STIM+: PET Biomarker Education & Disclosure: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for STIM+: PET Biomarker Education & Disclosure (NCT04818255), a na na study. The primary outcome is Percent of Individuals Demonstrating Disclosure Decision-making Capacity.

2. Clinical Question

This is a question about decision-making after an educational session, not a randomized test of a treatment. The capacity assessment covered understanding, appreciation, rationale, and communication of a decision. Examiners scored responses as correct or incorrect, with prompts or clarification available, and classified the assessment as pass or fail. The registry record also says the study investigated whether capacity differed by diagnosis, comparing MCI with dementia. It does not report the number who passed, the percentage who passed, or results by diagnosis. The study’s broader focus on reactions to biomarker disclosure is distinct from the primary capacity outcome: the registry record does not report those reaction results in the information available for this analysis.

3. Trial Design

STIM+: PET Biomarker Education & Disclosure is listed as a completed, single-group study sponsored by the University of Michigan. The registry record gives enrollment as 152, with a start date of 2020-12-10 and primary completion on 2024-11-07. Phase is listed as not applicable. Allocation is also listed as not applicable, and masking is listed as none.

The intervention is described as behavioral PET biomarker disclosure. The planned process included pre-disclosure education and an interactive interview to assess whether a participant could make an informed decision about receiving PET amyloid and tau information. For participants demonstrating capacity and interest, or when a care partner was able to make the decision, the record describes disclosure of the participant’s personalized biomarker status along with information about its meaning and clinical utility. The available arm description is incomplete, so additional details about the disclosure process are not reported in the registry record.

Because this is a single-group design rather than a randomized comparison, the study does not provide a like-for-like control group for estimating the effect of disclosure versus an alternative. The registry record identifies diagnosis-based differences in capacity as an aim, but it does not establish that diagnosis groups were randomized or otherwise comparable. The timing specified for the primary outcome is immediately following the pre-disclosure education session, within one month of enrollment. Other outcome timing and follow-up details are not reported in the registry record.

The registry record lists 14 outcome measures and 21 analyses. Those counts indicate that the record contains multiple outcomes and analyses, but do not by themselves describe which analyses were prespecified, how they were conducted, or how results were selected for reporting. The statistical plan and further details of the study design are not reported in 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.

Education Session

Disclosure Sesions

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Only participants were surveyed on their interest in learning biomarker results. At the time of this outcome measure, neither participants nor study team knew the participants' amyloid status; therefore, this outcome was designed to be measured independent of biomarker status.

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.

Population: 152 total individuals were eligible and enrolled in the study; they are characterized below. Of these, 2 dyads (2 participants and 2 study partners) did not enter the Education Session intervention (1 dyad lost to follow-up before session, 1 dyad declined after further consideration). Therefore, 148 total individuals began and completed the Education Session.

6. Primary Endpoint

The registry lists the primary outcome as Percent of Individuals Demonstrating Disclosure Decision-making Capacity, measured over Immediately Following Pre-Disclosure Education Session (within one month of enrollment).

The primary endpoint is the percentage of individuals demonstrating capacity to make a decision about PET biomarker disclosure. The registry describes an interactive interview assessing understanding, appreciation, rationale, and communication of a choice to participate or not participate. During education, participants were asked questions about the risks and benefits of disclosure, with prompts or clarification as needed. Examiners subjectively scored responses as correct or incorrect and used those scores to classify capacity as pass or fail.

This endpoint is used to address whether a participant can make the disclosure decision after education, rather than whether the biomarker information changes a clinical outcome. A pass/fail measure turns several dimensions of decision-making into a categorical outcome that can be summarized as a count or percentage. The registry record says the capacity assessment was conducted in participants and not study partners; it also identifies diagnosis-based assessment, comparing MCI with dementia.

The record does not report the number passing or failing, the denominator used for the percentage, or a numerical estimate of the endpoint. It also does not report a confidence interval or other measure of precision for the result. Accordingly, the endpoint’s purpose and assessment process can be described, but the magnitude and precision of the study’s capacity finding cannot be evaluated from the registry information available.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods determine how observations are turned into estimates and how uncertainty is described. The registry record identifies the primary outcome as a participant count summarized as a percentage, with a binary pass/fail classification. It does not report the analysis procedure, the numerical estimate, or its confidence interval. The explanations below describe general statistical concepts and distinguish them from methods that are not reported in the registry record.

What does a percentage estimate represent?

For a binary outcome, the percentage passing is based on the number classified as pass relative to the number included in the assessment. The denominator matters because it defines whose outcomes the percentage describes. In this study, the registry says capacity was measured in participants, not study partners, and that the assessment occurred after pre-disclosure education. However, the registry record does not give the number assessed, the number passing, the number failing, or the denominator used in the reported percentage. It also does not explain how an uncompleted or unclassifiable assessment would be handled.

