Software Treatment for Actively Reducing Severity of ADHD: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Software Treatment for Actively Reducing Severity of ADHD (NCT02674633), a randomized na study. The primary outcome is Test of Variables of Attention-Attention Performance Index (Change From Baseline to Posttreatment).

2. Clinical Question

3. Trial Design

This was a randomized, controlled, parallel-group intervention study sponsored by Akili Interactive Labs, Inc. The registry lists quadruple masking, but does not report which roles were masked or how masking was maintained. The study is marked completed. Its start is recorded as 2016-05, and primary completion is recorded as 2017-07-31.

The registry reports enrollment of 348. The primary outcome population is described as all randomized participants. The primary endpoint was measured from Day 0 to Day 28. Participants were assigned to AKL-T01 (EVO Multi) or AKL-T09 (EVO Words); the registry describes both as device interventions. The study model is parallel group, so the listed arms represent separate groups rather than a crossover comparison.

The posted primary outcome summaries include 180.0 participants in the AKL-T01 group and 168.0 in the AKL-T09 group. Their reported mean changes were 0.93 and 0.03, respectively, with a standard deviation of 3.2 in each group. The registry does not report the original design’s sample-size justification, planned allocation ratio, or detailed analysis plan. It also does not explain the operational details of randomization or masking.

The study’s stated purpose was to evaluate digital therapies in relation to attentional functioning and symptoms in children diagnosed with ADHD. The endpoint and intervention descriptions establish what was compared, but do not by themselves determine how broadly the findings apply beyond this trial’s participants, interventions, and short outcome timeframe.

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: Participants who met full criteria for ADHD at Screening and who the PI believed were not optimally treated with current medication were eligible to washout their medication regimen. For those electing to washout, treatment was discontinued between 7 and 3 days prior to their scheduled Baseline Visit.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intent to Treat Population - all randomized participants

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 Test of Variables of Attention-Attention Performance Index (Change From Baseline to Posttreatment), measured over Day 0 to Day 28.

The primary endpoint is change in the Test of Variables of Attention-Attention Performance Index, or TOVA API, from Day 0 to Day 28. The registry reports this continuous measure in z-score units and summarizes it as a mean with a standard deviation. Change is defined as the Day 28 API minus the Day 0 API.

The API combines measures of response time, response discriminability (d'), and response-time variability. The registry describes the API as indicating how similar performance is to an ADHD profile. A score less than 0 indicates performance similar to a normative ADHD population, and a lower score indicates a more severe ADHD profile. This makes the endpoint a measure of attentional performance framed in relation to that profile; it is not itself a direct count of symptoms.

A change score focuses on how the measured API shifted over the stated treatment period. Comparing mean change between randomized groups asks whether their average shifts differed, rather than whether either group’s posttreatment score alone was different from its baseline. Interpretation still depends on the scale’s direction, the precision of the group contrast, and the limits of the posted outcome summary. The endpoint description does not establish that a particular change is clinically important; a threshold for clinical importance is not reported in the registry record.

7. Results Posted in the Registry

• AKL-T09 (EVO Words): mean 0.03 versus 0.93 on control; difference -0.90 (95% CI -1.57 to -0.23), standardized effect d = -0.28; z-test p = 0.009.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

ADHD-RS Total (Change From Baseline to Posttreatment)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • AKL-T09 (EVO Words): mean -5.70 versus -6.20 on control; difference 0.50 (95% CI -1.19 to 2.19), standardized effect d = 0.06; z-test p = 0.562.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between AKL-T09 (EVO Words) and the control. The interval gives the range of effects that remain compatible with the data.

ADHD-RS Inattentive Subscale (Change From Baseline to Posttreatment)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • AKL-T09 (EVO Words): mean -3.20 versus -3.60 on control; difference 0.40 (95% CI -0.65 to 1.45), standardized effect d = 0.08; z-test p = 0.454.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between AKL-T09 (EVO Words) and the control. The interval gives the range of effects that remain compatible with the data.

ADHD-RS Hyperactivity Subscale (Change From Baseline to Posttreatment)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • AKL-T09 (EVO Words): mean -2.50 versus -2.60 on control; difference 0.10 (95% CI -0.83 to 1.03), standardized effect d = 0.02; z-test p = 0.833.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between AKL-T09 (EVO Words) and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcome set broadens the clinical picture beyond the primary attentional-performance measure. It includes ADHD-RS total score and subscales, BRIEF working memory and inhibit percentiles, overall impairment, and CGI-I. The numeric summaries available for ADHD-RS total, inattentive, and hyperactivity change all have unadjusted confidence intervals that include zero. The registry’s listed outcome set also includes measures for which numerical results are not reported in the registry record.

