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 CoolSculpting the Upper Arm Study (NCT02669329), a na na study. The primary outcome is Percentage of Pre-treatment Images Correctly Identified.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02669329 |
| Phase | NA |
| Condition | Body Fat Disorder |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 30 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Zeltiq Aesthetics |
| Results posted | Yes |
2. Clinical Question
Population
Thirty subjects with clearly visible upper-arm fat sufficient for treatment received bilateral treatment. Three subjects did not maintain weight per-protocol requirements and were excluded from the primary efficacy analysis.
Intervention
The intervention was the CoolSculpting device with a vacuum applicator. The description specifies one treatment on each arm.
Comparator
There was no separate randomized control group. The photo review compared treated-area images across baseline and post-treatment, with reviewers asked to identify the baseline photos. This image-review reference is not a like-for-like control arm.
Primary question
At 12 weeks post treatment, how often could independent reviewers correctly identify pre-treatment images in paired image series, using agreement by at least 2 of the 3 reviewers as the criterion for a correct identification?
The study was intended to evaluate safety and efficacy of a specialized surface applicator for non-invasive subcutaneous fat reduction in the upper arm. Its primary endpoint focused on judgments made from photographs, rather than a reported direct measurement of fat volume. Reviewers were practicing dermatologists or plastic surgeons and were blinded to post-treatment versus baseline untreated-area status, as described in the registry record.
The registry record states that the expected success rate for correct identification by at least 2 of the 3 reviewers was 75%. That is an expectation in the endpoint description, not the observed study result. The actual percentage of correctly identified images is not reported in the registry record, so the primary question cannot be answered from the posted results. The study's single-group structure also means the image-review question should not be read as a randomized comparison of treated participants with an untreated group.
3. Trial Design
This was a completed, single-group device study sponsored by Zeltiq Aesthetics. The registry identifies the phase as NA, allocation as NA, and masking as none. Enrollment was 30. The recorded start date is 2016-02-05 and the primary completion date is 2016-06-07.
Participants received bilateral upper-arm treatments with the CoolSculpting device and vacuum applicator, one treatment on each arm. The registry describes the treated population as subjects with clearly visible fat sufficient for treatment. It does not describe a randomized assignment to different treatments or an untreated control arm. The listed study arms therefore do not constitute a like-for-like controlled comparison.
The primary outcome was based on independent review of pre-treatment and post-treatment images at 12 weeks post treatment. The image-review process used randomized image presentation and randomized placement of the baseline pre-treatment image within each subject's image pair. These randomization procedures concern the review task; they do not make the treatment allocation randomized. Reviewers were blinded to post-treatment versus baseline untreated-area status, while the trial-level masking field is listed as none.
Three participants did not maintain weight per-protocol requirements and were excluded from the primary efficacy analysis. The record does not report further details of the analysis population or the handling of other missing or unusable observations. It also does not report a sample-size justification for this single-group trial, nor does it report interim analyses or a detailed statistical analysis plan. The study's completed status indicates the registry lists it as completed; it does not supply the missing primary endpoint result.
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 | Upper Arm Treatment Group |
|---|---|
| STARTED | 30 |
| COMPLETED | 30 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Thirty subjects received bilateral treatments to the upper arms. Three subjects did not maintain weight per-protocol requirements and were excluded from the primary efficacy analysis.
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 | Upper Arm Treatment With Vacuum Applicator |
|---|---|---|
| Participants analysed | 30 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 30 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | years | 45.7 (27 to 57) |
| Sex: Female, Male: Female | Participants | 30 |
| Sex: Female, Male: Male | Participants | 0 |
| Race/Ethnicity, Customized: African American | Participants | 0 |
| Race/Ethnicity, Customized: Asian | Participants | 1 |
| Race/Ethnicity, Customized: Caucasian | Participants | 24 |
| Race/Ethnicity, Customized: Hispanic | Participants | 0 |
| Race/Ethnicity, Customized: Others | Participants | 5 |
| Region of Enrollment: Canada | Participants | 30 |
| Body Mass Index | kg//m^2 | 28.2 (21.4 to 34.3) |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Pre-treatment Images Correctly Identified, measured over 12 weeks post treatment.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | percent correctly identified images |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was the percentage of pre-treatment images correctly identified at 12 weeks post treatment. An independent photo review assessed changes in surface contour and/or fat volume by asking reviewers to select the baseline photographs from each subject's photo series. Correct identification required agreement by at least 2 of the 3 reviewers. The review panel was to consist of practicing dermatologists or plastic surgeons.
