This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Effect of Aldosterone on Energy Starvation in Heart Failure (NCT00574119), a na phase 4 study. The primary outcome is Left Ventricular Work-metabolic Index (WMI) at Baseline.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00574119 |
| Phase | Phase 4 |
| Condition | Heart Failure, Nonischemic Dilated Cardiomyopathy |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 16 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Vanderbilt University |
| Results posted | Yes |
2. Clinical Question
Population
Patients with heart failure due to nonischemic dilated cardiomyopathy (NIDCM) were the focus. The record describes this condition as reduced heart pump function due to causes other than heart attack. The primary-outcome population is described as 12 patients who completed the study.
Intervention
The intervention was spironolactone, a drug described in the study summary as blocking the effects of aldosterone on the heart muscle. The planned evaluation included measurements before and after 6 months of treatment.
Comparator
No separate comparator group is listed. The study is recorded as a single-group study with allocation listed as not applicable and no masking. Its planned comparison was within the same group over time, rather than between treatment and control groups.
Primary question
The broad study question concerned whether measurements of cardiac metabolism, anatomy, function, blood flow, and efficiency changed with spironolactone treatment. The registered primary outcome is specifically the left ventricular work-metabolic index (WMI) at baseline. A post-treatment WMI value or a change estimate is not reported in the registry record.
3. Trial Design
This was a completed Phase 4, single-group study sponsored by Vanderbilt University. The registry record lists an enrollment of 16 and describes the condition as heart failure and nonischemic dilated cardiomyopathy. The recorded start was 2007-12, and the primary completion was 2012-07. The registry does not list a randomized allocation or a masking procedure.
The study summary describes an investigation of “energy starvation” in heart failure. Patients with NIDCM were to undergo positron emission tomography (PET) and magnetic resonance imaging (MRI) to assess metabolism, anatomy, function, blood flow, and efficiency. The arm description specifies 11C acetate PET and MRI using a vasodilator and gadolinium to assess myocardial blood flow. The planned assessments were before and after 6 months of spironolactone treatment.
Because the design is single-group, the registry does not identify a separate untreated or active-control group. The intended before-and-after structure can describe measurements over time among people receiving treatment, but it does not by itself separate a treatment-associated change from other changes over time. The registry record does not report a protocol explanation for the design, a sample-size justification, or details of how the planned imaging assessments were analyzed.
The primary outcome is listed as WMI at baseline, with a description defining it as left ventricular stroke work divided by the decay rate of 11C-acetate. The record says the primary-outcome population was 12 patients who completed the study. It does not provide a baseline WMI value or a corresponding post-treatment estimate. Therefore, the design and stated measurement plan are identifiable, while the registered primary outcome's numerical result is not reported in the registry record.
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
| Stage | Results With Spironolactone |
|---|---|
| STARTED | 16 |
| COMPLETED | 12 |
| NOT COMPLETED | 4 |
Reasons for not completing this period:
| Reason | Results With Spironolactone |
|---|---|
| Adverse Event | 1 |
| Protocol Violation | 1 |
| Withdrawal by Subject | 1 |
| Physician Decision | 1 |
Analysis population for the primary outcome, as defined in the registry: 12 patients completed study
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
Population: one patient excluded prior to drug administration due to normal LV function.
| Characteristic | Unit | Results With Spironolactone |
|---|---|---|
| Participants analysed | 15 | |
| Age, Continuous | years | 52 (45 to 54) |
| Sex: Female, Male: Female | Participants | 5 |
| Sex: Female, Male: Male | Participants | 10 |
| Race and Ethnicity Not Collected | Participants | — |
| Region of Enrollment: United States | participants | 15 |
6. Primary Endpoint
The registry lists the primary outcome as Left Ventricular Work-metabolic Index (WMI) at Baseline, measured over baseline.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | (x10^6), mL x mm Hg/m^2 |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the left ventricular work-metabolic index (WMI) at baseline. The registry describes WMI as left ventricular stroke work divided by the decay rate of 11C-acetate and gives the unit as “(x10^6), mL x mm Hg/m^2.” The endpoint combines a measure of mechanical work by the left ventricle with a PET-derived measure related to acetate metabolism. In general, a combined index can be used to characterize how cardiac work relates to metabolic activity, rather than treating those measurements as unrelated features.
The record places the WMI assessment at baseline, before the planned 6 months of spironolactone treatment. A baseline measure can describe the starting state of the study group and may help frame later assessments. However, the registered primary outcome is not described as a change from baseline, and no post-treatment WMI result is listed in the registry entries. The numerical baseline median and inter-quartile range are also not reported in the registry record.
