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 Therapeutic Approaches to HAART-Induced Lipodystrophy (NCT00461552), a randomized phase 2 study. The primary outcome is Fasting Serum Triglycerides.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00461552 |
| Phase | Phase 2 |
| Condition | HIV Infections, Lipodystrophy |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 23 |
| Arms in the primary outcome | 2 |
| Lead sponsor | University of Texas Southwestern Medical Center |
| Results posted | Yes |
2. Clinical Question
Population
People with HIV infections and lipodystrophy are the clinical population identified in the registry record. The record does not report additional eligibility criteria or baseline characteristics for the participants contributing to the primary outcome.
Intervention
The leptin arm used a weight- and gender-based dose, given by subcutaneous injection twice daily. The record describes the comparison as double-blind for the entire 6 months.
Comparator
The comparator was placebo, given by subcutaneous injection twice daily. The primary outcome summaries are reported for 7 participants in the leptin group and 5 in the placebo group.
Primary question
The primary outcome was fasting serum triglycerides, measured in mg/dL and summarized at 6 months. The registry also reports a mixed models analysis comparing leptin with placebo, with p = 0.84.
The trial is titled “Therapeutic Approaches to HAART-Induced Lipodystrophy,” and its brief summary describes a broader interest in interventions aimed at metabolic complications, including elevated lipids and insulin resistance or diabetes. However, the posted intervention arms and primary-outcome results described in the registry record are for leptin and placebo. The other approaches named in the brief summary are not represented in the posted arms for this comparison.
The clinical question that can be addressed from the posted results is therefore narrow: how did fasting serum triglycerides at 6 months compare between participants assigned to leptin and those assigned to placebo? The registry reports group medians and full ranges, as well as a p-value from a mixed models analysis. It does not report an adjusted treatment-effect estimate or confidence interval for that analysis. The record also does not report a broader conclusion about all four approaches named in the brief summary. These results describe the posted comparison and should not be read as evidence about the unreported interventions or outcomes.
3. Trial Design
The registry describes a phase 2, randomized, triple-masked, parallel trial. The recorded enrollment is 23. The registry lists the University of Texas Southwestern Medical Center as sponsor, a start date of 2003-01, a primary completion date of 2014-09, and a completed status. These dates and status describe the registry entry; further details of recruitment or follow-up are not reported in the registry record.
The posted arms for the primary-outcome comparison are leptin and placebo. Leptin is described as a weight- and gender-based dose administered subcutaneously twice daily. Placebo is described as a subcutaneous injection given twice daily. The arm description says that leptin versus placebo was double-blind for the entire 6 months. The registry’s masking classification is triple. The record does not explain which parties were masked or how masking was maintained.
The primary outcome is fasting serum triglycerides in mg/dL at 6 months. The registry reports a median and full range for each arm. The leptin summary is based on 7 participants, and the placebo summary is based on 5 participants. These outcome denominators are smaller than the recorded total enrollment; the reasons for the difference are not reported in the registry record. The registry also identifies body weight as a secondary outcome, but it does not provide a result for that outcome in the registry record for this account.
The trial’s brief summary describes four therapeutic approaches, including dietary approaches, aerobic exercise with dietary advice, omega-3 fish oil capsules, and leptin therapy. The posted intervention arms in this record identify leptin and placebo; the registered primary comparison is not a comparison among all four approaches. The allocation ratio, method used to generate the random sequence, concealment procedures, detailed protocol, and planned analysis populations are not reported in the registry record. The posted results support description of the reported comparison, but not reconstruction of unreported design details.
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 | Leptin | Placebo |
|---|---|---|
| STARTED | 7 | 7 |
| COMPLETED | 7 | 5 |
| NOT COMPLETED | 0 | 2 |
Reasons for not completing this period:
| Reason | Leptin | Placebo |
|---|---|---|
| Drug Dispensing error | 0 | 2 |
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 | Leptin | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 7 | 7 | 14 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 6 | 7 | 13 |
| Age, Categorical: >=65 years | Participants | 1 | 0 | 1 |
| Age, Continuous | years | 50.4 (SD 10.4) | 48.1 (SD 3.7) | 49.3 (SD 7.6) |
| Sex: Female, Male: Female | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Male | Participants | 7 | 7 | 14 |
| Body Weight | kg | 71.2 (SD 6.2) | 75.6 (SD 7.8) | 73.4 (SD 7.2) |
| Triglycerides | mg/dL | 336 (245 to 587) | 471 (238 to 1424) | 377 (238 to 1424) |
6. Primary Endpoint
The registry lists the primary outcome as Fasting Serum Triglycerides, measured over 6 months.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | mg/dL |
| Endpoint classification | not reduced to a single comparison |
Fasting serum triglycerides are a measure of circulating triglyceride concentration after fasting. The registry records this outcome in mg/dL and identifies the assessment timeframe as 6 months. Triglycerides are a lipid measure, which is relevant to the trial’s stated interest in metabolic complications of HAART-induced lipodystrophy, including elevated lipids. This is general clinical and statistical context; the registry does not provide a detailed rationale for selecting this endpoint.