A confidence interval, in general, gives a range of values compatible with the observed data under a specified statistical method. It helps readers judge precision: a narrower interval generally indicates greater precision, while a wider interval indicates more uncertainty. No interval for the primary outcome is reported in the registry information. Without the estimate and interval, the size and precision of the finding cannot be evaluated.

What can diagnosis-group comparisons establish?

The registry describes an aim to investigate capacity differences by diagnosis, MCI versus dementia. A comparison of group-specific percentages can describe how outcomes differed among those assessed, but interpreting that contrast requires information about group sizes, outcome counts, analysis methods, and uncertainty. Those results and details are not reported in the registry record. More generally, an observed group difference does not by itself show that diagnosis caused the difference. A single-group study without random assignment does not provide the same basis for causal comparison as a randomized trial.

Statistical adjustment can sometimes account for measured differences between groups, but it cannot guarantee control of unmeasured differences. The registry record does not report whether adjusted analyses were conducted, which covariates would have been considered, or how any diagnosis comparison was specified. No adjusted or unadjusted diagnosis result can therefore be described.

What does the planning information mean?

The record describes planning illustrations based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. For time-to-event outcomes, the illustrations are described as reporting total events using the Schoenfeld approach; for other outcomes, they are described as reporting participants per arm. The record also says the effect to detect is a stated fraction of the observed effect. The actual illustration values and the specific effect fractions are not reported in the information.

These assumptions describe a planning exercise, not the design or observed result of this single-group study. In particular, equal allocation between two arms does not turn the study into a randomized two-arm comparison. Sample-size illustrations estimate what a hypothetical future study might require under assumptions; they are not a measure of the study’s observed power. Observed power is not a substitute for reporting an effect estimate and its uncertainty.

Over-dispersion is a general issue for count outcomes when variability is greater than a chosen statistical model expects. If it is ignored, standard errors and confidence intervals may be inaccurate. The primary outcome is described as a binary capacity classification, not as an over-dispersed count outcome. The registry record does not report a model for the primary endpoint or any assessment of over-dispersion for other outcomes, so no claim about its use is warranted.

What analysis details are absent?

The registry record does not report the statistical test or model for the primary endpoint, the confidence-interval method, a prespecified hypothesis, covariate adjustment, or procedures for missing observations. It also does not report whether interim analyses took place. Such details affect how results should be interpreted, especially when outcomes are categorical, observations are incomplete, or multiple comparisons are considered. Their absence from the registry information means they cannot be inferred from the design description, the outcome title, or the study’s completed status.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Mild Cognitive Impairment", "Dementia")
n      <- c(32, 46)
events <- c(25, 10)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Mild Cognitive Impairment  32  25  78.1  60.0  90.7  61.2  89.0  61.1  88.9
ARM  Dementia  46  10  21.7  10.9  36.4  12.3  35.6  12.3  35.7

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 14 outcome measures and 21 analyses. Multiple outcomes and analyses create a general multiplicity concern: when many statistical questions are examined, the chance of at least one apparently notable result can rise, depending on how tests are conducted and interpreted. A multiplicity adjustment is one possible approach, but whether it is appropriate depends on the aims and analysis plan. The registry record does not report whether adjustments were planned or applied, how outcomes were prioritized beyond identifying the primary outcome, or how the 21 analyses relate to the listed outcome measures.

Missing data are also relevant to a percentage endpoint. If some participants were not assessed or could not be classified, the estimate could depend on how those cases were handled and on the denominator chosen. The registry record does not report missingness, exclusions, or any imputation or other missing-data procedure. It is therefore not possible to determine whether the endpoint represents all enrolled participants, only those completing the interview, or another analysis population.

The record identifies capacity as measured in participants and not study partners. It does not report a fuller definition of the analysis population, any per-protocol or other analysis sets, or how deviations from the planned assessment were addressed. The statistical analysis plan, including multiplicity and missing-data methods, is not reported in the registry record. Those absences limit assessment of the robustness and reproducibility of any result; they do not establish that a particular method was or was not used.

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 1% reporting threshold.

The registry lists four groups: amyloid-positive participants, amyloid-negative participants, and study partners of participants in each biomarker category. In each listed group, the reported count of serious adverse events is zero, the count of other adverse events is zero, and deaths are zero. The at-risk counts are reported separately for the serious-event and other-event listings: 60 and 60 for amyloid-positive participants, 18 and 18 for amyloid-negative participants, 59 and 59 for study partners of amyloid-positive participants, and 11 and 11 for study partners of amyloid-negative participants.

These are reported event counts, not estimates of the probability of an event. The registry record does not report the observation period for these safety counts, how events were collected or adjudicated, whether all listed individuals completed safety follow-up, or how missing safety information was handled. Zero reported events should therefore be read as a description of the registry entries, not proof that no events occurred outside the recorded information or that the process has no risk. The group entries should not be added together to infer a total number of distinct participants.

