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 Anticonvulsant Mood Stabilizers, Antipsychotic Drugs and the Insulin Resistance Syndrome (NCT00288366), a randomized na study. The primary outcome is HDL Ratio.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00288366 |
| Phase | NA |
| Condition | Schizophrenia, Schizoaffective Disorder, Bipolar Disorder |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 49 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Northwestern University |
| Results posted | Yes |
2. Clinical Question
Population
The record identifies people with schizophrenia, schizoaffective disorder, or bipolar disorder. It reports total enrollment of 49 but does not describe the outcome-analysis population or give further eligibility details. The study summary concerns patients receiving antipsychotic drugs, and describes a planned switch from their current antipsychotic medication unless the switch was clinically contraindicated.
Intervention
One study group received aripiprazole, also named Abilify in the record. The study summary describes switching medication to aripiprazole or ziprasidone, subject to clinical contraindications. The registry lists drug interventions comparing the two medications.
Comparator
The other listed group received ziprasidone, also named Geodon. The record describes a randomized, parallel-group comparison and names aripiprazole and ziprasidone as the study arms. It does not report how many participants were assigned to each arm for the primary outcome analysis.
Primary question
The primary outcome is change in HDL ratio after the medication switch, measured at 24 weeks from baseline. The record does not give a numerical comparison between the groups, an effect estimate, or a confidence interval. It therefore does not establish from the posted results how the groups differed on this outcome.
The broader study objective was to examine mood stabilizers in relation to insulin resistance syndrome, both alone and among patients treated with antipsychotic drugs. The registry summary describes metabolic syndrome as a constellation of metabolic abnormalities, including low HDL, that is associated with increased risks of cardiovascular disease, stroke, and some types of cancer. The record does not report how the primary outcome was analyzed or whether the listed comparison addresses every part of that broader objective. These distinctions matter: the study question described in the summary is broader than the single primary outcome description, and the available registry record does not provide the outcome results needed to quantify an answer.
3. Trial Design
The registry describes a randomized, parallel-group drug study with no masking. Its two named arms are aripiprazole and ziprasidone. The record lists total enrollment of 49 and describes the study as completed. The study phase is listed as not applicable. The sponsor is Northwestern University. The registry gives a start date of 2006-01 and a primary completion date of 2008-12.
The study summary says participants would be switched from their current antipsychotic medication to aripiprazole or ziprasidone, unless clinically contraindicated, so that metabolic levels could be compared with levels during treatment with the former medication. This description suggests that the study considered metabolic status in relation to a medication switch, but the registry record does not report the detailed switching procedures, the medications participants were taking before the switch, or how contraindications affected assignment or follow-up.
Randomization is a design method intended to make treatment groups comparable on average with respect to both measured and unmeasured characteristics. That is a general explanation, not evidence that the groups in this particular trial were balanced. No baseline comparison is reported. The parallel design means the record describes distinct arms rather than a crossover comparison, but details about follow-up, adherence, deviations, and analysis populations are not reported in the registry record.
The record lists one primary outcome measure, change in HDL ratio after medication switch, with a timeframe of 24 weeks from baseline. It does not report an outcome estimate or a statistical analysis for this measure. Accordingly, the design can be described, but the comparative outcome cannot be reconstructed from the available registry information.
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 | Aripiprazole | Ziprasidone |
|---|---|---|
| STARTED | 23 | 26 |
| COMPLETED | 23 | 26 |
| NOT COMPLETED | 0 | 0 |
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 | Aripiprazole | Ziprasidone | Total |
|---|---|---|---|---|
| Participants analysed | 23 | 26 | 49 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 23 | 26 | 49 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 44.3 (SD 8.5) | 45.5 (SD 9.4) | 44.9 (SD 8.95) |
| Sex: Female, Male: Female | Participants | 13 | 16 | 29 |
| Sex: Female, Male: Male | Participants | 10 | 10 | 20 |
| Region of Enrollment: United States | participants | 23 | 26 | 49 |
6. Primary Endpoint
The registry lists the primary outcome as HDL Ratio, measured over 24 weeks from Baseline.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Error |
| Unit | unit of Measure ''g/dL'' |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is described as change in HDL ratio after medication switch, assessed at 24 weeks from baseline. The record identifies the measure as a mean and gives its unit as g/dL. It does not explain the precise components or calculation of the HDL ratio, and that definition is not reported in the registry record. The registry also gives no group means, mean change, standard error, confidence interval, or test result for this endpoint.
The study summary places HDL within the metabolic-syndrome context: low HDL is one of the metabolic abnormalities it describes. In general, a continuous endpoint such as a laboratory measure can capture the degree of change rather than only whether a participant crossed a threshold. A mean summarizes the group’s central value, while a standard error describes the precision of an estimated mean. These are general statistical explanations; the record does not provide the actual estimates needed to apply them to this trial.
