Fat Reduction in the Submandibular/Submental Area: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Fat Reduction in the Submandibular/Submental Area (NCT02700165), a na na study. The primary outcome is Proportion of Accurately Identified Pre-Treatment Photos by a Panel of Blinded Independent Reviewers.

2. Clinical Question

The study was intended to assess safety and efficacy of non-invasive fat reduction in the chin area. Its question is therefore about a photographic assessment after treatment within a single group, rather than a comparison of treatment against a randomized alternative. The image-review design sought to reduce the influence of reviewer knowledge of image timing: reviewers were described as blinded to post-treatment versus baseline untreated area, and the order of images was randomized. Those design features concern the assessment process; they do not supply a comparison group or demonstrate that any observed change was caused by treatment.

The registry record also lists change in submental fat-layer thickness measured by caliper and subject satisfaction as secondary outcomes. It does not report their numerical results. The clinical question can be stated, but the posted information does not establish how often reviewers correctly identified pre-treatment images, what happened to measured fat-layer thickness, or how satisfied subjects were.

3. Trial Design

NCT02700165 is listed as a completed study sponsored by Zeltiq Aesthetics. It began in 2016-02, and primary completion is recorded as 2016-12. The recorded enrollment was 14. The study phase and allocation are listed as NA; the masking entry is NONE, and the model is SINGLE GROUP. These registry labels indicate that the record does not describe a randomized, masked, multi-arm efficacy comparison.

The intervention was the ZELTIQ CoolSculpting System, with the treatment arm described as CoolSculpting with CoolMini. The stated purpose was to further evaluate safety and efficacy of non-invasive reduction of subcutaneous fat in the submental and submandibular area. The primary endpoint was based on independent review of photographs at baseline and 12 weeks post treatment. The record describes practicing dermatologists or plastic surgeons as reviewers, with image order randomized and reviewers blinded to post-treatment versus baseline untreated area.

The study's single-group structure matters for interpretation. Although the photo assessment included treated and untreated areas, the record does not describe a separate participant group receiving another intervention or no intervention. Nor does it report that treatment assignment was randomized. The assessment therefore does not provide the same basis for a between-group treatment-effect estimate as a controlled trial.

The registry lists four outcome measures and one analysis. Besides the primary photo-review endpoint, the named secondary outcomes are change in fat-layer thickness measured by caliper and subject satisfaction. Details of the other outcome measures, the analysis methods, and the full statistical plan are not reported in the registry record. A sample-size justification and interim-analysis plan are also not reported in the registry record. The record identifies all subjects as included in the analysis population, but does not explain how missing or unusable observations were handled.

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: All subjects were included in the analysis population.

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 Proportion of Accurately Identified Pre-Treatment Photos by a Panel of Blinded Independent Reviewers, measured over Baseline (pre-treatment) and 12 weeks post treatment.

The primary endpoint is titled as the proportion of pre-treatment photographs accurately identified by a panel of blinded independent reviewers. Its unit is photos, and the registry describes assessment at baseline and 12 weeks post treatment. Reviewers were to inspect pre-treatment and post-treatment images for changes in surface contour and/or fat volume, select the baseline photographs for each subject photo series, and record their selections. Image presentation order was randomized; the record also says the baseline image placement was randomized for each pair of subject images.

This endpoint uses reviewer classification of photographs as an indirect assessment of visible change. Such an approach can provide an evaluation that is less dependent on a participant's or treating team's own judgment, particularly when reviewers are blinded to image timing. It assesses what can be distinguished in the photographs, not a direct measurement of fat volume or a clinical outcome. The registry separately lists caliper-measured fat-layer thickness and subject satisfaction as secondary outcomes.

