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 A Study of Aspirin and Simvastatin in Pulmonary Arterial Hypertension (NCT00384865), a randomized phase 2 study. The primary outcome is Distance Walked in Six Minutes.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00384865 |
| Phase | Phase 2 |
| Condition | Hypertension, Pulmonary |
| Allocation | Randomized |
| Design model | Factorial |
| Masking | Quadruple |
| Enrollment | 64 |
| Arms in the primary outcome | 4 |
| Lead sponsor | University of Pennsylvania |
| Results posted | Yes |
2. Clinical Question
Population
People with pulmonary arterial hypertension were studied. The registry record lists pulmonary hypertension as the condition and records enrollment of 64 participants. The eligibility criteria and other detailed characteristics of the participants are not reported in the registry record.
Intervention
The factorial study included aspirin 81 mg taken orally once a day for 6 months and simvastatin 40 mg taken orally once a day for 6 months. The combination arms paired each active drug with either the other active drug or its placebo.
Comparator
Placebo was used for aspirin, simvastatin, or both, depending on the factorial combination. The outcome summaries also distinguish aspirin 81 mg from aspirin placebo, and simvastatin 40 mg from simvastatin placebo.
Primary question
The primary endpoint was distance walked in six minutes, measured at 6 months. The registry summary reports least-squares means and 95% confidence intervals for the active-drug and placebo categories. A direct aspirin-versus-placebo or simvastatin-versus-placebo treatment-effect estimate is not reported in the registry record.
The study’s stated purpose was to determine whether aspirin and simvastatin were safe and effective for pulmonary arterial hypertension. That statement describes the study question; it is not itself a conclusion about treatment effects. The posted primary outcome addresses walking distance, while the listed secondary outcomes concern time to clinical worsening events and adverse events.
Because the design is factorial, the study considered two drug factors within the same trial. The arm descriptions include aspirin with simvastatin, aspirin with placebo, placebo with simvastatin, and placebo with placebo. This structure can support assessment of each drug factor and potentially their interaction, but the registry’s outcome summaries do not report those treatment contrasts or an interaction estimate. The reported group means alone therefore do not establish whether either drug changed six-minute walk distance.
3. Trial Design
This was a phase 2, randomized, quadruple-masked, factorial study sponsored by the University of Pennsylvania. The registry record lists enrollment of 64 and a status of terminated. The recorded start was 2006-09, and primary completion was 2009-10. The reason for termination is not reported in the registry record.
The factorial arrangement combined aspirin and simvastatin assignments. Participants could receive aspirin 81 mg and simvastatin 40 mg, aspirin 81 mg with simvastatin placebo, aspirin placebo with simvastatin 40 mg, or placebo for both drugs. Each drug was taken orally once a day for 6 months, as described in the record. The posted outcome groups are expressed separately by aspirin assignment and by simvastatin assignment, rather than as a single set of four combination-specific primary outcome means.
Randomization is intended to reduce systematic differences between assigned groups, while masking is intended to limit influences from knowledge of assignment. The registry record labels the masking quadruple but does not specify which roles were masked. Allocation concealment procedures, randomization details, and any stratification factors are not reported in the registry record.
The primary endpoint was distance walked in six minutes, measured at 6 months. The registry reports least-squares means with 95% confidence intervals for aspirin 81 mg, aspirin placebo, simvastatin 40 mg, and simvastatin placebo. The outcome group counts are 32 and 33 for each pair of drug assignments. These summaries do not provide a direct contrast, standard error for a contrast, or a test of treatment effect.
Two secondary outcomes are listed: time to clinical worsening events and adverse events. The registry records no posted analyses for the listed outcomes. The study’s protocol, planned enrollment rationale, interim analysis procedures, and detailed statistical analysis plan are not reported in the registry record. The terminated status is a record-level description and does not by itself explain whether outcome collection or analysis was complete.