The outcome is summarized by the median and full range in each arm. A median gives the central value when observations are ordered; unlike a mean, it is less affected by unusually high or low values. The full range describes the lowest and highest observed values, but it does not show how observations are distributed between those endpoints. A range can be especially wide when individual measurements vary substantially. This is general statistical explanation, not a claim about the distribution of individual values in this trial.
The leptin group’s reported median is 237.0 mg/dL, with a full range from 122.0 to 439.0. The placebo group’s median is 341.0 mg/dL, with a full range from 127.0 to 1099.0. The registry reports these summaries for 7 and 5 participants, respectively. A median and range are descriptive summaries; by themselves they do not quantify an adjusted treatment effect or its uncertainty. The registry does not report a confidence interval for the between-group effect, nor does it provide enough detail to reconstruct the individual-level data or the mixed-model estimate.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
At 6 months, the reported fasting serum triglyceride median was 237.0 mg/dL in the leptin group and 341.0 mg/dL in the placebo group. The reported full ranges were 122.0 to 439.0 mg/dL for leptin and 127.0 to 1099.0 mg/dL for placebo. These summaries show that the reported medians differ and that the ranges overlap. They do not, on their own, establish the size or precision of a treatment effect.
The registry reports a mixed models analysis comparing the arms, with p = 0.84. This is the reported inferential result for the primary comparison. A p-value is interpreted in relation to a specified statistical model and null hypothesis; general statistical interpretation does not make it a measure of the probability that a treatment effect exists. The registry does not report the model’s estimated contrast, standard error, confidence interval, or detailed specification. As a result, the direction and precision of the mixed-model treatment estimate cannot be assessed from the reported p-value alone.
The group summaries are based on 7 participants assigned to leptin and 5 assigned to placebo. The full enrollment is 23, and the registry does not explain why the primary-outcome denominators are smaller. The reported outcome sample sizes therefore need to be kept distinct from total enrollment. Whether the smaller outcome groups reflect missing measurements, analysis-population restrictions, or another reason is not reported in the registry record.
There is substantial spread in the posted observations, particularly in the placebo range, whose upper endpoint is 1099.0 mg/dL. A range does not indicate how many participants had values near either endpoint. The median may give a useful description of the center of a group, but the full ranges and small outcome groups counsel against treating the medians as a complete picture of variability. No individual-level values or additional distribution summaries are reported in the registry record.
The registry’s result is best read as a descriptive account of the two outcome groups accompanied by a reported mixed-model p-value. It does not provide a confidence interval that would show which treatment differences are compatible with the analysis, nor does it report an adjusted estimate with which to assess magnitude. The p-value alone does not demonstrate equivalence or rule out potentially important differences. The findings pertain to this leptin-placebo comparison and this endpoint at 6 months, not to every intervention discussed in the trial summary or to other outcomes.
9. Statistical Methods Explained
What does the median describe?
The registry reports the primary outcome as a median with a full range. In general, the median is the middle observation after measurements are ordered. It describes the center without being pulled as strongly as a mean by extreme values. The full range gives the lowest and highest values observed, but does not reveal how tightly or unevenly the remaining observations cluster. That distinction matters when a group’s observed values vary widely. Here, the reported summaries are 237.0 mg/dL and a range of 122.0 to 439.0 for leptin, and 341.0 mg/dL and a range of 127.0 to 1099.0 for placebo.
What does the mixed models result say?
The registry names a mixed models analysis and reports p = 0.84. In general, mixed models can represent correlated observations or structured data by accounting for sources of variation associated with groups or repeated measurements. Their exact form depends on the study design and model specification. The registry does not report the model formula, included covariates, covariance structure, analysis population, or the estimate produced by the model. It is therefore not possible to determine from the registry record which particular features of the data the model addressed.
