Cardiac Rehabilitation for Heart Event Recovery (HER): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Cardiac Rehabilitation for Heart Event Recovery (HER) (NCT01019135), a randomized na study. The primary outcome is CR Program Adherence.

2. Clinical Question

The registry describes the study purpose as comparing women’s cardiac rehabilitation program adherence across three program models. The posted result is a comparison of group means among participants with available adherence data. It does not, by itself, describe why participants attended or missed sessions, nor does the registry record give an explanation of missing adherence data. The intervention descriptions identify different delivery formats, but the record does not report a separate comparison of specific program components. The central statistical question is therefore about observed average attendance at 6 months across the three assigned models, with the women-only group as the reference for the posted pairwise comparisons.

3. Trial Design

This was a randomized, parallel-group trial with single masking, according to the registry record. It lists an enrollment of 169 and a status of completed. The phase is listed as NA. The sponsor is University Health Network, Toronto. The record lists the study start as 2009-11 and primary completion as 2014-03.

The trial compared women-only, traditional co-ed, and monitored home-based cardiac rehabilitation. In the women-only and co-ed descriptions, exercise training took place in on-site group sessions 1-2 days/week, participants were encouraged to walk at home on alternate days, and education was delivered in a group format. The home-based description says that participants attended an intake appointment where an exercise test formed the basis for an exercise prescription, and that they received written aerobic-conditioning guidelines. The registry record does not give the full descriptions of every program component.

Randomization means that assignment to program models was determined by an allocation process rather than being described as a choice made solely by participants or clinicians. General statistical context: random allocation can help make groups comparable on average, although it does not guarantee identical groups, and it does not eliminate concerns about missing outcome data or analysis choices. The registry record does not report the sequence-generation method, allocation concealment, or who was masked. It reports single masking but does not identify the masked party.

The primary endpoint was adherence at 6 months, recorded as a mean percentage of sessions attended. The arm-specific numbers contributing to that outcome differ from the enrollment figure, and the registry identifies the primary outcome population as participants with available adherence data. The reasons for the different outcome denominators and the trial’s original sample-size justification are not reported in the registry record. The record also does not report its original detailed statistical plan or whether the posted pairwise results came from a prespecified analysis.

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:

Analysis population for the primary outcome, as defined in the registry: Participants with available data for adherence

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 CR Program Adherence, measured over 6 months.

The primary endpoint is CR program adherence at 6 months, measured as the percentage of sessions attended. The registry reports the mean and standard deviation for participants with available adherence data. A mean summarizes the group’s average attendance percentage; the standard deviation describes how spread out individual attendance values are around that average. A larger standard deviation indicates greater variability among the observed values, not greater uncertainty in the mean itself.

Attendance is used to represent adherence to the rehabilitation program. That makes it directly relevant to the stated study purpose: comparing women’s participation across women-only, co-ed, and home-based program models. It is distinct from the listed secondary outcomes, which include exercise capacity, exercise, self-reported exercise, diet, medication adherence, and smoking.

The posted means describe the observed participants with available data, not necessarily every randomized participant. The registry record does not report why some participants lack endpoint data, whether missingness differed by program, or how missing values were handled. It also does not report a clinically meaningful threshold for interpreting a difference in the percentage of sessions attended. Consequently, the endpoint can be described statistically as average session attendance and compared across arms, while any judgment about the practical importance of a difference requires context not reported in the registry record.

7. Results Posted in the Registry

• Co-ed Cardiac Rehabilitation: mean 51.33 versus 54.40 on control; difference -3.07 (95% CI -16.42 to 10.28), standardized effect d = -0.09; z-test p = 0.652.
• Home-Based Cardiac Rehabilitation: mean 58.12 versus 54.40 on control; difference 3.72 (95% CI -10.08 to 17.52), standardized effect d = 0.11; z-test p = 0.597.

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.

Exercise Capacity

• 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:
  • Co-ed Cardiac Rehabilitation: mean 20.84 versus 21.61 on control; difference -0.76 (95% CI -4.30 to 2.77), standardized effect d = -0.11; z-test p = 0.673.
  • Home-Based Cardiac Rehabilitation: mean 21.07 versus 21.61 on control; difference -0.53 (95% CI -4.63 to 3.56), standardized effect d = -0.07; z-test p = 0.798.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Co-ed Cardiac Rehabilitation 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 Home-Based Cardiac Rehabilitation and the control. The interval gives the range of effects that remain compatible with the data.

