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 of the Distal Thigh Study (NCT02335749), a na na study. The primary outcome is Rate of Device- or Procedure-related Adverse Events.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02335749 |
| Phase | NA |
| Condition | Body Fat Disorder |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 40 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Zeltiq Aesthetics |
| Results posted | Yes |
2. Clinical Question
Population
The study enrolled 40 subjects with the condition recorded as Body Fat Disorder. The registry says the primary outcome was assessed in all subjects treated with the CoolSculpting System and the Small Area Applicator. Further eligibility details and characteristics of the enrolled participants are not reported in the registry record.
Intervention
The intervention was the ZELTiq System, a device. The arm description specifies treatment with a small area applicator on a single thigh in the distal region. The registry summary describes the intended evaluation as safety and efficacy for non-invasive subcutaneous fat reduction in the distal thigh.
Comparator
There was no separate comparator group in this single-group study. Each enrolled subject received treatment, and the record does not describe an untreated, sham-treated, or alternative-treatment group. Consequently, the study record does not present a between-group treatment comparison.
Primary question
The primary outcome was the number of device- or procedure-related adverse events collected from enrollment through the final follow-up visit. The registry gives the timeframe as through the 12-week final follow-up visit, approximately 15 weeks. The question was therefore about adverse events during the specified study period among treated subjects. The actual primary outcome count and a statistical analysis of it are not reported in the registry record.
3. Trial Design
This completed study, NCT02335749, is titled CoolSculpting of the Distal Thigh Study; its official title is CoolSculpting Treatment of the Distal Thigh. The registry lists Zeltiq Aesthetics as sponsor and identifies the intervention as the ZELTiq System. Enrollment was 40. The study began on 2014-12-17, reached primary completion on 2015-11-09, and has a completed status.
The design is recorded as single-group, with no allocation or masking details beyond entries of NA and NONE, respectively. The arm description says each enrolled subject was treated on a single thigh in the distal region using a small area applicator. With no distinct control arm, the record describes an assessment following treatment rather than a randomized comparison. The treated group cannot serve as a like-for-like control for itself; changes over time, if measured, would not by themselves separate treatment effects from other explanations.
The registry identifies the study as evaluating safety and efficacy for non-invasive subcutaneous fat reduction in the distal thigh. It lists two outcome measures, but only the primary measure is described in the available outcome detail. That measure is a count of device- or procedure-related adverse events collected during enrollment through final follow-up. The follow-up timeframe is described as the 12-week final follow-up visit, approximately 15 weeks from the start of the specified observation period.
Specific eligibility criteria, treatment settings, follow-up procedures beyond the stated timeframe, and the full description of the other outcome measure are not reported in the registry record. A formal sample-size justification, a statistical analysis plan, and an account of how efficacy outcomes were assessed are also not reported in the registry record. These gaps limit how fully the design and intended analyses can be reconstructed from the record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Treatment With Small Area Applicator |
|---|---|
| STARTED | 40 |
| COMPLETED | 40 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: All subjects treated with the CoolSculpting System and the Small Area Applicator were assessed for device- or procedure-lated adverse events.
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: All subjects who met inclusion/exclusion criteria were enrolled in the study. Once enrolled, each of the 40 subjects was treated on one distal thigh.
| Characteristic | Unit | Treatment With Small Area Applicator |
|---|---|---|
| Participants analysed | 40 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 40 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | years | 44.6 (26.0 to 61.0) |
| Sex: Female, Male: Female | Participants | 40 |
| Sex: Female, Male: Male | Participants | 0 |
| Race/Ethnicity, Customized: Asian | Participants | 2 |
| Race/Ethnicity, Customized: African American | Participants | 1 |
| Race/Ethnicity, Customized: Hispanic | Participants | 9 |
| Race/Ethnicity, Customized: Caucasian | Participants | 28 |
| Region of Enrollment: United States | participants | 40 |
| Body Mass Index | kg/m^2 | 25.4 (19.7 to 30.2) |
6. Primary Endpoint
The registry lists the primary outcome as Rate of Device- or Procedure-related Adverse Events, measured over Study enrollment through 12-week final follow-up visit, approximately 15 weeks.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | device-or procedure-related AEs |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the number of adverse events judged to be related to the device or procedure. The registry says adverse-event data were collected from enrollment through the final follow-up visit, described as the 12-week visit and approximately 15 weeks. All subjects treated with the system and small area applicator were assessed for this outcome. The registry does not give the resulting count, event descriptions, or an analysis of the primary endpoint.
A safety count is useful because it records events that occur during a defined period after exposure to a device or procedure. It can describe the observed event burden in the treated group and help identify what kinds of events were recorded. The interpretation depends on how events were defined, assessed, attributed, and counted. The registry identifies the outcome as device- or procedure-related, but does not report further details about those assessment procedures.