That overall pattern is not a clear replication of the primary comparison across the numeric secondary summaries. This need not be viewed as a contradiction: the measures assess different constructs, use different scales, and may have different variability. A primary contrast in TOVA API change is not expected to imply an identical contrast on symptom scales or functional measures. Conversely, the secondary summaries do not erase or independently confirm the primary result.

Secondary outcomes generally carry less inferential weight when many outcomes are examined and no adjustment for multiplicity is reported. Each additional comparison creates another opportunity for a nominally notable result to occur by chance. The registry record does not report a multiplicity strategy, so the unadjusted secondary p-values should be considered exploratory rather than treated as a set of independently definitive tests.

Interpretation is also limited by incomplete outcome reporting in the registry record. The listed measures indicate what was designated as secondary, but listed outcomes without numeric results do not tell readers whether results were favorable, unfavorable, or inconclusive. Their absence cannot be filled in from the primary endpoint. The secondary outcomes should therefore be considered as a wider planned assessment framework, with the available summaries interpreted cautiously and separately from the primary comparison.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• ADHD-RS Total (Change From Baseline to Posttreatment)
• ADHD-RS Inattentive Subscale (Change From Baseline to Posttreatment)
• ADHD-RS Hyperactivity Subscale (Change From Baseline to Posttreatment)
• BRIEF Working Memory Percentile (Change From Baseline to Posttreatment)
• BRIEF Inhibit Percentile (Change From Baseline to Posttreatment)
• Impairment Rating Scale, Overall Impairment (Change From Baseline to Posttreatment)
• CGI-I (at Posttreatment)

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: the registry reports a mean change and standard deviation for each randomized group. A mean is the arithmetic average of participant-level values. The standard deviation describes how dispersed those values are around the group mean. These quantities answer different questions: the mean describes the group’s average change, while the standard deviation describes variation among participants.

What does the mean difference represent?

The reported mean difference compares the AKL-T09 mean with the AKL-T01 mean. Its value is -0.9. The negative sign indicates that the AKL-T09 group’s average change was lower under this comparison’s stated ordering. The difference is expressed in the endpoint’s z-score units. It is not a percentage change or a count of participants. The endpoint’s own definition supplies the clinical direction: lower API scores indicate a more severe ADHD profile.

Random assignment is intended to make treatment groups comparable on average, including with respect to factors that are not measured. In a randomized comparison, a between-group difference is generally more informative about the assigned interventions than a before-and-after change within one group alone. However, the registry record does not describe the randomization procedure in detail, and the posted outcome summaries do not address every possible source of bias or uncertainty.

How should the confidence interval be understood?

A confidence interval gives a range of values compatible with the data and the method used to estimate the contrast. It conveys uncertainty around the mean difference; it is not a range containing a specified proportion of individual participants’ changes. The primary interval lies entirely below zero, which is consistent with a nonzero contrast in the stated direction under the unadjusted analysis. The interval does not by itself show whether the difference is important in practice. A threshold for clinical importance is not reported in the registry record.

The p-value of 0.009 is an unadjusted measure of how unusual data at least as incompatible with a zero-difference model would be under that model and the analysis assumptions. It is not the probability that the null hypothesis is true, nor does it measure the size or practical importance of the contrast. Because the registry does not report a multiplicity procedure, this p-value should be understood as unadjusted rather than as evidence corrected for examining multiple outcomes.

What do the secondary summaries add?

The secondary ADHD-RS summaries also report group means and standard deviations for change scores. The reported comparisons are unadjusted mean differences. Their confidence intervals include zero, and their unadjusted p-values do not provide strong evidence of a difference between groups in those summaries. This does not demonstrate equivalence or rule out differences that the data estimate imprecisely. The registry does not report equivalence margins or a prespecified interpretation threshold.

The registry lists additional secondary measures, including BRIEF percentiles, an impairment rating, and CGI-I. Numerical results for those measures are not reported in the registry record. The absence of a numerical result in the record should not be interpreted as a zero effect or as evidence that no outcome was collected.

What is known about the analysis population?