Exercise

• 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:
  • Co-ed Cardiac Rehabilitation: mean 6,130 versus 5,297 on control; difference 832.75 (95% CI -1,145 to 2,810), standardized effect d = 0.28; z-test p = 0.409.
  • Home-Based Cardiac Rehabilitation: mean 6,694 versus 5,297 on control; difference 1,397 (95% CI -940.45 to 3,735), standardized effect d = 0.38; z-test p = 0.241.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Co-ed Cardiac Rehabilitation 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 Home-Based Cardiac Rehabilitation and the control. The interval gives the range of effects that remain compatible with the data.

Self-reported Exercise

• 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:
  • Co-ed Cardiac Rehabilitation: mean 31.40 versus 31.32 on control; difference 0.08 (95% CI -10.06 to 10.21), standardized effect d = 0.00; z-test p = 0.988.
  • Home-Based Cardiac Rehabilitation: mean 29.56 versus 31.32 on control; difference -1.76 (95% CI -10.84 to 7.32), standardized effect d = -0.09; z-test p = 0.704.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Co-ed Cardiac Rehabilitation 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 Home-Based Cardiac Rehabilitation and the control. The interval gives the range of effects that remain compatible with the data.

The registry lists secondary outcomes covering exercise capacity, daily steps, self-reported exercise, diet, medication adherence, and smoking. It reports values for some secondary outcomes, including exercise capacity, daily steps, and self-reported exercise. The record indicates six secondary outcomes posted, while the available numerical detail in the record does not cover every listed secondary outcome. Values are generally presented at 6 months where a timeframe is stated.

Across the numerical secondary comparisons, the estimates vary in direction and their intervals include zero. That broad pattern is not a consistent signal of separation between the program models. It also does not establish that the models are the same on those outcomes: the secondary estimates have uncertainty, and some outcome-specific sample sizes are limited. The secondary results should be considered alongside, rather than as a replacement for, the primary adherence comparison.

These outcomes measure different aspects of behavior and capacity. Exercise capacity is not the same construct as session attendance; daily steps and self-reported exercise also differ from attendance at rehabilitation sessions. Consequently, a pattern in one secondary measure would not automatically explain the primary adherence result or establish a mechanism. The registry record does not report a formal analysis linking adherence to the secondary outcomes.

The registry does not report formal analyses for the posted secondary outcomes. The displayed comparisons are recalculated, unadjusted summaries. General statistical context: testing multiple outcomes and contrasts creates more opportunities for apparently notable results by chance, especially when no adjustment or hierarchy is specified. Unadjusted secondary results therefore carry less weight than a prespecified primary analysis, and should be treated as exploratory descriptions rather than independent confirmation. The multiplicity plan and any adjustment are not reported in the registry record.

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

• Exercise Capacity
• Exercise
• Self-reported Exercise
• Diet
• Medication Adherence
• Smoking

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: it is a percentage of sessions attended, summarized by a mean and standard deviation. General statistical explanation: a mean is the arithmetic average of observed values. The standard deviation describes variation among those observations. It is not a confidence interval, and it does not tell how precisely the mean has been estimated without also considering the number of observations.

The posted pairwise differences compare each program’s mean with the mean in the women-only reference group. A negative difference for co-ed versus women-only means the posted co-ed mean is lower than the reference mean; a positive difference for home-based versus women-only means the posted home-based mean is higher. This sign convention follows the posted contrasts. The arm means and the reported mean differences are consistent with that interpretation.

The recalculated comparisons use the posted group means, standard deviations, and outcome sample sizes to make simple unadjusted comparisons. They do not use participant-level data and do not adjust for other variables. General statistical context: participant-level analyses can account for factors or structures that summary-statistic calculations cannot represent, if those factors were measured and specified in an analysis plan. The registry record does not report such an analysis for the primary outcome. The sponsor’s own analysis takes precedence when a discrepancy is flagged; no discrepancy is flagged for this record.

A confidence interval gives a range of values compatible with the estimate under the assumptions of the method used. General explanation: intervals that include zero for a mean difference do not rule out a difference in either direction. A wide interval indicates that the estimate is not precise enough to narrow the plausible range substantially. The posted primary intervals include zero and extend to both negative and positive differences. The confidence level and interval-construction method are not reported in the registry record, so they should not be inferred from the figures alone.

