Randomized, Placebo-Controlled Study of Leptin for the Treatment of HIV Lipodystrophy and Metabolic Syndrome: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Randomized, Placebo-Controlled Study of Leptin for the Treatment of HIV Lipodystrophy and Metabolic Syndrome (NCT00140244), a randomized phase 2 study. The primary outcome is Serum Lipid Levels.

2. Clinical Question

The clinical question links a proposed leptin replacement intervention with metabolic changes associated with HAART. Serum lipid levels are the named primary outcome, while the study purpose also refers to fat distribution and other metabolic problems. Those broader aims do not establish that every such outcome was measured in the same way or yielded a result; the registry lists several secondary outcomes separately.

A crossover design compares treatments across intervention periods. In general, it can allow each participant to contribute information under both treatments, but the registry record does not describe the treatment sequence, washout arrangements, or the analysis used to account for repeated measurements. The record therefore supports describing the planned comparison, not reconstructing its implementation or estimating its effects.

3. Trial Design

The registry identifies this as a randomized, triple-masked, phase 2 crossover study of r-MetHuLeptin and placebo. Both interventions are described as subcutaneous injections once daily. The primary outcome timeframe is the end of each two month intervention. Enrollment is listed as 7, and the study status is completed. The recorded start is 2001-12 and primary completion is 2011-06.

Randomization means assignment to treatment order was intended to use a chance-based process. Triple masking indicates that the record labels the study as masked at three levels, but it does not identify which roles were masked or explain how masking was maintained. Those operational details are not reported in the registry record. The crossover label indicates that the design involved treatment periods rather than a parallel comparison alone; the treatment sequence and timing of any transition between treatments are also not reported.

The record names serum lipid levels as the primary outcome and lists insulin resistance assessed by HOMA-IR, fasting glucose, LDL cholesterol, free fatty acid levels, blood pressure, fibrinogen, insulin levels, and lean body mass among the secondary outcomes. It lists 13 outcome measures, while the analysis count is 0. This leaves no registry-recorded numerical treatment estimates to interpret.

The registry does not report a sample-size justification, a detailed protocol, the allocation sequence, the washout period, or the statistical model used for the crossover comparison. Although the study is marked completed, completion status alone does not supply the outcome estimates needed to judge the magnitude or precision of a treatment contrast.

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.

Intervention 1

Washout

Intervention 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.

6. Primary Endpoint

The registry lists the primary outcome as Serum Lipid Levels, measured over At the end of each two month intervention.

The primary outcome is titled serum lipid levels, measured in mg/dl and described as a mean with standard error. The stated timeframe is the end of each two month intervention. The registry does not specify in this primary outcome description which lipid components are included, how samples were collected, or whether the primary analysis combined or separately reported lipid measures.

Serum lipid measurements are used to characterize circulating lipid concentrations. As a continuous measure, a mean can describe the average measured level in a group or treatment period. The standard error describes the statistical precision of an estimated mean; it is not the same as the spread of individual measurements. These are general interpretations of the stated summary format, not findings from this trial.

For a treatment comparison, the change or contrast in means would be more informative than either mean alone. In a crossover study, interpretation also depends on how repeated measurements and treatment periods are handled. The registry record does not report the endpoint values, treatment contrast, confidence interval, or analysis details. Consequently, the named endpoint identifies what the study intended to assess, but the record does not establish the direction, size, or precision of any observed difference.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical methods that can be interpreted from the registry record are limited. It identifies randomization, triple masking, a crossover model, a continuous primary outcome summarized as a mean with standard error, and the endpoint timing. It does not report a detailed analysis plan or numerical outcome analyses. The explanations below describe general statistical concepts; they do not assert that a particular method was used in this trial.

What does a mean describe?

For a continuous outcome such as a measured concentration, the mean represents the arithmetic average of the observed values in the relevant set of measurements. It can summarize a treatment period, but its interpretation depends on which participants and observations were included. The registry identifies serum lipid levels in mg/dl and specifies a mean, yet it does not report the values or define the precise analysis population. A mean alone also does not describe how widely individual measurements vary.

What does the standard error describe?

The standard error reflects the precision of an estimated mean under the assumptions of the analysis. It is distinct from a standard deviation, which describes variability among individual observations. A smaller standard error generally indicates a more precise estimate, but it cannot be interpreted in isolation: the estimate, analysis method, and uncertainty interval are also needed. Since no primary outcome values are recorded, precision cannot be assessed for this study.

