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 Acceptability of Pharmacologic Treatment for Methamphetamine Dependence Among MSM (NCT00318409), a randomized phase 2 study. The primary outcome is Feasibility: Proportion of Scheduled Study Visits Completed.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00318409 |
| Phase | Phase 2 |
| Condition | Substance Abuse, HIV Infections |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 30 |
| Arms in the primary outcome | 2 |
| Lead sponsor | San Francisco Department of Public Health |
| Results posted | Yes |
2. Clinical Question
Population
The trial concerned men who have sex with men with methamphetamine dependence. The registry describes the study as a pilot focused on the feasibility of enrolling and retaining participants in a medication study, and on measuring medication tolerability and adherence. It also lists substance abuse and HIV infections among the conditions. Further eligibility criteria and participant characteristics are not reported in the registry record.
Intervention
The intervention was bupropion XL 300mg daily. The study was intended to assess whether a pharmacologic study could be conducted with this population, including whether participants could attend scheduled visits and whether medication tolerability and adherence could be measured. Results for medication adherence and tolerability are not reported in the registry record.
Comparator
The comparator was placebo 300mg daily. The registry describes randomized allocation, quadruple masking, and a parallel design. The posted arm counts are 20 for bupropion and 10 for placebo. Details about how randomization was generated or how masking was implemented are not reported in the registry record.
Primary question
The primary outcome was feasibility, expressed as the proportion of scheduled study visits completed during 12 weeks. The posted outcome values are counts of completed visits: 185 in the bupropion arm and 96 in the placebo arm. The number of visits scheduled in either arm is not reported in the registry record, so the posted counts cannot be interpreted as proportions. A two-arm comparison is not estimable from the posted information.
3. Trial Design
This was a randomized, quadruple-masked, parallel phase 2 pilot study of bupropion versus placebo. The registry lists enrollment as 30. The posted arm counts are 20 for bupropion and 10 for placebo. The study status is completed. Its start is recorded as 2006-09 and its primary completion as 2007-11. The sponsor is the San Francisco Department of Public Health.
The registry frames the study as an investigation of the feasibility and acceptability of conducting a pharmacologic intervention study among men who have sex with men with methamphetamine dependence. Its stated aims include enrolling and retaining participants, and measuring medication tolerability and adherence. The background rationale describes an association between methamphetamine use and high-risk sexual behavior among this population, with concern about HIV transmission or acquisition. That rationale provides context for the pilot; it is not an outcome result from the trial.
The intervention was bupropion XL 300mg daily, and the comparator was placebo 300mg daily. The primary outcome concerned scheduled study visits completed over 12 weeks. The registry labels the endpoint as a proportion, but the posted results are counts of completed visits. Scheduled-visit denominators are not reported in the registry record. Thus, the posted results do not supply the information needed to calculate the proportion in either arm or to compare those proportions.
Randomization and masking describe intended features of the design, but the record does not report the allocation sequence, concealment procedures, or who was masked. Detailed eligibility criteria, participant characteristics, and the protocol for visit scheduling are also not reported in the registry record. These omissions limit how fully the conduct and applicability of the pilot can be assessed from the registry entry alone.
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: After informed consent, participants were screened in two screening visits, with lab and HIV testing, medical history and physical exam, and urine meth testing.
Overall Study
| Stage | Bupropion | Placebo |
|---|---|---|
| STARTED | 20 | 10 |
| COMPLETED | 18 | 9 |
| NOT COMPLETED | 2 | 1 |
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 | Bupropion | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 20 | 10 | 30 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 20 | 10 | 30 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Male | Participants | 20 | 10 | 30 |
6. Primary Endpoint
The registry lists the primary outcome as Feasibility: Proportion of Scheduled Study Visits Completed, measured over 12 weeks.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Scheduled study visits completed |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “Feasibility: Proportion of Scheduled Study Visits Completed” and has a 12-week timeframe. Visit completion is a practical feasibility measure: it indicates whether participants attend the study visits that the protocol schedules. In a pilot whose stated purpose includes assessing whether participants can be enrolled and retained, attendance can provide relevant evidence about the demands of study participation.
The registry reports the endpoint as a number of scheduled study visits completed, rather than as a proportion. The posted value is 185 for bupropion and 96 for placebo. These are counts, not rates. To interpret them as proportions, the total number of visits scheduled in each arm would also be needed. Those denominators are not reported in the registry record. The counts therefore do not establish the fraction of scheduled visits completed in either arm, and they do not by themselves support a comparison of visit-completion proportions.