The p-values are unadjusted. General explanation: a p-value measures how surprising data at least as incompatible with a specified null hypothesis would be under the statistical model, if that null hypothesis and model assumptions held. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of an effect. A p-value by itself does not establish whether a difference matters in practice. These recalculated p-values should be read alongside the mean differences and intervals, and not as a replacement for the absent reported analysis.

The group standard deviations are similar in the posted summaries, while the observed arm means are relatively close. General statistical context: variability affects precision because more spread in individual outcomes makes group averages harder to distinguish unless there is sufficient information. This is one reason interval widths matter in addition to point estimates. The variability also means that an arm average does not describe every participant’s attendance; individuals within the same group may have very different values.

There are no reported formal analyses in the registry record for the primary endpoint. The record does not identify whether the intended comparison was an intention-to-treat analysis, a per-protocol analysis, or another analysis population. It describes the primary outcome population as participants with available adherence data, but does not explain whether all randomized participants were included in the outcome summaries. The handling of missing data, any covariate adjustment, and the approach to multiple comparisons are not reported in the registry record.

General statistical explanation: over-dispersion matters when outcome variability is greater than a model assumes, because standard errors can then be understated and intervals too narrow. The primary outcome is analyzed as a continuous mean with a standard deviation in each group; the registry does not report a model that assumes a count distribution or report a check for over-dispersion. It would therefore be inappropriate to assert that over-dispersion was present or that a particular correction was applied. More generally, the distribution of individual adherence values cannot be assessed from the reported means and standard deviations alone.

The planning calculations are illustrations based on observed effects, not the original trial’s design assumptions. General context: planning with an observed effect can be unstable because the observed estimate itself is uncertain, particularly when its interval is wide. Such figures describe hypothetical planning under stated assumptions and are not evidence about the probability that the trial detected an effect. The original sample-size justification and any interim analyses are not reported in the registry record.

11. Confidence Intervals and Precision

The primary mean differences are estimated with broad confidence intervals relative to their point estimates. For co-ed versus women-only, the interval runs from -16.42 to 10.28 percentage points around an estimate of -3.07. For home-based versus women-only, it runs from -10.08 to 17.52 around an estimate of 3.72. Each interval includes zero and permits both a negative and a positive difference.

General statistical explanation: a confidence interval expresses uncertainty around an estimate under the assumptions of its calculation. A narrow interval can rule out a wider range of values; a broad interval leaves more values compatible with the data. The primary intervals do not precisely locate the difference, so the point estimates should not be read as exact or definitive estimates of the population differences. The interval confidence level and method are not reported in the registry record.

The group standard deviations are 34.72, 35.7, and 35.39, while the primary outcome sample sizes are 54, 53, and 46 in the women-only, co-ed, and home-based arms, respectively. Those group-specific sample sizes describe participants with available adherence data, not the full enrollment. The registry record does not explain why the outcome sample sizes differ from each other or from the enrollment figure.

Precision is not the same as importance. A confidence interval may include values that could be relevant in practice, but the registry does not report a threshold for a practically meaningful adherence difference. The results therefore support a cautious description of uncertainty, not a conclusion that small differences are absent or that the program means are equivalent.

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 planning figures are participants per arm, not total events. They are calculated using the observed effect and stated planning assumptions: a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The planning scenarios consider detecting 100%, 75%, or 50% of the observed effect. The trial’s own original design assumptions and sample-size justification are not reported in the registry record.

The 80% power column gives the illustrated number of participants per arm for a hypothetical study to have an 80% chance of detecting the specified effect under those assumptions, if the effect and model assumptions were correct. The 90% power column gives the corresponding number per arm for a hypothetical 90% chance. These are planning illustrations based on the observed effect, not observed power.

Smaller effects require more participants to detect under the same assumptions. That pattern is reflected by the scenarios using 75% and 50% of the observed effect: as the target effect becomes smaller, the required per-arm planning figure increases. For example, the primary comparison of co-ed versus women-only lists 2,065 participants per arm for 80% power when planning for 100% of the observed effect, and 3,671 per arm when planning for 75% of that effect. These figures should not be treated as estimates of the trial’s actual design or as evidence that a particular effect is likely.

