Evaluating the Methylphenidate Patch to Treat Former Stimulant Users With ADHD: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluating the Methylphenidate Patch to Treat Former Stimulant Users With ADHD (NCT00780208), a na na study. The primary outcome is ADHD Symptom Severity.

2. Clinical Question

The research question is whether symptom scores changed over the study period among participants receiving the patch, alongside monitoring of safety. The record also lists the number of participants with a positive drug screen as a secondary outcome. It does not describe a comparison with placebo, usual care, or another active treatment. The findings that can be read from the registry record are therefore limited to its design description, endpoint definitions, and posted safety counts; the primary efficacy result is not reported in the registry record.

3. Trial Design

The registry record describes a completed, single-group study sponsored by the Medical University of South Carolina. It lists an enrollment of 14 and one intervention, Daytrana (methylphenidate patch). The study is not described as randomized: allocation is recorded as NA, masking is NONE, and the model is SINGLE GROUP. There is no like-for-like control comparison in this design.

The record gives a start date of 2007-04 and a primary completion date of 2008-10. It lists the condition as adult ADHD and describes the study population as adults who had abused stimulants in the past. The record does not report further details about participant eligibility, treatment duration, dose, dose adjustment, adherence, or the timing and conduct of study visits beyond the primary endpoint timeframe.

The primary outcome is ADHD symptom severity, described as mean change from baseline in the Wender-Reimherr Adult Attention Deficit Disorder Scale total score, with baseline and Week 8 identified as the timeframe. The record also lists the number of participants with a positive drug screen as a secondary outcome. Although two outcome measures are listed, the record reports no analyses. It does not state which statistical procedure was planned or used to evaluate the primary endpoint.

A single-group before-and-after design can describe how measurements changed among enrolled participants, but it cannot by itself separate a treatment effect from other explanations for change over time. These can include natural symptom fluctuation, concurrent care, changes in participant circumstances, or measurement effects. Without a comparison group, the design does not estimate what would have happened to similar participants over the same period without the patch. The registry record does not report a protocol or a rationale for choosing this design.

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

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 ADHD Symptom Severity, measured over Baseline, Week 8.

The primary endpoint is ADHD symptom severity measured with the Wender-Reimherr Adult Attention Deficit Disorder Scale (WRAADS) total score. The stated efficacy measure is mean change from baseline, with assessments identified at baseline and Week 8. A change score uses each participant’s measurements at two times to describe how the measured symptom level shifted over the interval; the mean summarizes those individual changes across the participants included in the analysis.

The WRAADS covers seven symptom categories: attention difficulties, hyperactivity/restlessness, temper, affective lability, emotional overreactivity, disorganization, and impulsivity. Individual items are rated from 0 to 2, where 0 means not present, 1 means mild, and 2 means clearly present. The stated total-score range is 0 to 56, with 0 described as no symptoms present and 56 as symptoms clearly present. This makes the endpoint a continuous score intended to represent symptom severity across multiple categories rather than a count of diagnoses.

Using a mean change can provide a concise description of the average direction and size of change in the measured group. The standard deviation describes how dispersed participant scores are around the mean; it is not itself a measure of the precision of the mean. The endpoint definition alone does not reveal the observed change, its uncertainty, or whether changes differed across participants. Those results are not reported in the registry record. The record also does not explain how a clinically important change was defined or whether the scale was administered or scored with any particular procedures.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does mean change describe?

For a continuous measure such as the WRAADS total score, a mean change summarizes the average difference between measurements over time among participants whose data are included. It reduces multiple individual trajectories to one group-level estimate. That summary is useful, but it does not show whether most participants changed in a similar way, whether a few large changes influenced the average, or how much scores varied. Participant-level data or additional summaries would be needed to examine those patterns.

The registry record calls the primary measure mean change from baseline and identifies baseline and Week 8. It does not specify the sign convention used to calculate change, the exact analysis population, or how repeated or unavailable measurements were handled. Those details matter when interpreting a change score. The scale description gives a meaningful orientation to the score itself: lower totals correspond to fewer symptoms on the stated scale. However, without the posted change estimate, there is no observed direction or magnitude to interpret.

What does the standard deviation tell a reader?

A standard deviation describes the spread of observations around their mean. In this setting, it can indicate how much individual change scores differ from the average change. It does not directly tell how precisely the average has been estimated. Precision depends on both the variability in the measurements and the amount of information contributing to the estimate. A confidence interval, when reported, is commonly used to communicate uncertainty around an estimated quantity; a narrower interval indicates greater precision under the assumptions of the analysis. No primary endpoint confidence interval or standard deviation is reported in the registry record.

General statistical interpretation should distinguish variability among participants from uncertainty about a group estimate. A group can have considerable variation in participant changes yet still have a more precisely estimated mean if it has sufficient information, or a seemingly consistent group can still have an uncertain estimate when information is limited. These are related but different questions. The record’s endpoint definition alone cannot answer either one for this study.

What can a single-group design estimate?

