Subcutaneous Fat Reduction in the Submental Area: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Subcutaneous Fat Reduction in the Submental Area (NCT02298322), a na na study. The primary outcome is Safety of CoolScupting in the Submental Area.

2. Clinical Question

The study also listed change in the treated-area fat layer measured by ultrasound and participant satisfaction as secondary outcomes. The clinical question is therefore principally about safety in people who received treatment, rather than whether treatment differs from an alternative or from no treatment. Without a comparison group, changes or events observed during follow-up cannot be contrasted with what would have occurred under another treatment condition. The registry record does not report results for the named secondary outcomes, so no conclusions about ultrasound-measured change or satisfaction can be drawn from the available results.

3. Trial Design

The registry record describes a completed, single-group device study sponsored by Zeltiq Aesthetics. The study evaluated the CoolSculpting System for non-invasive subcutaneous fat reduction in the submental area. Enrollment was 60, and the adverse-event population is described as 60 participants who received treatment. The study began on 2014-11-11, with primary completion on 2015-08-02.

Allocation is listed as NA, masking as none, and phase as NA. The record does not describe a randomized allocation or a masking procedure. It also does not identify a control arm. These features mean that the registry record supports a description of outcomes among treated participants, but not a randomized comparison of treatment groups. There is no like-for-like control comparison in the design.

The primary outcome concerned safety, measured as the incidence of device- and/or procedure-related adverse events. The stated observation period ran from enrollment through the 12 week post-final treatment follow-up. The record lists four outcome measures overall, including secondary outcomes concerning ultrasound measurement of the treated-area fat layer and participant satisfaction. Details of the treatment schedule, the number of treatment visits, eligibility criteria beyond the brief population description, and methods for measuring or adjudicating outcomes are 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

Analysis population for the primary outcome, as defined in the registry: As-treated population of 60 subjects who received CoolSculpting treatment for subcutaneous fat reduction in the submental area.

5. Baseline Characteristics

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

Population: Subjects treated with CoolSculpting for subcutaneous fat reduction in the submental area

6. Primary Endpoint

The registry lists the primary outcome as Safety of CoolScupting in the Submental Area, measured over Time of enrollment through12 week post-final treatment follow-up.

The primary endpoint is safety, expressed as the incidence of adverse events related to the device and/or procedure. The registry description says adverse-event reports were collected from enrollment through the 12 week follow-up visit after the final treatment. The listed outcome parameter is a number, and its population is the as-treated group of 60 participants who received CoolSculpting for submental fat reduction.

An adverse-event endpoint is used to describe harms or unwanted medical events observed during a defined period of exposure and follow-up. In general, an event count and the number of participants who experienced an event answer different questions: one participant can experience more than one event. The registry record’s primary endpoint description does not specify whether its reported measure is a count of events, the number of participants with events, or both, and no numerical result for this endpoint is reported.

The available safety figures distinguish serious adverse events from other adverse events, but the registry record does not state that these figures are limited to events judged device- or procedure-related. They therefore should not be treated as the numerical result for the primary endpoint without that attribution information. The endpoint is relevant to safety assessment, but the posted information does not provide enough detail to estimate the primary endpoint’s incidence or its precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a count-oriented safety measure: the registry describes incidence of device- and/or procedure-related adverse events and lists the parameter as a number. In general, count data describe how many events or affected participants are recorded. Interpreting a count requires knowing what is counted, the population in which it is counted, and the observation period. Here, the record identifies an as-treated population of 60 participants and a follow-up period extending from enrollment through the 12 week post-final treatment follow-up. It does not make clear whether the primary number represents events, participants with at least one event, or both.

It is useful to distinguish event counts from participant counts. One person may have more than one event, so the number of events need not equal the number of people affected. Conversely, a participant-level incidence measure usually counts each participant once for a specified event definition, even if that participant has repeated events. General statistical interpretation depends on which of these is being reported. The registry record does not provide the operational counting rule for the primary endpoint, nor a numerical primary-endpoint result.

The posted safety figures give the number at risk and the number affected for serious and other adverse-event categories. In general, a denominator helps place an observed count in context, but an affected-participant figure is not necessarily an event total. The record does not report whether the serious and other categories overlap, whether all events were considered related to treatment, or how event seriousness and relationship were determined. These details matter when interpreting safety summaries and when comparing them across studies.