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 | Aspirin 81 mg + Simvastatin 40 mg | Aspirin 81 mg + Placebo | Placebo + Simvastatin 40 mg | Placebo + Placebo |
|---|---|---|---|---|
| STARTED | 16 | 16 | 16 | 16 |
| Completed Six Month Assessment | 11 | 12 | 15 | 11 |
| COMPLETED | 16 | 16 | 16 | 16 |
| NOT COMPLETED | 0 | 0 | 0 | 0 |
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.
| Characteristic | Unit | Aspirin 81 mg + Simvastatin 40 mg | Aspirin 81 mg + Placebo | Placebo + Simvastatin 40 mg | Placebo + Placebo | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 16 | 16 | 16 | 16 | 64 | |
| Age, Continuous | Years | 59.6 (SD 16.6) | 56.75 (SD 13.2) | 58.6 (SD 11.7) | 63.5 (SD 14.2) | 59.6 (SD 13.9) |
| Sex: Female, Male: Female | Participants | 11 | 15 | 15 | 14 | 55 |
| Sex: Female, Male: Male | Participants | 5 | 1 | 1 | 2 | 9 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 2 | 1 | 5 | 0 | 8 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 14 | 15 | 11 | 16 | 56 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 1 | 0 | 2 | 3 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 2 | 3 | 3 | 5 | 13 |
| Race (NIH/OMB): White | Participants | 13 | 11 | 12 | 9 | 45 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 1 | 1 | 1 | 0 | 3 |
| Region of Enrollment: United States | Participants | 16 | 16 | 16 | 16 | 64 |
6. Primary Endpoint
The registry lists the primary outcome as Distance Walked in Six Minutes, measured over Measured at 6 months.
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | meters |
| Endpoint classification | Continuous Endpoint |
The primary endpoint, distance walked in six minutes, measures how far a participant can walk during a timed six-minute test. It is a continuous measure: values can vary across a range rather than falling into only event or no-event categories. The registry identifies the unit as meters and states that measurement took place at 6 months.
In general, a timed walking measure can capture functional capacity in a standardized activity. It is used as an outcome because a change in walking distance may reflect a change in participants’ ability to perform that task. The measure does not, by itself, describe every aspect of a person’s health or explain why a distance differs between groups. The record does not report details of test administration, assessor training, repeat testing, or baseline walking distance.
The posted endpoint values are least-squares means, a model-based type of mean, rather than a report of raw individual observations. Their 95% confidence intervals communicate uncertainty around each group estimate under the analysis used. The registry does not identify the model covariates, the exact analysis population, or the method for handling measurements unavailable at 6 months. Consequently, the adjusted means cannot be fully reconstructed from the registry record.
These summaries describe the estimated distance in each assignment category. A treatment effect requires a comparison between groups, with its own estimate and uncertainty. Since a direct treatment contrast is not reported, the group means should not be read as a quantified effect of aspirin or simvastatin.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
For aspirin 81 mg, the posted least-squares mean distance at 6 months is 438.0 meters, with a 95% confidence interval from 415.9 to 460.1. For aspirin placebo, the corresponding estimate is 438.5 meters, with a 95% confidence interval from 419.2 to 457.8. For simvastatin 40 mg, the estimate is 425.0 meters, with a 95% confidence interval from 400.2 to 449.9. For simvastatin placebo, it is 452.7 meters, with a 95% confidence interval from 431.9 to 473.4.
These are four group-level estimates, not direct treatment-effect estimates. The record does not report a difference between aspirin and aspirin placebo, a difference between simvastatin and simvastatin placebo, or a confidence interval or significance test for either contrast. The separate confidence intervals describe uncertainty in their respective means. They do not substitute for a confidence interval around a between-group difference.
In general, a confidence interval gives a range of values compatible with the data and the statistical model at the stated confidence level. It is not a guarantee that the true value lies inside the interval, nor does it establish whether a treatment caused a change. The interval’s meaning depends on the design and analysis assumptions. Here, the registry identifies the intervals as 95% confidence intervals but does not report enough model details to assess those assumptions fully.
