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 PPARγ Agonist Treatment for Cocaine Dependence (NCT02774343), a randomized phase 1, phase 2 study. The primary outcome is Craving as Assessed by the Brief Substance Craving Scale (BSCS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02774343 |
| Phase | Phase 1, Phase 2 |
| Condition | Cocaine Use Disorder, Alcohol Use Disorder |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 30 |
| Arms in the primary outcome | n/a |
| Lead sponsor | The University of Texas Health Science Center, Houston |
| Results posted | Yes |
2. Clinical Question
Population
The registry record concerns people with cocaine use disorder; alcohol use disorder is also listed as a condition. Enrollment was 30. The record does not give further details about participant characteristics or the population included in any outcome analysis, so the enrolled group should not be assumed to represent a wider clinical population.
Intervention
The experimental group received pioglitazone with therapy and contingency management. The description says pioglitazone began at 15 mg daily, increased to 30mg in the second week and 45 mg in the third week, and remained at 45 mg through the end of week 12. The dosing description after that point is truncated in the registry record.
Comparator
The comparison group received placebo with therapy and contingency management. The record describes placebo capsules once daily across all twelve weeks. Thus the comparison is between the two medication assignments on a shared behavioral-treatment background, as described in the record.
Primary question
The primary outcome is craving measured with the Brief Substance Craving Scale (BSCS), recorded at baseline and at weeks 1 through 12. The clinical question is whether the reported craving scores differ between randomized groups over the scheduled assessments. The registry record does not report a single comparison, group means, an effect estimate, or uncertainty for this outcome, so it does not establish the direction or precision of any between-group difference.
These elements define the intended comparison, not a conclusion about treatment effect. Random allocation can help balance prognostic factors on average, but the record does not state how allocation was generated or concealed. Triple masking is identified, but the masked parties are not named. Nor does the registry record describe which participants contributed to each outcome analysis. These gaps matter when interpreting any estimate: the treatment contrast, the analysis population, and the handling of repeated craving assessments all affect what an outcome comparison would mean.
3. Trial Design
The record identifies a completed, randomized, triple-masked, parallel-group trial in phase 1 and phase 2. It lists enrollment as 30 and gives the study start as 2012-08 and primary completion as 2015-06. The sponsor is The University of Texas Health Science Center, Houston. These are registry characteristics; they do not by themselves establish that all enrolled participants were randomized or included in an outcome analysis.
Both arms included therapy and contingency management. One arm also received pioglitazone and the other received placebo. The pioglitazone description specifies a starting dose of 15 mg daily, titration to 30mg in the second week and 45 mg in the third week, then continuation at 45 mg through the end of week 12. The record’s description of what happens after week 12 is incomplete. The placebo description states that capsules were taken once daily across all twelve weeks.
The primary outcome is craving measured by the BSCS at baseline and at week 1, week 2, week 3, week 4, week 5, week 6, week 7, week 8, week 9, week 10, week 11, and week 12. The registry also lists feasibility outcomes for retention, medication compliance, and tolerability, plus cocaine-use outcomes based on urine samples and self-reports. It lists 16 outcome measures overall.
The record does not report the randomization procedure, the identity of the masked groups, or details of the therapy and contingency-management protocols. It also does not state the intended analysis population, the statistical model, or how missing outcome observations were to be handled. Although the trial is marked completed, completion status does not supply those methodological details or numerical outcome findings.
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 | Pioglitazone + Therapy + Contingency Management | Placebo + Therapy + Contingency Management |
|---|---|---|
| STARTED | 15 | 15 |
| Received at Least One Capsule | 12 | 14 |
| COMPLETED | 9 | 12 |
| NOT COMPLETED | 6 | 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.
| Characteristic | Unit | Pioglitazone + Therapy + Contingency Management | Placebo + Therapy + Contingency Management | Total |
|---|---|---|---|---|
| Participants analysed | 15 | 15 | 30 | |
| Age, Continuous | years | 48.3 (SD 7.1) | 47.4 (SD 7.8) | 47.8 (SD 7.45) |
| Sex: Female, Male: Female | Participants | 4 | 4 | 8 |
| Sex: Female, Male: Male | Participants | 11 | 11 | 22 |
| Region of Enrollment: United States | Participants | 15 | 15 | 30 |
6. Primary Endpoint
The registry lists the primary outcome as Craving as Assessed by the Brief Substance Craving Scale (BSCS), measured over Baseline, week 1, week 2, week 3, week 4, week 5, week 6, week 7, week 8, week 9, week 10, week 11, week 12.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary outcome is craving measured with the Brief Substance Craving Scale (BSCS). The record describes the BSCS as a 16-item self-report instrument addressing craving for cocaine and other substances of abuse over a 24 hour period. It records intensity, frequency, and duration, with each domain scored from 0 to 4. The total is the sum of the three domains, ranges from 0 to 12, and higher scores indicate greater craving, which the record characterizes as a worse outcome.