Why does crossover structure matter?

In general, crossover studies expose participants to different treatments during separate periods. This can make within-participant comparisons useful, because measurements from the same person may share characteristics. Those repeated measurements are correlated rather than independent, so an analysis should account for that structure. Treatment period, order of treatment, and any lingering effect from an earlier period may also matter. Whether these issues arose or how they were handled cannot be determined: sequence, washout arrangements, and the statistical model are not reported in the registry record.

Randomization is intended to reduce systematic differences in treatment assignment, while masking is intended to limit expectations from influencing care, measurement, or assessment. The registry labels the study randomized and triple-masked, but does not describe the randomization procedure or identify the masked roles. The labels alone do not establish how well these safeguards worked in practice.

How should uncertainty and significance be read?

In general, a confidence interval gives a range of effect estimates compatible with the data and the method used, while a p-value describes how unusual the data would be under a specified null hypothesis and model. Neither conveys clinical importance by itself. Interpretation should consider the estimated contrast, its uncertainty, the outcome scale, and the analysis assumptions. The registry record does not report a treatment contrast, confidence interval, or p-value for the primary outcome, so none can be interpreted for this study.

The sample-size description refers to planning illustrations using a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect defined as a fraction of an observed effect. These are stated planning assumptions, not a report of the trial's original design justification or observed statistical power. The registry does not report the original sample-size justification or numerical planning estimates. It also notes that the primary outcome has several categories or time points and was not reduced to one comparison. No single primary contrast can therefore be inferred from the planning description.

Why can over-dispersion matter?

As a general concept, over-dispersion occurs when observed variability exceeds what a statistical model assumes. It can make standard errors too small and confidence intervals too narrow if the model does not account for the extra variability. This concern is especially relevant to some count outcomes, but the named primary outcome is continuous. The registry does not report a model or a variance assessment, so there is no basis for claiming that over-dispersion was present or affected this analysis.

The registry records 13 outcome measures and 0 analyses. A list of outcomes is not a substitute for an analysis plan: it does not establish which measures were designated primary at each time point, how repeated measures were handled, or how missing data were treated. Those details, along with any adjustment for multiple testing, are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists serum lipid levels as the primary outcome and names multiple secondary measures, including insulin resistance, fasting glucose, LDL cholesterol, free fatty acids, blood pressure, fibrinogen, insulin, and lean body mass. It records 13 outcome measures overall. When many outcomes or time points are examined, the chance of at least one apparently unusual result can increase. In general, multiplicity procedures can address that issue, but the appropriate approach depends on which comparisons were planned and their relationship to one another.

The registry record does not report a multiplicity adjustment, a hierarchy of outcomes, or a prespecified testing strategy. It also does not report numerical analyses for the listed outcomes. It is therefore not possible to determine whether an adjustment was used or how any findings should be interpreted across the outcome set.

Missing-data methods are likewise not reported in the registry record. The record does not state how many participants contributed to each endpoint, whether any measurements were missing, why data might be missing, or how incomplete follow-up was handled. In a crossover study, period-specific missing observations can affect within-participant comparisons, but the available record does not indicate whether that occurred.

The analysis population is not described. It is not possible to determine whether the analysis followed randomized assignment, included participants with any available measurements, or used another population definition. These omissions limit assessment of both bias and precision. The recorded analysis count is 0, so no registry-recorded statistical analysis can resolve these questions.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The adverse-event record lists 0 serious adverse events among 5 participants at risk for r-MetHuLeptin and 0 among 7 participants at risk for placebo. It also lists 0 other adverse events in the corresponding at-risk groups. These are the counts recorded for the listed groups; they do not show that risk was absent.

The risk sets are not identical across the treatment groups. The registry does not explain how those denominators were defined, how exposure periods were counted, or how the counts relate to crossover participation. They should not be interpreted as a direct comparison of event rates without those details. The registry also does not list serious adverse-event terms. Death counts are not reported in the registry record.

Zero recorded events means that no affected participants are listed in these registry fields. With no further event descriptions, follow-up information, or analysis, the figures do not establish the broader safety profile of either intervention and cannot rule out events not captured in the record.

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

The record establishes that a completed phase 2 study was registered as randomized, triple-masked, and crossover, with r-MetHuLeptin and placebo given subcutaneously once daily. It identifies serum lipid levels at the end of each two month intervention as the primary outcome. It also records the study's stated purpose of examining leptin replacement in relation to fat distribution, lipid profile, and other metabolic problems associated with HAART-induced lipodystrophy and metabolic syndrome.