The point estimates vary across the listed assignment categories, but a numerical difference between them should not be calculated or treated as a trial finding. A valid factorial analysis may account for the joint assignments, the structure of the data, and other model terms. No such contrast estimates are posted. The registry also does not report an interaction result, so the summaries cannot show whether the effect of one drug assignment depended on the other drug assignment.
Precision is also distinct from clinical importance. The record does not give a threshold for a clinically meaningful change in walking distance. Without that threshold and a treatment-effect estimate, the posted means cannot establish whether any observed difference would be important to participants. Nor do these outcome summaries establish safety: the safety counts are a separate descriptive part of the registry record and have their own limitations.
The record lists enrollment of 64, while the endpoint summaries list group counts of 32 and 33 for each drug comparison. These counts describe the participants represented in the posted endpoint summaries; they do not explain the analysis population or why those counts appear as recorded. The registry does not report participant flow, exclusions, or missing endpoint data. The status is terminated, but the reason and its effect on the planned analyses are not reported in the registry record.
Overall, the posted primary outcome gives estimated six-minute walk distances and uncertainty intervals for assignment categories. It does not report the inferential comparisons needed to determine the estimated effect of either drug. The appropriate interpretation is therefore descriptive and limited to the summaries that are available.
9. Statistical Methods Explained
What does a least-squares mean represent?
A least-squares mean is a mean estimated from a statistical model. In general, the model can account for specified features of the design or participant data, so the estimate need not equal the simple arithmetic average of observed measurements. The registry identifies the primary outcome parameter as a least-squares mean, but it does not report the model specification, adjustment variables, or the exact procedure used to estimate the means. That limits the ability to determine which features were adjusted for or to reproduce the analysis.
The reported estimates are 438.0 meters for aspirin 81 mg, 438.5 meters for aspirin placebo, 425.0 meters for simvastatin 40 mg, and 452.7 meters for simvastatin placebo. Each estimate has a 95% confidence interval. Those intervals characterize uncertainty in the corresponding model-based group means. They are not intervals for the difference between active treatment and placebo.
How should the confidence intervals be understood?
In general, a confidence interval describes the precision of an estimate under a particular analysis and its assumptions. A narrower interval indicates greater precision than a wider interval for the same quantity, but precision alone does not establish importance or causality. The intervals posted for these groups are 415.9 to 460.1 for aspirin 81 mg, 419.2 to 457.8 for aspirin placebo, 400.2 to 449.9 for simvastatin 40 mg, and 431.9 to 473.4 for simvastatin placebo.
Because these are intervals around separate group means, comparing their endpoints is not a substitute for estimating a treatment contrast. In general, a difference has its own sampling uncertainty, which depends on the study design, the relationship between observations, and the analysis model. The registry does not report confidence intervals for treatment differences or the tests used to evaluate them. It is therefore not possible to infer a reported treatment effect from the individual mean intervals alone.
What does the factorial structure add?
A factorial design assigns participants across combinations of treatment factors. In this study, the factors were aspirin and simvastatin, each with an active-drug and placebo option. This can permit estimation of the effect associated with each factor while using information across combinations, if the analysis plan and model support that approach. The design can also permit assessment of whether the effect of one factor varies according to assignment of the other factor; that is an interaction question.
The posted primary outcome summaries are organized into aspirin assignment groups and simvastatin assignment groups. They do not give combination-specific estimates, treatment contrasts, or an interaction estimate. The record also does not state whether the primary analysis used a factorial model, whether it assumed no interaction, or how any interaction was handled. Those details are not reported in the registry record, so the design label alone cannot answer them.
What do the outcome counts and estimates establish?
The group counts are 32 for aspirin 81 mg, 33 for aspirin placebo, 32 for simvastatin 40 mg, and 33 for simvastatin placebo. The registry also lists total enrollment of 64. The record does not explain the relationship between enrollment and the counts appearing in the endpoint summaries, nor does it report whether those counts refer to all randomized participants, participants with observed endpoint data, or a model-specific analysis population. No participant-flow information is reported.
