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 Safety and Performance Study of the RELIANCE 4-Front Passive Fixation Lead (NCT01856491), a na na study. The primary outcome is Complication Free Rate.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01856491 |
| Phase | NA |
| Condition | Tachycardia, Ventricular Fibrillation, Ventricular Flutter |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 167 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Boston Scientific Corporation |
| Results posted | Yes |
2. Clinical Question
The study was intended to gather information about the chronic safety, performance and effectiveness of the RELIANCE 4-FRONT Passive Fixation defibrillation lead. Its primary question concerned whether patients remained free of lead-related complications from implantation through 3 months after implantation. The registry record identifies the endpoint and its timeframe, but does not report the observed complication-free rate or its confidence interval. The result therefore cannot be quantified from the registry record.
Population
The record describes patients enrolled in a post-market clinical follow-up study. It reports that 167 were enrolled and that 165 were included in the primary analysis because the leads were not implanted in 2 patients. The conditions listed are tachycardia, ventricular fibrillation and ventricular flutter; additional eligibility details are not reported in the registry record.
Intervention
The intervention was implantation of the RELIANCE 4-FRONT Passive Fixation lead. The record describes a single arm in which all patients were to receive that lead.
Comparator
No comparison group is described. Allocation is recorded as not applicable, and the study is not a randomized comparison. The findings therefore do not provide a like-for-like comparison against another lead or a control group.
Primary question
What was the lead-related complication-free rate from implantation through 3 months after implantation? The registry record names this as the primary endpoint but does not report the rate, event count for that endpoint or confidence interval.
3. Trial Design
This was a completed, single-group post-market clinical follow-up study sponsored by Boston Scientific Corporation. The registry record gives the study title as “Safety and Performance Study of the RELIANCE 4-Front Passive Fixation Lead” and describes its objective as gathering data about chronic safety, performance and effectiveness. The intervention was implantation of the RELIANCE 4-FRONT Passive Fixation lead. The arm description says all patients would receive the lead.
The record lists enrollment of 167. It reports that 165 were included in the primary analysis because leads were not implanted in 2 patients. This distinction matters: enrollment and the primary analysis population are not identical. The record does not explain further how the non-implantation cases were handled in other outcomes.
The study is listed as unmasked, with allocation recorded as not applicable. It has no comparator arm, so it cannot estimate a randomized treatment contrast or separate the lead’s outcomes from differences between treatment groups. The study dates are listed as starting on 2013-12-16, with primary completion on 2015-11-02; its status is completed. The primary endpoint timeframe is 3 months from implantation.
The registry record lists six outcome measures overall and identifies Complication Free Rate as a secondary outcome as well as the named primary endpoint. Names and detailed definitions for the other outcome measures are not reported in the registry record. Statistical analyses are not listed. Protocol details such as eligibility criteria, follow-up procedures beyond the primary timeframe, sample-size justification and planned analysis methods are also 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 | RELIANCE 4-FRONT™ Passive Fixation |
|---|---|
| STARTED | 167 |
| COMPLETED | 152 |
| NOT COMPLETED | 15 |
Analysis population for the primary outcome, as defined in the registry: 167 have been enrolled. 165 were included in the analysis because for 2 patients the leads have not been implanted
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 | RELIANCE 4-FRONT™ Passive Fixation |
|---|---|---|
| Participants analysed | 167 | |
| Age, Continuous | years | 66.90 (SD 10.47) |
| Sex: Female, Male: Female | Participants | 33 |
| Sex: Female, Male: Male | Participants | 134 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 |
| Race (NIH/OMB): White | Participants | 166 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Complication Free Rate, measured over 3-months.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | percentage of patients without event |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the lead-related Complication-Free Rate from implantation through 3 months after implantation. Its unit is a percentage of patients without an event. In plain terms, this endpoint is intended to describe the proportion of the analysis population that had no lead-related complication during the stated period.