The stated success definition refers to 70% correct identification and to two out of three reviewers. The wording repeats the 70% criterion, so the precise operational rule is not fully clear from the description. Most importantly, the registry record does not report the observed number or proportion of correctly identified photographs, nor an uncertainty interval or test result. The endpoint's intended meaning can be described, but its observed performance cannot be determined from the posted information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is an image-classification measure. Reviewers were asked to identify which photographs were taken before treatment, using image series that included baseline and post-treatment images. In general, a classification endpoint turns judgments into a count of correct or incorrect selections. If a study then reports a proportion, that proportion depends on both the number classified correctly and the total number evaluated. The registry record does not report those quantities for this endpoint, so neither the proportion nor its precision can be assessed from the posted information.

What does blinded review contribute?

In general, blinding reviewers to image timing can reduce the risk that expectations about treatment influence their judgments. Randomizing image order can also limit systematic effects of presentation sequence. These safeguards address aspects of outcome assessment; they do not guarantee that images are indistinguishable in all respects, eliminate all reviewer variation, or control for factors that affect change over time. The record describes these procedures, but does not report an assessment of reviewer agreement or the specific method used to combine their judgments.

How should the success criterion be read?

The registry's wording defines success using 70% correct identification and two out of three reviewers. Because the description repeats the 70% criterion, it does not make entirely clear whether the criterion is intended to apply to the panel, individual reviewers, or both. The result needed to apply that rule is not reported in the registry record. This is a reporting limitation: the target is described, but readers cannot determine whether it was met.

What does the single-group structure imply?

In general, a within-group assessment compares observations made at different times or in different areas among the same participants. It can describe change, but absent a suitable control group it cannot separate the intervention's contribution from all alternative explanations. A control group can help estimate what would have happened over the same period without the intervention or under another treatment. The registry describes treated and untreated areas in the image assessment, but does not describe a separate randomized control arm. The photo review should therefore not be treated as equivalent to a controlled treatment comparison.

Because allocation is listed as NA and the study model as SINGLE GROUP, there is no described randomized assignment between treatment arms. Masking is listed as NONE, while the endpoint description specifies blinding of the independent photo reviewers to image timing. Those statements refer to different aspects of the design: the overall masking field and the endpoint-specific reviewer procedure. The record does not provide enough detail to infer additional masking procedures.

What can an uncertainty interval tell a reader?

In general, a confidence interval describes the range of values compatible with an estimate under a statistical model and sampling assumptions. A narrow interval indicates greater statistical precision than a wide interval, although precision is not the same as freedom from bias. For a proportion, interval estimation also depends on the number of observations and the method used. No confidence interval or other uncertainty interval for the primary endpoint is reported in the registry record. Since the endpoint estimate itself is also not reported, its statistical precision cannot be evaluated.

Reviewer judgments may be clustered: multiple judgments can concern the same subject or image series, and multiple reviewers may assess related material. In general, treating dependent judgments as if they were fully independent can make uncertainty appear smaller than it is. The record does not report the analysis unit, how repeated judgments were handled, or whether reviewer variation was incorporated into the analysis. No assumption about independence or a particular statistical model can be made from the description alone.

How should count outcomes and over-dispersion be understood?

In general, count outcomes record how many events or units occur. Some count-data models assume that the variability follows a particular relationship to the average count. Over-dispersion occurs when the observed variability is greater than that model assumes; ignoring it can lead to uncertainty estimates that are too small. This is a general statistical issue, not a finding about this study. The registry describes the primary endpoint as a count of photo units while titling it as a proportion, but does not report the data distribution or modeling method. It therefore does not support a claim that over-dispersion was present or that a count model was used.

The record lists one analysis. That count does not reveal which statistical test or estimator was used, whether any covariates were considered, or what criteria were applied to exclude data. These methods are not reported in the registry record. It also does not report a sample-size justification for the 14-subject enrollment or an interim-analysis plan. Those elements should not be inferred from the study's completed status or from the number of analyses listed.

