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 Better Than Study: Targeting Heavy Alcohol Use With Naltrexone Among Men Who Have Sex With Men (MSM) (NCT02330419), a randomized phase 2 study. The primary outcome is Binge Drinking Days Per Week.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02330419 |
| Phase | Phase 2 |
| Condition | Binge Drinking, HIV |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 120 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of California, San Francisco |
| Results posted | Yes |
2. Clinical Question
Population
Men who have sex with men (MSM) with binge drinking. The registry record describes a planned ethnically and racially diverse group of 120 participants. HIV is listed as a condition, but the record does not state that all participants were required to have HIV.
Intervention
Naltrexone 50mg, taken as needed in anticipation of heavy drinking, over 12 weeks. Participants were also scheduled for weekly visits that included study drug dispensing, alcohol-metabolite urine testing, and brief counseling for alcohol use.
Comparator
Placebo 50mg, taken as needed. The registry describes the trial as randomized and placebo-controlled. Medical Management counseling for alcohol use is also listed among the interventions.
Primary question
At 12 weeks, what was the mean number of binge drinking days per week among participants assigned to targeted naltrexone compared with those assigned to placebo? The registry record gives the endpoint definition but does not report the group results or the estimated difference between them.
The primary outcome is a comparison of group means, not a count of participants who did or did not binge drink. Binge drinking is defined in the outcome description as consuming 5 or more drinks on an occasion for men or 4 or more drinks on an occasion for women. The analysis population is described as participants who completed the ACASI survey at week 12, and the record notes that this differs from the participant flow chart population. The number of participants who completed that survey is not reported in the registry record.
The clinical question is therefore about the average frequency of binge drinking over the specified period, as measured in days per week. The record does not give the observed means, a between-group estimate, a confidence interval, or a p-value, so it cannot establish the size or precision of any difference in the primary outcome.
3. Trial Design
This is a phase 2, randomized, parallel-group trial with planned enrollment of 120 participants. The two drug arms are naltrexone and placebo, each described as 50mg taken as needed. The registry lists the masking as triple. Its brief summary calls the study double-blind; the record does not explain this difference in wording.
The study is described as lasting 12 weeks. Participants were to be seen weekly for alcohol-metabolite urine testing, study drug dispensing, and brief counseling for alcohol use. Safety assessments and behavioral surveys were scheduled monthly. Additional listed procedures include urinalysis for novel alcohol biochemical markers, dried blood spot testing for phosphatidylethanol, behavioral survey measurements, and ecological momentary assessment. These listed measures do not by themselves establish which were used in the primary efficacy analysis.
Recruitment was planned through Respondent Driven Sampling and active field recruitment, with the brief summary describing an ethnically and racially diverse participant group. The registry lists binge drinking and HIV as conditions. It does not specify in the record whether HIV status was an eligibility requirement, or provide detailed eligibility criteria in the registry record described.
The trial status is completed. The recorded start is 2015-04 and primary completion is 2021-01. The sponsor is the University of California, San Francisco. The record identifies the primary endpoint as binge drinking days per week at 12 weeks, but gives no primary outcome estimates or inferential results. Thus, design features can be described, but the comparative efficacy findings cannot be reconstructed from the registry record.
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: Potential participants completed a brief telephone screen to assess initial eligibility and, if eligible, were scheduled for an in-person screening visit. All participants gave informed consent using University of California, San Francisco (UCSF) IRB-approved consent forms. Participants were evaluated for eligibility based on the inclusion criteria during the in-person screening visit.
Overall Study
| Stage | Placebo | Naltrexone |
|---|---|---|
| STARTED | 60 | 60 |
| COMPLETED | 57 | 53 |
| NOT COMPLETED | 3 | 7 |
Reasons for not completing this period:
| Reason | Placebo | Naltrexone |
|---|---|---|
| Lost to Follow-up | 3 | 7 |
Analysis population for the primary outcome, as defined in the registry: The binge drinking days analysis between targeted naltrexone and placebo arms is different from the participant flow chart. The overall number of participants is calculated from those participants that completed the ACASI survey at week 12.