A complication-free measure can provide a direct summary of whether complications were observed over a specified follow-up interval. The timeframe is essential to its interpretation: the endpoint concerns the period ending 3 months after implantation, not an unspecified longer-term period. It also matters that the endpoint is described as lead-related. It is not a measure of every health event that might occur during follow-up.
The registry record describes the result as a number with a 95% confidence interval, but it does not report the estimate, event count or interval limits. Therefore, neither the observed percentage nor its precision can be assessed from the record. The stated endpoint definition also does not give further operational detail, such as the criteria used to classify a complication as lead-related. Those criteria are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The study’s stated purpose was to collect post-market information about chronic safety, performance and effectiveness for the RELIANCE 4-FRONT Passive Fixation lead. Its primary endpoint focuses on lead-related complications through 3 months after implantation. However, the registry record does not include the primary endpoint estimate or its 95% confidence interval. Consequently, it does not allow readers to determine the observed complication-free rate or how precisely that rate was estimated.
The distinction between a point estimate and its confidence interval is important. In general, a point estimate gives a summary of the observed data, while a confidence interval conveys statistical uncertainty around that estimate under the analysis assumptions. A narrow interval indicates greater precision than a wide interval, but neither the width nor the location of an interval can be assessed when its limits are not reported. The 95% confidence level alone is not a result.
The study is single-group and has no control arm. Its results, even if fully reported, would describe outcomes in the enrolled study group; they would not establish a comparative effect against another device or usual care. The registry record explicitly indicates that this is not a randomized comparison. Without a concurrent comparator, differences in patient characteristics, clinical care or other influences cannot be disentangled from outcomes observed after implantation.
The record reports that 167 patients were enrolled and that 165 were included in the primary analysis because the leads were not implanted in 2 patients. This gives context for the stated analysis population, but the missing primary endpoint result means that the impact of the analysis population on the estimate cannot be evaluated. Further information about the handling of missing follow-up or endpoint data is not reported in the registry record.
Safety figures are also listed, including serious adverse events, other adverse events, deaths and serious-event terms. Those figures are descriptive counts and percentages; the registry record does not establish that they were caused by the lead. Nor should the serious adverse event figures be treated as the primary endpoint: a broad adverse-event category and a specifically defined lead-related complication-free outcome are different measures.
Overall, the record identifies the study question and some features of the population and safety reporting, but it does not provide the primary result needed to assess the endpoint’s observed value or statistical precision. No conclusion about comparative performance can be drawn from a single-group design.
9. Statistical Methods Explained
The registry record names a percentage-based primary endpoint and a 95% confidence interval, but does not list the endpoint estimate, interval bounds, event count or statistical analysis. The explanations below describe general statistical concepts; they are not claims about methods used in this study unless explicitly stated as a registry-record detail.
What does a complication-free percentage represent?
For a binary outcome, each person is classified according to whether the defined event occurred during the specified period. A percentage without the event then summarizes the share of the analysis population classified as complication-free. The meaning depends on consistent outcome definitions, ascertainment and follow-up. Here, the registry record identifies the primary endpoint as lead-related and gives its timeframe as implantation through 3 months after implantation, but does not report the operational criteria for classifying complications.
A percentage is a summary, not a description of every individual’s experience. It does not show when events occurred, how many events an individual experienced, or how severity was distributed unless those details are reported separately. The primary outcome’s stated unit is a percentage of patients without an event. The numerical value is not reported in the registry record.
What does a confidence interval add?
In general, a confidence interval expresses uncertainty in an estimate under a statistical model and its assumptions. It is not a guarantee that the true value lies within the particular interval, and it is not a range of outcomes experienced by individual patients. The registry record specifies a 95% confidence interval for the primary outcome but gives no endpoints for it. Thus, its precision cannot be judged. A confidence level without the interval itself does not indicate whether the estimate was precise.
Why does the study design matter?
