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 MODULA Modul 7 VRR (NCT00180414), a randomized na study. The primary outcome is Percentage of Biventricular Pacing.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00180414 |
| Phase | NA |
| Condition | Atrial Fibrillation |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 8 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Boston Scientific Corporation |
| Results posted | Yes |
2. Clinical Question
Population
CRT patients with atrial fibrillation. The registry record describes enrollment of 8 participants, but does not report further eligibility details or a detailed description of the analyzed population.
Intervention
CRT devices with the CE-labeled Ventricular Rate Regulation feature switched ON.
Comparator
The same named device feature switched OFF. The record describes randomized groups but does not provide further details about device settings or other care in either group.
Primary question
At 6 month, how did the average percentage of biventricular pacing compare between participants randomized to VRR ON and those randomized to VRR OFF? The study also aimed to examine correlations between VRR and subjective quality of life, symptoms caused by conducted atrial arrhythmias, and physical ability.
The primary question is a comparison of an average between randomized groups. It is distinct from the secondary questions, which are described as correlations. A correlation asks whether measurements vary together; it does not by itself establish that a change in one measure caused a change in another. The registry record does not report results for either type of question: it says the endpoints were not analyzed because enrollment was insufficient and overall data quality did not allow conclusions. No treatment-group estimate, correlation estimate, or uncertainty measure is reported.
3. Trial Design
The registry identifies MODULA Modul 7 VRR as a randomized, single-masked, parallel study sponsored by Boston Scientific Corporation. Its stated condition is atrial fibrillation, and its intervention is a device described as CRT devices with ventricular rate regulation (VRR), CE labeled. The two arm labels are VRR feature ON and VRR feature OFF. The registry does not describe any other difference between the groups.
The study started on 2004-08-28, had a primary completion date of 2008-05-07, and is listed as terminated. Enrollment is recorded as 8. Phase is listed as NA. Although the record identifies the design as single-masked, it does not state who was masked or how masking was maintained. Further information about randomization procedures, allocation concealment, recruitment, eligibility criteria, and follow-up procedures is not reported in the registry record.
The primary endpoint was to compare the average percentage of biventricular pacing for the VRR ON and VRR OFF groups at 6 month. The listed secondary outcomes concern subjective quality of life, symptoms caused by conducted atrial arrhythmias, and physical ability, with the 6 Minute Walk Test and optional spiroergometry named for physical ability. The registry also lists four outcome measures, but it does not provide analyzed results for them. In its endpoint description, the record says that the number enrolled was insufficient and overall data quality did not allow conclusions; endpoints were not analyzed and the final report did not contain analysis information. Thus the design states what was intended to be compared, but the posted record does not show whether the planned comparisons were carried out.
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 | Ventricular Rate Regulation Feature ON | Ventricular Rate Regulation Feature OFF |
|---|---|---|
| STARTED | 4 | 4 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 4 | 4 |
Reasons for not completing this period:
| Reason | Ventricular Rate Regulation Feature ON | Ventricular Rate Regulation Feature OFF |
|---|---|---|
| Study cancellation due to lack of overall enrollments | 4 | 4 |
Analysis population for the primary outcome, as defined in the registry: An insufficient number of subjects was enrolled as well as the overall data quality of this investigation did not allow for any conclusions regarding the endpoint. Endpoints were not analyzed, final report does not contain information about analysis. Individual data deleted meanwhile per applicable data storage regulations and unavailable for further analysis, hence detailed results are impossible to be provided.
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 | Ventricular Rate Regulation Feature ON | Ventricular Rate Regulation Feature OFF | Total |
|---|---|---|---|---|
| Participants analysed | 4 | 4 | 8 | |
| Age, Continuous | years | NA (SD NA) | NA (SD NA) | 72.3 (SD 6.5) |
| Sex: Female, Male: Female | Participants | 1 | 1 | 2 |
| Sex: Female, Male: Male | Participants | 3 | 3 | 6 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Biventricular Pacing, measured over 6 month.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the percentage of biventricular pacing, with the stated comparison being the average in participants randomized to VRR ON versus the average in participants randomized to VRR OFF. The specified timeframe is 6 month. The registry does not provide a unit beyond the percentage named in the endpoint, further measurement details, a definition of how the average was calculated, or an analysis population.
In general, a pacing percentage describes the share of pacing activity attributed to biventricular pacing over a defined measurement period. Comparing group averages can indicate whether the measured endpoint tends to differ between the assigned groups. It does not, by itself, describe the distribution of individual observations, the range of values, or how precisely the group comparison is estimated. Those interpretations require the underlying results and an uncertainty measure, such as a confidence interval.
