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 Topiramate in the Treatment of Pathological Gambling (NCT00245583), a randomized phase 3 study. The primary outcome is Obsession Component of the Yale-Brown Obsessive-Compulsive Scale for Pathological Gambling (PG-YBOCS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00245583 |
| Phase | Phase 3 |
| Condition | Pathological Gambling |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 42 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Icahn School of Medicine at Mount Sinai |
| Results posted | Yes |
2. Clinical Question
Population
People with pathological gambling were the intended study population. The registry record describes the condition as involving difficulty resisting gambling impulses and disruption to personal, family, social, financial, or occupational functioning. It lists enrollment as 42, but does not report further eligibility criteria or a fuller description of the enrolled participants.
Intervention
The intervention was topiramate, with the arm description specifying a daily dose from 25mg to 300mg. The record does not report how doses were selected or adjusted for individual participants.
Comparator
The comparator was placebo, described as placebo-equivalent tablets. The trial is registered as randomized, double-blind, and parallel-group. The record does not explain the allocation procedure or the specific masking procedures.
Primary question
The registered primary outcome was the Obsession Component of the Yale-Brown Obsessive-Compulsive Scale for Pathological Gambling, or PG-YBOCS. The record describes the measure and lists its timeframe as Baseline, but does not report outcome values or a treatment comparison. It therefore does not allow a conclusion about how the groups differed on this endpoint.
3. Trial Design
This was a Phase 3, randomized, double-blind, parallel-group study comparing topiramate with placebo for pathological gambling. The registry lists enrollment as 42 and identifies Icahn School of Medicine at Mount Sinai as the sponsor. Its status is Terminated. The recorded study start is 2005-10 and the primary completion date is 2009-05.
The topiramate arm is described as receiving a daily dose from 25mg to 300mg; the placebo arm received placebo-equivalent tablets. Flexible dosing appears in the official study title, but the registry record does not describe the dose-adjustment process, treatment duration, visit schedule, allocation method, or masking procedures. Those details should not be inferred from the design labels alone.
The record lists the PG-YBOCS obsession component as the primary outcome and names several secondary measures, including the Gambling-Symptom Assessment Scale Total Score, Barratt Impulsiveness Scale-11, Young Mania Rating Scale, Montgomery-Asberg Depression Rating Scale, and Hamilton Anxiety Rating Scale. Barratt Impulsiveness Scale-11 appears twice in the listed secondary outcomes. The registry lists 8 outcome measures, but does not give a complete account of how each was measured or analyzed.
Although the study is marked Terminated, the reason for termination is not reported in the registry record. The record also does not explain whether termination affected enrollment, follow-up, or the planned analyses. The status alone does not establish why the trial ended or what conclusions can be drawn about treatment effects.
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.
Before assignment: Subjects were randomized in a 1:1 ratio to topiramate or placebo treatment. Following the baseline visit, participants underwent a 6-week titration period to 300mg/day or the maximum tolerated dose, followed by an 8-week maintenance. At the conclusion of the 14-weeks, study medication was tapered over a 7-day period.
Overall Study
| Stage | Topiramate | Placebo |
|---|---|---|
| STARTED | 20 | 22 |
| COMPLETED | 14 | 13 |
| NOT COMPLETED | 6 | 9 |
Reasons for not completing this period:
| Reason | Topiramate | Placebo |
|---|---|---|
| Lost to Follow-up | 1 | 5 |
| Adverse Event | 2 | 1 |
| Lack of Efficacy | 1 | 0 |
| Withdrawal by Subject | 2 | 3 |
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: Pathological Gamblers meeting criteria
| Characteristic | Unit | Topiramate | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 20 | 22 | 42 | |
| Age, Continuous | years | 50.45 (SD 10.44) | 44.91 (SD 8.01) | 47.5 (SD 9.5) |
| Sex: Female, Male: Female | Participants | 8 | 15 | 23 |
| Sex: Female, Male: Male | Participants | 12 | 7 | 19 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 7 | 5 | 12 |
| Race (NIH/OMB): White | Participants | 11 | 16 | 27 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 2 | 1 | 3 |
| Smoking: Smoker | participants | 8 | 15 | 23 |
| Smoking: Non-smoker | participants | 12 | 7 | 19 |
6. Primary Endpoint
The registry lists the primary outcome as Obsession Component of the Yale-Brown Obsessive-Compulsive Scale for Pathological Gambling (PG-YBOCS), measured over Baseline.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the obsession component of the PG-YBOCS, a clinician-rated measure adapted for pathological gambling. The registry describes it as assessing symptoms such as thoughts and urges related to gambling. Each item is rated from 0, indicating no symptoms, to 4, indicating extreme symptoms. The obsession and compulsion components each range from 0 to 20, and the combined total possible score ranges from 0 to 40; higher scores indicate more symptoms.