The registry describes a single-group study, with all patients assigned to implantation of the named lead and no comparator group. In general, a single-group estimate can describe outcomes in that group over the observed period, but it cannot by itself estimate how outcomes would have differed under another device or treatment. A randomized comparison can support a different kind of inference because treatment groups are compared under a design intended to balance factors between groups. That design is not described; the record explicitly says the study is not a randomized comparison.
The record lists allocation as not applicable and masking as none. These design details do not supply an analysis method. The statistical plan, including any adjustment for baseline factors, is not reported in the registry record.
How should the planning illustration be distinguished from trial results?
The registry record describes planning illustrations based on an observed effect, a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation. Such illustrations concern hypothetical future planning assumptions; they are not estimates of the outcome in this single-group study. The record’s assumptions for those illustrations do not establish that the trial itself used a two-arm design or that it was planned around those assumptions. The trial’s own sample-size justification is not reported in the registry record. Planning values are not observed power, and they cannot substitute for the missing endpoint estimate or confidence interval.
What can be inferred from the listed analyses?
No statistical analyses are listed in the registry record. This means the record does not give a test statistic, p-value, model specification, adjustment strategy or inferential comparison for the primary outcome. It is not appropriate to infer an unreported analysis or to treat the absence of a listed analysis as evidence that a particular statistical method was used.
General statistical considerations include choosing methods that match the outcome type and the way follow-up is measured. For a fixed-time binary endpoint, analysis may focus on a proportion and its uncertainty. For outcomes measured over varying follow-up times, time-to-event methods may be appropriate, with assumptions that differ from those for a simple proportion. The record does not report that the primary endpoint was analyzed using either approach, so no method can be attributed to this study.
Another general issue is over-dispersion: observed variation may exceed what a simple model assumes. When present, standard errors from an overly restrictive model can understate uncertainty. Whether over-dispersion is relevant depends on the data structure and model. The registry record does not describe a model, event-level data or checks for this issue, so it cannot be assessed for this outcome.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists six outcome measures overall, names Complication Free Rate as the primary endpoint, and also lists Complication Free Rate among the secondary outcomes. It does not provide the complete set of outcome definitions in the record, nor does it list statistical analyses. A prespecified strategy for handling multiple endpoints or repeated statistical tests is not reported in the registry record.
In general, multiplicity arises when several hypotheses or outcomes are assessed. Without an adjustment or a clearly stated hierarchy, the chance of at least one false-positive result across multiple tests can increase. This is a general statistical concern, not evidence that a particular error occurred in this study. Because no analyses or p-values are listed, the consequences of multiplicity cannot be evaluated.
The primary-outcome description reports that 167 patients were enrolled and that 165 were included in its analysis because leads were not implanted in 2 patients. This explains the stated difference between enrollment and the primary analysis population. It does not describe how missing endpoint observations, withdrawals, incomplete follow-up or other exclusions were handled. Those procedures are not reported in the registry record.
In general, missing data can affect an estimate if the likelihood of missingness is related to outcome status or patient characteristics. Analyses may use different assumptions or sensitivity checks to assess this issue, but no missing-data method or sensitivity analysis is listed in the registry record. The reason for non-implantation is stated; further information about missingness is not.
The record does not report an analysis population definition beyond the statement about the 165 included in the primary analysis. It also does not report whether any other outcomes used different populations. Therefore, the available information is insufficient to assess consistency of analysis populations across outcomes.