No primary endpoint value, group average, between-group estimate, or confidence interval is reported in the registry record. It explicitly states that the endpoints were not analyzed because enrollment was insufficient and overall data quality did not allow conclusions. Therefore, the intended endpoint is identifiable, but the posted results do not quantify the comparison or support an assessment of its direction or precision.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a randomized comparison of VRR ON and VRR OFF and names percentage of biventricular pacing as the primary endpoint at 6 month. However, it reports no analyzed primary endpoint results. In particular, it gives no group averages, estimate of the difference, measure of uncertainty, or test result. There is therefore no numerical treatment-group contrast to interpret, and the record does not establish whether the endpoint tended to be higher in either group.
The reason given for the absence of a conclusion is explicit: an insufficient number of subjects was enrolled, and overall data quality did not allow conclusions regarding the endpoint. The record further states that endpoints were not analyzed and that the final report does not contain information about analysis. These statements describe the limits of the available evidence; they are not evidence that the groups were similar or that VRR had no effect. Without an analysis, a null finding cannot be distinguished from an unmeasured, imprecise, or otherwise unavailable result.
The same caution applies to the secondary outcomes. The record lists correlations involving subjective quality of life, symptoms caused by conducted atrial arrhythmias, and physical ability, but posts no correlation estimates or underlying outcome summaries. Their direction, magnitude, and precision are not reported in the registry record. The intended physical-ability measures include the 6 Minute Walk Test and optional spiroergometry, but the record does not say which measures were collected or provide results.
Randomization is relevant to how a valid group comparison might be interpreted: in general, random assignment is intended to reduce systematic differences between groups at baseline. It does not guarantee that the realized groups will be comparable in every feature, and it cannot compensate for missing or unreliable outcome data. Here, because the registry reports that endpoints were not analyzed, randomization alone does not yield an estimate of the effect of assignment to VRR ON rather than VRR OFF.
The listed enrollment and adverse-event counts are descriptive record entries, not substitutes for endpoint analysis. The registry lists 8 enrolled participants and reports no serious or other adverse events in the two group entries, while deaths are not reported. These entries do not resolve the stated concerns about endpoint data quality, and they do not provide evidence about the primary pacing comparison. Overall, the posted record documents the trial question and its termination status, but leaves the clinical outcome comparisons unquantified.
9. Statistical Methods Explained
The registry describes a randomized, single-masked, parallel study. Those labels indicate the broad design, but they do not supply the analysis methods. The person or persons masked, the randomization sequence method, allocation concealment, and any procedures for maintaining masking are not reported in the registry record. More importantly, the record states that the endpoints were not analyzed and that the final report does not contain analysis information. Any explanation of statistical methods must therefore distinguish general principles from methods actually documented for this study.
What does randomization contribute?
In general, randomization assigns participants to groups through a chance-based process. Its statistical purpose is to reduce the possibility that allocation is systematically related to participants' characteristics. When outcomes are collected and analyzed appropriately, a comparison by randomized group can estimate the effect of assignment to the intervention strategy, subject to the trial's conduct and data quality. Randomization does not ensure that every relevant characteristic is balanced in a small realized sample, nor does it repair missing, inaccurate, or unanalysable outcome data. The registry does not report baseline characteristics or the randomization procedure, and it supplies no outcome analysis to interpret.
What would a comparison of averages mean?
For the primary endpoint, the stated aim was to compare the average percentage of biventricular pacing in the VRR ON and VRR OFF groups. In general, an estimated difference between group averages summarizes the direction and size of the observed contrast on the endpoint scale. A confidence interval expresses the range of values reasonably compatible with the data and statistical model, and is used to assess precision. A p-value, when reported, describes how surprising data at least as incompatible with a null model would be under that model's assumptions; it is not a measure of clinical importance. None of these quantities is reported for the primary endpoint in the registry record, so no such interpretation can be made for this trial.
How should the secondary correlations be understood?
In general, correlation measures the degree to which two variables vary together. It does not show that one variable causes the other to change, and its interpretation depends on the measures, their distributions, missingness, and the analysis method. The secondary outcomes refer to correlations between VRR and quality of life, symptoms, and physical ability. The registry does not define the correlation method, identify the precise paired variables or measurement timing, or report any correlation results. It therefore does not support claims about the strength, direction, or precision of those relationships.
Why does data quality matter?