The estimates are continuous-outcome summaries, not event counts. The registry does not report standard deviations, raw data, baseline values, or model diagnostics for six-minute walk distance. Without those items, an independent reader cannot reconstruct the means, assess the distribution of individual measurements, or evaluate the influence of missing observations. The record identifies 95% confidence intervals as the measure of dispersion but does not provide the derivation details.
What can sample-size illustrations say?
In general, sample-size calculations depend on assumptions about the effect to detect, variability, significance level, allocation, and analysis method. Planning illustrations based on an observed effect are hypothetical calculations, not evidence that a study had a particular probability of detecting an effect. The registry’s design rationale and sample-size justification are not reported in the registry record. Any planning illustration should therefore be understood as a conditional scenario, not as the trial’s original design calculation or observed power.
The record describes assumptions for planning illustrations, including a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also states that the effect to detect is defined as a fraction of the observed effect. These assumptions do not establish that the original trial used them. The actual sample-size target rationale is not reported in the registry record, and no posted analysis count is available for the outcome comparisons.
Why do event outcomes require different methods?
The secondary outcomes include time to clinical worsening events and adverse events. Time-to-event methods generally use the timing of events and account for participants who have not experienced an event by the end of observation. General methods for such outcomes differ from methods for a continuous walking-distance endpoint. The registry lists the outcome but does not post an analysis for time to clinical worsening. The analysis method, follow-up details, censoring rules, and treatment-effect estimate are not reported in the registry record.
Adverse-event summaries are counts of participants with events in the recorded groups. Such counts are descriptive and do not, on their own, adjust for exposure time, differences in follow-up, or other factors. The registry does not report an inferential safety comparison or detailed event-level data. The serious event counts should therefore be read as the recorded participant counts, not as adjusted estimates of risk.
The registry records zero analyses posted. It does not report the planned statistical analysis, interim monitoring, handling of multiplicity, missing-data method, or analysis populations. These absences matter because the choice of model, population, and handling of multiple outcomes can affect estimates and uncertainty. General statistical principles explain why such information is important, but they cannot fill in trial-specific methods that are not documented in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The record lists a primary endpoint and two secondary outcomes: time to clinical worsening events and adverse events. It does not report a multiplicity strategy for evaluating more than one endpoint or treatment contrast. In general, when several hypotheses are tested, the chance of at least one false-positive finding can increase unless the analysis plan addresses multiplicity. No treatment-effect tests are posted for the primary endpoint, and the registry records no posted analyses.
Missing-data methods are not reported in the registry record. The six-month endpoint summaries have group counts, but the record does not explain how those counts relate to all randomized participants, whether some measurements were unavailable, or how unavailable measurements were handled. It also does not report reasons for missingness, participant flow, or sensitivity analyses. The listed group counts should not be assumed to represent a particular analysis population beyond what the registry states.
The analysis populations are not reported in the registry record. In particular, it is not stated whether the primary summaries use all randomized participants, participants who received assigned treatment, or participants with an observed six-month measurement. The protocol’s rules for exclusions and treatment adherence are also not reported.
The record does not report interim analyses or a stopping rule. The terminated status alone does not establish why the study ended or whether termination affected data collection, planned comparisons, or outcome reporting. These omissions limit evaluation of the statistical plan and of how the posted summaries relate to the originally intended analyses.