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 |
|---|---|---|---|
| RELIANCE 4-FRONT™ Passive Fixation | 84 | 167 | 50.3% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| RELIANCE 4-FRONT™ Passive Fixation | 4 of 167 |
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 |
|---|---|
| RELIANCE 4-FRONT™ Passive Fixation | 55 of 167 |
Most frequent serious adverse event terms
| Event term | Organ system | RELIANCE 4-FRONT™ Passive Fixation |
|---|---|---|
| Gastrointestinal | Gastrointestinal disorders | 10 of 167 |
| Pulmonary | Respiratory, thoracic and mediastinal disorders | 9 of 167 |
| Dyspnea - Heart failure | Cardiac disorders | 8 of 167 |
| Genitourinary | Renal and urinary disorders | 7 of 167 |
| Renal | Renal and urinary disorders | 7 of 167 |
| Heart failure symptoms - Unspecified | Cardiac disorders | 6 of 167 |
| Myocardial infarction | Cardiac disorders | 6 of 167 |
| Chest pain - Other | Cardiac disorders | 6 of 167 |
| Cerebrovascular accident (CVA) | Vascular disorders | 6 of 167 |
| Multi-system failure - Heart failure | Cardiac disorders | 5 of 167 |
Most frequent non-serious adverse event terms
| Event term | Organ system | RELIANCE 4-FRONT™ Passive Fixation |
|---|---|---|
| Head, eyes, ears, nose, throat (HEENT) | General disorders | 10 of 167 |
| Dyspnea - Heart failure | Cardiac disorders | 7 of 167 |
| Chest pain - Other | Cardiac disorders | 7 of 167 |
| Physical trauma | General disorders | 6 of 167 |
| Musculoskeletal | Musculoskeletal and connective tissue disorders | 6 of 167 |
| Gastrointestinal | Gastrointestinal disorders | 5 of 167 |
| Inappropriate tachy therapy - SVT | Cardiac disorders | 4 of 167 |
| Atrial fibrillation (AF) | Cardiac disorders | 4 of 167 |
| Genitourinary | Renal and urinary disorders | 4 of 167 |
| Not yet classified | General disorders | 3 of 167 |
Serious events with the highest arm-level rate: gastrointestinal (6.0%), pulmonary (5.4%), dyspnea - heart failure (4.8%), genitourinary (4.2%), renal (4.2%).
The safety record lists 167 at risk for serious adverse events and reports 84 in the serious adverse event count. It also lists 167 at risk for other adverse events and reports 55 in that category. The record reports 4 deaths. These are descriptive safety figures; the registry record does not state that the events or deaths were caused by the lead.
The listed serious-event terms and percentages are Gastrointestinal, 6.0%; Pulmonary, 5.4%; Dyspnea - Heart failure, 4.8%; Genitourinary, 4.2%; Renal, 4.2%; and Heart failure symptoms - Unspecified, 3.6%. The registry record does not explain in this listing whether people could contribute to more than one term, or provide further details about severity, timing or attribution for each term. The percentages should therefore be read as reported categories, not as mutually exclusive groups or as evidence of a causal relationship.
Serious adverse events and the primary lead-related complication-free endpoint are not interchangeable. The latter is specifically described as lead-related and covers the period through 3 months after implantation. The safety listing does not establish how its categories correspond to that endpoint. Counts should not be added to infer a total number of affected people, since overlap and the relationship among categories are not reported.
12. What the Result Does, and Does Not, Mean
The registry record establishes that the study was designed to collect post-market information about the RELIANCE 4-FRONT Passive Fixation lead and that its primary question concerned lead-related complications through 3 months after implantation. It also establishes that the study used a single group, with all patients in that group receiving the lead, and that 165 were included in the primary analysis after 167 were enrolled.
What the record does not establish is the observed primary complication-free rate. Although the endpoint is identified as a percentage and a 95% confidence interval is specified, neither the estimate nor the interval is reported. The event count for that endpoint is also not reported. Without those data, the size and precision of the primary result cannot be assessed.
The study design also limits the kinds of conclusions it can support. A single-group study does not provide a randomized comparison with another device or a control group. Consequently, it cannot show whether outcomes would have been different under another option, and it cannot isolate the lead’s contribution from other influences on outcomes. This is a design limitation, not a finding that the lead did or did not perform well.
The adverse-event figures describe safety reporting in the registry, but they do not by themselves establish causation. The record does not state that the serious events, other adverse events or deaths were caused by the lead. It also does not provide enough detail to determine whether listed event categories overlap or how they relate to the primary endpoint.