A single-group before-and-after study can describe observed change over time within the enrolled group. It does not directly estimate the contrast between outcomes under treatment and outcomes under an alternative condition. The latter is the basis for a causal comparison: it asks how outcomes differ when otherwise comparable groups experience different treatment conditions. In a single group, the unobserved outcome that would have occurred without the intervention is not measured by a concurrent control.

Changes over time may reflect the intervention, but they may also reflect the natural course of symptoms, expectations, other care, changes in circumstances, or measurement variability. This general limitation is especially important when interpreting a pre/post mean as evidence of treatment effect. The registry record lists no separate comparator and no randomized allocation, so a causal comparison is not available from the design description.

How should the planning illustration be read?

Sample-size calculations are planning tools that explore how much information a future study might need under stated assumptions. The registry record’s illustration is based on the observed effect and assumes a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes a hypothetical two-arm comparison, whereas the listed study is single group. It should therefore not be mistaken for the actual allocation or analysis of this trial.

The illustration considers the effect to detect as a stated fraction of the observed effect. In general, planning for a smaller target effect requires more information than planning for a larger target effect, if other assumptions stay fixed. Such a calculation is conditional on assumptions about the effect, variability, test, and allocation. It does not show how likely a reported finding is to be true, and it is not observed power. The registry record does not report a trial-specific sample-size justification or the statistical plan underlying the study.

Why do missing data and analysis details matter?

When some planned measurements are unavailable, the analyzed group may differ from the participants who enrolled. If missingness is related to symptom severity, treatment experience, or other factors, an analysis limited to observed measurements can give a distorted picture of the group’s change. Different analytic approaches rely on different assumptions about missing observations; those assumptions should be stated rather than inferred. The registry record does not report the number with an available Week 8 measurement, the reasons for missing data, or a missing-data method.

The record lists no analyses. It does not specify a statistical test, model, adjustment, handling of multiple outcomes, or analysis population. General methods such as a paired analysis of baseline and follow-up measurements could be relevant to a continuous before-and-after endpoint, but the record does not establish that any particular method was planned or used. Naming a possible method should not be confused with a reported analysis. Without analysis details and numerical results, readers cannot assess model assumptions, reproduce an estimate, or evaluate its uncertainty.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Daytrana (Methylphenidate Patch)")
n   <- c(14)
m   <- c(-17.93)
sp  <- c(5.89)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Daytrana (Methylphenidate Patch)  14  -17.930  5.890  -21.331  -14.529

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists two outcome measures: ADHD symptom severity as the primary outcome and the number of participants with a positive drug screen as a secondary outcome. It reports no analyses. It does not state whether additional outcomes were planned, whether any outcome was measured more than once beyond the stated baseline and Week 8 timeframe, or whether statistical testing was performed. A multiplicity strategy for accounting for several outcomes or tests is not reported in the registry record.

Multiplicity is a general concern when many statistical questions are examined: the chance of obtaining an apparently notable result by chance can increase when results are selected from numerous tests. Whether that concern applies in a particular way depends on the analysis plan and what was actually tested. Because the record does not describe analyses, readers cannot determine whether tests were conducted, how many were considered, or whether any adjustment was used. No statistical significance claim for the primary endpoint can be evaluated from this record.

The analysis population is not reported in the registry record. The listed enrollment does not establish how many participants contributed to the primary outcome analysis. The record also does not report the number with missing baseline or Week 8 scores, reasons for missing measurements, or how missing data were handled. These details affect interpretation because the analyzed participants may not represent all enrolled participants if outcome availability is related to their experience or symptoms.

There is no reported intention-to-treat definition, per-protocol definition, or other analysis-population rule. The record does not state how protocol deviations, withdrawals, or unavailable observations were treated. These are unreported details, not proof that such events did or did not occur. As a result, the registry information does not support an assessment of potential bias from exclusions or missing outcomes, nor a reconstruction of the primary analysis.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

For the Daytrana (Methylphenidate Patch) group, the registry record lists 14 participants at risk for serious adverse events and 0 participants with a serious adverse event. It lists 14 at risk for other adverse events and 10 participants with other adverse events. The death count is 0. No serious adverse event terms are listed in the registry record.

These are counts of participants, not a description of the number, timing, duration, or severity of individual events. The record does not give event-level details for the other adverse events or state how events were attributed. The counts therefore describe what was posted, but do not determine whether an event was caused by the intervention. They also do not show how risks compare with another treatment, because the study has no separate comparator group listed.

A zero count for serious adverse events means none were recorded among the participants listed as at risk in this group; it does not prove that serious events cannot occur. Small studies have limited ability to characterize uncommon events. Conversely, the other adverse-event count alone cannot indicate clinical importance without information about event types, severity, and context. The registry record’s safety counts should be read as descriptive observations, not as a comparative estimate of safety.