The primary endpoint description specifies an intent-to-treat population consisting of all randomized participants. This identifies the intended population for that endpoint, but the registry record does not describe how missing outcome measurements were handled or whether every randomized participant contributed a Day 28 value. The endpoint-specific group counts in the posted summaries should therefore be read as the counts associated with those summaries, not as evidence about why records may be absent.

The registry does not report a detailed statistical analysis plan, covariate adjustment, model specification, or interim-analysis procedure. The comparisons discussed in these explanations are simple, unadjusted contrasts of the posted group summaries. The sponsor’s own analysis is not reported as a separate formal analysis in the registry record. With no discrepancy flagged between the posted summaries and the comparison, the result can be described as shown, while recognizing that the full sponsor analysis methods are not reported.

Standard deviations and confidence intervals have different roles in these methods. Standard deviations characterize participant-level spread; confidence intervals characterize estimation uncertainty for a group contrast. General statistical reasoning also cautions that unusually dispersed continuous outcomes can make a simple normal-based comparison less dependable. Whether that concern affected the sponsor’s analysis cannot be determined from the registry record because detailed modeling diagnostics are not reported.

11. Confidence Intervals and Precision

The primary mean difference is -0.9, and its reported confidence interval lies wholly below zero. This interval indicates that the estimated contrast is not pinpointed to a single exact value; it gives a range of values compatible with the data and the interval method. Because the interval does not include zero, it aligns with the unadjusted p-value of 0.009 in indicating a nonzero contrast under the analysis assumptions.

Precision is not the same as clinical importance. The interval describes uncertainty about the mean difference on the API scale, not the range of individual participant responses and not the probability that an intervention will produce a particular result for a particular person. The registry record does not report a clinically important difference threshold, so the interval cannot be classified against such a threshold using the registry information.

Both primary groups have a standard deviation of 3.2, indicating participant-level variation around their respective mean changes. That spread is considerably broader in meaning than the uncertainty in the group contrast: individual changes vary, while the confidence interval summarizes uncertainty in the estimated difference between group averages. A statistically detectable average contrast does not mean every participant changed in the same direction or by the same amount.

The secondary comparisons are less conclusive in their posted summaries: their confidence intervals include zero. That means the values compatible with those estimates include no between-group difference, as well as differences in either direction. It does not prove that the groups are identical. Precision depends on the observed variability and the amount of information available for each outcome, and the registry does not report a precision target or equivalence criterion.

For the primary comparison, the posted confidence interval can support a directional interpretation of the mean contrast, but cannot resolve questions the endpoint does not measure. Longer-term outcomes, clinical relevance thresholds, and the robustness of results under alternative analysis choices are not reported in the registry record.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm for 80% power and participants per arm for 90% power. They are not total events: this is a continuous-outcome study, and the stated planning quantities are participants per arm. The planning illustration uses a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It considers detecting the stated fraction of the observed effect, with rows for 100%, 75%, and 50% of that effect.

The 80% power column describes the planned group size under which the calculation would have an 80% chance of detecting the specified effect if that effect and the planning assumptions were correct. The 90% column uses a higher chance of detection under the same kind of assumptions and consequently calls for more participants per arm. These are planning illustrations based on the observed contrast, not a record of the original trial’s design rationale. The trial’s own sample-size justification and original design assumptions are not reported in the registry record.

Smaller effects are harder to distinguish from random variation, so the illustration requires more participants per arm when the target is a smaller fraction of the observed effect. The estimates therefore change substantially across the rows, especially when planning around a smaller effect. They should be read as conditional planning values, not as guarantees that a future study will obtain a particular result.

This is not observed power. It does not describe the probability that the completed trial’s result is true or the probability that a future trial will succeed. The trial’s reported enrollment was 348, but the planning illustration is a separate calculation using the stated assumptions, rather than a reconstruction of the original design.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -0.900; pooled standard deviation σ = 3.200.
2. n = 2 × (1.96 + 0.842)² × 3.200² / -0.900² = 198.5, rounded up to 199 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -0.9                      # observed difference in means
sigma <- 3.2                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(2674633)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 199 (80% power), 266 (90% power)
 75% of observed effect: n per arm = 353 (80% power), 473 (90% power)
 50% of observed effect: n per arm = 794 (80% power), 1,063 (90% power)
power.t.test: 199.4 
Simulated power at n = 199 per arm: 0.797 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry identifies a primary endpoint and multiple secondary outcomes. It reports an unadjusted p-value for the primary comparison and for the three numeric ADHD-RS secondary comparisons. It does not report whether a hierarchy, family-wise error procedure, false-discovery procedure, or other multiplicity adjustment was planned or applied. Without that information, the p-values should be read as unadjusted findings for their respective comparisons, not as values corrected for the number of outcomes examined.