Visit attendance is distinct from medication adherence, medication tolerability, or a reduction in methamphetamine use. Those topics appear in the study rationale, but corresponding results are not reported in the registry record. The endpoint should be read as a measure of study-visit completion, not as a direct measure of clinical benefit.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary outcome results are counts of completed scheduled study visits: 185 in the bupropion arm and 96 in the placebo arm. The registry lists 20 participants in the bupropion arm and 10 in the placebo arm. Because the number of visits scheduled per arm is not reported, these counts cannot be converted into the stated proportions. Nor can they show what share of scheduled visits was completed in either group.
The registry record indicates that a two-arm comparison is not estimable from the posted information. This is important for interpretation: the raw counts are not an estimate of the difference in visit-completion proportions. They also should not be treated as comparable rates simply because both arms are reported using the same endpoint label. The arm counts differ, and the scheduled-visit denominators are unavailable. No unadjusted or adjusted contrast, confidence interval, or p-value is reported for this outcome.
The posted results are consequently limited as evidence about the primary feasibility question. They document completed-visit counts, but do not show the proportion completed or quantify the uncertainty around such proportions. The registry also does not report visit-level data, reasons for missed visits, or whether participants who stopped attending differed from those who remained. Without such information, the counts cannot explain patterns of retention or attendance.
The study is identified as a pilot, and its stated aims extend beyond visit attendance to enrollment, retention, tolerability, and adherence. The posted primary result alone does not establish findings for those other aims. Results for medication adherence and tolerability are not reported in the registry record. Although the record lists eight outcome measures, it does not provide secondary results in the information summarized for this trial.
The result should not be read as evidence that bupropion improved or reduced feasibility relative to placebo. The raw counts do not establish that conclusion, and no comparative estimate is available. The registry records no affected participants for serious adverse events in either arm, while other adverse-event counts are also posted. Those safety figures describe reported events; they do not resolve the limitations of the primary endpoint or establish treatment benefit.
In short, the registry documents that visits were completed in both groups, but the primary endpoint is not interpretable as a proportion from the posted information. A reliable comparison would require the scheduled-visit denominator for each arm and an analysis that accounts for the structure of the data. Such details and a sponsor-reported comparative analysis are not reported in the registry record.
9. Statistical Methods Explained
The registry identifies the primary outcome as a count-type measure: the number of scheduled study visits completed. The outcome title uses the word “proportion,” but the posted values are counts. That distinction matters because a count records how many events occurred, whereas a proportion expresses a count relative to a defined denominator. For this endpoint, the relevant denominator would be the number of visits scheduled in each arm. Those denominators are not reported in the registry record.
Why the denominator matters
General statistical explanation: a count cannot be interpreted as a completion rate without knowing the number of opportunities for completion. If different participants have different numbers of scheduled visits, or if the number scheduled varies between arms, a total count alone does not describe the share completed. The posted visit counts therefore do not tell how consistently participants attended relative to their own scheduled visits.
The arm-level values are 185 completed visits for bupropion and 96 for placebo. These values are not percentages, and they are not adjusted for the number of participants or visits scheduled. The registry’s stated outcome unit and the posted numerical parameter do not supply a denominator. Consequently, no arm-specific proportion or between-arm difference in proportions is reported or calculable from the posted summary information.
What a comparison would require
General statistical explanation: a comparative analysis needs an outcome definition that can be evaluated consistently in each group, along with the information needed to estimate uncertainty. For visit completion, this could involve participant-level completion patterns or appropriate arm-level counts of completed and scheduled visits. The analysis would also need to address how repeated visits from the same participant are handled, since visits from one person may be related rather than independent observations.
The registry notes that values are missing or not estimable for a two-arm comparison for this count-type endpoint. It does not post a contrast, confidence interval, or p-value. A confidence interval, as a general concept, describes the precision of an estimated effect under a specified statistical model. Without a reported comparative estimate, there is no interval available to assess the precision of a treatment contrast. The record also does not report the model or other statistical procedures used for this endpoint.
Repeated observations and variability
General statistical explanation: visit counts can have more variability than a simple model assumes, especially when the number of events varies substantially among participants or when participants’ outcomes are correlated across visits. Over-dispersion refers to variability greater than expected under a model’s assumptions. If present, it can make conventional uncertainty estimates too small unless the analysis accounts for it. The registry record does not report a dispersion estimate, a model for repeated visits, or a method for assessing over-dispersion. No claim can therefore be made about whether these issues were examined.
The registry records the primary outcome as a number, but does not state whether the analysis used participant-level data, arm totals, or another approach. It also does not report handling of missed visits, incomplete follow-up, or participants with no completed visits. These choices can affect estimates of attendance and their uncertainty. They are not recoverable from the posted arm totals.