This endpoint uses blinded visual judgments as an assessment of whether images appear distinguishable, rather than reporting a direct numerical measure of contour or fat volume. Randomizing the presentation order can reduce the chance that a consistent display sequence influences reviewers' choices. Blinding is intended to limit the influence of knowing which image is post-treatment or baseline. These are general reasons for such procedures; they do not establish that reviewer judgments are free of bias.
The registry record gives a 95% confidence interval as the endpoint's dispersion measure. In general, a confidence interval communicates uncertainty around an estimated result, with its width reflecting precision under the analysis method used. The actual percentage and confidence interval are not reported in the registry record. The stated expected success rate of 75% is part of the endpoint description and should not be mistaken for the observed endpoint value.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes that 30 subjects received bilateral treatment and that the primary efficacy analysis excluded three subjects who did not maintain weight per-protocol requirements. It also describes an image-review endpoint at 12 weeks post treatment. However, the actual primary endpoint result, including its percentage and 95% confidence interval, is not reported in the registry record. Consequently, the posted information does not establish how often reviewers correctly identified baseline images or how precise that estimate was.
The expected success rate of 75% is a stated expectation for correct identification by at least 2 of the 3 reviewers. It is not an observed result and cannot stand in for one. Similarly, the study's completed status does not indicate whether its endpoint met a target or how large any observed change was. The registry description states that reviewers assessed changes in surface contour and/or fat volume, but the actual reviewer findings are not reported in the registry record.
The single-group structure matters to interpretation. All described subjects received bilateral treatment, and there was no randomized treatment allocation or separate like-for-like control group. The photo review's baseline images provide a reference for the reviewer task, but they are not equivalent to outcomes from a concurrent randomized control group. Thus the design does not support interpreting a difference as a randomized treatment effect against an untreated group.
The record reports no serious adverse events among 30 participants at risk and reports 9 participants with other adverse events among 30 at risk. These counts describe the registry's safety entries, but event details are not reported in the registry record. The figures alone do not establish the nature, timing, severity, or relationship of the other events to treatment.
Overall, the record gives a study design, endpoint definition, selected analysis exclusion, and aggregate safety counts, but not the primary efficacy estimate. Statistical interpretation therefore must remain limited to what was registered: the outcome was assessed using blinded image review, and the observed efficacy result and its precision are not reported in the registry record. No conclusion about the magnitude of an image-review finding can be drawn from the stated expectation or from the study's design alone.
9. Statistical Methods Explained
The primary endpoint is an image-review measure. Reviewers were asked to identify baseline photographs in subject photo series, and a correct identification was defined by agreement from at least 2 of the 3 reviewers. The registry describes review of changes in surface contour and/or fat volume and gives 12 weeks post treatment as the timeframe. It does not report the actual result or the detailed calculation used to produce the percentage.
What does the confidence interval represent?
In general, a confidence interval expresses uncertainty around an estimate. A narrower interval indicates greater precision under the statistical method and assumptions used; a wider interval indicates less precision. A confidence interval is not a guarantee that the true value lies within the particular calculated interval, and it does not by itself resolve design limitations such as the absence of a randomized control group. The registry lists a 95% confidence interval for the endpoint, but its numerical limits and the estimate itself are not reported in the registry record.
The percentage endpoint depends on a defined review rule: at least 2 of the 3 reviewers must identify the baseline image correctly. This rule turns individual judgments into a criterion for classifying a subject's image review. The registry also states that the expected success rate under this rule was 75%. That expectation is distinct from the observed result; it does not tell the reader what the reviewers actually selected in this study.
Why randomize image order and blind reviewers?
As a general matter, randomizing presentation order can help avoid a systematic order cue influencing image judgments. Randomizing placement of the baseline image within each subject's pair can likewise reduce the chance that a fixed position signals the answer. Blinding reviewers to post-treatment versus baseline untreated-area status is intended to reduce the influence of knowing the image's status. These safeguards apply to the assessment procedure. They do not change the fact that allocation is listed as NA and masking as none for the trial.
The record identifies the reviewers as practicing dermatologists or plastic surgeons. It does not report the individual reviewer judgments, agreement beyond the stated correct-identification rule, or any additional process for resolving disagreement. It also does not report whether image quality or missing images affected the endpoint assessment.
What is the role of the analysis population?