Statistical analysis depends on sufficiently complete and credible outcome observations. In general, missing measurements can reduce precision and may bias a comparison if the chance that an observation is missing is related to the outcome or group. Measurement errors can also distort group averages and associations. The registry specifically cites insufficient enrollment and overall data quality as reasons that conclusions about the endpoint could not be drawn. It does not describe the type or extent of missingness, the nature of data-quality concerns, or any method for addressing them. No assumptions about those issues can be attributed to the trial.
In general, over-dispersion means that observed variability exceeds what a chosen statistical model expects. A model that does not account for such variability can understate uncertainty. The registry record does not report a model, variance estimate, or indication that over-dispersion was assessed, so this general issue cannot be connected to a reported analysis in this study. Similarly, the record does not describe covariate adjustment, repeated-measures methods, handling of outliers, or a prespecified analysis set.
The sample-size assumptions described in the record refer to a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation, a normal approximation, and effects expressed as fractions of the observed effect. For non-time-to-event outcomes, such illustrations are stated as participants per arm for a specified power; time-to-event illustrations are stated as total events. Such calculations are planning illustrations, not observed power and not evidence that the trial was adequately sized. The registry record does not report a trial-specific sample-size justification, and it reports no analyzed effect estimate on which to base a meaningful interpretation of a planning calculation.
Overall, statistical design labels and general analysis principles help frame what the intended comparison would require. They do not fill in the missing trial analysis. The registry reports no primary estimate, confidence interval, p-value, secondary correlation estimate, or documented statistical model. Its stated conclusion is that endpoints were not analyzed, so statistical interpretation must stop short of estimating treatment effects.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary endpoint and secondary outcomes concerning quality of life, symptoms caused by conducted atrial arrhythmias, and physical ability. It also records four outcome measures. When a study assesses multiple outcomes, general statistical practice considers multiplicity: repeated testing can increase the chance of finding an apparently notable result by chance, and a prespecified strategy may address this. The registry does not report whether multiplicity was considered, whether any adjustment was planned, or which outcome would take priority beyond identifying percentage of biventricular pacing as primary.
Missing-data methods and analysis populations are also not reported in the registry record. It does not describe an intention-to-treat population, a per-protocol population, exclusions, imputation, or sensitivity analyses. The endpoint description says the number enrolled was insufficient and overall data quality did not allow conclusions, and it states that endpoints were not analyzed. The record also says individual data were deleted meanwhile, but does not identify the applicable basis in the available text. Consequently, it is not possible to determine how many endpoint observations were available, how missing measurements were handled, or whether the posted adverse-event group counts correspond to an endpoint analysis population.
In general, a clear account of missingness and analysis populations helps readers assess which participants contribute to an estimate and how robust it may be. Here, no estimate is reported, and the information needed to assess those choices is not reported in the registry record. The record's absence of analysis should not be mistaken for a documented complete-case analysis, a particular missing-data method, or an adjustment for multiple comparisons.
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 |
|---|---|---|---|
| Ventricular Rate Regulation Feature ON | 0 | 4 | 0.0% |
| Ventricular Rate Regulation Feature OFF | 0 | 4 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Ventricular Rate Regulation Feature ON | 0 of 4 |
| Ventricular Rate Regulation Feature OFF | 0 of 4 |
The adverse-event entries list the VRR ON group with 4 participants at risk for serious adverse events and 0 affected; for other adverse events, 4 were at risk and 0 were affected. The VRR OFF group likewise lists 4 at risk for serious adverse events and 0 affected, and 4 at risk for other adverse events and 0 affected. These are the counts recorded for the listed groups.
Deaths are not reported in the registry record. The record does not provide event definitions, observation windows, severity details, relatedness assessments, or further information about safety monitoring. A zero count in a registry entry means no events are listed as affecting participants in that entry; it does not establish that an event could not occur, and it does not address the uncertainty associated with a small study. These safety counts also do not provide evidence about the primary endpoint, which the record says was not analyzed.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized comparison of VRR feature ON and OFF was intended in CRT patients with atrial fibrillation, and that percentage of biventricular pacing was the primary endpoint at 6 month. It also documents that the study was terminated and that enrollment was 8. The record's endpoint description states that the enrolled number was insufficient and overall data quality did not allow conclusions. It further states that endpoints were not analyzed and that the final report does not contain information about analysis.
Accordingly, the posted record does not show whether the primary endpoint differed between groups. It provides no group averages, effect estimate, confidence interval, or test result. It also gives no results for the listed secondary correlations. The absence of these estimates is not a finding of no difference, no association, or equivalence. Those conclusions require analyses and an assessment of uncertainty that are not reported.