Those design details do not supply an estimate of what happened to serum lipid levels. No numerical primary results or analyses are reported in the registry record. The listed secondary outcomes likewise do not establish observed effects. The study's completed status cannot be used to infer a direction or magnitude of findings.

In general, a treatment comparison is most informative when it includes an effect estimate and an assessment of uncertainty. Without either, the available information does not show whether the observed data favored r-MetHuLeptin, favored placebo, or were compatible with a range of effects. It also does not show how precisely any comparison was estimated. The registry entry should not be read as evidence that the treatments were equivalent or that there was no effect.

Enrollment of 7 is recorded, but the analysis population and endpoint-specific participation are not. The crossover design also makes treatment sequence and repeated-measure methods relevant, yet those details are not reported. These limitations prevent a reliable reconstruction of the primary comparison from the registry record.

The safety fields list no affected participants for the recorded serious or other adverse-event counts, with the stated risk sets. Those fields have limited context and do not establish absence of risk. Overall, the record describes a research question and design, but does not provide the outcome evidence needed to answer the clinical question.

13. Why This Trial Matters Statistically

This study is statistically notable because it combines a crossover design with a continuous metabolic endpoint and a broad set of secondary measures. Such a design requires attention to within-participant dependence and treatment periods. In general, measurements from the same participant cannot be treated as independent without justification. The registry labels the design as crossover but does not provide the model or sequence information needed to assess how that structure was handled.

The record also illustrates the difference between registering outcomes and reporting results. Serum lipid levels are identified as the primary endpoint, and multiple secondary outcomes are named, but the analysis count is 0 and numerical estimates are absent. Without those analyses, readers cannot assess effect size, uncertainty, or the consistency of findings across outcomes. Nor can they determine how multiplicity or missing data were addressed.

Enrollment is recorded as 7, making clear that the registry describes a small study, but the record does not provide the estimates needed to assess precision. A sample-size illustration, even when available, would not substitute for observed estimates and uncertainty. The stated planning assumptions do not amount to observed power.

The statistical importance of this record is therefore in the limits it places on interpretation. It identifies a defined clinical question and study structure, while leaving key analysis details and outcome results unreported. That distinction helps prevent design labels, completion status, or event counts from being mistaken for evidence about treatment effects.

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 most consequential limitation is that numerical primary outcome results are not reported in the registry record. The entry names serum lipid levels and its measurement scale and summary format, but does not give the means, a treatment contrast, or uncertainty estimates. The analysis count is recorded as 0. No effect direction, magnitude, or precision can therefore be assessed.

The primary outcome description does not specify which lipid measures were included, and the record notes that the outcome has several categories or time points rather than a single reduced comparison. The timing is described as the end of each two month intervention, but the registry does not provide the values by measure or period. This prevents identification of a unique primary contrast from the record.

The crossover design is not described in sufficient detail to reconstruct treatment order, washout arrangements, or the statistical handling of repeated observations and period effects. The randomization and triple-masking labels are present, but operational details are not reported. The analysis population, endpoint-specific participation, missing-data patterns, and missing-data methods are also absent.

The record names several secondary outcomes but does not report their numerical results or a multiplicity strategy. It does not report the study's sample-size justification or numerical planning estimates. Finally, the safety fields provide event counts and at-risk groups without explaining the denominator definitions or reporting death counts. These omissions constrain interpretation of both efficacy-related outcomes and safety information.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Randomized, Placebo-Controlled Study of Leptin for the Treatment of HIV Lipodystrophy and Metabolic Syndrome — NCT00140244.
• Registry record last updated 2017-05-11; status last verified 2017-04.
• Results first posted 2017-04-06.
• 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

NCT00140244 is a completed phase 2 study sponsored by Beth Israel Deaconess Medical Center. The registry records a randomized, triple-masked crossover design and enrollment of 7. Its recorded start is 2001-12, with primary completion in 2011-06.

The study compares daily subcutaneous r-MetHuLeptin with placebo in people with HIV receiving HAART who have lipodystrophy and metabolic syndrome. Serum lipid levels, expressed in mg/dl as a mean with standard error at the end of each two month intervention, are named as the primary outcome. The record also lists 13 outcome measures and 0 analyses.

Numerical outcome results, analysis details, and the analysis population are not reported in the registry record. The adverse-event fields record zero serious and other events in the stated risk sets, while death counts are not reported.