence generation, concealment, or who was masked.

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

Analysis population for the primary outcome, as defined in the registry: The analyzed population was based on the threshold sessions: a minimum of 24 exercise sessions and 16 education classes. The presented results considered the Per Protocol analysis, explaining the different numbers in the flow diagram and the analyzed numbers.

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 Functional Capacity Assessed by Changes in Total Distance Walked in the Incremental Shuttle Walk Test, measured over Functional capacity measured by walked distance in the ISWT at 6 months.

The primary endpoint is the change in functional capacity assessed by total distance walked in the Incremental Shuttle Walk Test at 6 months. The registry describes the ISWT as an externally paced, incremental walking test along a 10-meter course. Walking speed increases in steps, with audio signals setting the pace. Exercise heart rate and perceived exertion are recorded during the test, but the posted primary measure is distance walked in meters.

Distance is used as a functional measure because the test requires participants to sustain progressively faster walking. The registry record states that a higher number of meters indicates higher functional capacity. This makes the endpoint interpretable as a continuous measure: group averages can be compared, and a mean difference expresses the average distance contrast between an intervention group and wait-list control. It does not describe every participant’s performance or show how individual responses varied.

The endpoint is assessed at 6 months, so it concerns functional capacity at that follow-up point. Although the outcome title refers to changes in distance, the posted group results are means and standard deviations at the stated time point; baseline values and a reported change-score analysis are not reported in the registry record. The available comparison should therefore be understood as a contrast in the posted 6-month summaries, rather than assumed to be a baseline-adjusted change estimate.

7. Results Posted in the Registry

• Comprehensive CR: mean 488.10 versus 394.00 on control; difference 94.10 (95% CI 20.25 to 167.95), standardized effect d = 0.65; z-test p = 0.013.
• Exercise-based CR: mean 464.80 versus 394.00 on control; difference 70.80 (95% CI -7.02 to 148.62), standardized effect d = 0.47; z-test p = 0.075.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Risk Factors Measurement of Systolic Blood Pressure

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Comprehensive CR: mean 114.60 versus 120.00 on control; difference -5.40 (95% CI -15.29 to 4.49), standardized effect d = -0.29; z-test p = 0.285.
  • Exercise-based CR: mean 114.40 versus 120.00 on control; difference -5.60 (95% CI -14.77 to 3.57), standardized effect d = -0.32; z-test p = 0.232.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Comprehensive CR and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Exercise-based CR and the control. The interval gives the range of effects that remain compatible with the data.

Risk Factors Measurement of Waist Circumference.

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Comprehensive CR: mean 95.50 versus 94.90 on control; difference 0.60 (95% CI -5.70 to 6.90), standardized effect d = 0.05; z-test p = 0.852.
  • Exercise-based CR: mean 93.00 versus 94.90 on control; difference -1.90 (95% CI -7.20 to 3.40), standardized effect d = -0.20; z-test p = 0.483.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Comprehensive CR and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Exercise-based CR and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes with numerical summaries available in the registry record cover systolic blood pressure and waist circumference at 6 months. Across those measures, the posted group averages do not show a consistent pattern of clear separation from wait-list control: the recalculated confidence intervals for each active-arm comparison span zero. The point estimates vary in direction and size across outcomes, so they should be read as separate descriptive comparisons rather than as a single coherent estimate of a broad risk-factor effect.

These secondary measures address cardiovascular risk factors, whereas the primary outcome assesses functional capacity through walking distance. They provide context about other domains examined in the trial, but they do not replace or confirm the primary result. Nor do the secondary summaries establish that a difference in one domain explains a difference in another. The registry record names fasting blood glucose and total cholesterol outcomes, but numerical results for those measures are not reported in the registry record.

Secondary results generally carry less inferential weight when many outcomes or comparisons are examined without a reported multiplicity strategy. Each additional test creates another opportunity for a chance finding, and the registry record does not report an adjustment for this issue. The posted secondary comparisons are unadjusted recalculations, and no reported analyses are listed. Their estimates and intervals can inform descriptive interpretation, but isolated p-values should not be treated as definitive evidence of a treatment effect.