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 | Placebo | Naltrexone | Total |
|---|---|---|---|---|
| Participants analysed | 60 | 60 | 120 | |
| Age, Continuous | years | 34 (30 to 42) | 38 (30 to 50) | 37 (30 to 45) |
| Sex/Gender, Customized: Gender Identity – Cis-gender male | Participants | 59 | 60 | 119 |
| Sex/Gender, Customized: Gender Identity – Transgender male (female to male) | Participants | 1 | 0 | 1 |
| Race/Ethnicity, Customized: White | Participants | 32 | 33 | 65 |
| Race/Ethnicity, Customized: Asian | Participants | 4 | 2 | 6 |
| Race/Ethnicity, Customized: Black | Participants | 5 | 12 | 17 |
| Race/Ethnicity, Customized: Latino | Participants | 10 | 2 | 12 |
| Race/Ethnicity, Customized: Other | Participants | 9 | 11 | 20 |
| Region of Enrollment: United States | Participants | 60 | 60 | 120 |
| Education: high school or less | Participants | 6 | 7 | 13 |
| Education: some college | Participants | 19 | 17 | 36 |
| Education: college or above | Participants | 35 | 36 | 71 |
| Income: under $20,000 | Participants | 13 | 16 | 29 |
| Income: $20 - 39,999 | Participants | 17 | 12 | 29 |
| Income: $40,000 and above | Participants | 30 | 32 | 62 |
| Employment: not employed | Participants | 14 | 21 | 35 |
| Employment: full-time | Participants | 29 | 28 | 57 |
| Employment: part-time | Participants | 12 | 9 | 21 |
| Employment: employed student | Participants | 5 | 2 | 7 |
| Ever hospitalized for alcohol problem: No | Participants | 54 | 50 | 104 |
| Ever hospitalized for alcohol problem: Yes | Participants | 6 | 10 | 16 |
| Ever received alcohol treatment: No | Participants | 43 | 42 | 85 |
| Ever received alcohol treatment: Yes | Participants | 8 | 11 | 19 |
| Ever received alcohol treatment: Missing | Participants | 9 | 7 | 16 |
| Alcohol Craving Scale-Visual Analog | units on a scale | 25 (10 to 40) | 30 (10 to 50) | 30 (10 to 50) |
| HIV Status: HIV-positive | Participants | 17 | 14 | 31 |
| HIV Status: HIV-negative | Participants | 43 | 46 | 89 |
| Has health insurance: No | Participants | 6 | 5 | 11 |
| Has health insurance: Yes | Participants | 54 | 55 | 109 |
| Has regular health care provider: No | Participants | 10 | 8 | 18 |
| Has regular health care provider: Yes | Participants | 50 | 52 | 102 |
| Center for Epidemiological Studies Depression scale (CES-D) | units on a scale | 13 (8 to 21) | 12 (7 to 20) | 12 (8 to 20) |
6. Primary Endpoint
The registry lists the primary outcome as Binge Drinking Days Per Week, measured over 12 weeks.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | days per week |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the mean number of binge drinking days per week at 12 weeks. It is a continuous measure: each participant contributes a frequency, and the arm-level result is summarized by a mean and standard deviation. The outcome description defines binge drinking as consuming 5 or more drinks on an occasion for men or 4 or more drinks on an occasion for women.
Days per week captures frequency rather than the total amount consumed, the number of drinks on a drinking occasion, or the proportion of participants meeting a separate response threshold. A mean can describe the average pattern in each randomized arm, while the standard deviation describes how dispersed participants’ values are around that average. Those summaries answer different questions and should not be treated as interchangeable.
The endpoint is specified for the 12-week timeframe. The registry states that the analysis population consists of participants who completed the ACASI survey at week 12, and that this population differs from the participant flow chart. The number contributing to the endpoint is not reported in the registry record. Nor are the arm-specific means, standard deviations, treatment contrast, or uncertainty estimates reported. Without those results, the endpoint’s observed values and the precision of the comparison cannot be assessed.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a randomized comparison of targeted naltrexone and placebo, with binge drinking days per week at 12 weeks designated as the primary outcome. It does not report the primary outcome results. In particular, no arm-specific mean or standard deviation, between-arm estimate, confidence interval, or p-value is reported in the registry record. Consequently, the direction, magnitude, and statistical precision of the primary comparison cannot be stated from this record.
The study lists 120 participants as its enrollment and describes the trial as randomized. For safety reporting, 60 participants are listed as at risk in each arm. These safety denominators do not establish the number of participants included in the week 12 ACASI endpoint analysis. The outcome description explicitly says that its analysis population differs from the participant flow chart, and the endpoint completion counts are not reported in the registry record.