A symptom scale can make clinical features more structured and measurable than an unstandardized judgment. The registry states that the PG-YBOCS has been shown to be reliable and valid and to correlate with global severity and South Oaks Gambling Screen scores. These are descriptions of the instrument in the record, not findings from this trial.
The registered timeframe for this primary measure is Baseline. Although the scale description refers to measuring severity and change in severity, the registry does not provide a follow-up timepoint, group means, variability, or an estimate of change for the primary outcome. It is therefore not possible to determine from the record how endpoint values were compared or what the results were.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record identifies a randomized comparison of topiramate and placebo, but it does not report a numerical result for the primary endpoint. There are no arm-level PG-YBOCS values, measures of uncertainty, or reported treatment-effect estimate in the registry record. The primary outcome entry identifies the measure and lists its timeframe as Baseline; it does not establish a result at a later assessment or a difference between study groups.
The outcome list and the outcome findings are not interchangeable. Listing a scale indicates that it was registered as an outcome, but does not show what participants scored, how scores changed, or how the groups compared. The registry record does not report results for the secondary measures either. It lists 8 outcome measures and identifies several scales, but does not give numerical outcome estimates for them.
Randomization and double masking describe aspects of the intended design. In general, random allocation can reduce systematic differences between groups at assignment, while masking can reduce some influences on treatment delivery or outcome assessment. These design features do not substitute for results, and the registry record does not detail the procedures used to implement them. Nor does it report whether the intended allocation and masking were maintained.
The status is Terminated, but the reason is not reported in the registry record. Termination does not by itself establish whether the study ended early, whether the planned enrollment was reached, or whether the termination was related to results, recruitment, or another circumstance. The registry lists enrollment as 42, but does not explain how that figure relates to the termination status or to the numbers assessed for each outcome.
Accordingly, the posted information supports a description of the trial design, planned measures, and recorded adverse-event counts. It does not support an estimate of the primary treatment effect, an assessment of its precision, or a conclusion about whether the groups differed. Any planning illustrations based on an observed effect should be understood as planning calculations under stated assumptions, not as evidence of the treatment effect or of power achieved in this trial.
9. Statistical Methods Explained
Statistical methods describe how outcomes are converted into estimates and how uncertainty is assessed. The registry record does not report the statistical analysis plan or a primary outcome analysis. The explanations below are general and should not be mistaken for procedures confirmed in this study.
What does a group mean describe?
For a continuous measure such as a symptom score, a mean describes the average score among the observations included in the calculation. A standard deviation describes how spread out individual observations are around that mean. They answer different questions: the mean summarizes the group’s central score, while the standard deviation characterizes participant-level variation. The registry identifies the primary outcome parameter as a mean and its dispersion as a standard deviation, but supplies no corresponding outcome values.
What would a treatment comparison estimate?
A comparison of group means would quantify how the average scores differ between the topiramate and placebo groups at a specified assessment, or how their changes differ if change from baseline were analyzed. These are not equivalent estimands: comparing endpoint scores and comparing changes rely on different outcome definitions. The registry does not report which comparison was used, whether baseline scores were incorporated into an adjusted model, or what timepoint beyond the listed Baseline timeframe was analyzed. No comparison should be attributed to the investigators without that information.
How should uncertainty be read?
In general, a confidence interval gives a range of values compatible with the data and the method used, reflecting sampling uncertainty under that method’s assumptions. A narrow interval indicates greater precision than a wide interval, but neither an interval nor a point estimate alone establishes clinical importance. A p-value, when reported, is a measure of how compatible the data are with a specified null model; it is not the probability that the null hypothesis is true. Neither a confidence interval nor a p-value for the primary comparison is reported in the registry record.
What do the planning assumptions mean?
