Selegiline Patch for Treatment of Nicotine Dependence: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Selegiline Patch for Treatment of Nicotine Dependence (NCT01330030), a randomized phase 2 study. The primary outcome is Expired-air Carbon Monoxide Confirmed Smoking Abstinence.

2. Clinical Question

The registry describes the study purpose as examining whether selegiline delivered through a skin patch is effective in stopping smoking. The outcome is a count of participants who were not smoking and had that status confirmed by expired-air carbon monoxide. The reported counts are 24 in the selegiline group and 25 in the matching-placebo group. These are descriptive results; the registry record does not post an inferential analysis comparing the groups.

The record identifies tobacco use disorder as the condition and lists selegiline and matching placebo as the interventions. It does not report further details about participant characteristics, how smoking abstinence was established beyond the stated carbon-monoxide confirmation, or the procedures used to deliver follow-up assessments. Those omissions limit how specifically the clinical question can be interpreted beyond the registered outcome definition and timeframe.

3. Trial Design

This was a randomized, quadruple-masked phase 2 study with a factorial model, sponsored by Stanford University. The registry lists enrollment of 243 and describes a selegiline patch group and a matching-placebo group. The group counts recorded for the primary outcome are 121 for selegiline and 122 for placebo. The record does not explain the factorial structure, identify any additional factors or comparisons, or describe how those elements relate to the two groups displayed in the primary outcome record.

The selegiline regimen was a 6 mg transdermal patch worn for 24 hours for 8 weeks. The matching-placebo patch was also described as worn for 24 hours for 8 weeks. The primary endpoint was assessed at 52 weeks, and its population is identified as intention to treat. The record does not provide further detail about adherence, treatment discontinuation, follow-up procedures, or the handling of participants whose smoking status could not be confirmed.

The study began in 2005-07, had primary completion in 2008-08, and is marked completed. Randomization indicates assignment by chance, while quadruple masking indicates that the record classifies the study as masked at that level; the identities of the masked roles and the procedures used to maintain masking are not reported in the registry record. Although the design is labeled factorial, the available outcome information should not be taken as a complete account of every randomized comparison. Details needed to interpret the factorial design are not reported in the registry record.

The registry lists 1 outcome measure and 0 posted analyses. This distinction matters: numerical outcome observations are present, but the record does not include a posted statistical comparison or an accompanying estimate of uncertainty. The registered design labels alone do not establish which statistical methods were planned or used.

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: The original target enrollment was 230. Over recruitment led to a study sample size =243

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: intention to treat

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.

6. Primary Endpoint

The registry lists the primary outcome as Expired-air Carbon Monoxide Confirmed Smoking Abstinence, measured over 52 weeks.

The primary endpoint is titled expired-air carbon monoxide-confirmed smoking abstinence. It records the number of participants who were not smoking at 52 weeks and whose abstinence was confirmed using expired-air carbon monoxide. The listed unit is participants not smoking, and the population is intention to treat. The registry reports 24 participants for selegiline and 25 for matching placebo.

Carbon-monoxide confirmation adds an objective measurement to a report of smoking status. As a general measurement principle, an objective confirmation can help distinguish an outcome based on a reported behavior from one supported by a measured marker. The registry record does not describe the threshold used, the timing or frequency of carbon-monoxide testing, or how missing or inconclusive tests were classified. It therefore supports interpretation of the endpoint only at the level of its stated name and definition.

The endpoint is a count at a specified follow-up time, not a measure of how long abstinence lasted or when relapse occurred. The record does not report a time-to-event outcome, repeated abstinence assessments, or a secondary outcome. A single endpoint can be clinically interpretable, but its meaning depends on the exact assessment rules and missing-data handling, which are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary result is a count of participants meeting a binary outcome definition: smoking abstinence confirmed by expired-air carbon monoxide at 52 weeks. A count records how many participants met the endpoint, while a group comparison asks whether the observed outcomes differ beyond what could plausibly arise from sampling variation. The registry reports the counts and group sizes, but it does not post a statistical comparison for this outcome.

What does a confidence interval add?

In general, a confidence interval communicates uncertainty around an estimated effect. It helps readers distinguish a precise estimate from one that is compatible with a broad range of possible effects. Its interpretation depends on the method used, the data, and the assumptions of the model. No confidence interval is reported for the primary outcome in the registry record, so the precision of a treatment comparison cannot be read from these posted results.

A count alone is not an effect estimate. One possible way to compare binary outcomes is to estimate a difference in the proportions meeting the endpoint; other measures are also possible. The choice depends on the clinical question and the analysis plan. No comparison measure is posted, and the record marks the values as missing or not estimable for a two-arm comparison of this count-other endpoint. No difference, ratio, or other comparison should therefore be reconstructed from the displayed counts.

Why does the endpoint form matter?

