Controlling and Lowering Blood Pressure With The MOBIUSHD™: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Controlling and Lowering Blood Pressure With The MOBIUSHD™ (NCT01831895), a na na study. The primary outcome is Adverse Events.

2. Clinical Question

Statistically, the study asks what safety and performance observations were recorded among participants receiving MobiusHD™ in this multicenter study. Its single-group design can describe events and changes observed during follow-up, but cannot by itself separate intervention-associated effects from the natural course of participants’ health, other care, or measurement variation. The registry record does not report a randomized comparison, a control group, or a prespecified statistical analysis plan. The primary outcome is a count of participants with events, rather than a comparison of event risk between treatment groups. Accordingly, the central question is descriptive: what events were recorded, and how completely and precisely can those observations be characterized from the registry record?

3. Trial Design

The registry record identifies NCT01831895 as a prospective multicenter safety study titled “Controlling and Lowering Blood Pressure With The MOBIUSHD™.” Its official title is “CALM-FIM US -Controlling and Lowering Blood Pressure With the MobiusHD™ - A Prospective Multicenter Safety Study.” The sponsor is Vascular Dynamics, Inc. The study is listed as completed, with enrollment of 17. The recorded start is 2013-05 and the primary completion date is 2020-07-08.

The design is single group, with MobiusHD™ as the intervention. Allocation is listed as NA and masking as NONE. No separate comparator arm is described. These design features matter for interpretation: the record can report what happened among the participants receiving the device, but does not support a controlled estimate of how outcomes differ from another treatment or from no device. The study’s stated purpose was to evaluate safety and performance in subjects with resistant hypertension.

The primary outcome is Adverse Events, described as the number of participants with adverse events, with a timeframe of 3 years. The record also lists two secondary outcomes: change in Systolic Office Blood Pressure (OBP) and change in Systolic Ambulatory Blood Pressure (ABPM). Although the registry record notes 3 outcome measures, it records 0 analyses. Numerical results or statistical comparisons for the secondary outcomes are not reported in the registry record.

Further design details—including eligibility criteria, the number and location of participating centers, follow-up visit schedules, device-use procedures, and the statistical analysis plan—are not reported in the registry record. The record also does not state whether the observed enrollment was the planned enrollment or explain how enrollment was determined. These omissions limit assessment of how participants were selected, how measurements were collected, and whether the results correspond to a prespecified analysis.

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

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Adverse Events, measured over 3 years.

The primary endpoint is Adverse Events, described as the number of participants with adverse events over 3 years. A participant count answers how many people experienced at least one event under the endpoint’s definition; it is not necessarily the same as a count of every event episode. A single participant could experience more than one event, but the endpoint wording focuses on participants rather than event episodes.

Safety studies commonly track adverse events to characterize unwanted health events during or after an intervention. This type of outcome is useful because it makes safety observations central to the study’s purpose and can help identify events requiring closer scrutiny. However, the interpretation depends on how events are defined, collected, classified, and attributed. Those details are not reported in the registry record. The record does not specify whether the primary endpoint includes all adverse events or a particular subset, or how the 3-year timeframe was applied to participants with different follow-up.

The posted adverse-event results distinguish serious adverse events from other adverse events. They report 1 participant with a serious adverse event and 7 participants with other adverse events, each among 17 participants at risk. The registry record also lists 1 death. These figures should be read as separate reported categories, without assuming that the categories are mutually exclusive or that the death was caused by the device. Attribution and event-level details are not reported in the registry record.

The two secondary outcomes concern changes in systolic blood pressure measured in the office and by ambulatory monitoring. Their names identify different measurement settings, but their numerical results and analysis details are not reported in the registry record. Consequently, they cannot supplement the posted safety counts with a quantitative assessment of blood-pressure change.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count represent? The primary outcome is a count of participants with adverse events. In general, a participant-level count indicates how many people meet the outcome definition, rather than the total number of event episodes. This distinction matters when an individual can experience repeated events: a participant count does not describe the frequency of all episodes. The registry record’s wording focuses on participants, but the precise event definition and counting rules are not reported in the registry record.