Planning illustrations and power
The sample-size planning assumptions described for the illustrations use a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation; the effect to detect is defined as a stated fraction of the observed effect. These are planning assumptions, not a report of the trial’s own design justification. The resulting sample-size values are not reported in the registry record. Any such planning illustration is not observed power and should not be interpreted as a retrospective measure of the trial’s ability to detect an effect.
General statistical explanation: a sample-size calculation depends on assumptions about the target effect, variability, outcome distribution, allocation, and analysis. If an observed effect is used for a planning illustration, the result describes a hypothetical future design under those assumptions. It does not show that the current study had a particular probability of finding a statistically significant result. The registry record does not report a prospective sample-size justification or a statistical analysis plan.
What can be concluded statistically
The posted summaries support a descriptive statement that the arms had the reported counts of completed visits. They do not support an estimate of completion proportions, a comparative treatment effect, or its precision. This distinction is especially important for a feasibility endpoint: a count can be useful as a record of activity, but it is not sufficient to quantify attendance relative to the schedule. The registry record does not report the additional denominator or analysis details needed for that interpretation.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists eight outcome measures and one analysis, while no secondary results are posted in the record summarized for this trial. It does not report a multiplicity strategy, such as whether outcomes were prioritized, whether statistical testing was adjusted for multiple comparisons, or whether any analyses were considered exploratory. The presence of multiple outcome measures does not by itself establish that multiple statistical tests were conducted.
Missing-data methods are not reported in the registry record. In particular, the record does not explain how missed visits, withdrawal, incomplete follow-up, or unavailable outcome measurements were handled. This matters for a visit-completion endpoint because the scheduled-visit denominator and the disposition of missed visits are central to interpreting a completion proportion. The available arm-level counts do not describe those details.
Analysis populations are also not reported in the registry record. It is not stated whether the analysis included everyone randomized, only participants with follow-up information, or another defined group. The posted arm counts are given, but the record does not describe the population used to produce the outcome values or whether the arm counts refer to the same analysis population as the enrollment figures.
No inferential comparison for the primary outcome is reported. With no reported analysis population, missing-data approach, scheduled-visit denominators, or multiplicity plan, the precision and robustness of any treatment contrast cannot be assessed. These are reporting gaps, not evidence that particular methods were or were not used.
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 |
|---|---|---|---|
| Bupropion | 0 | 20 | 0.0% |
| Placebo | 0 | 10 | 0.0% |
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 |
|---|---|
| Bupropion | 17 of 20 |
| Placebo | 6 of 10 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Bupropion | Placebo |
|---|---|---|---|
| Increased ALT | Hepatobiliary disorders | 4 of 20 | 2 of 10 |
| Increased AST | Hepatobiliary disorders | 3 of 20 | 2 of 10 |
| Soft tissue infection | Infections and infestations | 4 of 20 | 0 of 10 |
| Upper respiratory infection | Respiratory, thoracic and mediastinal disorders | 2 of 20 | 2 of 10 |
| Gastroenteritis | Gastrointestinal disorders | 3 of 20 | 0 of 10 |
| Increased creatinine | Renal and urinary disorders | 3 of 20 | 0 of 10 |
| Sleep Disturbances | General disorders | 2 of 20 | 1 of 10 |
| Sexually transmitted infection | Infections and infestations | 1 of 20 | 1 of 10 |
| Hyperbilirubinemia | Hepatobiliary disorders | 2 of 20 | 0 of 10 |
| Hyponatremia | Metabolism and nutrition disorders | 1 of 20 | 1 of 10 |
The registry reports zero participants affected by serious adverse events in the bupropion arm, with 20 at risk, and zero affected in the placebo arm, with 10 at risk. These are the posted serious-event figures. No top serious-event terms are listed. Death counts are not reported in the registry record.
For other adverse events, the record reports 17 affected participants in the bupropion arm, with 20 at risk, and 6 affected participants in the placebo arm, with 10 at risk. The registry does not provide event-specific details in the information available for these summaries, so the counts should not be used to infer which events occurred, their severity, or their timing.
These figures are descriptive safety reports, not a formal comparison of risk. The record does not report comparative estimates or uncertainty for adverse events. The zero serious-event counts should be read as the recorded counts for the reported arms, not as proof that serious events are impossible or that the treatments have equivalent safety.
12. What the Result Does, and Does Not, Mean
The result documents completed study visits in both randomized arms: 185 in the bupropion arm and 96 in the placebo arm. That is the direct descriptive finding available for the primary outcome. The registry calls the endpoint a proportion, but does not report the scheduled-visit denominators needed to interpret these counts as proportions. A two-arm comparison is not estimable from the posted information.