The absence of a statistically clear contrast in these posted summaries is not proof that the groups are equivalent. Conversely, a nominally notable result among multiple unadjusted comparisons would need cautious interpretation. The secondary findings are best viewed as exploratory context alongside the primary outcome, with attention to their uncertainty and the fact that not all named outcomes have posted numerical results.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Risk Factors Measurement of Systolic Blood Pressure
• Risk Factors Measurement of Waist Circumference.
• Risk Factors Measurement of Fasting Blood Glucose Values
• Risk Factors Measurement of Total Cholesterol Values.

9. Statistical Interpretation

10. Statistical Methods Explained

The outcome is continuous: distance walked is measured in meters, and the registry reports a mean and standard deviation for each analyzed group. A mean gives the group’s average result. A standard deviation describes how dispersed individual observations are around that average; it is not the uncertainty in the mean itself and does not imply that every participant had a result near the group mean.

The posted comparison is a mean difference between a rehabilitation group and wait-list control. A positive difference means the rehabilitation group’s reported average distance is higher; a negative difference means it is lower. For comprehensive rehabilitation, the recalculated difference is 94.1 meters. For exercise-based rehabilitation, it is 70.8 meters. These estimates are based on the posted group summaries and are identified as unadjusted recalculations, rather than reported adjusted model estimates.

A confidence interval gives a range of values compatible with the observed data under the assumptions of the calculation. Its width reflects statistical uncertainty, and its endpoints help show which effect sizes remain plausible. The comprehensive comparison has an interval from 20.25 to 167.9 meters, entirely above zero. The exercise-based comparison has an interval from -7.019 to 148.6 meters, which spans zero. An interval spanning zero does not prove that the true difference is zero; it means that the data do not rule out zero at the interval’s stated confidence level.

The unadjusted p-value summarizes how unusual results at least as incompatible with a zero-difference hypothesis would be if that hypothesis and the calculation assumptions held. It is not the probability that the null hypothesis is true, and it does not measure the clinical importance of the estimate. The posted unadjusted p-values are 0.013 for comprehensive rehabilitation and 0.075 for exercise-based rehabilitation. They should be interpreted alongside the estimates and intervals, not as stand-alone verdicts.

Random allocation can help make groups comparable at the point of assignment, on average, but the primary results are described as per protocol. Requiring attendance at a minimum of 24 exercise sessions and 16 education classes changes the analyzed population after allocation. If attendance is associated with health, motivation, access, or other prognostic characteristics, comparisons among threshold-meeting participants can be affected by selection. The registry record does not report an intention-to-treat primary analysis or an adjustment for any resulting selection.

The reported comparisons are each against wait-list control. A shared reference group does not make the two active-arm estimates a direct comparison with one another. Comparing the numerical sizes of the two estimates is descriptive; assessing whether the active programs differ would require a direct contrast and its uncertainty. That direct primary contrast is not reported in the registry record.

The standard deviation is relevant to precision because more variability generally makes a group mean less precisely estimated when the number of observations is fixed. The posted summaries include standard deviations of 106.3 meters for comprehensive rehabilitation, 121.6 meters for exercise-based rehabilitation, and 171.9 meters for wait-list control. The group sizes in the primary summaries are 26, 25, and 30, respectively. These are analyzed numbers, not necessarily the numbers initially allocated; the record explicitly notes that per-protocol analysis accounts for differences from the flow diagram.

The registry record does not report the original statistical analysis plan, whether covariates were included in a sponsor analysis, how missing outcomes were handled, or whether there was an interim analysis. The posted recalculations use the available summary statistics and do not resolve those unanswered design and analysis questions. The record also lists no reported analyses. Accordingly, the estimates and tests can be read as transparent unadjusted summaries, but not as evidence about unreported modeling choices.

Dispersion can matter especially when data are more variable than a simple model expects. In general, over-dispersion means observed variability exceeds what a model’s assumed distribution allows; ignoring it can make uncertainty appear too small. The posted endpoint is a continuous measure with group standard deviations, and the stated sample-size illustration uses a normal approximation. The registry record does not report a specific over-dispersion assessment or a model-based adjustment, so no such procedure should be assumed.