In general, a confidence interval describes a range of estimates compatible with the data and the statistical model used. Its width conveys precision: a narrower interval indicates greater precision under that model, while a wider interval indicates more uncertainty. Because no confidence interval or primary estimate is reported, the precision of the treatment comparison is unknown. A p-value, if reported, would address compatibility with a specified null hypothesis under an analysis model; it would not by itself describe the size or practical importance of an effect. No primary p-value is reported.
The record lists 0 analyses. That is distinct from saying that the trial collected no outcome data: the registry identifies an endpoint and describes a week 12 survey population. Rather, the record does not give a statistical comparison that can be interpreted as a trial result. The absence of a posted estimate should not be read as evidence that the arms were equal, nor as evidence of a difference.
Safety results are reported separately. Each arm lists 1 serious adverse event among 60 participants at risk, and 0 deaths in each arm. Other adverse events are listed for 20 participants in the placebo group and 43 in the naltrexone group, each among 60 at risk. These are descriptive counts. The registry information does not provide enough detail about event definitions, severity, duration, or statistical comparisons to support a causal interpretation of the difference in other adverse-event counts.
The sample-size assumptions describe planning illustrations based on an observed effect, but the primary effect estimate and illustration values are not reported in the registry record. Such illustrations are not observed power and should not be interpreted as evidence that the study did or did not have adequate power. Overall, the posted record allows a description of the design, endpoint, and selected safety counts, but not a conclusion about the primary comparative outcome.
9. Statistical Methods Explained
The registry identifies a continuous primary outcome, a mean number of binge drinking days per week, with standard deviation as its dispersion measure. It also identifies a randomized parallel-group design. These features indicate the broad structure of the intended comparison, but the record does not state the specific statistical model, covariates, or inferential procedure used for the primary endpoint. No primary analysis is listed in the registry record.
What does a mean comparison describe?
In general, the mean is the arithmetic average of measured values within a group. For this endpoint, the value represents average binge drinking days per week among participants included in the relevant analysis. Comparing arm means addresses an average difference, not whether every participant changed in the same way or whether a particular participant experienced a benefit or harm. A group average can also conceal variation between individuals, which is why the standard deviation is informative alongside the mean.
The standard deviation describes the spread of individual measurements around the group mean. It is not the uncertainty in the estimated mean, and it is not a confidence interval. In general, uncertainty in a group mean or treatment contrast depends on the amount of information and the variability in the data, as well as the analysis method. The registry record does not report the means, standard deviations, or confidence interval for this endpoint, so neither the observed spread nor the precision of the comparison can be assessed.
Why does the analysis population matter?
The outcome description says the endpoint analysis includes participants who completed the ACASI survey at week 12. It also says that this group differs from the participant flow chart. This distinction matters because an analysis based on survey completers can include a different set of participants from an analysis based on everyone randomized. If completion is related to participants’ drinking patterns or other characteristics, the observed group means among completers may not represent the outcomes that would have been observed for all randomized participants. This is a general concern, not evidence that such a relationship occurred in this trial.
The registry does not report the number of week 12 survey completers, the reasons for noncompletion, the amount or handling of missing endpoint data, or whether any sensitivity analyses were conducted. It also does not state whether the primary comparison followed an intention-to-treat principle or another analysis population. These details are needed to understand how the endpoint results were formed and how missing measurements might affect interpretation.
What can randomization and masking contribute?
In general, random allocation is intended to make the assigned groups comparable at the time of assignment, on average, including for characteristics that are not measured. It supports a fair comparison of outcomes by assigned group when the trial is analyzed appropriately. Randomization does not guarantee identical groups in a particular trial, and it does not resolve issues such as missing outcome data or departures from the planned treatment strategy.
The registry labels the study randomized and triple-masked, while the brief summary describes it as double-blind. The record does not explain the difference. Masking is generally intended to reduce the influence of treatment knowledge on participant reports, care, or outcome assessment, depending on who is masked. The registry does not identify in the registry record described which roles were masked or how masking was maintained.
How should planning illustrations be read?
In general, a sample-size calculation uses assumptions about the outcome, the effect one wishes to detect, the error rate, allocation, and statistical method to estimate a number of participants needed for a specified design goal. The registry describes planning illustrations based on a stated fraction of an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. It distinguishes participants per arm for ordinary outcomes from total events for time-to-event outcomes. The primary endpoint is continuous, and no time-to-event endpoint is identified as the primary outcome.
Those illustrations are planning aids, not observed power. Observed power is not a substitute for an estimate and its confidence interval after a trial. The registry record does not report the observed primary effect or illustration values, so no numerical sample-size interpretation can be made from the available record. It also does not report the trial’s own sample-size justification; the stated illustration assumptions should not be mistaken for the original design rationale.