The endpoint should therefore be read as the study's specified baseline physiological measure, not as evidence of a treatment effect. The study summary describes a wider imaging program covering metabolism, anatomy, function, blood flow, and efficiency, but the primary outcome title alone does not establish that all those dimensions were captured by WMI.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies a clinically focused imaging study, but it does not report a numerical result for its named primary outcome. WMI is specified at baseline, with the primary-outcome population described as 12 patients who completed the study. Although the outcome's unit, calculation, summary statistic, and dispersion measure are identified, the baseline median and inter-quartile range are not reported in the registry record. A treatment-associated difference, confidence interval, or test result for WMI is likewise not reported.
The study summary describes measurements before and after 6 months of spironolactone, but the primary outcome listed in the record is baseline WMI. That distinction matters: a baseline description answers what the starting measurement was, whereas a treatment-effect analysis would ordinarily require a post-treatment value, a change estimate, or another prespecified comparison. None of those WMI results is stated in the record. It is therefore not possible to quantify the direction, size, or precision of a WMI change from the posted outcome information.
The sample-size record lists enrollment of 16, while the primary-outcome population is described as 12 patients who completed the study. These statements do not establish which participants contributed usable baseline or follow-up imaging data, whether anyone was excluded from a particular analysis, or why some people did not complete the study. Those details are not reported in the registry record. The completion statement should not be treated as confirmation that every planned outcome was available for every completer.
The design also affects what conclusions could be drawn from any before-and-after measurements. In general, repeated measurements in a single group can show the pattern observed over time, but without a control group they cannot distinguish the effects of treatment from other explanations for change. The study is listed as unmasked, which may also matter for measurements or assessments that involve judgment; the record does not explain whether outcome assessment was blinded or how measurements were standardized.
Accordingly, the posted information supports a description of the study's purpose, imaging approach, design, and outcome definition. It does not support a quantitative conclusion about change in WMI or about the effect of spironolactone. The listed adverse-event counts are separate safety summaries and do not supply evidence about the primary endpoint or its precision.
9. Statistical Methods Explained
What does the registered summary statistic mean? The primary outcome is designated as a median, with an inter-quartile range as the measure of dispersion. In general, the median is the middle value when observations are ordered. It is less influenced by unusually high or low observations than the arithmetic mean. The inter-quartile range describes the spread of the middle portion of the observed values. These summaries can be useful when a measurement is skewed or includes extreme observations, but they do not show the full distribution or the precision of an estimated treatment effect.
The registry record does not give the baseline median or inter-quartile range for WMI. Thus, although the planned summary approach is stated, the values needed to describe the observed baseline distribution are not reported in the registry record. No standard error, confidence interval, or other uncertainty estimate for WMI is listed either.
What would a confidence interval add?
In general, a confidence interval expresses the uncertainty around an estimated quantity under the assumptions of the analysis method. It helps readers assess which effect sizes are compatible with the data, rather than relying only on a single point estimate. For a before-and-after study, an interval around a change estimate could convey the precision of the estimated change. No WMI change estimate or confidence interval is reported in the registry record, so its precision cannot be evaluated from the posted results.
What does a single-group before-and-after design estimate?
In general, comparing repeated measurements in the same participants can account for stable differences between those participants, because each person contributes measurements at more than one time. But an observed change can also reflect time trends, changes in other care, measurement variability, or changes in who contributes data at each assessment. A separate control group can help distinguish those explanations, depending on the design and analysis. This study is recorded as single-group, with no separate comparator listed. The record does not report an analysis plan addressing these potential explanations.
The study summary describes measurement before and after 6 months of treatment. The listed primary outcome, however, is WMI at baseline, not an explicitly named change or follow-up WMI endpoint. Without a reported follow-up value and analysis, the intended schedule should not be mistaken for a reported treatment-effect estimate.
Why can over-dispersion matter?
In general, a statistical model may assume a particular level of variability in its data. Over-dispersion means that the observed variability is greater than that assumed by the model. If it is not accounted for, standard errors may be too small and confidence intervals may be too narrow, making results appear more precise than they are. Whether over-dispersion is relevant depends on the outcome and model. The registry record does not report a model for WMI, a dispersion assessment, or a method for handling over-dispersion. It would be speculative to claim that a particular model or correction was used.
How should the planning illustration be understood?