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 |
|---|---|---|---|
| Aspirin 81 mg | 4 | 32 | 12.5% |
| Aspirin Placebo | 1 | 33 | 3.0% |
| Simvastatin 40 mg | 0 | 32 | 0.0% |
| Simvastatin Placebo | 0 | 33 | 0.0% |
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 |
|---|---|
| Aspirin 81 mg | 32 of 32 |
| Aspirin Placebo | 33 of 33 |
| Simvastatin 40 mg | 32 of 32 |
| Simvastatin Placebo | 33 of 33 |
Most frequent serious adverse event terms
| Event term | Organ system | Aspirin 81 mg | Aspirin Placebo | Simvastatin 40 mg | Simvastatin Placebo |
|---|---|---|---|---|---|
| Major Bleeding Episode | Blood and lymphatic system disorders | 4 of 32 | 1 of 33 | 0 of 32 | 0 of 33 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Aspirin 81 mg | Aspirin Placebo | Simvastatin 40 mg | Simvastatin Placebo |
|---|---|---|---|---|---|
| Minor Bleeding Episode | Blood and lymphatic system disorders | 11 of 32 | 12 of 33 | 14 of 32 | 13 of 33 |
| Upper Respiratory Infection | Respiratory, thoracic and mediastinal disorders | 10 of 32 | 11 of 33 | 12 of 32 | 9 of 33 |
| Bruising | General disorders | 8 of 32 | 8 of 33 | 10 of 32 | 6 of 33 |
| Myalgia | Musculoskeletal and connective tissue disorders | 3 of 32 | 5 of 33 | 3 of 32 | 5 of 33 |
| Headache | General disorders | 5 of 32 | 3 of 33 | 5 of 32 | 3 of 33 |
| Other Infections | Infections and infestations | 4 of 32 | 4 of 33 | 4 of 32 | 4 of 33 |
| Diarrhea | Gastrointestinal disorders | 3 of 32 | 4 of 33 | 3 of 32 | 4 of 33 |
| Dyspnea | Respiratory, thoracic and mediastinal disorders | 2 of 32 | 4 of 33 | 3 of 32 | 3 of 33 |
| Rash | Skin and subcutaneous tissue disorders | 3 of 32 | 3 of 33 | 4 of 32 | 2 of 33 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 3 of 32 | 3 of 33 | 4 of 32 | 2 of 33 |
Serious events with the highest arm-level rate: major bleeding episode (12.5%).
The registry’s serious adverse-event summaries report 4 affected participants among 32 at risk in the aspirin 81 mg group, 1 among 33 in the aspirin placebo group, 0 among 32 in the simvastatin 40 mg group, and 0 among 33 in the simvastatin placebo group. These are participant counts in the categories recorded by the registry. The record does not report a statistical comparison of these counts, an adjustment for follow-up time, or a treatment-effect estimate for serious adverse events.
Major Bleeding Episode is listed among the top serious-event terms with 12.5%. The registry summary does not specify the denominator or provide enough context to assign this term to a particular comparison group. It should therefore be read as a listed serious-event term, not as a complete group-specific event rate.
For the other adverse-event category, the posted affected counts are 32 among 32 for aspirin 81 mg, 33 among 33 for aspirin placebo, 32 among 32 for simvastatin 40 mg, and 33 among 33 for simvastatin placebo. Death counts are not reported in the registry record. These summaries do not establish that an event was caused by treatment, and the small recorded counts and absent comparative analysis limit conclusions about differences in safety.
12. What the Result Does, and Does Not, Mean
The registry record documents a randomized factorial study of aspirin and simvastatin in pulmonary arterial hypertension and posts six-month least-squares mean estimates for six-minute walk distance. The group estimates and their 95% confidence intervals describe the recorded outcome summaries. They do not supply a direct estimate of the effect of aspirin, the effect of simvastatin, or the interaction between the two assignments.
That distinction is central. A difference between group means is not itself a reported treatment effect unless the relevant comparison is estimated and its uncertainty is assessed using an appropriate analysis. The registry does not report those contrasts, significance tests, or a model description. The available summaries therefore cannot support a definitive inferential claim about whether the assignments changed walking distance.
The estimates also do not indicate whether any difference would be clinically meaningful. A threshold for an important change in six-minute walk distance is not reported in the registry record. The primary endpoint captures a particular functional task, not all potential benefits, harms, symptoms, or experiences. Other outcomes listed in the registry include clinical worsening and adverse events, but the clinical-worsening analysis is not posted.
The safety counts are descriptive. They give the numbers of participants recorded with serious and other adverse events in assignment categories, but the record does not post comparative safety analyses or enough context to interpret the serious-event term as a group-specific rate. Null death fields mean deaths are not reported in the registry record, not that the record establishes an absence of deaths.
