Chronotropic Incompetence in Patients With HFpEF: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Chronotropic Incompetence in Patients With HFpEF (NCT02524145), a non-randomized na study. The primary outcome is Cardiac Beta-receptor Sensitivity.

2. Clinical Question

The study concerns how heart rate is regulated in people with HFpEF, with particular interest in chronotropic incompetence: an inability to increase heart rate with exercise. Its stated purpose is to examine central command regulation and cardiac beta-receptor sensitivity as possible mechanisms involved in heart-rate control.

Consequently, the registry record establishes the physiological question and the groups under study, but not whether their measured responses differed, by how much, or with what precision. It also does not report the results for the other listed outcome measure.

3. Trial Design

The registry record describes a completed, non-randomized, parallel-group study. Its listed enrollment is 40. The record does not clarify whether that figure is the final number of participants analyzed or the enrollment target, and it does not report the number analyzed in each group. The study is listed as having no masking, and its phase is recorded as not applicable.

The groups are Healthy Seniors, HFpEF, and Healthy Young. The senior volunteers are described as older than 60 years, with no chronic medical problems and no cardiac medications other than statins. Their description also includes a body mass index below 30 and an exercise history of less than 3 days per week of aerobic exercise. Healthy young volunteers are described as younger than 45 years, with no chronic medical problems and no cardiac medications other than statins, and a body mass index below 30. The HFpEF group was described by clinical signs and symptoms, an ejection fraction > 0.50, and objective evidence of diastolic dysfunction.

Static handgrip and the agents Dexmedetomidine, Glycopyrrolate, and Isoproterenol appear in the intervention listings. The descriptions of the group procedures are incomplete in the registry record, so the exact sequence and details of each procedure are not reported there. The primary outcome timeframe is listed as 1 day, with the outcome complete for each subject in 1 day.

Because participants were not randomized, the groups should be read as observational comparisons rather than as exchangeable treatment arms. Differences between groups could reflect characteristics other than the physiological response being studied. The registry record does not report a statistical adjustment plan that would address such differences. The study status is completed, but completion does not by itself establish that results were posted.

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 Cardiac Beta-receptor Sensitivity, measured over 1 day; primary outcome was complete for each subject in 1 day.

The primary endpoint is cardiac beta-receptor sensitivity. The registry record defines its measurement as the slope of heart rate versus isoproterenol serum level, with the unit beats per ng/kg/min ISO. The outcome is classified as a continuous measure summarized by a mean and standard deviation.

In general, a slope describes how one measured quantity changes in relation to another. In this setting, the heart-rate measurements are related to the measured serum level of isoproterenol. The slope is intended to characterize the heart-rate response across those levels, rather than to represent a single heart-rate reading. The registry record states that this measure was used to study cardiac beta-receptor sensitivity as part of the broader investigation into heart-rate regulation in HFpEF.

The registry record does not report the observed mean, standard deviation, or group-specific endpoint values. It also does not describe the exact measurement schedule or calculation details beyond the stated slope. The listed timeframe is 1 day, and the record says the primary outcome was complete for each subject in 1 day. Without the posted endpoint results, the direction, size, and precision of any group differences cannot be evaluated.

In general, a mean describes the central value of a set of measurements, while a standard deviation describes their spread around that mean. Neither statistic alone establishes whether a difference between groups is statistically distinguishable from chance variation. That assessment depends on the group data and the analysis used, which are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical methods that were actually used for the outcome analysis are not reported in the registry record. The record does specify that the primary outcome is continuous, that it is summarized by a mean and standard deviation, and that it is calculated as a slope relating heart rate to isoproterenol serum level. The explanations below describe general statistical concepts relevant to that measure; they do not establish which procedures the investigators used.

What does a slope represent?

In general, a slope expresses the change in one variable in relation to a change in another variable. For this endpoint, heart rate is related to isoproterenol serum level, and the stated slope is used as a measure of cardiac beta-receptor sensitivity. The slope condenses a relationship across measurements into a single value. Its interpretation depends on how the underlying measurements were collected and how the slope was estimated. Those details, apart from the stated relationship and unit, are not reported in the registry record.

A slope can be estimated for an individual or for a group, but the registry record does not specify the estimation procedure or whether the posted outcome was calculated at an individual or group level before summarization. It identifies the reported summary as a mean and standard deviation. The mean conveys a typical value across observations, whereas the standard deviation conveys how dispersed those values are. Neither provides the full distribution of measurements, and neither is a substitute for a confidence interval or a formal comparison.

What would a confidence interval add?

In general, a confidence interval gives a range of values compatible with the data and the statistical assumptions used to construct it. It conveys uncertainty around an estimate, rather than merely describing variation among individual observations. A narrow interval indicates greater precision under the chosen method; a wider interval indicates less precision. No confidence interval for the primary endpoint is reported in the registry record, so its precision cannot be described numerically.

For a comparison between groups, the estimated difference and its uncertainty are often more informative than separate group summaries alone. The registry record does not report an estimated contrast, its confidence interval, or a test result. It is therefore not possible to determine whether any apparent difference would be large relative to sampling uncertainty. No difference should be calculated from group values because the group values themselves are not reported.