The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two hypothetical arms, and a normal approximation. It says that the effect to detect is a stated fraction of the observed effect, and that non-time-to-event planning results are expressed as participants per arm. These are planning assumptions, not a description of this trial's single-group design. They should not be interpreted as the study's actual allocation, as an observed power calculation, or as proof that the trial had a particular probability of detecting an effect. The registry record does not report a sample-size justification for the actual study design. Because no numerical observed WMI effect is reported, the planning assumptions do not provide a basis for independently interpreting the primary outcome.
In general, planning calculations describe how sample size might relate to a chosen effect size, variability assumption, significance level, and power target. They do not establish what the study observed. A planning illustration based on an observed effect can also be sensitive to uncertainty in that effect estimate, especially when the underlying study is small. No numerical planning result or power target for the actual trial is stated in the registry record.
What can be inferred from the reported analysis information?
The registry lists no analysis entries. This does not establish that no analyses were conducted; it means that analysis details are not reported in the registry record. The record does not identify a statistical test for WMI, an adjustment strategy, a model specification, a confidence-interval method, or a rule for handling incomplete measurements. Those omissions prevent readers from checking the analysis against a prespecified plan or evaluating whether the summary method matched the observed data.
In general, transparent reporting distinguishes a prespecified analysis from analyses selected after examining results. It also makes clear which participants and measurements contributed to each estimate. The registry describes the primary-outcome population as 12 completers, but does not give outcome-specific analysis counts or state whether the analysis followed an intention-to-treat, per-protocol, or other population definition. No such population label should be inferred from the completion statement.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 9 outcome measures overall and names secondary outcomes involving the 6 Minute Walk Test (6MWT) and the Minnesota Living With Heart Failure Questionnaire at baseline and at 6 Months. It identifies baseline WMI as the primary outcome. The record does not report a hierarchy among secondary outcomes, a multiplicity adjustment, or a statistical analysis plan specifying how multiple outcomes or time points were handled.
In general, testing multiple outcomes can increase the chance of finding at least one apparently unusual result by chance. Prespecifying a primary outcome and a testing strategy can help readers understand which findings are confirmatory and which are exploratory. The primary outcome title provides a stated focus, but the absence of reported analysis details leaves uncertainty about how the listed outcomes were evaluated. The registry lists no analysis entries; it does not establish whether analyses were conducted outside the registry record.
Missing-data information is limited. Enrollment is listed as 16, while the primary-outcome population is described as 12 patients who completed the study. The record does not explain why all enrolled patients did not complete the study, which measurements were missing, whether any participants lacked imaging data, or how missing values were handled. It also does not report outcome-specific denominators for the secondary measures. In general, missingness can affect an estimate when the availability of measurements is related to participant characteristics or outcomes. Without reasons for missingness and an analysis method, the direction or magnitude of any resulting bias cannot be assessed.
The registry does not report a protocol-based analysis population, imputation approach, sensitivity analysis, or assessment of the effect of missing data. Consequently, neither completeness of outcome collection nor robustness to missingness can be established from the posted information.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Results With Spironolactone | 0 | 16 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Results With Spironolactone | 0 of 16 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Results With Spironolactone | 2 of 16 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Results With Spironolactone |
|---|---|---|
| shortness of breath | Respiratory, thoracic and mediastinal disorders | 1 of 16 |
| pacemaker insertion | Cardiac disorders | 1 of 16 |
The registry reports safety counts for the group titled Results With Spironolactone. It lists 16 participants at risk for serious adverse events, with 0 affected, and 16 at risk for other adverse events, with 2 affected. Deaths are listed as 0. These figures are registry safety summaries, separate from the imaging outcome and its analysis.
The record does not list serious adverse-event terms, and the serious-event term list is empty. It does not identify the two other adverse events, their severity, timing, relationship to treatment, or whether they led to treatment changes. The counts therefore describe only what is recorded in these categories; they do not permit assessment of event types or clinical context.
In general, a count of zero reported serious events does not prove that an intervention has no serious risks. The ability to detect uncommon events depends on the amount and duration of observation and on how events were collected and reported. The registry record does not provide enough detail to characterize those aspects. The safety counts should also not be interpreted as evidence for or against a change in WMI.
12. What the Result Does, and Does Not, Mean
The record describes a focused investigation of cardiac energy-related measurements in heart failure due to nonischemic dilated cardiomyopathy. It specifies spironolactone treatment, a planned before-and-after imaging approach, and a primary physiological measure connecting left ventricular stroke work with 11C-acetate decay rate. This makes the scientific aim and the intended measurement approach understandable.
What the record does not provide is the numerical baseline WMI result or a post-treatment result. Although it lists a baseline median and inter-quartile range as the planned summary approach, neither value is stated. It also does not report a treatment-related change, confidence interval, or statistical test. The information therefore cannot establish whether WMI changed, how large any change was, or how precisely it was estimated.