The record's planning assumptions describe a general sample-size illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Such a calculation is a planning illustration, not observed power. It does not establish that those assumptions governed the trial's design, particularly because the trial is described as single-group. The record does not provide the numerical calculation needed to discuss a resulting sample size. More generally, post hoc planning calculations based on an observed effect do not replace prospective design justification and do not change what the study observed.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures and one analysis. The named outcomes include the primary photo-review endpoint, change in submental fat-layer thickness measured by caliper, and subject satisfaction. The names and details of all remaining measures are not reported in the registry record. The record does not describe a hierarchy of endpoints, an adjustment for multiple testing, or a prespecified approach to interpreting several outcomes together.

Multiplicity matters in general when multiple outcomes or multiple statistical comparisons are examined: the chance of a chance-positive finding can increase if each is assessed separately without an appropriate plan. That general concern cannot be quantified for this study from the available information. The registry does not provide the analysis details, tests, or results needed to determine how multiplicity was handled. A listing of one analysis does not establish that there was only one statistical test or that all outcome questions were addressed in a single procedure.

The analysis population is described as including all subjects. This indicates the stated population for analysis, but the record does not report whether outcome data were available for every subject, how missing photographs or measurements were handled, or whether any observations were excluded. It also does not describe imputation or sensitivity analyses. Missing-data methods are therefore not reported in the registry record.

In general, missingness can affect an estimate when the likelihood of an observation being unavailable is related to its value or to participant characteristics. Complete-case analysis, imputation, and sensitivity analysis rely on different assumptions. Without the number and pattern of missing observations and the method used, readers cannot assess those assumptions. The record also does not report a protocol-level sample-size justification or interim-analysis plan. These omissions limit appraisal of how the statistical analysis was planned and how robust the reported findings would be; in this case, the primary numerical finding itself is not reported.

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: hip replacement (7.1%).

The safety entries report that 1 of 14 subjects had a serious adverse event, 3 of 14 had other adverse events, and 0 deaths were recorded. These are counts within the CoolSculpting With CoolMini Applicator group. The registry also lists Hip Replacement as the top serious term at 7.1%. The record does not provide further detail on the event description, timing, severity criteria, or relationship to the device or procedure.

These figures describe recorded events in a single group; they do not estimate a difference in risk compared with another treatment or with no treatment. A serious adverse event is not necessarily caused by the intervention. The registry record does not report an attribution assessment, and the event term alone should not be interpreted as evidence of causation. Likewise, the count of other adverse events does not show whether each event occurred in a different subject or whether any subject had more than one event.

Counts can be useful for describing what was recorded, but their interpretation depends on consistent event definitions, follow-up, and complete reporting. The registry does not provide enough detail to assess those elements or to characterize the full event profile. The listed counts should therefore be read as a limited summary of the safety entries, not as a comparative estimate or a complete account of safety.

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

The study addresses whether independent reviewers could identify pre-treatment photographs in image series assessed at baseline and 12 weeks post treatment. It also names caliper-measured fat-layer thickness and subject satisfaction as secondary outcomes. The registry record does not report the primary endpoint result or numerical findings for those secondary outcomes. As a result, the posted information does not show the observed magnitude or direction of change on these measures.

The stated photo-review criterion refers to 70% correct identification and two out of three reviewers, but the description's wording is repetitive. Without the observed classifications and a clear operational explanation, readers cannot determine whether the criterion was met. The absence of that result does not mean the endpoint was negative; it means the registry record does not report the information needed to assess it.

The single-group design also constrains causal interpretation. A photographic comparison across time may describe a visible difference, but without a separate control group it cannot establish how much of any change would have occurred without treatment. Blinded review and randomized image order may limit some forms of assessment bias, but do not answer that counterfactual question.

The safety counts show recorded serious and other adverse events and no deaths in the enrolled group. They do not establish whether an event was caused by the intervention, and they do not permit comparison with an alternative. The listed serious-event term should be read as a registry classification, not as a causal conclusion.