The design identifies a randomized comparison, but the design alone cannot answer the study question. In general, a randomized study can support a causal comparison when outcomes are measured and analyzed appropriately. Here the record itself flags limitations in enrollment and data quality and says that analysis was not performed. It therefore does not allow a quantitative estimate of the effect of assignment to VRR ON versus VRR OFF.
The adverse-event entries list zero affected participants for serious and other events in both groups, with deaths not reported. These descriptive entries should be read separately from the efficacy-related endpoint question. They do not establish the absence of risk or replace a complete safety analysis. Likewise, the intended secondary outcomes and the names of the physical-ability measures indicate what investigators sought to examine, not what the study demonstrated.
The useful conclusion is about the record's evidential limits: it documents the comparison that was planned, but does not provide an analyzed result capable of resolving that comparison. Any stronger claim about pacing, quality of life, symptoms, physical ability, or safety would go beyond the posted information.
13. Why This Trial Matters Statistically
This study is statistically notable because its registry record separates a clearly stated research question from an interpretable result. It identifies the intervention contrast, the primary endpoint, and the timeframe, but also states that endpoints were not analyzed. That distinction matters: registering a question and enrolling participants do not by themselves produce an estimate of an intervention effect.
The record also illustrates why enrollment and data quality are integral to inference rather than administrative details. The registry attributes the lack of conclusions to an insufficient number of enrolled subjects and overall data quality. In general, a smaller or less reliable evidence base can limit precision and can undermine the validity of estimates. In this trial, the concern is more direct: the registry says analysis was not conducted, so no estimate is available to assess for either precision or direction.
Another statistical lesson is the difference between outcome plans and results. The primary outcome is a between-group comparison of an average, while the secondary aims are described as correlations. These analyses answer different questions and require clear definitions and reporting. The record names several outcomes but provides no analysis methods or estimates, making it impossible to assess multiplicity, model choice, or the uncertainty of any association.
Finally, the adverse-event entries demonstrate the limits of reading zero counts without context. They report no affected participants in the listed groups, but do not provide detailed definitions or monitoring information, and the trial record does not report deaths. These entries should be interpreted as registry counts rather than definitive evidence about safety. Overall, the study is a useful example of why transparent reporting of methods, data availability, and uncertainty is essential for readers to distinguish a planned comparison from a supported conclusion.
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 trial-specific limitations are stated directly in the registry. Enrollment was 8, and the endpoint description says the number enrolled was insufficient to support conclusions. The same description cites overall data quality as a barrier, states that endpoints were not analyzed, and says that the final report contains no analysis information. As a result, the primary and secondary questions cannot be answered from the posted results.
The record does not provide group-level endpoint values, estimates of between-group differences, uncertainty intervals, p-values, or correlation results. It does not identify the analysis population or explain how endpoint observations were collected, how much information was available, or what data-quality problems occurred. Individual data are described as having been deleted meanwhile, but the associated basis is not identified in the available registry text. This restricts the ability to evaluate the data independently or understand the missingness.
Design details are also limited. Although the study is labeled randomized, single-masked, and parallel, the registry does not identify the masked party or describe randomization and concealment procedures. It does not provide eligibility details, baseline characteristics, or details of the measurement process. These omissions limit assessment of how closely the conduct followed the intended comparison.
The record lists secondary outcomes but does not report how they were defined or analyzed, and it does not report a multiplicity strategy. Safety entries lack event definitions and observation details. These limitations are in addition to, not a substitute for, the record's central statement that endpoints were not analyzed. No conclusion about the direction or size of an endpoint effect can be drawn from the posted information.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: MODULA Modul 7 VRR — NCT00180414.
- Registry record last updated 2022-06-24; status last verified 2022-06.
- Results first posted 2022-03-29.
- 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
MODULA Modul 7 VRR (NCT00180414) is listed as a randomized, single-masked, parallel study in CRT patients with atrial fibrillation. The comparison was the CE-labeled VRR feature ON versus OFF, with percentage of biventricular pacing at 6 month as the primary endpoint. Listed secondary outcomes concern quality of life, symptoms caused by conducted atrial arrhythmias, and physical ability.
The study started on 2004-08-28, reached its primary completion date on 2008-05-07, enrolled 8, and is listed as terminated. The registry says the enrolled number was insufficient and overall data quality did not allow conclusions; endpoints were not analyzed and the final report does not contain analysis information. No efficacy estimates are reported. Adverse-event entries list 0 affected for serious and other events in each group; deaths are not reported in the registry record.