In general, a p-value assesses how compatible observed data are with a null hypothesis under the assumptions of a statistical model. It is not the probability that the null hypothesis is true, and it does not quantify the size of a difference. A p-value also does not show the range of effect sizes compatible with the data. The reported p = 0.84 should therefore be read as the inferential result the registry reports, not as an estimate of treatment magnitude or precision. No confidence interval or model-based treatment estimate is reported in the registry record.
Why are confidence intervals useful?
In general, a confidence interval gives a range of values compatible with the data and the method used to calculate it, subject to the method’s assumptions. It helps readers assess the precision of an effect estimate as well as its direction and possible magnitude. The registry record does not report a confidence interval for the mixed-model comparison. The posted medians and ranges are not a substitute for a confidence interval for the between-group effect: they summarize observations within each arm, rather than uncertainty around a model-based contrast.
What can the group sizes tell readers?
The registry reports primary-outcome summaries for 7 participants in the leptin arm and 5 in the placebo arm, while overall enrollment is 23. In general, smaller outcome groups tend to give less precise estimates than larger groups, though precision also depends on the variability of the outcome and the analysis method. The registry does not report a confidence interval that would quantify precision for this result. It also does not state why the primary-outcome group sizes differ from total enrollment. The distinction between enrollment and participants contributing to a reported outcome should be retained when interpreting the result.
The full ranges give a limited view of variability. In general, a range can be strongly influenced by extreme observations and does not show the distribution’s shape. The placebo range extends to 1099.0 mg/dL, but the registry does not report individual measurements or a further distribution summary. It is not possible to determine how many observations were near that upper endpoint or how much it influenced the model result.
What is not reported about the analysis?
The registry does not report whether the model was adjusted for baseline values or other covariates, how missing outcome data were handled, or whether assumptions were checked. The statistical analysis plan, prespecified contrasts, and analysis populations are not reported in the registry record. These details can affect how an inferential result is interpreted and whether it directly answers the stated clinical question. Without them, the mixed-model finding can be described, but not independently evaluated in detail.
General statistical context: model-based analyses can make more efficient use of repeated or structured observations when their assumptions are appropriate, but they do not eliminate uncertainty. Model specifications should match the design and data, and readers need estimates with uncertainty measures to judge practical magnitude and precision. The registry’s p-value alone does not supply those elements.
The registry lists a randomized, parallel design and a double-blind description for the leptin-placebo period, while its overall masking classification is triple. Randomization is generally intended to support comparable groups at assignment, and masking is generally intended to reduce influences on care or outcome assessment. These are general design principles. The registry does not report the sequence-generation or concealment methods, identify the masked parties, or describe checks of masking. Accordingly, the design labels can be stated, but their implementation cannot be assessed from the recorded details.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| Mixed Models Analysis | not reported | 0.840 |
The registry reports the sponsor’s primary-outcome comparison as a mixed models analysis with p = 0.84. It does not report a model-based effect estimate, confidence interval, or enough detail to reconstruct the analysis from the posted summaries. The available outcome summaries are medians and full ranges for each group, rather than the inputs needed to reproduce a mixed-model comparison. No recalculated treatment estimate is reported in the registry record for this account, so there is no independent recalculation to compare with the sponsor’s analysis.
The descriptive summaries show a median of 237.0 mg/dL in the leptin group and 341.0 mg/dL in the placebo group, with the full ranges reported separately for each arm. Those summaries are not equivalent to the sponsor’s mixed-model result: they do not adjust for model terms or provide the same inferential quantity. The p-value should therefore be attributed to the reported mixed models analysis, not derived from the difference between the medians.
The registry does not report whether the mixed model used baseline measurements, repeated measurements, covariates, or a particular missing-data method. Without these details and a model estimate with uncertainty, the sponsor’s inferential result can be quoted but cannot be independently assessed for magnitude, precision, or specification. The reported p-value does not reveal whether the fitted model estimated a clinically meaningful contrast.
11. Multiplicity, Missing Data and Analysis Populations
The trial’s brief summary describes multiple therapeutic approaches and metabolic concerns, while the posted arms for the primary comparison are leptin and placebo. The registry lists a primary endpoint of fasting serum triglycerides and identifies body weight as a secondary outcome. It also records 2 outcome measures and 2 analyses. The registry record does not explain how these analyses relate to the broader intervention objectives or whether other outcomes were assessed but not posted.