Overall, the record allows readers to understand the study's basic design, intended endpoint, and limited safety summary. It does not provide the primary numerical result, its uncertainty, or enough analysis detail to judge the strength of evidence for the study's efficacy question. It also does not support a treatment recommendation or a conclusion that treatment does or does not work.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of how the design and reporting of an endpoint determine what can be concluded. The study used a photo-review question that is not the same as a direct measurement of fat volume: reviewers were asked to identify pre-treatment images based on visual changes. The registry also named caliper-measured thickness and subject satisfaction, which represent distinct kinds of outcomes. Keeping these measures separate helps prevent a visual assessment from being treated as though it were a direct physical measurement or a participant-reported outcome.

The endpoint procedure includes features intended to reduce assessment bias, including independent reviewers, blinding to image timing, and randomized image order. These safeguards are relevant, but they do not substitute for a control group. With a single-group design, changes over time cannot be cleanly separated from other influences through a randomized between-group comparison. This distinction is important when interpreting before-and-after studies, even when outcome assessment is carefully described.

The record also illustrates why result reporting is essential. A target or success criterion is not an observed result. Without the number of correctly identified photographs, an estimate, and some measure of uncertainty, readers cannot assess the endpoint's magnitude or precision. Similarly, a list of secondary outcomes does not establish their findings, and a count of analyses does not specify the methods used.

Finally, adverse-event counts need context. Counts from a single group can describe recorded events but do not show comparative risk or establish causation. The record's brief safety summary therefore has a narrower interpretation than a comparative safety analysis. These distinctions help readers separate the study's question, the evidence actually reported, and the limitations imposed by design and missing statistical detail.

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 primary limitation for interpreting efficacy is that the registry record does not report the primary endpoint result. It gives the endpoint's title, unit, timeframe, and assessment description, but not the observed count or proportion of correctly identified photographs. No uncertainty interval or test result is reported. The stated success wording is also repetitive, leaving the exact application of the criterion unclear.

The study is described as single-group, with allocation listed as NA and masking listed as NONE. The photo-review procedure includes reviewer blinding to image timing, but there is no described randomized control arm. This means the design does not offer a direct between-group estimate of treatment effect. The record does not detail how treated and untreated areas were selected or analyzed, so no additional control structure should be assumed.

Enrollment was 14, and all subjects are described as included in the analysis population. However, the record does not state how many photographs, measurements, or reviewer judgments were available, how repeated judgments were handled, or how missing observations were addressed. It does not report a sample-size justification, an interim-analysis plan, the statistical test or estimator, or the method for combining reviewer assessments.

Four outcome measures and one analysis are listed, but the record does not report a multiplicity plan or numerical results for the named secondary outcomes. The safety summary is also limited: event attribution, timing, definitions, and participant-level event details are not reported. These gaps restrict assessment of both the statistical evidence and the completeness of outcome and safety reporting.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Fat Reduction in the Submandibular/Submental Area — NCT02700165.
• Registry record last updated 2021-11-16; status last verified 2021-05.
• Results first posted 2021-05-17.
• 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

NCT02700165 is a completed, single-group study of the ZELTIQ CoolSculpting System with the CoolMini applicator for non-invasive fat reduction in the submental and submandibular area. The registry records enrollment of 14 subjects and describes a primary photo-review endpoint assessed at baseline and 12 weeks post treatment. Independent reviewers were to identify pre-treatment images, with image order randomized and reviewers blinded to image timing.

The record lists change in fat-layer thickness measured by caliper and subject satisfaction as secondary outcomes. It describes all subjects as included in the analysis population. Numerical primary and secondary outcome results, analysis details, missing-data methods, and a multiplicity plan are not reported in the registry record.

Safety entries report 1 of 14 subjects with a serious adverse event, 3 of 14 with other adverse events, and 0 deaths. Hip Replacement is listed as the top serious term at 7.1%. These counts do not establish causality or provide a comparison with another group.