The posted data give separate counts for serious adverse events and other adverse events. In the MobiusHD™ group, 1 participant is reported with a serious adverse event among 17 at risk, and 7 participants are reported with other adverse events among 17 at risk. The record also lists 1 death. These entries should be treated as recorded categories, not added together. The record does not explain whether categories overlap, how events were classified, or whether the death is included in another category.

Why is a single-group result descriptive? General statistical principle: a comparison estimates a difference between groups, while a single-group summary describes the observations in one group. Because this study has a single-group model and no control arm, the event counts do not estimate a contrast with another intervention or with no intervention. They also cannot by themselves attribute an event to the device. A causal interpretation would require a suitable comparison and design assumptions that are not available in this record.

In comparative trials, random allocation can help balance measured and unmeasured factors between groups on average. That general advantage does not apply as a treatment contrast when the record has no randomized comparator. The record lists allocation as NA and masking as NONE. It does not report a control group, so no between-group effect or comparative confidence interval is available in the posted results.

How should uncertainty be considered? General statistical principle: a confidence interval describes a range of values compatible with data and a specified statistical model, and its width reflects precision as well as the amount and variability of information. No confidence interval for the adverse-event counts is reported in the registry record. The participant counts therefore should not be treated as exact estimates of what would occur in a wider population. Nor should a lack of a reported interval be mistaken for evidence that uncertainty is small.

For event outcomes, uncertainty can depend on how many participants are observed, how completely events are captured, and how long each participant is followed. The registry record reports enrollment of 17 and a primary outcome timeframe of 3 years, but does not report participant-level follow-up duration, loss to follow-up, or completeness of outcome collection. It is therefore not possible to assess whether every participant contributed observation over the same period or whether any events could have been missed.

What does the time-to-event approach add? General statistical principle: time-to-event methods account for the time until an event and can accommodate participants whose observation ends before an event occurs, when appropriate follow-up information is available. Such methods typically rely on event times and censoring information. Those data and analyses are not reported in the registry record. The listed primary outcome is a participant count over 3 years, not a reported time-to-event estimate.

Why can over-dispersion matter? General statistical principle: for count outcomes, a statistical model may assume a particular relationship between the average count and its variability. If the observed variability is greater than the model assumes, standard errors can be too small and uncertainty can be understated. This issue is relevant when analyzing repeated event counts or counts that vary markedly across participants. The posted primary outcome is framed as participants with an event, and the registry record provides no event-level data, variability estimates, or model details with which to evaluate over-dispersion.

How should planning illustrations be read? General statistical principle: sample-size planning depends on the target effect, variability, significance level, allocation, and analysis method. The planning illustrations described for this record use a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. These are planning assumptions, not evidence that the study used that design. They do not describe the actual single-group study’s design justification, and they are not observed power. The registry record does not report the original sample-size justification.

Planning based on an observed effect also needs cautious interpretation. General statistical principle: an effect estimated from a study can be unstable, particularly when information is limited, and planning for a fraction of that estimate is an illustrative scenario rather than a guaranteed target. The record’s planning description cannot supply a missing control group, change the study allocation, or establish that a future comparison would have the assumed effect. No numerical sample-size results are repeated in this explanation.

What analyses are actually recorded? The registry record lists 3 outcome measures and 0 analyses. It names changes in Systolic Office Blood Pressure (OBP) and Systolic Ambulatory Blood Pressure (ABPM) as secondary outcomes, but does not report their results, estimates, or analytic methods. No adjustment strategy, hypothesis-testing procedure, or statistical analysis plan is reported in the registry record. Consequently, the available information supports a limited description of safety counts rather than a reconstructed inferential analysis.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 3 outcome measures: the primary adverse-event outcome and two secondary outcomes concerning changes in systolic office and ambulatory blood pressure. It records 0 analyses. Numerical results for the secondary outcomes and a statistical analysis plan are not reported in the registry record. It is therefore not possible to determine which hypotheses were tested, whether testing was planned in a hierarchy, or whether any adjustment for multiple comparisons was intended.