Craving is relevant to the study’s stated purpose, which includes examining whether pioglitazone can reduce craving and drug use among people with cocaine dependence. A repeated self-report measure can describe how a participant’s reported craving changes across scheduled assessments. In this trial, the outcome is scheduled at baseline and weekly from week 1 through week 12, giving a time profile rather than a single follow-up measurement.
That schedule also creates an interpretation challenge: a group contrast at one assessment is not necessarily the same question as a contrast in change over time or an overall comparison across assessments. The registry record does not identify which summary or comparison was intended as the primary statistical test. It does not report group means, standard deviations, a treatment-effect estimate, or a confidence interval for craving. Consequently, the measure and schedule can be described, but the magnitude, direction, and precision of a treatment-group difference cannot be read from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies craving on the BSCS as the primary outcome and gives repeated assessment times from baseline through week 12. However, it does not report a numerical primary-outcome result or a single comparison that can be interpreted as the trial’s primary treatment-effect estimate. The record flags the primary outcome as having several categories or time points and not being reduced to one comparison. No group means, standard deviations, confidence intervals, or p-values for craving are reported in the information available in the registry record.
This distinction is important. An outcome definition explains what was measured; it is not itself evidence of a between-group effect. Likewise, describing the scheduled assessments does not reveal whether craving fell, rose, or differed between the groups. Without a reported estimate and its uncertainty, the direction and magnitude of any difference cannot be evaluated. It is also not possible to judge whether an apparent difference, if one were reported elsewhere, would be compatible with a small or substantial effect.
The registry lists 16 outcome measures and reports 0 analyses. Secondary outcomes include retention through all 12 weeks, medication compliance based on riboflavin-positive urine samples and self-reports of capsule-taking, tolerability, serious adverse events, and cocaine-use measures based on urine samples and self-reports. Their names describe intended measures, not results. Numerical outcomes for these measures are not reported in the registry record.
The sample-size assumptions describe planning illustrations based on an observed effect, using a two-sided significance level of 0.05, equal allocation, and a normal approximation. They are not a report of observed power, and the registry record does not provide numerical planning estimates in the registry record. An illustration based on an observed effect cannot substitute for the trial’s original design justification or for an effect estimate with uncertainty.
In general, a confidence interval communicates the range of effect estimates compatible with the data and the statistical procedure used. A narrow interval can indicate greater precision, while a wide interval indicates substantial uncertainty. Here, no confidence interval for the primary outcome is reported, so precision cannot be assessed. The available record supports a description of the design, measures, and posted safety counts, but not a conclusion about whether the groups differed in craving or other outcomes.
9. Statistical Methods Explained
The study is described as randomized, triple-masked, and parallel-group. In general, randomization assigns participants to groups by chance and is intended to reduce systematic differences in prognostic characteristics between groups. It does not guarantee balance in a small trial, and it cannot address bias caused by missing outcomes, departures from assigned treatment, or selective reporting. The registry record does not report the randomization method, allocation concealment, or the parties covered by triple masking. Those details therefore cannot be used to assess how these design features were implemented.
What a parallel-group comparison means
In a parallel-group design, participants are assigned to a group and followed under that assignment rather than crossing between study treatments. Here the named arms combine medication assignment with therapy and contingency management. The intended contrast is therefore pioglitazone versus placebo on the behavioral-treatment background described in the record. The registry does not describe whether the behavioral treatments were delivered in exactly the same way across groups, or how adherence to them was assessed.
How to think about a continuous outcome
The BSCS total is a continuous score, and the registry identifies the outcome summary as a mean with standard deviation. In general, a mean describes the average score in a group, while a standard deviation describes the spread of individual scores around that average. A between-group mean difference can summarize an average contrast, but its interpretation depends on the assessment time and the analysis used. No means, standard deviations, or mean differences for the BSCS are reported in the registry record, so none can be interpreted for this trial.
Repeated assessments and the treatment contrast
Craving was scheduled at baseline and across weekly visits through week 12. Repeated observations from the same participant are generally correlated: a participant’s score at one visit may be related to their score at another. General statistical approaches for repeated measures account for this dependence rather than treating every observation as unrelated. A model may estimate change over time, a group-by-time pattern, or a contrast at a prespecified visit. These answer different questions. The registry record does not report the model, the primary time contrast, or whether baseline was incorporated as an adjustment variable.
When there are several assessment times, results can also depend on whether the analysis focuses on one visit, an average across visits, or the overall trajectory. Selecting among many comparisons after inspecting the data can increase the chance of a false-positive finding. Prespecification and transparent reporting help readers distinguish a planned primary comparison from exploratory analyses. The registry record does not report the intended primary contrast or a multiplicity procedure for the repeated craving assessments.