Multiplicity is the issue that arises when many outcomes or comparisons are examined. Testing several endpoints can increase the chance that at least one result appears notable by chance. The registry lists multiple outcome domains, but the adjustment strategy for multiple testing is not reported. Thus, the unadjusted p-values should not be treated as multiplicity-adjusted evidence, and isolated secondary findings would warrant particular caution.

Finally, statistical significance and practical importance are different questions. The estimate describes an average distance contrast; the confidence interval describes its statistical uncertainty. The registry record does not specify a threshold for a clinically important difference in walking distance. Without such a threshold, these statistics alone cannot determine whether a difference is important to patients or to clinical practice.

11. Confidence Intervals and Precision

The precision of a mean difference is conveyed by its confidence interval as well as by its point estimate. For comprehensive rehabilitation compared with wait-list control, the recalculated mean difference is 94.1 meters, with a 95% confidence interval from 20.25 to 167.9. The interval supports a positive average contrast in the posted analysis, but the range of compatible values is broad enough that the exact size remains uncertain.

For exercise-based rehabilitation compared with wait-list control, the recalculated mean difference is 70.8 meters, with a 95% confidence interval from -7.019 to 148.6. Because the interval extends from a value below zero to a value above zero, the estimate is imprecise with respect to whether the average contrast is positive or absent. The point estimate alone should not obscure that uncertainty.

Confidence intervals are not guarantees that the true effect lies within the reported endpoints. They describe the behavior of an interval procedure under its assumptions. These intervals were recalculated from posted summary statistics, and the registry record does not report a sponsor analysis from which to verify modeling or adjustment choices. Both estimates should therefore be interpreted as unadjusted comparisons in the stated per-protocol population.

Precision is also limited by the analyzed group sizes and the variability in walking distance. The standard deviations are substantial relative to the group means, especially in wait-list control. The sample-size illustrations use the observed effects for planning purposes, but they do not make the current estimates more precise. In particular, a confidence interval that includes zero is not evidence of no effect; it signals that a range of values remains compatible with the data and assumptions.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size illustrations are planning calculations based on the observed mean differences, not the original trial’s sample-size justification. The registry record does not report the assumptions used to plan the trial. For these illustrations, the stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The calculations consider effects equal to 100%, 75%, and 50% of the observed effect. All figures are participants per arm; they are not total participants across arms and are not event counts.

The 80% power column gives the estimated participants per arm needed for an assumed design to have an 80% chance of detecting the chosen effect if that effect is the true one and the calculation assumptions hold. The 90% power column represents a higher target chance of detection and therefore generally requires more participants per arm. For comprehensive rehabilitation, planning for 100% of the observed effect corresponds to 38 participants per arm for 80% power and 51 participants per arm for 90% power. Planning for 75% of the observed effect corresponds to 67 and 90 participants per arm, respectively; planning for 50% corresponds to 150 and 201.

For exercise-based rehabilitation, the corresponding figures are 72 and 96 participants per arm for 100% of the observed effect, 128 and 171 for 75%, and 287 and 384 for 50%. Smaller effects are harder to distinguish from random variation, so they require more participants under the same planning assumptions. These values are not observed power: they are prospective planning illustrations based on the observed estimates, not a measure of how well the completed trial was powered.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 94.100; pooled standard deviation σ = 145.260.
2. n = 2 × (1.96 + 0.842)² × 145.260² / 94.100² = 37.4, rounded up to 38 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 94.1                      # observed difference in means
sigma <- 145.260362669804                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(2575976)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 38 (80% power), 51 (90% power)
 75% of observed effect: n per arm = 67 (80% power), 90 (90% power)
 50% of observed effect: n per arm = 150 (80% power), 201 (90% power)
power.t.test: 38.4 
Simulated power at n = 38 per arm: 0.794 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry record identifies several outcome domains, including functional capacity, cardiovascular risk factors, health behavior, disease-related knowledge, depressive symptoms, and mortality. It also lists multiple risk-factor outcomes. When multiple outcomes and comparisons are assessed, the chance of at least one apparently notable result arising by chance can increase. The record does not report a multiplicity-adjustment method, a hierarchy of outcomes beyond identifying the primary endpoint, or a detailed strategy for interpreting secondary tests. The posted p-values are unadjusted and should be understood accordingly.