General statistical principle: when several outcomes or hypotheses are tested, the chance of obtaining at least one apparently notable result can increase unless the analysis accounts for multiplicity or interprets results accordingly. The existence of several outcomes does not mean a correction was necessarily required; that depends on the study questions and analysis plan. Since the plan and analyses are not reported, multiplicity procedures cannot be evaluated. No claim about statistical significance for the secondary outcomes can be made from their names alone.

Missing-data information is also not reported in the registry record. It does not describe withdrawals, loss to follow-up, missing outcome measurements, or how any missing observations were handled. The 3-year timeframe identifies the stated primary outcome period, but does not establish that each participant was observed for that entire period. Without follow-up and missingness details, completeness of event ascertainment cannot be assessed.

The analysis populations are not reported in the registry record. The record does not state whether the posted results include all enrolled participants, only participants who received the device, or another defined group. The at-risk denominator shown for adverse-event results is 17, but the record does not provide a broader description of analysis-set rules. These limitations constrain reproducibility and make it difficult to judge whether exclusions or incomplete follow-up could affect the reported counts.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 1% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: hypotension - acute (5.9%).

The registry record reports 1 participant with a serious adverse event among 17 at risk, and 7 participants with other adverse events among 17 at risk. It also lists 1 death. These are registry-reported counts for the MobiusHD™ group. They should be read as separate entries; the record does not state whether the categories overlap or how the death relates to the adverse-event categories.

The most frequently listed serious adverse-event term is “Hypotension - acute,” with 5.9% displayed. The registry record does not describe the event’s timing, severity beyond its classification, outcome, or relationship to the device. The listed term and percentage do not establish that the device caused the event.

General statistical principle: safety counts are easier to interpret when the case definitions, observation time, event adjudication, and completeness of follow-up are known. Those details are not reported in the registry record. The denominator is recorded as 17 at risk, but participant-level follow-up and censoring are not described. These counts are therefore descriptive, not comparative estimates of risk, and the absence of a control group prevents a like-for-like safety comparison.

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

The posted results document adverse events recorded among participants in a prospective, single-group safety study of MobiusHD™. The registry reports 1 participant with a serious adverse event and 7 participants with other adverse events, each among 17 at risk, as well as 1 death. It lists “Hypotension - acute” at 5.9% among the serious-event terms. These observations are the scope of the available quantitative safety information.

The results do not establish whether MobiusHD™ caused or prevented any event. A single-group study has no concurrent comparator for estimating how outcomes would have differed under another approach. The registry record does not provide event attribution, detailed clinical descriptions, or participant-level follow-up. The recorded death cannot be assumed to be related to the intervention, and the record does not report a cause.

The record’s stated purpose includes evaluating performance, and it lists changes in Systolic Office Blood Pressure (OBP) and Systolic Ambulatory Blood Pressure (ABPM) as secondary outcomes. Their numerical results are not reported in the registry record. The posted information therefore cannot quantify blood-pressure change or support a statistical conclusion about performance.

Nor do the event counts alone determine how common similar outcomes would be in a wider population. General statistical principle: estimates from a study have uncertainty, and generalizability depends on who enrolled, how participants were selected, how outcomes were defined, and how completely they were observed. Several of those details are not reported in the registry record. No confidence intervals or inferential analyses are recorded.

The appropriate statistical reading is limited but useful: the registry documents safety observations and identifies a serious-event term for scrutiny, while leaving major questions about comparison, attribution, precision, outcome ascertainment, and blood-pressure results unresolved. This description does not make a treatment recommendation or claim that the intervention works or does not work.