General statistical context: a count is not the same as a participant-level risk. One participant may experience more than one event, so a total event count and the number of participants experiencing at least one event can differ. A count also needs context, including the number of participants observed and the length and completeness of follow-up. The registry describes the treated population and the observation period, but does not provide the primary event count or the corresponding analysis. The separate adverse-event summary reports serious and other adverse-event figures, but those summaries should not be mistaken for a reported result of the specifically defined primary endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the study’s purpose and design, but it does not provide a result for the primary endpoint. The endpoint was the number of device- or procedure-related adverse events during the specified follow-up period. Although the record says those events would be tabulated, it lists no statistical analyses. The primary count, its event-level details, and any estimate of uncertainty are not reported in the registry record. The stated aim of evaluating efficacy also does not establish that an efficacy result is available: the outcome details and analyses needed to interpret efficacy are not reported in the registry record.
The adverse-event summary contains a separate safety description: serious adverse events affected 0 of 40 at risk, other adverse events affected 5 of 40 at risk, and deaths were 0. These entries describe the counts recorded in that summary. They do not substitute for the missing primary endpoint result, whose definition specifically concerns events related to the device or procedure. The record does not provide enough detail to determine how the summary categories correspond to the primary outcome, or to identify the nature of the other adverse events.
General statistical context: observed counts describe what was recorded in the study population; they do not, on their own, establish how often events would occur in a broader population. Precision depends on the amount of information and the variability in the observations. Confidence intervals, when reported, communicate a range of values compatible with the data under the analysis assumptions. No confidence interval for the primary outcome is reported, so the precision of that outcome cannot be assessed from the record.
The single-group design also constrains interpretation. Without a separate comparator group, the record cannot directly estimate a difference between treated and untreated participants or between alternative interventions. Even if an outcome changes after treatment, the design alone cannot rule out other causes of that change. This is a design limitation, not a judgment about whether a change occurred; outcome results sufficient to assess such a change are not reported in the registry record.
The record’s completed status and enrollment count describe study conduct, not the direction or strength of the findings. The most defensible reading is therefore limited: 40 subjects were enrolled in a single-group study, and the registry documents adverse-event summary counts, but it does not report the primary endpoint analysis or enough efficacy results to support a statistical conclusion about the stated efficacy objective.
9. Statistical Methods Explained
The registry classifies the primary outcome as a count of device- or procedure-related adverse events. The description says events were to be tabulated over the period from enrollment through the final follow-up visit. No analysis entries are listed. The statistical methods used to summarize or analyze the primary count, including any model, uncertainty interval, or inferential test, are not reported in the registry record.
What does a count measure?
General statistical context: a count records how many events occur within a defined observation period. It is important to distinguish the number of events from the number of participants who experience events. Someone may have more than one event, so those quantities are not interchangeable. Counts also depend on observation time: participants followed for different lengths of time may have different opportunities for events to be recorded. The stated outcome timeframe defines the intended window, but the record does not report individual follow-up completeness or event-level data.
For a count to be interpretable, the event definition and counting rules matter. For example, a report can count all events, count only events judged related to treatment, or report the number of people with at least one event. The primary endpoint is described as related events, but the specific attribution process, rules for repeated events, and adjudication procedures are not reported in the registry record. The separate adverse-event summary gives affected-participant counts by category; it does not provide the primary endpoint’s event total.
Why can counts require special methods?
General statistical context: count data are often nonnegative whole-number observations and may have a distribution unlike continuous measurements. A simple count model can be inappropriate if event counts vary more than the model assumes. This excess variability is called over-dispersion. When over-dispersion is present, a method that assumes less variability may make uncertainty appear smaller than it is. Whether over-dispersion was assessed or whether any count model was used in this study is not reported in the registry record.
Some count analyses include the time each participant was observed, particularly when follow-up differs. This can be handled by modeling an event rate rather than only a raw total. Such an analysis requires adequate information about person-time and the analysis approach. The registry specifies a follow-up window but does not report person-time, differences in follow-up, or a rate analysis. It would therefore be inappropriate to infer an event rate or a model from the posted summary.
What does an uncertainty interval add?
General statistical context: a confidence interval describes uncertainty around an estimate under a specified statistical method. A narrow interval generally indicates greater precision than a wide interval, but the interval’s meaning depends on the data, assumptions, and analysis. An interval around a count, a rate, or a proportion answers different questions. The record does not report a confidence interval for the primary endpoint, nor does it specify a method from which one could be interpreted.
A p-value, if reported, would address compatibility between the observed data and a particular null hypothesis under a chosen model. It would not measure the size or importance of an effect. No primary endpoint p-value or hypothesis test is reported in the registry record. In addition, this is a single-group study, so a treatment-versus-control hypothesis test is not described by the design information available in the record.
What can the planning information establish?