The record lists no reported analyses. It therefore does not establish whether the posted summary comparisons were prespecified, whether any covariate adjustment was planned, or what inferential procedures the sponsor intended. The confidence intervals and p-values discussed in this analysis are recalculated from the posted group summaries. They are not a replacement for a sponsor analysis that is not reported.

The primary results are described as per protocol, using a minimum of 24 exercise sessions and 16 education classes. This attendance-based definition explains why the analyzed counts differ from the flow diagram, according to the registry record. A per-protocol analysis can answer a question about participants who met the specified participation thresholds, but it can lose some of the comparability created by random allocation if attendance is related to prognosis. An intention-to-treat result, which would preserve participants in their allocated groups regardless of attendance, is not reported in the registry record.

How missing outcome data were handled is not reported in the registry record. The record does not specify the amount or pattern of missingness, whether any imputation was used, or whether sensitivity analyses assessed the effect of missing observations. These omissions limit assessment of whether the analyzed results could be affected by incomplete follow-up. The registry record also does not report interim analyses or stopping rules, so none should be presumed.

These gaps do not invalidate the posted summaries, but they narrow the conclusions that can be drawn from them. In particular, the results should be interpreted as unadjusted summaries for the threshold-defined analyzed population, with uncertainty about multiplicity and missing-data handling.

15. 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 record reports serious adverse events as zero in the comprehensive rehabilitation group among 37 at risk, zero in the exercise-based rehabilitation group among 39 at risk, and zero in wait-list control among 39 at risk. Other adverse events are also reported as zero in each group, using the same respective at-risk counts. The record lists one death in comprehensive rehabilitation, zero in exercise-based rehabilitation, and one in wait-list control.

These are descriptive safety counts. A zero reported event count does not establish that an intervention is free of risk, particularly when the number at risk is limited and the record does not provide event-level detail. The registry record does not list serious-event terms, and it does not report whether the deaths were considered related to an intervention. No causal attribution should be inferred from the group counts alone.

The safety counts also use at-risk numbers that differ from the analyzed primary-outcome group sizes. They should not be combined with the per-protocol efficacy summaries or treated as if they necessarily describe the same analysis population. The registry record does not report further details about timing, ascertainment procedures, or the circumstances of the deaths.

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

The posted primary summaries show a higher mean 6-month walking distance for comprehensive rehabilitation than for wait-list control, with a recalculated unadjusted mean difference of 94.1 meters and a confidence interval entirely above zero. The exercise-based comparison also has a positive point estimate, 70.8 meters, but its confidence interval spans zero. Together, these estimates describe the observed group summaries and the uncertainty around the comparisons; they do not establish that the two rehabilitation approaches differ from each other.

The results do not demonstrate that every participant improved, or that an individual participant would experience the group-average contrast. A group mean can conceal substantial variation between people, as reflected in the reported standard deviations. Nor does an unadjusted p-value describe the magnitude or practical importance of a difference. The registry record does not report a threshold for a clinically important change in walking distance, so statistical evidence alone cannot determine the importance of the estimate to patients.

The results concern the per-protocol population defined by attendance thresholds and the 6-month assessment. They should not automatically be generalized to participants who did not meet those thresholds, to all patients with cardiovascular disease, or to settings outside the stated Brazilian public-health-care context. Randomization is an important design feature, but the post-allocation attendance requirement and the absence of a reported intention-to-treat analysis limit how confidently the posted comparisons can be interpreted as effects of assignment.

The primary outcome also represents only one part of the trial’s broader aims. Numerical results for some named secondary outcomes are not reported in the registry record, and the reported safety counts do not establish causality or rule out uncommon harms. The findings therefore offer information about functional capacity and selected secondary measures, not a complete assessment of all intended outcomes or long-term consequences.

Most importantly, a confidence interval that includes zero does not prove no effect, and a confidence interval that excludes zero does not by itself prove clinical importance. The estimates are best treated as evidence about the observed comparisons, within the limits of the posted analyses and their uncertainty.