The endpoint is relevant to the stated metabolic focus, but it is not itself a complete measure of insulin resistance syndrome or of every metabolic outcome described in the study summary. The registry’s primary endpoint wording and broad study objective should therefore be read as related but not interchangeable. Without posted outcome results and a fuller measure definition, the direction and size of any group difference cannot be assessed.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive limitation is that the registry record lists the outcome but provides no numerical outcome comparison. The primary measure is change in HDL ratio at 24 weeks from baseline, yet no mean change, between-group difference, standard error, confidence interval, or p-value is reported. The record also lists no outcome analyses. Therefore, there is no posted estimate from which to describe the observed direction, magnitude, or precision of an aripiprazole-versus-ziprasidone difference on this endpoint.
A confidence interval, in general, shows a range of values compatible with the data and the statistical method used. Its width conveys precision: a wider interval indicates less precision than a narrower one. Since the registry record gives no interval or underlying outcome summary, the uncertainty around the treatment comparison cannot be evaluated. It would be inappropriate to infer a null result from the absence of an estimate; absence of a posted result is not the same as evidence that groups had the same outcome.
The randomized, parallel-group design describes how the comparison was intended to be organized, but randomization alone does not supply an outcome finding. The registry reports enrollment of 49, but does not report how many participants contributed data to the primary endpoint, whether participants discontinued, or whether the analysis followed the original assignment. Those omissions prevent assessment of the effective information available for the outcome and of potential effects of missing observations.
The study summary also states a broader objective involving mood stabilizers, antipsychotic drugs, and insulin resistance syndrome. The single endpoint description concerns change in HDL ratio after a switch between two antipsychotics. Since no outcome results are posted, the broader objective cannot be evaluated from the available comparison either. No conclusions about other metabolic components, mood stabilizers, or clinical outcomes can be drawn from the endpoint description alone.
The safety record does include event counts, but these are separate from the primary efficacy outcome. It lists no serious adverse events in either arm, and lists one other adverse event in the aripiprazole arm and none in the ziprasidone arm. These counts are descriptive. The record does not provide enough detail about event definitions, timing, attribution, or statistical comparison to interpret them as a comparative safety estimate.
Any planning illustrations displayed elsewhere on the page should be understood as hypothetical calculations based on stated assumptions, not as observed trial findings or observed power. The record does not report the trial’s own sample-size justification. Overall, the available registry information establishes the planned comparison and endpoint, but it does not provide the outcome evidence required to quantify or interpret an effect.
9. Statistical Methods Explained
What does randomization contribute?
In general, randomization assigns participants to study groups using a chance-based process. Its purpose is to reduce systematic differences between groups at the point of assignment, including differences that investigators may not have measured. It does not guarantee that the groups will be identical, especially in a study with a limited number of participants. Nor does randomization by itself show whether an outcome differed: that requires outcome data and an analysis.
This registry describes the study as randomized and parallel, with aripiprazole and ziprasidone arms. It does not describe the randomization sequence, how allocation was concealed, or whether assignment was stratified. Those details are not reported in the registry record. The record also says masking was absent. In general, lack of masking means participants or study personnel may know the assigned treatment; whether that knowledge affected measurement or follow-up cannot be determined from the information.
What kind of endpoint is listed?
The primary endpoint is a mean for a continuous measure: change in HDL ratio after medication switch, at 24 weeks from baseline. For a continuous outcome, an analysis may estimate group averages and compare them, or model the outcome while accounting for other variables. The registry record does not say which approach was used. It does not report an adjusted or unadjusted comparison, model specification, standard error, confidence interval, or p-value.
The record names standard error as the dispersion type for the primary measure, but gives no numerical standard error. In general, a standard error describes the variability of an estimated quantity across repeated samples under a statistical model; it is not the same thing as the spread of individual measurements. A confidence interval commonly uses an estimate and its standard error, together with a method and assumptions, to express uncertainty. No interval can be interpreted for this trial because the result is not reported.
Why can over-dispersion matter?
General statistical context: count outcomes are sometimes analyzed with models that assume a particular relationship between their mean and variability. If the observed variability exceeds that assumption, over-dispersion can make conventional standard errors too small and uncertainty appear lower than it is. This concept is relevant to some event-count analyses, but the primary endpoint is described as a continuous mean, not a count. The registry record does not report an over-dispersion assessment or a model for the primary endpoint, so no such method can be attributed to this trial.
What can planning calculations tell us?