The calculations do not incorporate design features or adjustments unless they are part of the stated assumptions. The registry record does not report whether the original study used different assumptions, allowed for missing outcomes, or planned a different analysis. Planning values based on an observed estimate can also change substantially when that estimate is uncertain; the primary confidence intervals illustrate that uncertainty.

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 = -3.070; pooled standard deviation σ = 35.209.
2. n = 2 × (1.96 + 0.842)² × 35.209² / -3.070² = 2,064.7, rounded up to 2,065 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 <- -3.07                      # observed difference in means
sigma <- 35.2087428536341                     # 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(1019135)
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 = 2,065 (80% power), 2,765 (90% power)
 75% of observed effect: n per arm = 3,671 (80% power), 4,914 (90% power)
 50% of observed effect: n per arm = 8,259 (80% power), 11,057 (90% power)
power.t.test: 2065.7 
Simulated power at n = 2,065 per arm: 0.800 (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 primary endpoint has two posted pairwise comparisons, each using the women-only group as the reference. The registry record does not report whether these comparisons were prespecified as co-primary contrasts, whether a testing hierarchy was used, or whether any adjustment was made for multiple comparisons. The posted p-values are unadjusted recalculations from summary statistics. Their interpretation should account for the fact that more than one comparison is presented, without assuming a particular correction was applied.

The record lists six secondary outcomes and reports numerical summaries for some of them. It does not report a multiplicity strategy for secondary outcomes, nor does it identify a confirmatory order or family of hypotheses. General statistical explanation: when many outcomes or comparisons are examined, the chance of observing at least one apparently unusual result can increase. Adjusting for multiplicity is one possible approach, but the appropriate approach depends on the trial’s objectives and prespecified analysis plan. No such plan is reported.

Missing-data handling is also not reported. The primary outcome is defined for participants with available adherence data, and the arm-specific outcome sample sizes differ. The registry does not state why data were unavailable, whether missingness was related to attendance or program assignment, or whether any imputation or sensitivity analysis was conducted. General statistical context: if outcome availability is related to the outcome or to participant characteristics, a summary among those with data may not represent all randomized participants.

The analysis population is not described beyond the available-data wording for adherence. The registry does not say whether the intended primary analysis followed randomized assignment regardless of participation, included only those who started rehabilitation, or applied another eligibility rule. It also does not report a protocol-deviation analysis or a comparison of included and excluded participants. The absence of these details limits assessment of how well the posted summaries preserve the randomized comparison.

The registry lists no reported analyses for the primary or the described secondary outcomes. The original statistical analysis plan, sample-size justification, interim-analysis plan, and any prespecified subgroup analyses are not reported in the registry record. These omissions do not show that such plans did not exist; they mean that the record does not document them.

15. Safety Results

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

Other (non-serious) adverse events

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

The adverse-event figures list zero serious adverse events and zero other adverse events in each program group. The numbers at risk are reported separately for each group: 55 for women-only, 59 for co-ed, and 55 for home-based cardiac rehabilitation. These denominators are specific to the adverse-event reporting and should not be substituted for the sample sizes used in the primary adherence outcome.

General statistical explanation: a count of zero reported events is a description of what was recorded in the stated group, not proof that the underlying risk is zero. The precision of any risk estimate depends on the number of people observed, the duration and completeness of follow-up, and the event definition. Those details are not fully reported in the registry record. The record does not list serious adverse-event terms.

Deaths are not reported in the registry record. These adverse-event summaries do not compare the programs through a formal safety analysis, and the record does not provide a statistical comparison or confidence intervals for event rates. They should be read as registry reporting counts, not as evidence that the program models have identical safety profiles.

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

The posted primary results describe mean adherence at 6 months among participants with available data. The women-only group mean was 54.4 percentage points, compared with 51.33 for co-ed and 58.12 for home-based cardiac rehabilitation. The recalculated unadjusted differences are -3.07 and 3.72 percentage points, respectively, and both confidence intervals include zero. This means the posted estimates do not establish a clear difference in average attendance between either comparison group and the women-only group.

That interpretation is not the same as saying that the program models are equivalent. Equivalence requires a defined margin and an analysis designed to assess whether the entire uncertainty range lies within that margin. The registry record does not report an equivalence margin or such an analysis. The intervals allow for differences in either direction and do not tightly determine the size of any underlying difference.