Uncertainty and significance
In general, a p-value describes how incompatible observed data are with a specified null model, under the assumptions of the test. It does not measure the probability that the null hypothesis is true, nor does it quantify clinical importance. An effect estimate and confidence interval are needed to understand the size and precision of a contrast. The sample-size assumptions mention a two-sided significance level of 0.05, but no primary-outcome p-value, effect estimate, or confidence interval is reported. The planning assumption is not a trial result.
Dispersion and model choice
For a continuous measure, standard deviation describes variability in the recorded score. In general, if an outcome is more variable than a statistical model assumes, uncertainty estimates and tests can be misleading unless the analysis accounts for that variability. The record identifies standard deviation as the dispersion measure for the primary outcome, but it provides no observed standard deviations and no statistical model. Over-dispersion is more often discussed for count outcomes; in general, it means variability exceeds what a basic count model expects. The record does not state that such a model was used for any outcome, so no claim about over-dispersion in this trial is warranted.
Planning illustrations are not observed power
The registry describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. Such calculations can illustrate how a hypothetical target effect relates to a planned sample size under assumptions. They do not show the probability that this completed trial detected an effect, and they cannot replace the original sample-size justification. No numerical illustration is included in the registry record details, and the original design justification is not reported in the registry record.
Sample-size calculations are sensitive to the assumed effect, variability, significance level, allocation, and analysis method. If an assumed effect is taken from observed data, the illustration is conditional on that estimate and can be optimistic or otherwise unrepresentative. In general, a calculation framed around detecting a fraction of an observed effect is a planning scenario, not evidence that the trial was adequately powered for the actual treatment contrast. The registry does not report enough detail to assess the assumptions behind the original design.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome is measured at baseline and at multiple visits through week 12, and the registry lists 16 outcome measures. These features create more than one potential comparison. In general, testing many outcomes or time points without an analysis plan can increase the chance that at least one result appears statistically notable by chance. A prespecified primary contrast and an explicit approach to multiplicity help readers understand which comparisons were confirmatory and how uncertainty was handled. The registry record does not report a multiplicity-adjustment plan, and it does not reduce the repeated primary outcome to one comparison.
The record reports 0 analyses. It therefore provides no analysis results from which to determine which participants were included, how repeated observations were handled, or whether analyses followed randomized assignment. The analysis population is not reported in the registry record. It is not possible to assume an intention-to-treat, per-protocol, or other analysis population from the design label alone.
Missing-data methods are also not reported. In general, incomplete follow-up can affect interpretation if the likelihood of a missing score is related to the outcome or differs between groups. Appropriate methods depend on the amount and pattern of missingness, the reasons for missing observations, and the assumptions of the chosen model. The registry lists retention as a secondary feasibility outcome, but does not give a retention result in the registry record. No missing-data assumptions or sensitivity analyses are described.
These omissions limit assessment of how robust a treatment comparison would be. They do not establish that missing data or multiplicity problems occurred; they mean the registry record does not provide the information needed to evaluate them.
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 |
|---|---|---|---|
| Pioglitazone + Therapy + Contingency Management | 0 | 12 | 0.0% |
| Placebo + Therapy + Contingency Management | 0 | 14 | 0.0% |
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 |
|---|---|
| Pioglitazone + Therapy + Contingency Management | 0 of 12 |
| Placebo + Therapy + Contingency Management | 0 of 14 |
The registry reports serious adverse events affecting 0 participants among 12 at risk in the pioglitazone, therapy, and contingency-management group, and 0 participants among 14 at risk in the placebo, therapy, and contingency-management group. The record also reports 0 participants with other adverse events in each group, using the same respective at-risk counts. These are counts in the posted safety fields, not proof that no adverse experiences occurred outside the definitions or reporting captured by those fields.
The deaths field is null for both groups. A null entry is not the same as a reported count of zero, so deaths should be described as not reported in the registry record rather than as absent. No serious-event terms are listed. The record does not provide additional event details, timing, severity categories, or participant-level follow-up information in the registry record.
Safety counts should be interpreted alongside their denominators and the scope of the reporting. The at-risk counts are 12 and 14, while overall enrollment is listed as 30; the record does not explain the difference between enrollment and the at-risk counts. It is not appropriate to infer why they differ or to treat the posted counts as a complete safety profile. With no event terms or further follow-up detail, these figures describe only the adverse-event counts reported in the registry.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized, triple-masked, parallel-group study compared pioglitazone with placebo, with therapy and contingency management listed in both arms. It identifies craving on the BSCS as the primary outcome and schedules assessment from baseline through week 12. It also lists feasibility, tolerability, and cocaine-use outcomes. These registry entries describe the study’s intended comparison and measurements, not what the comparison found.