General sample-size planning estimates how many participants might be needed to detect a specified effect under assumptions about the outcome, allocation, significance level, and analysis. A planning illustration based on an observed effect is not the same as the trial’s original design justification. It is also not observed power: observed power is not a substitute for interpreting the effect estimate and its uncertainty. The planning assumptions described for this page use a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect set as a stated fraction of the observed effect. These are planning conditions, not reported features of the trial’s own statistical plan. The trial’s sample-size justification is not reported in the registry record.
The enrollment count and the number needed in a hypothetical planning exercise answer different questions. Enrollment describes the number entered into the study, while a planning illustration describes a hypothetical requirement under its assumptions. Neither establishes how many participants had usable primary-outcome data. The registry record does not provide that analysis count or a primary-outcome result.
Why is no effect estimate shown?
The posted registry information identifies the primary measure and timeframe, but the outcome is not reduced to one comparison in the available record. The record indicates that the primary outcome has several categories or time points, and no outcome analyses are listed. Because no underlying comparison or estimate is available, there is no basis for recalculating a result from summary statistics. A recalculation would require posted summary values, and none are included.
These distinctions separate a design description from a statistical finding. The study has a randomized comparison and a specified primary endpoint, but no reported estimate with which to judge the direction, size, or precision of a difference. General statistical concepts can explain what such an estimate would mean; they cannot fill in the missing result.
10. Multiplicity, Missing Data and Analysis Populations
The registry record identifies one primary outcome measure, but also indicates that the primary outcome has several categories or time points and was not reduced to one comparison. The listed timeframe for the endpoint is 24 weeks from baseline. The record does not clarify how categories or time points were handled, which comparison was considered primary in the final analysis, or whether any hierarchy among analyses was specified. The multiplicity plan is not reported in the registry record.
In general, multiplicity arises when several statistical hypotheses are tested. Testing many hypotheses can increase the chance of at least one apparently notable result by chance, so a prespecified plan may define which tests are primary or adjust how results are interpreted. No adjustment method or prespecified testing strategy is reported. Since there are no posted outcome analyses, it is not possible to assess the consequences of multiple comparisons in this study.
The record does not report the extent of missing primary-outcome data, reasons for missingness, or methods for handling missing observations. It also does not describe whether the analysis used all randomized participants, only participants with available measurements, or another population. These analysis populations and missing-data methods are not reported in the registry record.
In general, missing data can affect an estimate when the participants with observed measurements differ from those without them in ways related to treatment or outcome. Statistical approaches make assumptions about the missingness process; those assumptions need to be described to assess an analysis. Here, neither the missingness pattern nor the analysis method is available. It is therefore not possible to determine whether missing data influenced the primary comparison.
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 |
|---|---|---|---|
| Aripiprazole | 0 | 23 | 0.0% |
| Ziprasidone | 0 | 26 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Aripiprazole | 0 of 23 |
| Ziprasidone | 0 of 26 |
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 |
|---|---|
| Aripiprazole | 1 of 23 |
| Ziprasidone | 0 of 26 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Aripiprazole | Ziprasidone |
|---|---|---|---|
| Worsening of psychiatric symptoms | Nervous system disorders | 1 of 23 | 0 of 26 |
The registry lists serious adverse events separately for the two arms. For aripiprazole, 23 participants were at risk for serious events and 0 were affected; for ziprasidone, 26 were at risk and 0 were affected. Deaths are listed as 0 in each arm. These are the posted counts, not a comparative statistical analysis.
For other adverse events, the record lists 1 affected participant among 23 at risk in the aripiprazole arm and 0 among 26 at risk in the ziprasidone arm. The registry does not provide event terms, severity details for these other events, timing, or attribution. It also does not report a statistical comparison of the counts. The record’s list of top serious event terms is empty.
In general, a count of zero observed events does not establish that the risk is absent; it describes what was recorded in the observed group. Such counts also do not by themselves show that one treatment is safer than another. The number of participants at risk, follow-up completeness, event definitions, and uncertainty around comparisons all matter. The registry record does not provide sufficient detail to evaluate those considerations beyond the counts shown.
12. What the Result Does, and Does Not, Mean
This record documents a randomized comparison of aripiprazole and ziprasidone in a study focused on metabolic outcomes associated with antipsychotic treatment. It names change in HDL ratio at 24 weeks from baseline as the primary endpoint. It also reports enrollment, study status, and limited adverse-event counts. These registry entries describe the trial’s structure and the information that appears in the registry.
They do not establish the size or direction of a difference between the treatment groups. No numerical primary-outcome result, uncertainty interval, or statistical test is reported. The absence of those results should not be read as proof that the treatments produced the same outcome, nor as evidence that one produced a better outcome. The comparative endpoint simply cannot be assessed from the available record.