17. Why This Trial Matters Statistically

This trial raises several statistical issues that are common in clinical research. First, it compares three groups but the posted primary estimates are each against a shared wait-list control. That distinction matters: two comparisons with a common reference do not answer whether the active interventions differ from one another. A direct contrast is needed to assess that question, and it is not reported in the registry record.

Second, the record identifies a per-protocol population based on attendance thresholds. This makes the target of inference important. The posted results describe participants who met those thresholds, rather than necessarily representing the effect of assignment for everyone initially allocated. Attendance-related selection can weaken the balance achieved by randomization, so the population definition and analysis approach need to be considered together.

Third, the trial’s wider aims involve multiple outcomes. Without a reported multiplicity strategy, unadjusted findings across several endpoints require cautious interpretation. The primary functional-capacity outcome has a positive estimate against wait-list control for comprehensive rehabilitation, while the exercise-based comparison remains more uncertain. The secondary summaries add context but do not resolve the limitations around multiple testing or missing analyses.

Finally, confidence intervals communicate more than a binary significant/not-significant label. They show that the comprehensive comparison is estimated as positive but with uncertainty about its size, while the exercise-based interval remains compatible with zero and a range of positive values. Reading estimates and intervals together, while distinguishing statistical uncertainty from practical importance, gives a more informative account than relying on p-values alone.

18. 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 features specific to this trial limit interpretation. The primary analysis is per protocol and uses attendance thresholds of a minimum of 24 exercise sessions and 16 education classes. The registry record says this accounts for differences between the flow diagram and analyzed counts, but does not report an intention-to-treat analysis. Since attendance occurs after randomization, the analyzed groups may not retain the full comparability of the original allocation.

The posted primary contrasts are against wait-list control, not direct comparisons between comprehensive and exercise-based rehabilitation. The group means may look different, but without a reported direct contrast and its uncertainty, they cannot establish whether adding education to exercise changes the primary outcome. The record also does not report baseline walking-distance values or a stated change-score analysis, although the endpoint title refers to changes. The available numerical summaries are described at 6 months.

The registry record lists no reported analyses and does not report the original analysis plan, missing-data methods, covariate adjustment, multiplicity handling, interim analyses, or the original sample-size justification. Numerical results are not reported for fasting blood glucose or total cholesterol, despite those outcomes being named. These omissions restrict evaluation of the full analysis and of the broader outcome set.

Finally, the reported enrollment and analyzed group counts arise from different stages or populations, and the record notes per-protocol selection. The setting is Brazilian public health care; transferability to other populations or health systems is not established by the posted summaries. The record does not provide a clinical-importance threshold for walking distance, making the practical meaning of the estimated differences uncertain.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Effects of Cardiac Rehabilitation (CR) on Functional Capacity and Cardiovascular Risk Factors — NCT02575976.
• Registry record last updated 2022-04-28; status last verified 2022-04.
• Results first posted 2022-04-28.
• 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.

22. Record Summary

NCT02575976 is a completed randomized, parallel-group trial sponsored by the Federal University of Minas Gerais. It compared comprehensive cardiac rehabilitation, exercise-based rehabilitation, and wait-list control in Brazilian patients assisted by public health care. The registry record lists enrollment of 115 and identifies cardiovascular disease and coronary disease as conditions.

The primary outcome was functional capacity measured by distance walked in the Incremental Shuttle Walk Test at 6 months. The posted per-protocol analysis used attendance thresholds of a minimum of 24 exercise sessions and 16 education classes. Recalculated unadjusted comparisons against wait-list control show a positive mean difference for comprehensive rehabilitation, while the exercise-based estimate has a confidence interval spanning zero. The registry record does not report a direct primary comparison between the active arms.

Numerical secondary results are available for systolic blood pressure and waist circumference; results for fasting blood glucose and total cholesterol are not reported in the registry record. Serious and other adverse events are reported as zero in each group, with deaths reported separately. The original analysis plan, missing-data methods, multiplicity strategy, and original sample-size justification are not reported.