Multiplicity arises in general when several outcomes, treatment comparisons, time points, or statistical tests are considered. Repeated testing can increase the chance of obtaining a statistically notable result by chance if no adjustment or prespecified testing strategy is used. The registry does not report a multiplicity adjustment, testing hierarchy, or prespecified analysis plan. It is therefore not possible to determine whether the reported p = 0.84 was adjusted for other analyses or how it was intended to be interpreted within a broader testing strategy.
The registry reports primary-outcome summaries for 7 leptin participants and 5 placebo participants, compared with total enrollment of 23. It does not state whether all randomized participants were included in the analysis, explain the difference in denominators, or describe missing-data handling. The analysis population and reasons for missing primary-outcome data are not reported in the registry record. General statistical context: missingness can affect interpretation when the likelihood of an unobserved result is related to participant characteristics or outcomes; without the reasons and methods, the extent of any such effect cannot be assessed.
The record does not report an intention-to-treat population, a per-protocol population, rules for exclusions, or a sensitivity analysis for missing values. These are not interchangeable choices: an analysis population determines which participants contribute to an estimate, while missing-data methods determine how unavailable measurements are treated. No conclusion about those choices can be drawn from the group summaries alone.
There is also no reported protocol-level sample-size justification or account of interim analyses. These details are not reported in the registry record. In general, planning rationale and stopping or monitoring procedures can help readers understand how a trial was designed and how its results should be interpreted, but they cannot be inferred from enrollment or the posted p-value.
12. 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 |
|---|---|---|---|
| Leptin | 1 | 7 | 14.3% |
| Placebo | 0 | 5 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Leptin | 0 of 7 |
| Placebo | 0 of 5 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Leptin | 4 of 7 |
| Placebo | 1 of 5 |
Most frequent serious adverse event terms
| Event term | Organ system | Leptin | Placebo |
|---|---|---|---|
| cerebrovascular accident | Nervous system disorders | 1 of 7 | 0 of 5 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Leptin | Placebo |
|---|---|---|---|
| Itching | Skin and subcutaneous tissue disorders | 4 of 7 | 1 of 5 |
Serious events with the highest arm-level rate: cerebrovascular accident (14.3%).
The registry reports serious adverse events among 1 of 7 participants in the leptin group and 0 of 5 participants in the placebo group. It lists cerebrovascular accident as a top serious-event term at 14.3%. The registry also reports other adverse events among 4 of 7 leptin participants and 1 of 5 placebo participants. No deaths are reported in either group. These are the counts and term listed in the registry; the record does not provide further clinical detail about the events or their timing.
These small group counts should be read descriptively. In general, an event count does not by itself establish whether an event was caused by an intervention, and a difference in observed counts does not quantify the underlying risk precisely. The registry does not report a comparative statistical analysis or confidence interval for serious adverse events. The top-term percentage is reported as 14.3%; the record does not provide additional detail about its calculation in the registry record.
The adverse-event counts have denominators of 7 and 5, so they should not be confused with total enrollment of 23. The registry does not report whether the safety population included all enrolled participants or whether all participants had the same duration of safety observation. Further details about event definitions, ascertainment, relatedness, severity beyond the serious-event classification, and withdrawals due to adverse events are not reported in the registry record. The counts are therefore a limited description of the safety results, not a complete assessment of comparative safety.
13. What the Result Does, and Does Not, Mean
The posted result describes fasting serum triglycerides at 6 months for participants in the leptin and placebo arms. It provides each group’s median and full range, along with a mixed models analysis reporting p = 0.84. The medians differ, while the ranges overlap; the record does not provide an adjusted effect estimate or confidence interval to quantify the comparison’s magnitude and precision.
These results do not establish that the groups were equivalent. In general, a nonsignificant p-value is not an equivalence test, and the absence of a reported confidence interval prevents assessment of which effect sizes remain compatible with the fitted analysis. The reported p-value is not a measure of the probability that leptin has no effect. These are general statistical principles; the registry does not report an equivalence margin or a formal equivalence analysis.
The result also does not answer every question raised by the trial’s brief summary. The posted primary comparison concerns leptin and placebo, not the full set of dietary, exercise, and fish-oil approaches described in the summary. The endpoint is fasting serum triglycerides, not every metabolic complication named there. Body weight is listed as a secondary outcome, but a result is not reported in the registry record for the registry entries.
The primary outcome denominators are 7 and 5, while enrollment is 23. The reasons for this difference, missing-data handling, analysis population, and detailed model specification are not reported. These omissions limit assessment of representativeness, precision, and the assumptions behind the inferential result.