The broader study objective includes mood stabilizers and insulin resistance syndrome, while the listed arms concern aripiprazole and ziprasidone. The primary outcome description concerns HDL ratio, which the study summary places among metabolic-syndrome measures. The record does not provide results for other metabolic measures or explain how the broader objective was analyzed. Conclusions about those wider questions would go beyond the reported information.
The safety counts are similarly limited. They show no serious adverse events recorded in either arm, and one other adverse event in the aripiprazole arm compared with none in the ziprasidone arm. Without fuller event descriptions, follow-up information, and a comparative analysis, those counts cannot establish a difference in safety.
In general, a clinical trial’s interpretation depends not only on its design but also on its estimated effects, uncertainty, analysis population, and completeness of follow-up. Here, the registry provides the design and endpoint description but not the primary statistical results or many analysis details. The appropriate reading is therefore narrow: the study was registered as a randomized, unmasked, parallel comparison, but the posted record does not allow a quantitative conclusion about its primary outcome.
13. Why This Trial Matters Statistically
This trial is statistically instructive because it illustrates the difference between a registered question and a reported answer. The record names a randomized comparison, a primary metabolic endpoint, and a follow-up timeframe. Those details identify what the study was set up to examine. Without an outcome estimate, however, they do not show what the comparison found.
That distinction is important when readers encounter study descriptions alongside tables, plots, or planning material. A planned endpoint is not an observed result. A sample-size planning illustration is not a substitute for an effect estimate, and it should not be described as observed power. Interpretation requires the result itself and information about its precision, along with a clear account of the participants included in the analysis.
The record also makes clear why endpoint definition matters. The study summary discusses insulin resistance syndrome and several metabolic abnormalities, while the primary measure is described as change in HDL ratio. A single endpoint can address a focused part of a broader scientific question, but it cannot automatically stand in for every component of that question. The record does not give enough detail to determine how the broader objectives were assessed.
Finally, safety counts and efficacy outcomes answer different questions. The posted adverse-event figures are descriptive and do not provide a comparative statistical estimate. Keeping these evidence types distinct prevents readers from treating sparse event counts as a full safety analysis or treating the absence of a posted efficacy result as a null finding. The record is useful for understanding design and reporting limits, but not for quantifying the primary treatment comparison.
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 main trial-specific limitation for interpretation is that no numerical primary-outcome results are reported. Although the endpoint is identified as change in HDL ratio at 24 weeks from baseline, there is no group estimate, between-group contrast, standard error, confidence interval, or test result. The record also lists no outcome analyses.
The endpoint itself is not fully defined. The record gives the measure name as HDL ratio and lists the unit as g/dL, but does not explain how the ratio is calculated or what components it includes. The registry’s outcome description also indicates several categories or time points without reducing them to one comparison, leaving the relationship between the listed 24-week timeframe and the broader outcome structure unclear.
The record describes randomization and no masking, but does not report allocation procedures, baseline characteristics, adherence, treatment discontinuation, or the number included in the primary analysis. It also does not report missing-data methods, analysis populations, or the statistical model. These omissions limit assessment of how the planned comparison was carried out and how robust an eventual estimate would be.
The study summary describes a broader objective involving mood stabilizers and metabolic syndrome, but the listed intervention arms and primary endpoint do not provide results for all aspects of that objective. Detailed eligibility criteria, the handling of clinical contraindications to switching, and the original sample-size justification are not reported in the registry record.
Safety reporting is limited to counts. Event descriptions, timing, attribution, and a comparative safety analysis are not reported. These constraints mean the record supports a description of the study and its reported event counts, but not a comprehensive assessment of efficacy or safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Anticonvulsant Mood Stabilizers, Antipsychotic Drugs and the Insulin Resistance Syndrome — NCT00288366.
- Registry record last updated 2019-08-06; status last verified 2019-07.
- Results first posted 2019-08-06.
- 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.
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18. Record Summary
The registry describes NCT00288366, titled “Anticonvulsant Mood Stabilizers, Antipsychotic Drugs and the Insulin Resistance Syndrome.” It is listed as a completed, randomized, unmasked, parallel-group study sponsored by Northwestern University, with enrollment of 49. The recorded start is 2006-01 and primary completion is 2008-12; phase is listed as not applicable.
The named arms are aripiprazole and ziprasidone. The primary outcome is mean change in HDL ratio after medication switch at 24 weeks from baseline. The record includes limited adverse-event counts but no numerical primary-outcome analysis. The study’s statistical analysis plan, sample-size justification, missing-data approach, analysis population, and outcome estimates are not reported in the registry record.