The single-group design is important to interpretation. In general, observations before and after treatment can describe changes over time in the group studied. Without a separate control group, however, those changes cannot be attributed to treatment alone. The registry does not report details that would allow other explanations for change to be evaluated.
The listed safety counts provide limited descriptive information: 0 participants are recorded as affected by serious adverse events, 2 by other adverse events, and deaths are listed as 0. The record does not give the event terms for the other adverse events or further context for either category. Those counts should not be treated as a complete characterization of safety.
Overall, the registry supports understanding what the investigators set out to study and how the primary outcome was defined. It does not support a quantitative conclusion about a treatment effect or the precision of that effect. This distinction is especially important when a study's stated purpose and planned assessments are more extensive than the numerical results reported in the registry.
13. Why This Trial Matters Statistically
This trial illustrates why the design, endpoint definition, and posted results need to be read together. The study's broad purpose concerns cardiac metabolism, function, blood flow, and efficiency, while the registered primary outcome is a specific baseline index. Knowing the endpoint's definition is useful, but without its numerical value and a follow-up estimate it is not possible to assess the magnitude or precision of an observed treatment-related change.
It also demonstrates the interpretive limits of a single-group before-and-after plan. Repeated measurement can be informative about what happened over time in a treated group. In general, though, a control group is needed to help distinguish a treatment-associated pattern from concurrent changes or other influences. The absence of a separate comparator does not erase the descriptive value of the design, but it limits causal interpretation.
Another statistical lesson is that completion and analysis populations are not interchangeable concepts. The record lists enrollment of 16 and describes 12 patients as having completed the study, but it does not state which participants contributed to each outcome analysis or why measurements may be unavailable. Outcome-specific denominators and missing-data methods are important for judging how representative a reported estimate may be.
Finally, registry transparency includes more than a study title and outcome definition. The record lists 9 outcome measures but no analysis entries, and it does not report multiplicity handling or a detailed statistical plan. These gaps make it harder to distinguish planned confirmatory analyses from exploratory ones and to evaluate the precision of findings. The case is therefore a useful reminder that a clearly stated research question does not substitute for complete numerical results and analysis reporting.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
Several limitations are specific to the information recorded for this study. First, the primary outcome is named as WMI at baseline, but its median and inter-quartile range are not reported in the registry record. The record also does not report a post-treatment WMI value, a change estimate, or an uncertainty interval. This prevents quantitative interpretation of the primary endpoint.
Second, the study is listed as single-group, with no separate comparator and no masking. The summary describes measurements before and after 6 months of treatment, but the registry record does not provide a control-based comparison. In general, within-group changes cannot rule out explanations such as time trends or other concurrent influences. The record also does not describe blinded outcome assessment or measurement standardization.
Third, enrollment is listed as 16 and the primary-outcome population as 12 patients who completed the study. Reasons for non-completion, outcome-specific data availability, and missing-data handling are not reported. It is not possible to determine from the record whether the completion population represents everyone with usable primary outcome data.
Fourth, no analysis entries are listed. The statistical test, model, adjustment approach, and analysis population are not reported. The record also does not describe multiplicity handling across the 9 outcome measures. The planning assumptions recorded for hypothetical two-arm calculations should not be confused with the actual single-group design or a justification for its enrollment.
Finally, the record gives limited clinical detail about participants beyond the condition description. Demographic and other baseline characteristics are not reported in the registry record for this account. This restricts assessment of the study group's composition and the extent to which its findings, if fully reported, might apply to other populations.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Effect of Aldosterone on Energy Starvation in Heart Failure — NCT00574119.
- Registry record last updated 2019-06-18; status last verified 2019-05.
- Results first posted 2019-06-18.
- 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.
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18. Record Summary
The registry record describes a completed Phase 4 study sponsored by Vanderbilt University, with enrollment of 16 and a recorded start of 2007-12 and primary completion of 2012-07. It concerns patients with heart failure due to nonischemic dilated cardiomyopathy and evaluates spironolactone in a single-group, unmasked design. The planned imaging program included 11C acetate PET and MRI, with assessments before and after 6 months of treatment.
The registered primary outcome is baseline left ventricular work-metabolic index, defined using left ventricular stroke work and the decay rate of 11C-acetate. The primary-outcome population is described as 12 patients who completed the study. The baseline summary values, post-treatment WMI results, and treatment-related analysis are not reported in the registry record. Safety listings record 0 affected by serious adverse events, 2 affected by other adverse events, and 0 deaths; descriptions of the other events are not reported.