In general, a trial’s randomized design can support a comparative interpretation when its conduct, follow-up, and analysis are adequately described. The registry identifies randomization and masking, but provides limited detail on their implementation. The result should therefore be understood as the posted comparison and analysis, not as a definitive account of all possible effects, outcomes, populations, or intervention approaches.
14. Why This Trial Matters Statistically
This trial is statistically informative as an example of why descriptive summaries and inferential analyses answer different questions. The medians and ranges describe the observed fasting serum triglyceride values within each arm. The mixed models p-value reports an inferential test, but the registry does not provide the corresponding model estimate or confidence interval. Readers therefore have a descriptive view of the groups without a reported measure of the model-based effect’s size or precision.
The contrast between total enrollment of 23 and primary-outcome groups of 7 and 5 also highlights the importance of outcome-specific denominators. Enrollment alone does not show how many participants contributed to a particular analysis. When these numbers differ, reasons for missing outcome measurements and the analysis population are important to interpreting the result; those details are not reported in the registry record.
The reported ranges illustrate another general point: a median and range can show central tendency and overall span, but they do not show the full distribution. The placebo range extends to 1099.0 mg/dL, yet the registry does not provide individual values or further distribution summaries. A statistical interpretation based only on group summaries must therefore avoid assuming how observations are arranged within the ranges.
The record also contains a broader intervention summary while the posted comparison concerns leptin and placebo. This distinction matters for multiplicity and scope: a single reported endpoint comparison does not resolve every question associated with the broader research aims. The registry does not describe a testing strategy across outcomes or interventions. The case underscores the value of reporting prespecified analyses, model estimates, uncertainty intervals, outcome-specific denominators, and missing-data methods. Those details would make it easier to assess what the result estimates and how robustly it answers the clinical question.
15. 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-outcome groups are small: 7 participants in the leptin arm and 5 in the placebo arm. The registry does not report a confidence interval for the between-group estimate, so precision cannot be judged directly. The medians and ranges are descriptive and do not replace an effect estimate with an uncertainty interval. The full range in the placebo group extends to 1099.0 mg/dL, but individual observations and further distribution details are not reported.
Total enrollment is 23, whereas the primary-outcome summaries include 7 and 5 participants. The reason for the difference is not reported in the registry record. The analysis population, missing-data methods, and any sensitivity analyses are also not reported. This makes it difficult to assess whether the outcome summaries represent all randomized participants or how unavailable measurements may have affected the result.
The registry identifies a mixed models analysis and reports p = 0.84, but does not provide the model estimate, confidence interval, formula, covariates, or covariance structure. The model’s assumptions and their assessment are not reported. Without those details, the sponsor’s reported inference cannot be independently evaluated for its exact specification or its estimated magnitude.
The record identifies the trial as randomized and triple-masked, and the intervention description says the leptin-placebo comparison was double-blind for 6 months. It does not report the random-sequence method, allocation concealment, identities of masked parties, or procedures for maintaining masking. The registry lists body weight as a secondary outcome but does not report its result in the registry record. It also does not report multiplicity procedures, a sample-size justification, or interim analyses.
Finally, the brief summary describes several therapeutic approaches, but the posted comparison is leptin versus placebo. The primary endpoint is limited to fasting serum triglycerides at 6 months. Results for unposted interventions or other metabolic outcomes cannot be inferred from this comparison.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Therapeutic Approaches to HAART-Induced Lipodystrophy — NCT00461552.
- Registry record last updated 2019-05-09; status last verified 2019-05.
- Results first posted 2019-03-05.
- 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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19. Record Summary
The registry record describes a completed phase 2, randomized, triple-masked, parallel trial titled “Therapeutic Approaches to HAART-Induced Lipodystrophy.” It lists total enrollment of 23 and identifies leptin and placebo as the arms for the posted primary comparison. Leptin was given by subcutaneous injection twice daily at a weight- and gender-based dose; placebo was also injected subcutaneously twice daily.
The primary outcome was fasting serum triglycerides in mg/dL at 6 months, summarized by median and full range. The leptin group’s median was 237.0 mg/dL, with a range of 122.0 to 439.0; the placebo group’s median was 341.0 mg/dL, with a range of 127.0 to 1099.0. The registry reports a mixed models analysis with p = 0.84, but no model-based estimate or confidence interval.
Outcome summaries are reported for 7 leptin participants and 5 placebo participants. The reasons these denominators differ from total enrollment, the analysis population, and missing-data methods are not reported in the registry record. Body weight is listed as a secondary outcome, without a result in the registry record.