The planning illustration assumptions describe a two-sided significance level of 0.05, equal allocation between the arms, and a normal approximation. The illustration is based on a fraction of the observed effect, rather than being identified as the trial’s original design calculation. Such calculations answer a conditional planning question: how many participants per arm would be needed under those assumptions to target a chosen power for a specified effect. They are not observed power, do not show how many participants the trial actually needed, and do not establish the effect that would occur in a future study. The registry record does not report the original sample-size justification or the trial’s own design calculation.
Why can over-dispersion matter?
General statistical note: over-dispersion occurs when outcome variability is greater than a model assumes. If a model understates variability, its uncertainty estimates may be too small, making results appear more precise than they are. The relevance of over-dispersion depends on the outcome and model. The primary measure is described as a continuous score, and the registry does not report a model or a diagnostic assessment of dispersion. There is no basis in the record to say that over-dispersion was present or that a particular correction was used.
What can be inferred from the analysis record?
The registry lists 0 analyses. This means the record does not present a reported analysis entry to interpret; it does not establish what analyses may have been conducted outside the registry. Statistical methods such as covariate adjustment, handling of repeated assessments, or correction for multiple comparisons are not reported in the registry record. The reported outcome descriptions should therefore be read as registered measurement information, not as a complete statistical analysis.
10. Multiplicity, Missing Data and Analysis Populations
Multiplicity arises when several outcomes, timepoints, or statistical comparisons are examined. If many hypotheses are tested, the chance of at least one apparently notable result can increase unless the analysis plan accounts for that. In general, researchers may define a primary comparison in advance, use a correction, or describe secondary analyses as exploratory. The registry record lists a primary outcome and multiple secondary measures, but does not report a multiplicity strategy or the tests performed.
The secondary-outcome list includes the Barratt Impulsiveness Scale-11 twice. The record does not explain whether this reflects distinct assessments, duplicate registration, or another distinction. It also lists 8 outcome measures, without presenting a complete analysis-by-outcome account. The number of analyses listed is 0, and statistical analyses are not reported in the registry record. No claim about adjustment for multiple testing can be made.
Missing-data handling is not reported in the registry record. It does not state how many participants contributed data to each outcome, why observations may have been missing, whether any imputation was used, or whether a sensitivity analysis was conducted. The enrollment figure alone cannot establish how complete outcome follow-up was.
Analysis populations are also not described. The record does not say whether analyses followed randomized assignment, included only participants who completed treatment, or used another population definition. These choices can affect interpretation, particularly when a trial is terminated or outcome data are incomplete. The registry does not report enough information to assess their impact in this study.
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 |
|---|---|---|---|
| Topiramate | 0 | 20 | 0.0% |
| Placebo | 0 | 22 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Topiramate | 0 of 20 |
| Placebo | 0 of 22 |
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 |
|---|---|
| Topiramate | 7 of 20 |
| Placebo | 11 of 22 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Topiramate | Placebo |
|---|---|---|---|
| Nausea | Gastrointestinal disorders | 3 of 20 | 4 of 22 |
| Headache | General disorders | 2 of 20 | 3 of 22 |
| Tiredness | General disorders | 1 of 20 | 2 of 22 |
| Shoulder Pain | Musculoskeletal and connective tissue disorders | 1 of 20 | 2 of 22 |
The adverse-event entries list 0 serious adverse events in the topiramate group and 0 in the placebo group. For other adverse events, the registry lists 7 affected among 20 at risk in the topiramate group and 11 affected among 22 at risk in the placebo group. Deaths are listed as 0 in both groups. These are the recorded counts; they do not include a statistical comparison or an uncertainty estimate.
Serious adverse events and other adverse events are separate categories in the record. The absence of recorded serious events does not show that no adverse effects of any kind occurred, since the record lists other affected participants. The entries also do not describe event types, severity, timing, or whether an event was considered related to treatment. The list of top serious terms is empty.
These counts should be interpreted as descriptive registry data, not as proof of a safety difference or equivalence between groups. The record does not report a safety analysis plan, the duration of adverse-event monitoring, or how events were solicited and classified. No medical advice or treatment conclusion follows from these entries.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a randomized, double-blind, placebo-controlled, parallel-group Phase 3 study of topiramate for pathological gambling was registered, with enrollment listed as 42 and status marked Terminated. It identifies the PG-YBOCS obsession component as the primary outcome and names secondary symptom and mood measures. It also records adverse-event counts for the two groups.