What is not specified about analysis?
The record does not report whether the primary analysis adjusted for baseline drinking, included other covariates, used a repeated-measures model, or addressed features such as skewness or over-dispersion. These are possible general considerations when analyzing repeated behavioral measurements, but none can be attributed to this trial without a stated analysis plan. The record also does not report interim analyses, multiplicity procedures, or sensitivity analyses. Without these details and the endpoint results, the primary comparison cannot be independently evaluated or recalculated.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 6 outcome measures and 0 analyses. The record does not identify a multiplicity adjustment, a hierarchy of outcomes, or a plan for controlling the chance of false-positive findings across multiple tests. In general, testing multiple outcomes or time points can increase the chance that at least one result appears statistically noteworthy by chance. Whether an adjustment is needed depends on the prespecified questions and analysis plan; that plan is not reported in the registry record.
The primary endpoint is defined at 12 weeks, but the record does not specify the statistical procedure used to compare arms or how any secondary outcomes were analyzed. It does not report interim analyses. No interim monitoring plan or stopping rule is reported in the registry record.
The endpoint population is described as participants who completed the ACASI survey at week 12, and it is said to differ from the participant flow chart population. The number of completers, missing endpoint values, reasons for missingness, and method for handling missing data are not reported in the registry record. In general, missing-data methods rely on assumptions about why values are missing, and different assumptions can lead to different estimates. The record gives no basis for assessing those assumptions or the robustness of the endpoint comparison.
The registry also does not state whether the primary analysis included all randomized participants, only participants with observed surveys, or another analysis set. Therefore, the analysis population and the treatment of missing outcomes remain important uncertainties. No conclusions about multiplicity control or missing-data robustness can be drawn from the posted record.
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 |
|---|---|---|---|
| Placebo | 1 | 60 | 1.7% |
| Naltrexone | 1 | 60 | 1.7% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Placebo | 0 of 60 |
| Naltrexone | 0 of 60 |
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 |
|---|---|
| Placebo | 20 of 60 |
| Naltrexone | 43 of 60 |
Most frequent serious adverse event terms
| Event term | Organ system | Placebo | Naltrexone |
|---|---|---|---|
| bowel obstructions | Gastrointestinal disorders | 1 of 60 | 0 of 60 |
| soft-tissue infection | Musculoskeletal and connective tissue disorders | 0 of 60 | 1 of 60 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Placebo | Naltrexone |
|---|---|---|---|
| nausea | Gastrointestinal disorders | 4 of 60 | 14 of 60 |
| hyperglycemia | Renal and urinary disorders | 9 of 60 | 8 of 60 |
| headache | Vascular disorders | 2 of 60 | 7 of 60 |
| increased ALT | Hepatobiliary disorders | 3 of 60 | 5 of 60 |
| increased AST | Hepatobiliary disorders | 2 of 60 | 6 of 60 |
| rash | General disorders | 0 of 60 | 3 of 60 |
| diarrhea | Metabolism and nutrition disorders | 0 of 60 | 3 of 60 |
Serious events with the highest arm-level rate: bowel obstructions (1.7%), soft-tissue infection (1.7%).
The safety record lists 60 participants at risk in each arm. It reports 1 serious adverse event in the placebo arm and 1 in the naltrexone arm. The listed deaths are 0 in each arm. These are counts, not estimates of comparative risk, and the registry does not report a statistical comparison for them.
For other adverse events, the record lists 20 affected participants among 60 at risk in the placebo arm and 43 among 60 at risk in the naltrexone arm. The record does not provide event-level definitions or clarify the extent to which multiple events in one participant were handled. The counts should therefore be read as the registry’s reported affected-participant figures, not as a detailed description of event frequency, severity, or clinical importance.
The serious-event terms listed are bowel obstructions and soft-tissue infection, each shown as 1.7%. The record does not assign these terms to an arm in the details described. They should not be attributed to either group on that basis. In general, adverse-event counts are descriptive and can be influenced by how events are defined, collected, and classified. The registry does not provide enough information to infer causation or to determine whether the between-arm difference in other adverse-event counts reflects a treatment effect.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a randomized, parallel-group phase 2 trial compared targeted naltrexone with placebo and designated binge drinking days per week at 12 weeks as its primary endpoint. It also describes the intended dosing, follow-up activities, and selected safety counts. These details clarify the question the study was designed to address, but they are not a substitute for the primary outcome results.