13. Why This Trial Matters Statistically

This trial matters statistically because it illustrates the distinction between a safety description and a comparative treatment estimate. A single-group study can record adverse events in a population receiving an intervention, which is relevant to characterizing what occurred during the study. Without a control group, however, those observations do not quantify how event occurrence compares with another care strategy or establish causation.

The registry record also shows why endpoint wording and event classification matter. The primary outcome is described as the number of participants with adverse events, while the posted data separate serious events, other events, and a death. These categories may answer different safety questions, but the record does not state whether they overlap or provide definitions and attribution details. Reading them as one combined total would not be justified by the reported information.

Another important statistical issue is the gap between outcomes named in a registry and outcomes with posted analyses. The record lists systolic office and ambulatory blood-pressure changes as secondary outcomes, yet records 0 analyses. Thus, the stated performance questions cannot be evaluated quantitatively from the posted results. This is a reminder that an outcome’s presence in a registration record is not itself evidence of a reported result.

Finally, interpretation depends on follow-up and uncertainty, not just the event counts. The record gives a 3-year primary-outcome timeframe, but does not describe participant-level observation or missing data, and it reports no confidence intervals. The counts are meaningful as recorded observations, but they cannot provide a precise population estimate or a controlled comparison. Recognizing those limits is central to interpreting safety-study evidence carefully.

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 single-group design has no control group, so the adverse-event observations cannot be compared directly with outcomes under another intervention or no intervention. Allocation is listed as NA and masking as NONE. The registry record does not describe a randomized comparison or a blinded assessment.

Second, the available safety reporting is sparse. The record gives participant counts for serious and other adverse events, lists 1 death, and identifies “Hypotension - acute” at 5.9%. It does not provide event narratives, timing, duration, severity details, causality assessment, or a description of how serious events were adjudicated. It also does not state whether the listed categories overlap.

Third, although the primary endpoint has a 3-year timeframe, participant-level follow-up, censoring, and completeness of event collection are not reported in the registry record. This prevents assessment of whether the at-risk participants had comparable observation time. Missing-data methods and analysis populations are also not reported.

Fourth, the record lists secondary blood-pressure outcomes but no analyses. It therefore does not provide numerical evidence for changes in Systolic Office Blood Pressure (OBP) or Systolic Ambulatory Blood Pressure (ABPM). The number of outcome measures is recorded as 3, while the number of analyses is recorded as 0; the statistical plan and multiplicity procedures are not reported.

Finally, the record does not report eligibility criteria, the definition of resistant hypertension, the original sample-size justification, or detailed device-use procedures. These gaps limit assessment of selection, reproducibility, and generalizability. The reported enrollment of 17 should be understood as a registry fact, not proof that the study was designed to estimate outcomes with a specified precision.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Controlling and Lowering Blood Pressure With The MOBIUSHD™ — NCT01831895.
• Registry record last updated 2023-05-06; status last verified 2023-05.
• Results first posted 2022-03-03.
• 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.

18. Record Summary

NCT01831895 is a completed, prospective multicenter safety study of MobiusHD™ in subjects with resistant hypertension. The registry record lists Vascular Dynamics, Inc. as sponsor, enrollment of 17, a start date of 2013-05, and primary completion on 2020-07-08. The design is single group; allocation is NA and masking is NONE.

The primary outcome is the number of participants with adverse events over 3 years. The posted safety results report 1 participant with a serious adverse event among 17 at risk, 7 with other adverse events among 17 at risk, and 1 death. “Hypotension - acute” is listed at 5.9% among serious-event terms. The record also lists changes in Systolic Office Blood Pressure (OBP) and Systolic Ambulatory Blood Pressure (ABPM) as secondary outcomes, but records 0 analyses.

Comparative effects, event attribution, follow-up completeness, analysis populations, and statistical methods are not reported in the registry record. The counts are descriptive observations from a single group and do not establish causation or a treatment comparison.