How does the design affect comparisons?

In general, non-randomized groups can differ in characteristics related to the outcome. Those differences can make a simple comparison difficult to interpret. Statistical adjustment can sometimes account for measured characteristics, but it cannot guarantee removal of bias, particularly when relevant characteristics are unmeasured or poorly measured. The registry record says allocation was non-randomized and warns that the arms are not a like-for-like control comparison. It does not report whether adjustment was performed, which variables might have been considered, or what model was used.

The parallel-group designation indicates that the record describes distinct groups rather than a randomized crossover comparison. The group descriptions identify healthy volunteers and people with HFpEF, but do not establish that the groups were matched or otherwise made comparable. The statistical analysis plan, including any planned contrasts among the groups, is not reported in the registry record.

What do the planning illustrations mean?

In general, a sample-size calculation estimates how many participants would be needed under stated assumptions to detect a specified effect with a chosen error rate and power. The planning assumptions listed for the illustrations are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The illustrations are based on the observed effect, with the effect to detect expressed as a stated fraction of that effect. The actual illustration values and the fractions are not reported in the registry record used for this account.

These calculations are planning illustrations, not observed power. In general, observed power calculated after a study is complete does not add a reliable summary of the evidence beyond the estimate and its uncertainty. A planning illustration instead asks what sample size would be required under assumptions about the effect and analysis. It does not show that the study achieved a particular power or that a result is statistically significant.

The assumptions also describe a simplified setting: equal allocation between two arms and a normal approximation. The registry record lists three groups and does not report how any two-arm illustration maps onto the study’s comparisons. The illustrations should therefore not be mistaken for the study’s original design justification or for a reconstruction of its actual allocation. The sample-size justification used to plan the study is not reported in the registry record.

What role does dispersion play?

In general, greater variability in a continuous outcome makes it harder to distinguish group averages with a given sample size, because the outcome values are less concentrated around their means. Standard deviations help describe that variability, but the registry record does not report the observed standard deviations. Over-dispersion is a concern when variation is greater than a model assumes; in general, that mismatch can make standard errors too small and intervals too narrow if the model does not account for it. No distributional checks, variance assessments, or alternative methods are reported in the registry record, so no claim can be made about whether over-dispersion arose or how it was handled.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Healthy Seniors", "HFpEF", "Healthy Young")
n   <- c(13, 13, 7)
m   <- c(0.254, 0.156, 0.365)
sp  <- c(0.166, 0.133, 0.129)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Healthy Seniors  13  0.254  0.166  0.154  0.354
CARM  HFpEF  13  0.156  0.133  0.076  0.236
CARM  Healthy Young  7  0.365  0.129  0.246  0.484

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists two outcome measures, but it does not report the full details or results for both. The primary endpoint is identified as cardiac beta-receptor sensitivity. The identity and role of the other outcome measure are not reported in the registry record. No multiplicity plan is reported, including whether there was a prespecified hierarchy of outcomes or how the chance of false-positive findings across multiple tests would be handled.

In general, multiplicity arises when several outcomes, comparisons, or analyses are examined. Testing many hypotheses can increase the chance that at least one result appears statistically notable by chance. Methods such as prespecifying a primary outcome or adjusting for multiple tests can address parts of this issue, but the registry record does not state whether any such approach was planned or used. It would be inappropriate to infer a multiplicity procedure from the number of outcome measures alone.

The record lists no outcome analysis entries. It does not report the analysis populations, exclusions, or the number of participants with endpoint data in each group. Although the primary outcome description says it was complete for each subject in 1 day, the record does not explain how missing observations, incomplete measurements, or participants without usable endpoint data were handled. The missing-data method and the definition of the population used for analysis are therefore not reported in the registry record.

In general, missing-data methods matter because results can depend on who contributes data and on assumptions about why observations are missing. An analysis restricted to participants with complete measurements may differ from an analysis using other assumptions or methods. Without the group-specific analysis counts and the missing-data approach, the effect of missingness on the endpoint estimate cannot be evaluated.

The record also does not report interim analyses, stopping rules, or a formal statistical analysis plan. This does not establish that these procedures did or did not occur; their status is not reported in the registry record. The completed status and enrollment listing do not fill these reporting gaps.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

The registry record lists serious adverse event counts for Healthy Seniors, HFpEF, and Healthy Young. The numbers at risk for serious adverse events are 13, 13, and 7, respectively; the serious events recorded are 0 in each group. The listed deaths are also 0 in each group. For other adverse events, the numbers at risk are 13, 13, and 7, and the recorded counts are 0 in each group.

These figures describe the registry’s recorded counts and denominators; they do not establish that every participant represented by the enrollment listing was included in safety follow-up. The record does not report the adverse-event observation period, the method of collection, or whether follow-up was complete for all participants. The groups’ listed numbers at risk also do not add up to the overall enrollment listing, and the reason for that difference is not reported in the registry record.