Statistical methods should match the form of the outcome and the design. A binary endpoint distinguishes whether each participant met the abstinence definition, whereas the registry’s primary data are presented as counts of participants meeting it. Analysis may require information about the underlying denominator, outcome ascertainment, and allocation structure. The group sizes are recorded, but further details about outcome availability and the analysis procedure are not reported in the registry record.

Because the study is labeled factorial, an analysis might need to account for more than a single treatment-versus-control contrast. In general, factorial designs can assess assigned factors separately and may examine whether the effect of one factor depends on another. That latter question is an interaction. The registry record does not describe the factors or state whether such effects were estimated. It is therefore not possible to infer the intended model or to reinterpret the posted outcome counts as a factorial analysis.

Why can over-dispersion matter?

Over-dispersion is a general concern when count data vary more than a chosen statistical model expects. If a model assumes less variability than is present, its uncertainty estimates can be too narrow. The primary outcome is a participant count for abstinence, not a repeated-event count or a rate, and no count model or dispersion estimate is reported. Over-dispersion should not be presumed to apply to this endpoint; the general point is that an analysis should reflect the actual outcome structure and variability.

For binary outcomes, the key uncertainty also depends on the number of participants with observed outcomes and on how missing outcomes are treated. The record identifies the primary population as intention to treat but does not define how participants without an ascertainable outcome were handled. It does not state whether missing assessments were classified as smoking, excluded, imputed, or treated by another rule. These choices can change the interpretation of a binary endpoint, so the label alone is not a full analysis description.

What does randomization contribute?

Randomization assigns participants by chance and is intended to make the groups comparable on average with respect to measured and unmeasured baseline factors. It does not guarantee exact balance in a particular trial, and it does not remove the need for a prespecified analysis. Masking can reduce the influence of expectations on treatment delivery, assessment, or interpretation, depending on who is masked and how masking is maintained. The record labels the study randomized and quadruple-masked but does not give operational details about sequence generation, concealment, masked roles, or masking checks.

The record lists a two-sided significance level of 0.05 and equal allocation as assumptions for a planning illustration, together with a normal approximation and an effect defined as a stated fraction of the observed effect. These are planning assumptions, not evidence about the observed treatment effect. Sample-size illustrations are not observed power. The record does not state that these assumptions were the original protocol’s design assumptions, nor does it provide a protocol-based sample-size justification in the available information.

No sponsor analysis is posted for the primary endpoint, so there is no sponsor-reported estimate to compare with a simple unadjusted recalculation. The record does not report the statistical plan, interim analyses, or details of any adjustment for multiple testing. Those matters cannot be inferred from the phase, randomization, masking, or factorial labels. The most defensible statistical reading is therefore descriptive: the registry provides the abstinence counts at the stated time point, but not an inferential analysis of them.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 1 outcome measure and 0 posted analyses, with no secondary outcomes posted. The primary outcome is expired-air carbon monoxide-confirmed smoking abstinence at 52 weeks. No multiplicity strategy is reported in the registry record. In general, multiplicity arises when several outcomes, time points, treatment contrasts, or subgroup analyses are tested; considering many tests can increase the chance of an apparently notable result by chance. The factorial label may involve multiple questions, but the record does not describe them, so the scope of any multiplicity issue cannot be established.

The primary endpoint is identified as an intention-to-treat outcome. In general, intention-to-treat analysis aims to retain participants in the groups to which they were assigned, regardless of treatment adherence. The registry record does not define its operational population, explain the treatment of missing abstinence assessments, or state whether participants without carbon-monoxide confirmation were counted as smoking or handled another way. No missing-data method is reported.

These omissions matter because follow-up availability and endpoint classification can affect a count of participants meeting an outcome. The posted group sizes do not show how many outcome assessments were complete or how missing observations were addressed. No sensitivity analyses are reported. The record therefore does not permit assessment of how robust the primary result is to alternative assumptions about missing data or to any unreported additional analyses.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry’s serious adverse event figures list 0 serious events affecting participants in the selegiline group and 0 in the matching-placebo group. The record also lists no serious-event terms among the top serious terms. These are the posted counts; they do not establish that no serious event could occur, or that the groups have identical safety profiles.

For other adverse events, the record lists 110 participants affected among 121 at risk in the selegiline group and 108 affected among 122 at risk in the matching-placebo group. These figures are separate from the serious adverse event counts. The registry record does not provide event types, severity categories, event-level counts, or a statistical comparison for these other adverse events. The recorded counts should not be read as a measure of treatment causation, because the record does not describe attribution procedures or provide an analysis that compares risk.

Deaths are not reported in the registry record. Adverse-event summaries also depend on how events were defined, collected, and coded; those details are not reported. The figures are descriptive registry entries, not a complete assessment of safety.

12. What the Result Does, and Does Not, Mean

The registered result establishes that the record contains counts of 24 participants meeting the abstinence endpoint in the selegiline group and 25 in the matching-placebo group at 52 weeks. The endpoint is described as confirmed by expired-air carbon monoxide and applies to an intention-to-treat population. These registry entries describe what was recorded, not the causal effect of assignment to either patch.