In general, randomized assignment can support causal comparisons when the relevant outcome data and analysis are reported and the design is appropriately analyzed. Here, the registry’s treatment contrasts, analysis populations, missing-data procedures, and detailed statistical plan are not reported. The appropriate conclusion is limited: the record contains group-level endpoint and adverse-event summaries, while the comparative effects and their precision remain unreported.
13. Why This Trial Matters Statistically
This study illustrates why trial design labels and outcome summaries must be interpreted together. A factorial design involves combinations of assignments, while the posted primary outcome is summarized by the aspirin and simvastatin categories separately. Without reported contrasts and an interaction analysis, readers cannot determine how the combinations were analyzed or what treatment effects were estimated.
It also demonstrates the difference between group estimates and comparative evidence. Least-squares means with confidence intervals describe each category, but the research question concerns differences attributable to assignment. Those differences require their own estimates and uncertainty. A list of group means, even when accompanied by confidence intervals, does not replace that comparison.
The record also shows why reporting the statistical analysis plan matters. Model details, analysis populations, missing-data methods, multiplicity procedures, and interim analyses can influence the interpretation of trial findings. In their absence, statistical readers must distinguish what is directly documented from what would require assumptions. The terminated status adds context, but without a stated reason it cannot be used to infer how the trial’s conduct or results were affected.
Finally, safety summaries require the same careful distinction between description and inference. Counts of participants with events are useful descriptive information, but comparative safety conclusions require context about exposure, follow-up, event definitions, and analysis. The record’s lack of posted comparative analyses makes the counts informative as registry entries but limited as evidence about between-group differences.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The registry record does not report a direct treatment-effect estimate for the primary endpoint. It provides least-squares means and 95% confidence intervals for the four assignment categories, but not contrasts, contrast intervals, or tests. The statistical model and any adjustment variables are also not reported, which limits interpretation and reproducibility.
The posted endpoint counts do not come with participant flow or an explanation of the analysis population. The record does not state whether every randomized participant had a six-month measurement, how missing measurements were handled, or whether exclusions occurred. It also does not provide baseline walking-distance values, raw observations, standard deviations, or model diagnostics.
The factorial design raises questions about the analysis of the two treatment factors and their possible interaction. The registry does not report the interaction estimate, combination-specific primary outcome summaries, or whether an assumption about interaction was used. The exact statistical analysis plan and sample-size justification are not reported in the registry record.
The registry lists time to clinical worsening events and adverse events as secondary outcomes, but does not post a clinical-worsening analysis or inferential treatment comparisons. Safety details are limited to participant counts and a serious-event term; the record does not provide event-level timing, exposure-adjusted rates, or deaths. It does not explain the terminated status or report interim analyses. These limitations constrain interpretation of both efficacy-related and safety-related summaries.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study of Aspirin and Simvastatin in Pulmonary Arterial Hypertension — NCT00384865.
- Registry record last updated 2017-07-21; status last verified 2017-07.
- Results first posted 2017-07-21.
- 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
NCT00384865, titled “A Study of Aspirin and Simvastatin in Pulmonary Arterial Hypertension,” is listed as a phase 2 randomized, quadruple-masked factorial study sponsored by the University of Pennsylvania. Enrollment is recorded as 64, and status is terminated. The record lists a start of 2006-09 and primary completion of 2009-10.
The primary endpoint was distance walked in six minutes at 6 months, reported as least-squares means with 95% confidence intervals for aspirin and simvastatin assignment categories. The registry also lists time to clinical worsening events and adverse events. It posts serious and other adverse-event counts but does not report a clinical-worsening analysis or direct primary treatment contrasts.
The registry records no posted analyses. Details of the statistical plan, analysis populations, missing-data handling, multiplicity procedures, interim analyses, and sample-size justification are not reported in the registry record. The posted summaries are therefore descriptive and do not establish comparative treatment effects.