Precision is also important. In general, a confidence interval gives a range of values compatible with the observed data and a chosen statistical procedure. A point estimate alone does not communicate how precisely an underlying event frequency has been estimated. No confidence interval or other precision measure for the primary endpoint is reported in the registry record. No p-value or inferential comparison for that endpoint is reported either. Since there is no control group, a between-group treatment effect is not available from this design.

The registry record lists one analysis, but its statistical method, model, and estimand are not reported. An estimand defines the treatment effect or outcome quantity a study aims to estimate, including how events and participant follow-up are handled. Without a stated analysis method, it is not possible to determine whether the posted safety figures reflect a prespecified analysis, how incomplete follow-up was handled, or whether adjustments were made for participant characteristics. None of those details should be inferred from the count summaries alone.

The record also includes general planning assumptions for sample-size illustrations: 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. It specifies that time-to-event illustrations use total events under the Schoenfeld approach, while other illustrations express participants per arm. These are planning assumptions, not evidence that the actual trial used a two-arm design or those methods. The study itself is described as single-group, and the registry record does not report its own sample-size justification. Any sample-size illustration based on an observed effect is not observed power and should not be interpreted as a result of this study.

In general, over-dispersion occurs when count data vary more than a simple model assumes. It can make model-based uncertainty too small if the model does not accommodate that variability. Whether over-dispersion is relevant depends on the unit counted, the distribution of repeated events, and the analysis model. The registry record does not report a count model or enough event-level information to assess over-dispersion. It would therefore be inappropriate to claim that a particular count distribution or variance assumption was used.

The single-group design also limits what statistical modeling can answer. Descriptive summaries can characterize recorded events among participants who received treatment, but they do not by themselves isolate a treatment effect from background event occurrence or other influences. General adjustment methods cannot replace a missing control group when estimating a comparative effect. The posted information is best read as a limited descriptive safety account, with the primary outcome’s exact numerical result and statistical uncertainty not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists four outcome measures, including the safety primary outcome and secondary outcomes concerning ultrasound-measured fat-layer change and participant satisfaction. It lists one analysis, but does not report which outcomes were included in that analysis or how each outcome was analyzed. A statistical plan specifying outcome hierarchy, testing order, or adjustment for multiple comparisons is not reported in the registry record.

In general, multiplicity arises when several outcomes or statistical tests are considered: the chance of at least one apparently unusual result can increase as the number of tests grows. Methods for controlling that issue depend on the study’s aims and prespecified plan. Because the registry record does not report a multiplicity strategy or numerical results for the secondary outcomes, it is not possible to assess how multiple outcomes were handled or to interpret their statistical evidence.

Rules for missing data, incomplete follow-up, withdrawals, and participants with unevaluable outcomes are not reported in the registry record. The safety population is described as 60 treated participants, but that does not establish that all participants completed follow-up or had complete outcome information. The record does not specify any imputation, censoring, or sensitivity-analysis approach.

The record identifies the safety population as as-treated, meaning the described population consists of participants who received CoolSculpting. It does not report an intention-to-treat population or explain how deviations from treatment, if any, were handled. These omissions limit assessment of the analysis population and the potential effect of missing outcome information on the results.

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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: food poisoning (1.7%), skin cancer (1.7%).

The safety figures list 2 participants affected by serious adverse events among 60 at risk, 15 affected in the other adverse-event category among 60 at risk, and 0 deaths. The serious-event terms are Food poisoning and Skin Cancer, each reported at 1.7%. These figures describe the categories and counts recorded for the CoolSculpting Treatment group.

They do not, on their own, show whether an event was caused by treatment. The primary endpoint concerns events related to the device and/or procedure, but the registry record does not connect the posted serious and other event categories to that specific attribution rule. It also does not report whether categories overlap, how many total events occurred, or how event relatedness was assessed. Counts of participants affected should not be read as counts of all events.

Seriousness is a classification of an adverse event; it is not the same as treatment relatedness. The named serious events should therefore be understood as reported safety events, not as evidence that CoolSculpting caused them. The record gives no comparison group, so these counts cannot establish whether event occurrence differs from another treatment condition.

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

The posted information establishes that the registry record describes a completed, single-group study in which 60 participants received CoolSculpting for submental fat reduction. It reports serious and other adverse-event counts for that treated group, names two serious-event terms, and records 0 deaths. These observations offer a limited description of events recorded in the study population.