In general, zero events recorded in a study does not prove that an event cannot occur. It means that no events of the listed type were recorded among the listed participants at risk in the registry record. With no event counts to compare, these safety entries do not establish a between-group safety difference. They also do not provide a detailed account of non-serious events, event severity beyond the registry categories, or the timing of events. The serious adverse event term list is empty.

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

This study asks a physiological question about heart-rate regulation in HFpEF. Its primary endpoint is a slope relating heart rate to isoproterenol serum level, used to measure cardiac beta-receptor sensitivity. The registry record also describes interest in central command regulation and lists procedures and agents relevant to the study.

The record does not report the primary endpoint’s observed values or any outcome analysis. It therefore does not establish the direction or size of a difference between the HFpEF group and the healthy volunteer groups. No conclusion about statistical significance or precision can be drawn because no estimated effects, confidence intervals, or test results are reported. The record’s completed status is a study-status entry, not a substitute for outcome results.

Even with results, the non-randomized design would require careful interpretation. In general, people in different groups may differ in ways that influence the outcome. The registry record explicitly notes that the arms are not a like-for-like control comparison. An observed difference would not, by itself, show that group status or a particular procedure caused the difference. The record does not report an adjustment plan that might help account for measured differences between groups.

The posted safety entries record no serious adverse events, other adverse events, or deaths among the listed participants at risk. These counts should be interpreted within the denominators and follow-up information reported, which is limited. They do not establish that an event is impossible or describe safety outside the recorded observations.

Overall, the registry record supports statements about the study’s question, design, groups, endpoint definition, and recorded safety counts. It does not support a claim about the primary outcome’s result, its statistical uncertainty, or the causal effect of any intervention. Those matters are not reported in the registry record.

14. Why This Trial Matters Statistically

The study is statistically notable for combining a mechanistic question with comparisons across groups that were not randomized. Its endpoint is not simply a resting heart-rate value; it is defined as a slope relating heart rate to isoproterenol serum level, intended to characterize cardiac beta-receptor sensitivity. That makes the measurement strategy central to interpreting the question, while also making clear why details of data collection and slope estimation matter.

The comparison structure calls for restraint. The groups include people with HFpEF and healthy volunteers of different age categories, with eligibility criteria that distinguish them. In general, such groups can differ for reasons beyond the outcome mechanism being investigated. The registry record itself warns that the arms are not a like-for-like control comparison. This is a useful reminder that the design determines the strength of the inferences a statistical analysis can support.

The record also illustrates the distinction between a completed study and a reported result. It lists an enrollment of 40 and identifies two outcome measures, but provides no outcome analysis entries and no numerical primary endpoint results. Without estimates and measures of uncertainty, readers cannot assess how variable the observations were or how precisely any comparison was measured.

Finally, planning calculations answer a different question from study findings. The listed assumptions describe planning illustrations based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Such illustrations are not observed power and do not supply missing endpoint results. Keeping design calculations separate from reported evidence is important for interpreting a small mechanistic study without overstating what its registry record establishes.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main limitation of the registry record for statistical interpretation is that it does not report the primary endpoint results. Group means, standard deviations, endpoint contrasts, confidence intervals, and test results are not reported in the registry record. The second outcome measure is not identified in the available record details, and no outcome analyses are listed. As a result, the study’s measured findings cannot be evaluated from these entries.

The study is non-randomized, and the record specifically cautions that the arms are not a like-for-like control comparison. The group eligibility descriptions differ, and baseline characteristics that might help readers judge comparability are not reported. The record does not describe statistical adjustment, matching, or another method for addressing group differences.

The enrollment listing is 40, but group-specific enrollment and analysis counts are not reported. The safety entries list 13 participants at risk in Healthy Seniors, 13 in HFpEF, and 7 in Healthy Young; the registry record does not explain how those denominators relate to overall enrollment. The handling of missing endpoint data and the definition of analysis populations are not reported.

The outcome description states a one-day timeframe, but details of measurement timing, the exact slope-estimation procedure, and quality-control methods are not reported. The registry record also does not report a statistical analysis plan, multiplicity approach, or the study’s original sample-size justification. These gaps limit assessment of both the reproducibility of the endpoint and the strength of any statistical inference.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Chronotropic Incompetence in Patients With HFpEF — NCT02524145.
• Registry record last updated 2020-08-06; status last verified 2020-08.
• Results first posted 2019-04-23.
• 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.

19. Record Summary

The registry record describes a completed, non-randomized, parallel-group study of chronotropic incompetence in HFpEF, with listed enrollment of 40 and no masking. The groups are Healthy Seniors, HFpEF, and Healthy Young. Listed procedures or agents include Static Handgrip, Dexmedetomidine, Glycopyrrolate, and Isoproterenol.

The primary outcome is cardiac beta-receptor sensitivity, defined as the slope of heart rate versus isoproterenol serum level and summarized as a mean and standard deviation. Its timeframe is 1 day. The registry record lists two outcome measures but no outcome analysis entries and does not report numerical results for the primary endpoint.

Recorded serious adverse events, other adverse events, and deaths are 0 in each group among the listed participants at risk. Group-specific follow-up details, analysis populations, missing-data methods, and the statistical analysis plan are not reported in the registry record.