General statistical context: a planning calculation asks how many participants might be needed under stated assumptions to detect a specified effect with a chosen error rate and power. Such an illustration is not a description of what the study observed, and it does not establish that a study had a particular probability of finding a result after completion. The record’s planning note describes an illustration based on an observed effect and general assumptions, but no resulting sample-size values are included in the registry record for interpretation. It is not the trial’s own design justification. A trial-specific sample-size justification is not reported in the registry record.
Because there are no listed statistical analyses, the posted information does not identify an analysis population beyond the primary outcome description that all treated subjects were assessed. It does not say how missing observations, incomplete follow-up, repeated events, or deviations from the intended observation window were handled. Nor does it specify an adjustment for covariates or a method for handling multiple outcomes. Those are methodological choices that can affect estimates and uncertainty, and they should not be inferred from the outcome definition alone.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists two outcome measures, while the detailed information available for the primary outcome describes the count of device- or procedure-related adverse events. No analyses are listed. The full definition and results for the other outcome measure, and any statistical testing across outcomes, are not reported in the registry record.
General statistical context: when investigators assess multiple outcomes or conduct multiple tests, the chance of at least one apparently unusual result can increase if each test is interpreted separately. A prespecified hierarchy or an adjustment for multiplicity can help define how evidence across tests should be interpreted. The record does not report whether a hierarchy or adjustment was planned or used. This absence means it is not possible to determine how any multiple-outcome testing would have been interpreted.
The primary outcome description says all treated subjects were assessed. That identifies the intended population for the endpoint, but it does not explain whether every enrolled participant completed follow-up or had complete event data. The handling of missing data, withdrawals, incomplete follow-up, and any participants excluded from an analysis is not reported in the registry record. The analysis population used for any statistical result is likewise not reported.
These omissions matter because missing outcomes can affect both the observed count and its interpretation. General statistical context: an analysis based only on participants with complete data can differ from one that accounts for missing observations, especially if missingness is related to outcomes or follow-up. The appropriate approach depends on the circumstances and the prespecified plan. No missing-data method or sensitivity analysis is reported, so the potential influence of incomplete information cannot be evaluated from the registry record.
The record also does not describe a protocol, statistical analysis plan, interim analyses, or a sample-size justification. Their absence from the record should not be filled in by assumption. Without the analysis details, outcome definitions, and accounting for follow-up, the reported safety summary can be read descriptively, but it cannot establish how all planned analyses were conducted.
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 |
|---|---|---|---|
| Treatment With Small Area Applicator | 0 | 40 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Treatment With Small Area Applicator | 0 of 40 |
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 |
|---|---|
| Treatment With Small Area Applicator | 5 of 40 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Treatment With Small Area Applicator |
|---|---|---|
| Throat infection | Infections and infestations | 1 of 40 |
| Shingles | General disorders | 1 of 40 |
| Knee injury | General disorders | 1 of 40 |
| Erythema | Skin and subcutaneous tissue disorders | 1 of 40 |
| Bruise | Skin and subcutaneous tissue disorders | 1 of 40 |
The adverse-event summary reports serious adverse events for 0 of 40 at risk, other adverse events for 5 of 40 at risk, and 0 deaths. These are counts in the registry summary; they are not percentages, rates, or comparative estimates. No additional calculation is needed to read them. The registry does not list top serious event terms.
These categories should be kept distinct from the primary endpoint. The primary endpoint is defined as the number of device- or procedure-related adverse events. The adverse-event summary reports serious and other adverse-event counts, but does not give the primary endpoint’s related-event total or clarify how the categories map to that endpoint. The detailed event names and the method used to judge relatedness are not reported in the registry record.
General statistical context: observing no serious events in a study does not demonstrate that serious events cannot occur. A count of zero is a description of what was recorded in the observed group and period; it does not by itself establish a zero underlying risk or precise safety estimate. The size and duration of observation, completeness of follow-up, and the way events were assessed all matter to interpretation. The registry gives an enrollment count and a follow-up timeframe, but does not report follow-up completeness or an uncertainty interval for the serious-event count.
The figures therefore describe the recorded adverse-event summary for this treated group. They should not be read as a comparison with another treatment, because the study has no separate comparator group.
12. What the Result Does, and Does Not, Mean
The study record supports a limited descriptive account: 40 subjects were enrolled in a completed, single-group study of treatment with the ZELTiq System and small area applicator on a single distal thigh. The registry defines a primary safety outcome based on the number of device- or procedure-related adverse events during enrollment through final follow-up. It also reports serious adverse events for 0 of 40 at risk, other adverse events for 5 of 40 at risk, and 0 deaths in its adverse-event summary.
Those details do not provide the primary endpoint result. The primary event count and analysis are not reported in the registry record. The adverse-event summary should not be substituted for that missing result, because the record does not establish that its categories are equivalent to the primary endpoint. The detailed nature of the other adverse events and the assessment of relatedness are not reported either.