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

The study is designed to address whether people with MCI or DAT can demonstrate decisional capacity after receiving education about PET amyloid and tau disclosure. Its assessment focuses on understanding, appreciation, rationale, and communicating a choice. That is a meaningful statistical distinction: the outcome concerns the process of making an informed decision, not whether biomarker disclosure changes disease progression or another clinical outcome.

The registry record states that the study was completed and describes its goals, design, and endpoint, but it does not report the primary outcome result in the information available for this analysis. No pass percentage, uncertainty interval, or diagnosis-specific estimate can be interpreted. The result therefore cannot establish how often participants demonstrated capacity, how precise that estimate was, or whether capacity differed by diagnosis.

The single-group design also limits what can be concluded about cause and effect. There is no randomized control group to distinguish outcomes associated with education and disclosure from outcomes that might have occurred without that process. The study can be understood as an assessment of capacity and reactions in the study context, but a causal treatment-effect claim is not supported by the design information described in the registry.

The record’s safety entries show zero reported serious events, other events, and deaths in each listed group. Their meaning is bounded by the absence of details on monitoring time, event ascertainment, and missing safety information. They should not be expanded into a general claim that disclosure is risk-free.

More broadly, the registry information does not report results for the second goal concerning reactions of participants and care partners. It also does not provide analysis methods or details needed to assess missing data and multiplicity. The scientifically appropriate conclusion is therefore limited: the record documents a completed study with a defined capacity assessment and disclosure aims, but the numerical outcome findings and much of the information needed to judge their precision and robustness are not reported in the registry record.

14. Why This Trial Matters Statistically

This study raises a statistical question that differs from the usual comparison of a treatment against a control: whether a person can make a decision about receiving sensitive biomarker information after education. The primary endpoint is a binary assessment of a decision-making process, built from examiner-scored responses about understanding, appreciation, rationale, and communication. Readers therefore need to understand both the construct being measured and the rules used to classify a pass or fail.

Its design also highlights why the analysis population and denominator matter. A percentage is only interpretable when readers know who was assessed and how incomplete or unclassifiable assessments were treated. The registry record does not report those details or the primary estimate, so it cannot show either the level of capacity observed or the precision of that estimate.

The study includes two related but distinct aims: capacity following education and reactions after biomarker disclosure. Separating them is important because success on a decision-capacity assessment is not the same outcome as a participant’s or care partner’s reaction to receiving results. The registry record identifies both aims, but does not report numerical results for them in the information.

Finally, the record illustrates the limits of interpreting multiple outcomes and analyses without a statistical plan. It lists many measures and analyses, but does not report multiplicity procedures, missing-data methods, or the analysis populations. Clear reporting of these elements would help readers judge how stable and reproducible any findings are. The study’s statistical importance lies in the careful framing of informed disclosure as an assessable decision-making question, while the missing result and analysis details constrain conclusions from the registry record.

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 main limitation for interpreting the study from the registry record is that it does not report the primary outcome estimate. The number of participants who passed or failed, the denominator for the percentage, and a measure of uncertainty are not available. Without these, the capacity finding cannot be quantified or evaluated for precision.

The record also does not report the outcome results for the stated aim of assessing participant and care-partner reactions to biomarker disclosure. The timing and methods for those assessments are not described in the information. Although the primary capacity timing is stated, the registry record does not give further follow-up details for the broader aims.

The single-group design has no randomized comparator, limiting causal interpretation. The record mentions interest in differences by diagnosis but does not report group-specific results, group comparability, or the statistical method for such comparisons. The available description of the intervention is incomplete, and further details of the education and disclosure procedures are not reported.

Important analytical details are also absent: the statistical model or test, confidence-interval method, handling of missing observations, analysis populations, and any multiplicity adjustment. Safety entries report zero events, but observation time, event ascertainment, and completeness of safety follow-up are not reported. These gaps do not show that methods were not used; they mean the registry record does not permit their evaluation. The listed enrollment and completed status alone do not resolve these interpretive limitations.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: STIM+: PET Biomarker Education & Disclosure — NCT04818255.
• Registry record last updated 2026-01-29; status last verified 2026-01.
• Results first posted 2026-01-29.
• 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

STIM+: PET Biomarker Education & Disclosure (NCT04818255) is listed as a completed, single-group behavioral study sponsored by the University of Michigan. Enrollment is reported as 152. The study focused on people with MCI or DAT and aimed to assess capacity for PET amyloid and tau disclosure after education, as well as reactions among participants and care partners.

The primary endpoint was the percentage demonstrating disclosure decision-making capacity, assessed immediately after pre-disclosure education. Capacity was classified as pass or fail following an interactive interview. The registry record does not report the primary result, its precision, or the findings for reactions to disclosure. It lists zero serious adverse events, zero other adverse events, and zero deaths in each reported group. Further details on statistical methods, missing data, and safety follow-up are not reported in the registry record.