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

This study record is useful for identifying a clinical question: symptom severity was to be assessed in adults with ADHD who had abused stimulants in the past while receiving the methylphenidate patch Daytrana. It specifies the primary measure, WRAADS total-score mean change from baseline to Week 8, and posts safety counts for the single intervention group. These details help clarify what the investigators intended to measure and what observations the registry record makes available.

The record does not report the primary symptom result or any analysis. It therefore does not show the observed mean change, how variable changes were, or how precise an estimate might be. It does not establish whether symptom scores increased, decreased, or remained similar. This lack of a reported result should not be read as evidence of no effect; it means the efficacy estimate is not available in the registry record.

Even if a before-and-after change estimate were available, the single-group design would limit causal interpretation. Without a concurrent comparator, change during the study cannot be separated from other influences over time. The record also does not report the analysis population, missing-data handling, or statistical procedure, so the robustness of an efficacy estimate cannot be evaluated from the posted information.

The safety observations are similarly descriptive. The record reports 0 participants with serious adverse events, 10 with other adverse events, and 0 deaths in the listed group. These counts do not establish comparative safety or prove that an event was or was not caused by treatment. They also cannot rule out uncommon harms. In short, the registry record defines the question and provides limited design and safety information, but does not provide enough efficacy results to quantify symptom change or support a causal conclusion.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of how much the design and reporting context determine what a result can mean. A continuous symptom measure is specified, with a defined scale and an intended change-from-baseline endpoint. That gives readers a clear account of the target measurement. Yet the registry record does not report the estimate or its uncertainty, and it lists no analyses. An endpoint definition without an analyzed result cannot answer the efficacy question quantitatively.

The single-group structure also makes the distinction between observed change and treatment effect important. A before-and-after difference, if reported, would describe the measured group over time. A causal effect requires a comparison that helps distinguish the intervention from other possible causes of change. The record lists no such comparator. Recognizing this distinction prevents a within-group change from being interpreted as though it were a randomized treatment contrast.

The record also illustrates why safety counts need context. Counts can be stated accurately while still leaving questions about event types, severity, timing, attribution, and comparison unanswered. The posted counts describe this group; they cannot establish comparative risks. Finally, a planning calculation based on an observed effect and hypothetical assumptions is not evidence of the trial’s actual statistical power. Planning illustrations answer a different question from an observed analysis.

For clinical researchers and biostatisticians, the practical statistical lesson is to separate what is defined, what is observed, and what is inferentially supported. Here the measurement and design are described, some safety counts are posted, but the primary efficacy analysis and several interpretive details are absent. Those distinctions matter when evaluating evidence and when planning future studies with appropriate comparisons, explicit analysis populations, and transparent reporting of uncertainty.

15. 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 key limitation for interpreting efficacy is that the primary endpoint result is not reported in the registry record. Although the endpoint, scale, and baseline-to-Week 8 timeframe are described, no mean change, variability estimate, confidence interval, or analysis is posted. The record therefore does not permit assessment of the size, direction, or precision of symptom change.

The study is listed as single group, with no comparator and no masking. These design features mean that any measured change over time would not provide a controlled estimate of the intervention’s effect. Other explanations for change cannot be separated using a concurrent control contrast because none is listed. The registry record does not provide additional design details that would address this limitation.

The record lists enrollment of 14 but does not state how many participants contributed to the primary endpoint analysis. It does not report missing measurements, withdrawals, adherence, or methods for handling unavailable data. The analysis population and statistical procedure are also not reported. These omissions prevent evaluation of whether the analysis reflects the enrolled group and whether its assumptions were appropriate.

For safety, the posted counts are not accompanied by event descriptions for the other adverse events, timing, severity, or attribution. No serious adverse event terms are listed. The absence of a comparator also means that the record does not provide a comparative safety estimate. The limited group size further constrains what can be learned about uncommon events.

The record does not report a protocol, a sample-size justification, or an analysis plan. Its planning illustration is based on an observed effect and hypothetical assumptions, but it does not replace a trial-specific design rationale or provide observed power. These limitations are specific to the information and design described in the registry record; they should not be filled in by assumption.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Evaluating the Methylphenidate Patch to Treat Former Stimulant Users With ADHD — NCT00780208.
• Registry record last updated 2018-06-14; status last verified 2018-06.
• Results first posted 2018-06-14.
• 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.

19. Record Summary

The registry record describes a completed, single-group study of Daytrana (methylphenidate patch) in adults with ADHD who had abused stimulants in the past. Enrollment is listed as 14. The primary endpoint is mean change from baseline to Week 8 in WRAADS total score, a measure spanning seven ADHD symptom categories. The secondary outcome listed is the number of participants with a positive drug screen.

The record does not report the primary efficacy result or any analyses. Its safety counts for the intervention group are 0 participants with serious adverse events, 10 with other adverse events, and 0 deaths, with 14 listed at risk for each adverse-event category. The single-group design provides no concurrent treatment comparison, and analysis-population and missing-data details are not reported in the registry record. These data support a description of the study and posted safety observations, but not a quantified efficacy estimate or causal treatment conclusion.