Thus, the registry record supports a description of the study’s objective, design, enrollment and reported safety counts. It does not support a numerical assessment of the primary endpoint, a comparative effectiveness conclusion or a causal interpretation of the adverse-event counts. Those questions require results and methods that are not reported in the registry record.
13. Why This Trial Matters Statistically
Post-market follow-up studies can address questions about device outcomes after implantation in a clinical setting. Statistically, their value depends not only on identifying an outcome but also on reporting the estimate, its uncertainty, the population analyzed and the methods used to define and assess events. This record states a specific lead-related complication-free endpoint and timeframe, which helps define the question. Yet the absent estimate and confidence interval prevent readers from assessing the result’s magnitude or precision.
The enrollment and analysis-population information is also important. The record distinguishes 167 enrolled patients from 165 included in the primary analysis and explains that the leads were not implanted in 2 patients. Clear accounting of who enters an analysis helps readers understand the population to which an estimate applies. Further details about follow-up completeness and missing-data handling are not reported in the registry record.
The single-group design makes the study’s inferential scope especially important. Descriptive follow-up can characterize events in the studied group, but without a comparator it does not estimate a contrast between treatment options. This distinction prevents a descriptive safety record from being mistaken for evidence of comparative benefit or harm.
Finally, safety counts require careful interpretation. Serious adverse events, other adverse events, deaths and a lead-related primary endpoint are different measures. Reporting counts without attribution details or information about overlap does not answer whether a device caused an event. Statistical interpretation therefore depends on both the design and the precision and definition of the reported outcomes—not on event counts alone.
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 main limitation for interpreting the primary result is that the registry record does not report the complication-free rate, its event count or its 95% confidence interval. The endpoint is defined by a 3-month timeframe and described as lead-related, but detailed event-classification criteria are not reported. Without the estimate and definition details, neither the outcome’s observed level nor its measurement can be fully assessed.
The single-group design provides no like-for-like control comparison. Allocation is recorded as not applicable, and the study is identified as not randomized. Therefore, the record cannot support a comparative estimate against another lead or control condition. Masking is listed as none; further details about outcome assessment procedures are not reported in the registry record.
The record states that 165 patients were included in the primary analysis after 167 were enrolled because leads were not implanted in 2 patients. It does not report further details about missing endpoint data, incomplete follow-up, withdrawals or the handling of other exclusions. The analysis population and follow-up completeness for outcomes beyond the primary endpoint are not described in detail.
Statistical analyses are not listed, and a sample-size justification for the study is not reported in the registry record. There is no reported analysis plan, model specification, adjustment strategy, multiplicity procedure or missing-data sensitivity analysis. The record lists six outcome measures overall, but does not provide enough detail to assess how all outcomes were defined or analyzed.
The safety listing does not establish event causality, explain possible overlap among categories or provide the timing and clinical context for each event. These limitations restrict interpretation of both the primary outcome and the adverse-event figures; they do not themselves demonstrate a favorable or unfavorable result.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety and Performance Study of the RELIANCE 4-Front Passive Fixation Lead — NCT01856491.
- Registry record last updated 2019-04-30; status last verified 2019-04.
- Results first posted 2017-11-20.
- 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, single-group post-market follow-up study of the RELIANCE 4-FRONT Passive Fixation defibrillation lead. Its stated objective was to gather data about chronic safety, performance and effectiveness. Enrollment was 167; 165 were included in the primary analysis because the leads were not implanted in 2 patients. The primary endpoint was lead-related Complication-Free Rate from implantation through 3 months after implantation, expressed as a percentage with a 95% confidence interval.
The record does not report the primary endpoint estimate, interval limits or endpoint event count. It describes no comparator group and identifies the study as not randomized. Safety reporting includes 84 serious adverse events, 55 other adverse events and 4 deaths, with 167 at risk in each adverse-event category; causation is not established in the registry record. Statistical analyses, missing-data procedures and the study’s sample-size justification are not reported.