The record also does not provide a statistical efficacy result that can be interpreted in relation to the study’s stated aim of evaluating subcutaneous fat reduction. It lists two outcome measures, but the result and analysis details needed to understand efficacy are not reported in the registry record. Enrollment and study completion are details about conduct; they do not indicate whether an outcome improved or whether any observed change was attributable to treatment.
General statistical context: a single-group study can describe observations in treated participants, but it lacks a concurrent untreated or alternative-treatment group for direct comparison. As a result, it cannot by itself separate the effects of treatment from other factors that may influence an outcome. Even a precisely estimated within-group change would not resolve that comparison problem.
Accordingly, the registry record is informative about the study’s structure, intervention, target population, observation period, and recorded adverse-event summary counts. It does not establish the magnitude or precision of the primary safety outcome, nor does it support a treatment-effect estimate. Those conclusions require results and analysis details that are not reported in the registry record.
13. Why This Trial Matters Statistically
This study is statistically notable for the gap between a clearly identified safety question and the limited results recorded for that question. The registry defines a primary endpoint as a count of device- or procedure-related adverse events and specifies an observation period. However, the count and its analysis are not reported. As a result, readers can identify what the study intended to tabulate but cannot evaluate the primary outcome’s observed value or precision.
The single-group design is also central to interpretation. It can describe events among treated subjects, but does not provide a concurrent comparator for estimating a treatment-versus-control difference. This is particularly relevant to the stated efficacy objective: the record does not report an efficacy analysis, and the design information does not describe a control group against which efficacy could be directly compared.
The adverse-event summary illustrates why outcome definitions matter. It reports serious and other adverse-event counts, while the primary outcome specifically concerns events judged related to the device or procedure. Without a clear mapping between these summaries and the primary endpoint, the counts should be read as distinct pieces of registry information rather than combined into a single conclusion.
General statistical context: a study’s enrollment and completion status do not determine the precision or reliability of a result. Interpretation also requires the outcome values, analysis methods, handling of missing observations, and a clear account of the analysis population. These details are not reported for the primary analysis in the registry record. The record therefore offers a useful example of how design information and result reporting answer different questions: design identifies the intended comparison and measurements, while results and methods are needed to assess what the observations show.
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 principal trial-specific limitation is the absence of a reported primary endpoint result. The registry defines the outcome and its follow-up timeframe, but gives no event count or analysis. The separate adverse-event summary does not resolve this omission because it does not identify the primary endpoint total or explain how its categories relate to device- or procedure-related events.
The study is recorded as single-group and has no separate comparator. This prevents a direct comparison with an untreated group or another intervention in the registry record. The record therefore cannot support a comparative estimate, and any before-and-after interpretation would require outcome data and further assumptions that are not reported.
Although the study is described as evaluating safety and efficacy, detailed results for efficacy are not reported in the registry record. The registry lists two outcome measures, but only the primary outcome is described in detail. Eligibility criteria, participant characteristics, device settings, and additional procedures are also not reported in the registry record. These omissions limit assessment of who was studied, what was measured beyond the primary endpoint, and how broadly observations might apply.
The record does not report the statistical analysis plan, methods for event attribution or repeated events, handling of missing data, analysis population for a final result, multiplicity procedures, or a trial-specific sample-size justification. Follow-up is described by a target timeframe, but individual follow-up completeness is not given. These details are important for interpreting both safety counts and outcome estimates.
Finally, the serious-event count is a descriptive summary in a study of 40 enrolled subjects, not a comparative or definitive estimate of safety. The registry does not provide an uncertainty interval or detailed serious-event terms. The scope of any conclusion must therefore remain limited to the recorded summary and the information explicitly documented in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: CoolSculpting of the Distal Thigh Study — NCT02335749.
- Registry record last updated 2021-12-01; status last verified 2017-01.
- Results first posted 2021-12-01.
- 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
NCT02335749 is a completed, single-group study titled CoolSculpting of the Distal Thigh Study, sponsored by Zeltiq Aesthetics. It enrolled 40 subjects and evaluated the ZELTiq System with a small area applicator. Each subject was treated on a single thigh in the distal region.
The primary outcome was the number of device- or procedure-related adverse events from enrollment through the final follow-up visit, described as the 12-week visit and approximately 15 weeks. The primary outcome result and statistical analyses are not reported in the registry record. The adverse-event summary reports serious adverse events for 0 of 40 at risk, other adverse events for 5 of 40 at risk, and 0 deaths. The record lists two outcome measures, but detailed results for the other measure are not reported.
With no separate comparator group, the study provides no direct between-group comparison. The registry record does not report an efficacy analysis, a statistical analysis plan, or details on missing-data handling.