The counts therefore do not establish which arm had a higher visit-completion proportion, nor do they quantify the size or precision of a difference. They should not be treated as evidence that bupropion improved or worsened study feasibility relative to placebo. The reported arm sizes do not replace the missing denominator of scheduled visits, and no inferential analysis for this endpoint is posted.
The trial’s stated purpose was to examine the feasibility of conducting a pharmacologic study in this population, including enrollment and retention, and to measure medication tolerability and adherence. The posted primary result addresses completed visits only. Results for medication adherence and tolerability are not reported in the registry record. The record also does not provide the information needed to assess reasons for missed visits or patterns of retention.
This is a pilot study, and the available registry results are not a clinical efficacy finding. Visit completion is a measure of participation in the study, not a direct measure of methamphetamine use, sexual behavior, HIV outcomes, or clinical benefit. No conclusion about those outcomes follows from the posted visit counts.
The serious adverse-event summaries record zero affected participants in both arms, and other adverse-event counts are reported. These summaries are limited descriptive information; they do not establish equivalence in safety or settle the feasibility question. Overall, the registry provides a record of visit counts and adverse-event counts but not the denominators, comparative analyses, or additional outcome results needed for broader conclusions.
13. Why This Trial Matters Statistically
This trial illustrates a basic statistical distinction between an outcome’s label and the information needed to interpret its reported value. The primary endpoint is described as a proportion of scheduled visits completed, but the posted values are counts. Without the number of visits scheduled in each arm, the counts cannot answer the proportion question. A descriptive total may document activity while still being insufficient for the planned interpretation.
The distinction is particularly relevant in feasibility studies. Attendance and retention can be important operational outcomes, but their meaning depends on a clear definition of the opportunity to attend and on transparent handling of missed visits and incomplete follow-up. The record’s visit counts do not show whether participants had the same number of scheduled visits or how missed visits were treated. This limits comparison and makes the missing denominator consequential rather than merely technical.
The entry also shows why a randomized design does not guarantee that a comparative result can be estimated from the registry summary. Randomization describes the design, but a comparative estimate still depends on the outcome data and analysis being reported. Here, the registry states that a two-arm comparison is not estimable for the primary count outcome. The randomized assignment alone cannot turn arm totals into completion proportions.
Finally, the pilot’s aims include enrollment, retention, tolerability, and adherence, yet the available results are narrow. Reading those aims separately from the outcomes actually reported helps prevent a feasibility count from being mistaken for a treatment effect or a complete assessment of study conduct. The record is most informative when the limits of the posted endpoint and its reporting are kept explicit.
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 primary limitation is that the outcome is labeled as a proportion but reported as counts of completed visits. Scheduled-visit denominators are not reported in the registry record, preventing calculation or interpretation of arm-specific completion proportions. The registry also indicates that a two-arm comparison is not estimable. No comparative estimate, confidence interval, or p-value is reported.
The record does not describe how visits were scheduled or how missed visits were classified. It does not report reasons for missed visits, participant-level completion patterns, or details about follow-up and withdrawal. Missing-data methods and analysis populations are not reported in the registry record. These omissions make it difficult to assess how the endpoint reflects retention or whether the posted counts represent comparable opportunities for attendance.
Although the study is randomized and quadruple-masked, details about randomization procedures and masking implementation are not reported. Eligibility criteria and participant characteristics are also not reported in the information, limiting assessment of how the enrolled group relates to the population named in the study rationale.
The registry lists eight outcome measures, but secondary results are not posted in the information summarized for this trial. Results for medication adherence and tolerability, which are among the stated study aims, are not reported in the registry record. A statistical analysis plan, multiplicity approach, and prospective sample-size justification are also not reported. The safety summaries lack event-specific detail, and death counts are not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Acceptability of Pharmacologic Treatment for Methamphetamine Dependence Among MSM — NCT00318409.
- Registry record last updated 2014-10-17; status last verified 2014-10.
- Results first posted 2014-10-17.
- 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
This completed phase 2 pilot was a randomized, quadruple-masked, parallel comparison of bupropion and placebo among men who have sex with men with methamphetamine dependence. The registry lists enrollment as 30, with posted arm counts of 20 for bupropion and 10 for placebo. The primary outcome was scheduled study visits completed over 12 weeks.
The posted primary outcome values are 185 completed visits for bupropion and 96 for placebo. Scheduled-visit denominators are not reported, and the registry indicates that a two-arm comparison is not estimable. The counts therefore cannot be interpreted as completion proportions or as a comparative effect.
The registry records zero participants affected by serious adverse events in each arm and reports other adverse-event counts of 17 for bupropion and 6 for placebo. Results for medication adherence and tolerability are not reported in the registry record. The available findings are descriptive and do not establish a treatment effect.