No numerical primary-outcome results are reported in the registry record. In particular, there is no reported between-group estimate for craving, no measure of its uncertainty, and no single primary comparison identified among the scheduled assessments. Accordingly, the record does not show whether craving differed between the groups, how large any difference was, or how precisely it was estimated. It also does not support a conclusion about the listed secondary outcomes.
In general, a nonsignificant test would not demonstrate that groups are equivalent, while a statistically significant test would not by itself establish that an effect is important. Both interpretations require a clearly defined contrast, a numerical estimate, and uncertainty information. None of those primary-result details is reported. No claim that pioglitazone does or does not reduce craving or cocaine use can be drawn from the outcome information in this registry record.
The reported safety counts show 0 serious adverse events among the reported at-risk participants in each arm, and 0 participants with other adverse events in each arm. These counts do not characterize event types or establish the absence of all adverse experiences. The deaths field is null, and therefore does not report a zero count. The safety information is limited to the entries recorded in the registry.
The most defensible reading is therefore descriptive: the design and outcome schedule are documented, but numerical efficacy findings and key analysis details are not reported in the registry record. The absence of posted results is not evidence for either benefit or no benefit.
13. Why This Trial Matters Statistically
This trial is statistically notable for the distinction between a clearly named outcome and a reportable treatment-effect result. The BSCS is described in detail, including its scoring direction and repeated schedule, but the registry record does not report a single primary comparison or numerical outcome findings. Readers need both a measurement definition and an analysis result to assess an intervention contrast. Without the latter, the endpoint description cannot answer the clinical question.
The repeated assessments make the estimand—the precise quantity a study intends to estimate—especially important. A comparison at one visit, change from baseline, and a difference in score trajectories are not interchangeable. Each answers a different statistical question. The registry record specifies assessment times but does not state which contrast was primary, and it does not report an analysis model. This leaves uncertainty about what result would have represented the planned primary test.
The record also illustrates why trial status and enrollment alone do not establish evidential strength. A completed study with enrollment listed as 30 can still lack the outcome estimates, uncertainty intervals, analysis population, and missing-data information needed for interpretation. The registry lists 16 outcome measures and 0 analyses, making transparent reporting especially important for distinguishing planned outcomes from analyses and findings.
Finally, planning calculations should be separated from trial results. The record’s described illustrations use stated assumptions, but they are not observed power and do not supply a primary effect estimate. The statistical value of the record lies in documenting design and measurement choices while also making clear which analytical conclusions cannot be drawn from the posted information.
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.
Several trial-specific limitations of interpretation follow from the registry record. The primary outcome is assessed repeatedly, but no single primary contrast is reported. Without that definition, readers cannot tell whether the intended inferential target was a group difference at a particular visit, a change from baseline, or a pattern across time. No numerical BSCS results or uncertainty estimates are reported, so the treatment effect and its precision cannot be assessed.
The registry lists 16 outcome measures but reports 0 analyses. Results for the secondary outcomes are not reported in the registry record. The analysis population, statistical model, missing-data approach, and multiplicity plan are also not reported. These are material gaps for interpreting repeated self-report outcomes and the listed urine-based and self-reported measures of cocaine use.
The enrollment count is 30, while the reported at-risk counts for safety are 12 and 14. The record does not explain how those counts relate, so no explanation for the difference should be assumed. It also does not report participant characteristics, reasons for nonparticipation or missing follow-up, or detailed adherence and retention findings.
Some design descriptions are incomplete: the pioglitazone arm description ends during its account of medication after week 12, and the masked parties, randomization procedure, and behavioral-treatment details are not specified. The deaths entries are null, not reported zero counts. These limitations constrain interpretation of the record; they do not establish that a particular bias or adverse outcome occurred.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: PPARγ Agonist Treatment for Cocaine Dependence — NCT02774343.
- Registry record last updated 2018-04-26; status last verified 2018-03.
- Results first posted 2018-04-26.
- 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 record describes a completed phase 1 and phase 2 randomized, triple-masked, parallel-group trial sponsored by The University of Texas Health Science Center, Houston. Enrollment is listed as 30; the study start is 2012-08 and primary completion is 2015-06. The groups combined pioglitazone or placebo with therapy and contingency management.
Craving measured by the BSCS is the primary outcome, scheduled at baseline and weekly through week 12. The record lists 16 outcome measures and 0 analyses, and does not report a single primary comparison or numerical outcome results. It reports 0 serious adverse events in each group among the stated at-risk counts of 12 and 14. Deaths are not reported in the registry record.
The registry documents study structure and intended measurements, but does not provide the outcome estimates or analysis details needed to determine the direction, size, or precision of a treatment-group difference.