The information does not provide a numerical result for the stated primary endpoint: incidence of device- and/or procedure-related adverse events. It also does not report a confidence interval or other uncertainty estimate for that endpoint. Without a clear endpoint result and its precision, the underlying frequency of the defined treatment-related events cannot be characterized from the record.

The single-group design cannot determine how the observed counts compare with event occurrence under another condition. It does not support attributing an event to treatment solely because the event occurred during the study. The record does not report numerical results for the secondary outcomes concerning ultrasound-measured fat-layer change or participant satisfaction, so those outcomes cannot be evaluated from the posted results.

These findings should be understood as a registry-level account of the available outcome information, not as a complete clinical or causal assessment. The record does not report detailed event histories, treatment-relatedness judgments, missing-data methods, or the statistical analysis used for the primary endpoint. Those absences constrain interpretation; they do not establish that an unreported analysis or assessment was or was not performed.

13. Why This Trial Matters Statistically

Safety endpoints often involve event counts, participant counts, and judgments about whether events are related to a device or procedure. Those quantities are not interchangeable. This study illustrates why readers need to know both what was counted and how an event was attributed before interpreting a safety summary as the result for a specifically defined endpoint.

The registry record identifies a primary safety question and an observation period, but the posted adverse-event counts are not explicitly linked to the primary endpoint’s device- and/or procedure-related definition. That distinction matters statistically because a broad category of events and a treatment-related endpoint can represent different outcome sets. Without a reported endpoint-specific result, the listed counts cannot answer the primary question precisely.

The design also makes the scope of inference clear. A single treated group can describe events observed among those participants, but it cannot provide a like-for-like comparison with a control group. This is important when interpreting event frequency: observed events do not by themselves indicate what would happen under another condition or establish causation.

Finally, the record shows why statistical interpretation depends on more than a count. Precision estimates, missing-data rules, analysis methods, and a clear definition of the analysis population help readers assess how stable and complete a result may be. Several of those details are not reported in the registry record. Recognizing those limits is part of interpreting registry results carefully, especially when the outcome is safety-related and the design is not comparative.

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 is the absence of a numerical result for the primary endpoint as defined: incidence of device- and/or procedure-related adverse events. Although the record reports serious and other adverse-event counts, it does not state whether those counts meet the primary endpoint’s relatedness definition. A primary-endpoint estimate and its precision are not reported in the registry record.

The study is single-group, with no reported comparator, so the observed safety counts cannot be contrasted with a control condition. Masking is listed as none, and allocation as NA. The record does not report the process for determining whether events were related to the device or procedure, or how outcome assessments were conducted.

Additional details that would affect interpretation are not reported in the registry record: the number and timing of individual events, whether affected-participant categories overlap, follow-up completeness, rules for missing data, and the statistical analysis method. The record lists four outcome measures but gives no numerical results for the named secondary outcomes. It also does not report the study’s sample-size justification or a multiplicity plan.

The posted safety counts therefore have limited scope. They summarize information recorded in the treated group, but do not establish causation, comparative safety, or the result of the specifically defined primary endpoint. The limitations concern what can be concluded from the registry record; they do not demonstrate that additional information was absent from other study materials.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Subcutaneous Fat Reduction in the Submental Area — NCT02298322.
• Registry record last updated 2020-09-24; status last verified 2020-09.
• Results first posted 2020-09-24.
• 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

NCT02298322 is a completed, single-group study titled “Subcutaneous Fat Reduction in the Submental Area.” It evaluated the CoolSculpting System in healthy adult men and women with submental skin fold thickness >1cm who desired reduction of submental fat. The registry lists 60 enrolled participants and an as-treated safety population of 60 participants who received treatment.

The primary outcome was safety, defined as incidence of device- and/or procedure-related adverse events from enrollment through the 12 week post-final treatment follow-up. The record lists serious adverse events affecting 2 participants, other adverse events affecting 15 participants, and 0 deaths. The primary endpoint’s numerical result is not reported in the registry record. The record also lists ultrasound-measured fat-layer change and participant satisfaction as secondary outcomes but does not report their numerical results.

Allocation is listed as NA, masking as none, and phase as NA. The absence of a control group means the posted safety counts are descriptive rather than comparative.