The result also does not show that the programs have the same effects on health outcomes. The endpoint is session attendance, not a clinical event. Secondary outcomes address other domains, but their posted comparisons are unadjusted and the registry does not report formal analyses. Nor can the group averages establish that each participant experienced the group’s average level of adherence. Individual attendance varied substantially, as reflected by the reported standard deviations.

The trial’s randomized design is relevant to interpreting comparisons, but the record does not report enough analysis detail to assess how missing adherence data, deviations from assigned programs, or other factors were handled. The primary summaries are restricted to participants with available data. As a result, the posted comparisons describe those observed data and should not automatically be generalized to all randomized participants.

In plain terms, the registry reports different numerical averages, but the uncertainty around the pairwise estimates is broad and includes no difference. The result is inconclusive about the direction and size of a population-level adherence difference. It does not establish that any particular rehabilitation format is preferable for an individual, and it is not medical advice.

17. Why This Trial Matters Statistically

This trial poses a practical statistical question about adherence across three ways of delivering cardiac rehabilitation. The comparison is not simply between a treatment and no treatment: the program models vary in delivery format, including women-only group sessions, traditional co-ed group sessions, and a monitored home-based format. The statistical focus is whether observed attendance averages differ across those models.

The primary measure is straightforward to describe but has important interpretive limits. A mean percentage of sessions attended compresses individual attendance patterns into one value. The reported standard deviations show that there is substantial spread within each group, so a group mean does not characterize every participant. This makes it useful to consider the mean difference and its interval together rather than rely on the point estimate alone.

The record also illustrates why outcome-specific denominators matter. The primary adherence summaries use participants with available data, while adverse-event reporting uses different group-specific numbers at risk. Those counts refer to different reporting contexts and cannot be treated as interchangeable. The registry does not explain the missing primary outcome data or the distinction between these populations.

Finally, the trial illustrates the difference between a posted result and a fully documented statistical analysis. The registry includes group summaries and recalculated pairwise comparisons, but reports no formal analyses. Without information about missing-data methods, multiplicity, and the original analysis plan, the results support a descriptive, cautious interpretation rather than a definitive inferential account. This distinction is important in clinical research: uncertainty and analysis provenance are part of what a reader needs to understand alongside the estimated effects.

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.

The registry record leaves several trial-specific questions unresolved. The primary endpoint is reported only for participants with available adherence data, but the reasons for unavailable data, the missing-data approach, and the resulting analysis population are not described. The outcome-specific group counts also differ from the enrollment figure, so the extent and pattern of missing primary outcome data cannot be assessed from the record alone.

The record reports randomization and single masking but does not specify the method used to generate or conceal allocation, or identify who was masked. It does not report whether participants adhered to their assigned formats, whether crossovers occurred, or how deviations were handled. The intervention descriptions are not complete, which limits detailed comparison of program content beyond the elements stated in the record.

The registry does not report a formal analysis for the primary endpoint or the secondary outcomes. The posted pairwise comparisons are unadjusted recalculations from summary statistics, so they cannot account for participant-level covariates or other features not represented in those summaries. The record does not state a confidence-interval level or method, an analysis plan for multiplicity, or a clinically meaningful threshold for adherence differences. It also does not report the original sample-size justification or interim analyses.

Finally, the primary outcome measures session attendance, not a clinical endpoint. Its relevance to other outcomes cannot be determined from the group summaries. The registry lists multiple secondary domains, but does not provide reported formal analyses or a documented plan for interpreting them collectively. These limitations describe gaps in the registry record; they do not establish that the trial did not address these issues elsewhere.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Cardiac Rehabilitation for Heart Event Recovery (HER) — NCT01019135.
• Registry record last updated 2015-11-30; status last verified 2015-10.
• Results first posted 2015-11-30.
• 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

The registry describes a randomized, parallel-group, single-masked trial comparing women-only, co-ed, and monitored home-based cardiac rehabilitation. Enrollment is listed as 169, and the study status is completed. The primary outcome is mean percentage of sessions attended at 6 months among participants with available adherence data.

Mean adherence was 54.4 in the women-only group, 51.33 in the co-ed group, and 58.12 in the home-based group. The recalculated unadjusted differences versus women-only were -3.07 for co-ed and 3.72 for home-based; both confidence intervals include zero. The registry does not report formal analyses, the original sample-size justification, missing-data methods, or a multiplicity plan. The posted results describe average attendance and remain uncertain about the size and direction of differences.