The result does not show whether a group difference is statistically persuasive. There is no posted effect estimate, confidence interval, p-value, or analysis method. Without those, the precision of any comparison is unknown. Nor does the record explain how the factorial design was analyzed, how missing outcome data were treated, or whether the reported group counts reflect all participants intended for the analysis.

The counts also do not describe duration of abstinence, relapse timing, or abstinence at other time points. They concern the stated assessment at 52 weeks. The record does not report additional outcomes that would broaden interpretation beyond this endpoint. As a general principle, an observed count is not by itself proof that treatment caused the outcome or that any difference is clinically important.

Likewise, the absence of serious adverse event counts in the posted groups should be interpreted as a registry observation, not a guarantee about safety. The other adverse-event figures are descriptive and do not provide event details or a comparative statistical analysis. The data support a narrow description of the registered outcome and safety counts, while important questions about uncertainty, analysis, missingness, and design remain unanswered in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of why design labels and outcome counts do not replace a report of the analysis. The record identifies randomization, quadruple masking, and a factorial model, yet it does not explain the factorial structure or post an analysis of the primary comparison. Readers need the design details and analysis methods to know which treatment question a reported estimate answers.

The outcome is a participant count for abstinence confirmed by a measurement. That makes the endpoint’s definition and assessment procedures central to interpretation. The registered title and timeframe identify the intended endpoint, but details such as the confirmation threshold and handling of unobserved assessments are not reported in the registry record. A clearly stated outcome is important, but it does not remove uncertainty about ascertainment or missing data.

The record also illustrates the difference between descriptive results and inferential evidence. Counts are available, while a treatment-effect estimate and its uncertainty are not. Without an inferential analysis, readers cannot assess the precision of a group comparison. In general, reporting estimates with uncertainty helps separate the magnitude of an observed pattern from how much the data can establish about the underlying effect.

Finally, the distinction between a trial’s own design justification and a planning illustration matters. Planning calculations based on an observed effect are exploratory sizing aids, not observed power and not evidence that a study was adequately designed. The registry record does not report the original sample-size justification. These limitations make transparent reporting of protocol assumptions, analysis plans, and results especially important for interpreting this study.

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 available record does not describe the factorial factors, their allocation levels, or the comparisons intended by the design. Although the primary outcome presents a selegiline group and a matching-placebo group, those entries do not establish the full structure of the trial. The absence of a posted analysis also prevents assessment of whether the reported outcome was analyzed in a way that reflects the factorial design.

Further participant eligibility criteria and baseline characteristics are not reported in the registry record. Without them, readers cannot assess the population’s clinical profile or how broadly the outcome might apply. The record does not describe random-sequence generation, allocation concealment, the roles included in quadruple masking, or procedures for maintaining masking.

The primary outcome is identified at 52 weeks, but the record does not explain the carbon-monoxide threshold, the timing of assessment, or how absent and inconclusive measurements were handled. Although the analysis population is labeled intention to treat, no operational definition or missing-data procedure is reported. No sensitivity analysis is posted.

The record lists 0 posted analyses and provides no statistical comparison, confidence interval, or p-value for the primary outcome. It also does not report secondary outcomes or a multiplicity strategy. Deaths are not reported in the registry record, and the adverse-event entries lack event descriptions and a comparative analysis. These gaps limit evaluation of both the efficacy comparison and the safety summaries.

The registry lists enrollment and group sizes, but does not report a protocol-based sample-size justification. The planning assumptions described for an illustration should not be treated as proof of the original design rationale or as observed power. Overall, the available information supports descriptive reading of the registered counts, while leaving key design, analysis, and outcome-assessment details unresolved.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Selegiline Patch for Treatment of Nicotine Dependence — NCT01330030.
• Registry record last updated 2016-08-10; status last verified 2016-05.
• Results first posted 2016-04-04.
• 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.

18. Record Summary

The registry record describes a completed, randomized, quadruple-masked phase 2 study sponsored by Stanford University, with a factorial model and enrollment of 243. It lists a selegiline patch at 6 mg, worn for 24 hours for 8 weeks, and a matching-placebo patch worn for 24 hours for 8 weeks. The study began in 2005-07 and had primary completion in 2008-08.

The primary endpoint was expired-air carbon monoxide-confirmed smoking abstinence at 52 weeks in an intention-to-treat population. The record lists 24 participants meeting the endpoint in the selegiline group and 25 in the matching-placebo group. It reports 0 serious adverse events in each group and lists other adverse events affecting 110 participants among 121 at risk with selegiline and 108 among 122 at risk with placebo.

The registry lists 1 outcome measure and 0 analyses. It does not post a statistical comparison, uncertainty estimate, secondary outcome, or details needed to interpret the factorial structure and missing-data handling.