The registry states that three subjects did not maintain weight per-protocol requirements and were excluded from the primary efficacy analysis. That is an analysis-population decision, and it means the primary efficacy analysis did not include every enrolled subject. The reason for exclusion is recorded, but the criteria for maintaining weight, the timing of those assessments, and any analysis including the excluded subjects are not reported in the registry record. The record also does not describe how other missing data were handled.
In general, excluding participants after enrollment can affect how representative the analyzed group is of the full enrolled group. The direction and size of any effect cannot be determined without the participant-level information and analyses, which are not reported in the registry record. The exclusion should therefore be noted rather than treated as evidence that the endpoint is either biased or unbiased.
How should planning illustrations be read?
Any sample-size calculation described for this study is a planning illustration, not a record of the original trial design or an observed-power analysis. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect is expressed as a stated fraction of the observed effect. Those assumptions do not match the registered single-group design, which has no randomized allocation or separate control arm. The magnitude of the observed effect and the numerical planning results are not reported in the registry record.
In general, sample-size planning asks how many observations a hypothetical study would need under specified assumptions. It does not establish the probability that the completed study's result is true, and it should not be described as observed power. An illustration based on a hypothetical two-arm comparison cannot supply the missing primary endpoint estimate or convert this study into a controlled comparison.
The registry lists two outcome measures and one analysis. It does not report a detailed statistical analysis plan, the statistical test used for the primary endpoint, any adjustment for multiple outcomes, or interim analyses. Without those details and the numerical endpoint result, independent reconstruction of the primary analysis is not possible from the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists two outcome measures and one analysis. It does not report whether the outcomes were treated as co-primary, how secondary outcomes were prioritized, or whether any adjustment for multiple statistical tests was made. Multiplicity matters in general because examining several outcomes can increase the chance of at least one apparently notable result when each is assessed separately. Whether that concern applies to the reported analysis cannot be determined from the registry record.
The registry does not report a detailed statistical analysis plan, a prespecified hierarchy of outcomes, interim analyses, or a correction method. The actual primary efficacy result is also not reported in the registry record, so the relationship between the outcome listing and the reported analysis cannot be assessed.
For the primary efficacy analysis, the record states that three participants who did not maintain weight per-protocol requirements were excluded. It does not report whether those participants had usable endpoint images, whether additional observations were missing, or how missing images or reviewer assessments were handled. Details of the per-protocol weight requirements and any sensitivity analyses are not reported in the registry record.
These omissions limit assessment of the analysis population and robustness of the endpoint result. They do not show that a particular method was or was not used; they mean the method is not reported in the registry record.
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 |
|---|---|---|---|
| Upper Arm Treatment With Vacuum Applicator | 0 | 30 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Upper Arm Treatment With Vacuum Applicator | 0 of 30 |
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 |
|---|---|
| Upper Arm Treatment With Vacuum Applicator | 9 of 30 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Upper Arm Treatment With Vacuum Applicator |
|---|---|---|
| Prolonged bilateral numbness | Nervous system disorders | 3 of 30 |
| Cold symptoms | General disorders | 2 of 30 |
| Tingling outside of treatment area | Nervous system disorders | 1 of 30 |
| Erythema | Skin and subcutaneous tissue disorders | 1 of 30 |
| Prolonged unilateral numbness | Skin and subcutaneous tissue disorders | 1 of 30 |
| Numbness | Skin and subcutaneous tissue disorders | 1 of 30 |
| Stomach flu | General disorders | 1 of 30 |
The registry lists 30 participants at risk for serious adverse events and 0 participants affected. It also lists 30 participants at risk for other adverse events and 9 affected. Deaths are recorded as 0. These are participant counts in the safety record, not measures of event duration or severity.
No serious adverse-event terms are listed among the top serious terms. The descriptions, timing, severity, and relatedness of the 9 other adverse events are not reported in the registry record. The aggregate counts therefore do not identify what happened to those participants or whether any event was considered related to the device.
Zero reported participants with serious adverse events means none were recorded in that category for this study's safety entry. It does not demonstrate that the risk is absent, particularly because the record describes a study with 30 participants at risk. The safety counts should be read as descriptive results for this group, not as a comparative estimate against an untreated group.
12. What the Result Does, and Does Not, Mean
The record describes a completed study of bilateral upper-arm treatment with a vacuum applicator, using independent photo review at 12 weeks post treatment as the primary efficacy assessment. It reports that 30 subjects received treatment and that three were excluded from the primary efficacy analysis for not maintaining weight per-protocol requirements. It also supplies aggregate adverse-event counts.