The record does not report arm-level endpoint means, standard deviations, a treatment contrast, confidence interval, or p-value. As a result, it does not show the observed direction or size of the primary comparison, or how precisely that comparison was estimated. No claim that naltrexone reduced, increased, or had no effect on binge drinking days can be supported by the posted primary outcome information.
The safety counts document reported events in each arm, including one serious adverse event in each group and no deaths in either group. They do not by themselves establish that an event was caused by the assigned treatment. Nor do the other-adverse-event counts alone establish a comparative safety effect, because event definitions and analysis details are not reported.
In general, a trial result is best interpreted using the estimated treatment contrast and its uncertainty, alongside the design, analysis population, missing-data handling, and safety context. Those primary statistical results and several analysis details are not reported in the registry record. The record therefore supports a description of the trial and its planned endpoint, but not a conclusion about the size, precision, or clinical meaning of the treatment comparison.
13. Why This Trial Matters Statistically
This trial’s statistical question is framed around a behavioral outcome: the average number of binge drinking days per week at 12 weeks. That endpoint focuses on frequency, which is distinct from alcohol quantity, drinking intensity, or the proportion of participants meeting a response definition. Keeping the endpoint’s meaning clear helps prevent readers from treating different measures of alcohol use as equivalent.
The randomized, parallel-group design provides a framework for comparing assigned treatment strategies. The registry describes targeted use of naltrexone in anticipation of heavy drinking, rather than simply naming a medication without a dosing context. It also describes placebo assignment and masking, although the summary and masking field use different terms for the masking level. These design details matter when evaluating what comparison was intended.
The record also makes an important population distinction: the week 12 endpoint analysis is described as using participants who completed the ACASI survey, and this population differs from the participant flow chart. That distinction highlights why the analysis denominator and missing-data approach matter when interpreting an outcome. Without those details, the number of participants contributing to the primary estimate and the representativeness of that group are uncertain.
Most importantly, the registry record does not report the primary comparison itself. This illustrates the difference between knowing a trial’s design and being able to assess its findings. An endpoint definition can show what investigators intended to measure, but it cannot communicate an effect estimate, its uncertainty, or the evidence for a difference between groups. Readers need those results, as well as analysis details, to evaluate the statistical evidence.
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 principal limitation for statistical interpretation is that no primary outcome results are reported in the registry record. The record identifies the endpoint and timeframe but gives no group means, standard deviations, treatment contrast, confidence interval, or p-value. Consequently, the size, direction, and precision of the primary comparison cannot be assessed.
The endpoint analysis population is described as participants completing the ACASI survey at week 12 and as different from the participant flow chart population. The number of endpoint completers and the reasons for noncompletion are not reported in the registry record. The method for handling missing values, the analysis set, and any sensitivity analyses are also not reported.
The statistical analysis plan is not described in the information recorded. The model, any covariate adjustment, and any approach to repeated measurements are not reported. The record lists 6 outcome measures but does not describe multiplicity procedures. Interim analyses and the trial’s own sample-size justification are not reported. Although planning assumptions are described, numerical illustration results and the primary observed effect are not reported.
The masking information is not fully clear: the registry field says triple masking, while the brief summary describes a double-blind study. The record does not explain this difference or identify which roles were masked. The safety information also has limits: serious-event terms are listed without an arm assignment in the details described, and other event definitions and statistical comparisons are not reported. These limitations restrict interpretation of both efficacy and safety from the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Better Than Study: Targeting Heavy Alcohol Use With Naltrexone Among Men Who Have Sex With Men (MSM) — NCT02330419.
- Registry record last updated 2025-04-20; status last verified 2025-04.
- Results first posted 2025-04-20.
- 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
NCT02330419 is a completed phase 2 randomized parallel-group trial sponsored by the University of California, San Francisco. It lists planned enrollment of 120 participants and compares naltrexone 50mg as needed with placebo 50mg as needed among MSM with binge drinking. The recorded start is 2015-04 and primary completion is 2021-01.
The primary endpoint is mean binge drinking days per week at 12 weeks, based on participants completing the ACASI survey. The registry record does not report the primary endpoint results or a statistical analysis. It lists 6 outcome measures and 0 analyses. Safety records show 1 serious adverse event in each arm and 0 deaths in each arm; other adverse events are listed for 20 participants in the placebo arm and 43 in the naltrexone arm, among 60 at risk per arm.