The record does not report the primary outcome results, secondary outcome results, treatment-effect estimates, confidence intervals, or statistical tests. Consequently, it cannot show from the posted results whether scores differed between groups, how large any difference was, or how precise an estimate might be. The outcome description and scale properties do not stand in for the trial’s results.
Likewise, the adverse-event counts are not a complete safety assessment. The record provides no event descriptions or comparative analysis, and zero recorded serious events does not mean that no other adverse events were recorded. The counts can be stated as recorded, but their context and uncertainty are not reported.
Planning illustrations, if considered, address hypothetical sample-size requirements under stated assumptions. They are not observed power and do not repair missing outcome results. The registry does not report the trial’s original sample-size justification, detailed statistical plan, reasons for termination, missing-data procedures, or analysis populations.
The defensible interpretation is therefore limited: the record describes the study’s registered design, measures, status, and selected safety counts, while leaving the clinical outcome comparison unreported. Neither a positive nor a negative treatment conclusion can be drawn from the available registry entries.
13. Why This Trial Matters Statistically
This trial is statistically notable because the registry record describes a randomized, double-blind comparison but does not report the primary outcome analysis. The contrast between a registered endpoint and absent outcome estimates illustrates why registration details and results serve different purposes. Design information explains what a study set out to compare; an analysis is needed to estimate what the data show and how uncertain that estimate is.
The primary outcome is a continuous clinician-rated symptom score, for which interpretation would ordinarily depend on group summaries, a clearly defined comparison, and some measure of uncertainty. Without those results, neither magnitude nor precision can be evaluated. The measure’s scoring range and description do not tell readers what scores participants achieved.
The trial also lists several secondary measures. When outcomes multiply, transparent reporting of the prespecified hierarchy, timepoints, and multiplicity approach helps readers distinguish confirmatory results from exploratory findings. Those analysis details are not reported in the registry record. The duplicate listing of Barratt Impulsiveness Scale-11 further highlights why outcome labels and assessment details need clear documentation.
Finally, the Terminated status and the absence of an analysis entry limit interpretation of the trial’s progress and findings. Termination does not itself explain what happened, and a planning illustration is not a substitute for a completed treatment-effect analysis. The record is useful for identifying the intended comparison and the information that remains unavailable; it cannot establish a treatment effect.
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 limitation for interpreting efficacy is that the registry record does not report results for the primary endpoint. It gives no arm-level scores, changes, effect estimate, or measure of uncertainty. The timeframe is listed as Baseline, and the record does not identify a follow-up comparison for this outcome.
The registry marks the study Terminated, but the reason is not reported in the registry record. The record does not explain the relationship between termination, enrollment, follow-up, and analysis completion. Enrollment is listed as 42, but this does not establish the number contributing data to any particular outcome.
Important design and analysis details are absent, including eligibility criteria, allocation procedures, dose-adjustment details, treatment duration, assessment schedule, the statistical analysis plan, missing-data handling, and analysis populations. Multiplicity procedures and the rationale for the duplicated secondary-outcome listing are not reported either. These omissions make it difficult to assess the planned and implemented analyses.
The adverse-event entries are limited to counts and at-risk figures. Event names, severity, timing, relatedness, and the monitoring approach are not described. The record therefore cannot support a detailed comparative safety assessment.
These limitations concern what the registry record contains. They do not establish that information was never collected or analyzed elsewhere, and they do not explain why it is absent from this record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Topiramate in the Treatment of Pathological Gambling — NCT00245583.
- Registry record last updated 2019-07-02; status last verified 2019-07.
- Results first posted 2019-07-02.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The record describes a Phase 3, randomized, double-blind, parallel-group study of topiramate versus placebo for pathological gambling. Enrollment is listed as 42; the status is Terminated. The sponsor is Icahn School of Medicine at Mount Sinai. The recorded start is 2005-10 and primary completion is 2009-05.
The primary outcome is the PG-YBOCS obsession component, with Baseline listed as its timeframe. The record names secondary symptom and mood scales but does not report outcome results or statistical analyses. It lists 0 analyses. The reason for termination, missing-data procedures, analysis populations, and statistical plan are not reported in the registry record.
Safety entries list 0 serious adverse events and 0 deaths in each group, alongside other adverse-event counts. These entries are descriptive and do not include a comparative analysis. The registry record supports a description of the design and reported counts, but not a conclusion about efficacy or comparative safety.