The central efficacy result is not reported in the registry record. The actual percentage of pre-treatment images correctly identified and its 95% confidence interval are unavailable in the record. The expected success rate of 75% is not a result from the enrolled subjects. Accordingly, the record does not establish the observed size or precision of the primary endpoint.
The study's single-group design also limits what can be inferred. Image reviewers used baseline photographs as a reference, but there was no randomized allocation to treatment and control groups. A baseline reference in an image-review task is not a concurrent randomized comparator. The design therefore does not provide a randomized comparison of outcomes between treated and untreated participants.
The record does not report the detailed statistical plan, multiplicity handling, missing-image procedures, or analyses of the excluded participants. Those details matter when assessing how an endpoint was calculated and how sensitive it may be to analysis choices. Their absence does not establish that the study used an incorrect method, but it prevents a reader from evaluating those choices from the registry record.
The reported safety counts are limited to aggregate categories. They show 0 participants with serious adverse events, 9 with other adverse events, and 0 deaths among the stated at-risk groups. The event descriptions and further clinical context are not reported in the registry record. These counts should not be interpreted as a comparative safety estimate or as proof of no risk.
13. Why This Trial Matters Statistically
This study illustrates the distinction between an outcome's definition and its observed result. The registry provides a detailed description of how image reviewers were to identify baseline photographs, including the agreement rule and review procedures. Yet the primary endpoint value and its confidence interval are not reported in the registry record. A clearly defined endpoint is useful, but it cannot answer the efficacy question without the result.
It also illustrates why design features must be interpreted at the right level. Randomizing the order of images can protect the review task from order cues, while blinding reviewers can reduce knowledge-related influence on judgments. Those procedures do not amount to randomizing participants to treatment groups. The study remains a single-group design with no like-for-like randomized control arm.
The population used in the primary efficacy analysis also deserves attention. The record identifies three exclusions related to weight requirements, but does not describe other missing-data procedures or sensitivity analyses. Reporting who was analyzed and why is important because exclusions can affect interpretation of an endpoint, while the direction of any effect cannot be determined from counts alone.
Finally, the record distinguishes planned expectations from observed findings. The 75% expected success rate belongs to the endpoint description, not the study's observed efficacy result. A planning illustration based on a hypothetical two-arm design likewise cannot substitute for the actual result or change the trial's single-group structure. These distinctions help keep procedural details, expectations, and outcome evidence separate.
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 observed endpoint percentage and its 95% confidence interval are not reported in the registry record. Although the image-review procedure and its 12-week timeframe are described, the posted record does not show the endpoint result needed to assess its magnitude or precision.
The study has a single-group design, with allocation listed as NA and no separate randomized control group. The baseline images used in the review task are not a concurrent control group. As a result, the design does not support a randomized treatment-versus-control interpretation.
Three subjects were excluded from the primary efficacy analysis for not maintaining weight per-protocol requirements. The record does not give details of those requirements, identify whether other data were missing, or describe sensitivity analyses. The primary efficacy analysis population and the impact of these exclusions therefore cannot be fully assessed.
The registry does not report a detailed statistical analysis plan, the method used to calculate the endpoint, procedures for missing images or reviewer judgments, or multiplicity handling. The actual adverse-event descriptions are also not reported in the registry record. These gaps limit assessment of analysis choices and clinical context; they do not establish that unreported procedures were absent or that any particular bias occurred.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: CoolSculpting the Upper Arm Study — NCT02669329.
- Registry record last updated 2021-11-04; status last verified 2020-08.
- Results first posted 2020-09-17.
- 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.
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18. Record Summary
The registry record identifies NCT02669329 as the CoolSculpting the Upper Arm Study, with the official title CoolSculpting the Upper Arm Using a Vacuum Applicator. Zeltiq Aesthetics is listed as sponsor. The study is marked completed, with phase NA, allocation NA, and masking none.
Enrollment was 30. Subjects received bilateral upper-arm treatment using a CoolSculpting device with a vacuum applicator. The primary endpoint concerned correct identification of pre-treatment images by independent reviewers at 12 weeks post treatment, with a 95% confidence interval listed as the dispersion measure. The primary efficacy analysis excluded three subjects who did not maintain weight per-protocol requirements.
The registry lists 0 participants with serious adverse events, 9 with other adverse events, and 0 deaths. The primary efficacy result, its confidence interval, detailed analysis methods, and descriptions of the other adverse events are not reported in the registry record.