Multiplicity matters because considering many outcomes can increase the chance of at least one apparently unusual result even when there is no underlying difference. This is a general statistical concern, not evidence that any particular result in this study is false. The primary endpoint’s designation is relevant to interpretation, but the registry record does not explain whether the analysis plan gave it a formally protected testing position or how secondary findings were intended to be interpreted.

The primary population is defined as all randomized participants. That definition is useful, but does not describe the actual handling of missing endpoint values. Missing-data rules, imputation methods, sensitivity analyses, and reasons for unavailable measurements are not reported in the registry record. The secondary outcome summaries have endpoint-specific participant counts, and the registry does not explain differences between those counts and the primary endpoint counts.

The registry record also does not report a detailed model specification, covariate adjustments, interim analyses, or prespecified sensitivity analyses. Such details can affect the interpretation of uncertainty and the degree to which the results depend on analysis choices. Their absence means readers cannot assess those features from the registry record alone. It does not establish that such methods were or were not used outside the posted record.

15. 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

The registry reports zero serious adverse events in each group: the AKL-T01 group had 0 among 180 participants at risk, and the AKL-T09 group had 0 among 168 participants at risk. Deaths are reported as 0 in both groups. These figures describe the serious-event and death counts recorded during the study; they do not establish that no other adverse events occurred.

Other adverse events are reported separately: 12 in the AKL-T01 group and 3 in the AKL-T09 group. These are not the serious adverse event counts. The registry does not report event descriptions or a causal assessment in the information available for these summaries, so the counts alone do not show whether an event was related to an intervention or how severe the non-serious events were.

Zero recorded serious events in these groups should be interpreted as a count in this study, not proof that serious events cannot occur. The registry record does not provide enough detail to characterize event timing, duration, recurrence, or the completeness of safety follow-up. Safety figures are descriptive and should be considered alongside the study’s recorded population and timeframe.

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

The posted primary results show a difference in average change in TOVA API between the randomized groups over Day 0 to Day 28. AKL-T01 had a mean change of 0.93, while AKL-T09 had a mean change of 0.03. The reported contrast for AKL-T09 relative to AKL-T01 was -0.9, with an unadjusted p-value of 0.009 and a confidence interval lying below zero. This is evidence of a group-level difference on the specified endpoint in the posted comparison.

The endpoint’s direction matters: the registry says lower API scores indicate a more severe ADHD profile. That description provides context for interpreting the contrast but does not transform the result into a general conclusion about symptoms or everyday functioning. The trial compared two digital interventions, not either intervention with no intervention or an untreated control. The result therefore addresses their relative mean changes in this particular study, rather than an effect relative to no treatment.

The result does not establish that every participant benefited, that the observed average difference is clinically important, or that it would continue beyond the measured period. The registry record does not report a clinical-importance threshold, longer-term primary endpoint, or detailed missing-data and analysis procedures. The secondary results also do not show a clear unadjusted difference across the numeric ADHD-RS summaries, and numerical findings for other listed secondary measures are not reported in the registry record.

Statistical evidence is not a substitute for a complete account of the study. The posted means, standard deviations, contrast, confidence interval, and p-value describe the available endpoint summary; they do not answer every question about adherence, individual response, masking success, or outcome relevance. Those details are not reported in the registry record. The safest reading is specific: a nonzero unadjusted mean contrast was reported for the primary API change measure, while broader clinical conclusions are not established by that result alone.

17. Why This Trial Matters Statistically

This study illustrates why the definition and direction of a clinical endpoint matter. TOVA API is a composite attentional-performance measure built from response time, discriminability, and variability. The registry also supplies an interpretation of its scale: lower values indicate a more severe ADHD profile. Without that scale context, the negative sign of the reported mean difference could be easy to misread.

It also demonstrates the distinction between a group mean contrast and participant-level outcomes. The primary comparison concerns average change, while the standard deviations describe variation among participants. A statistically notable average difference can coexist with a broad distribution of individual changes. Reporting both the contrast and its uncertainty is therefore more informative than relying on a p-value alone.

The comparison is between two different digital interventions, making the estimand relative rather than a comparison against no intervention. This shapes the question the randomized design can answer: whether the groups differed on the endpoint, not whether either intervention has an effect relative to an untreated condition. That distinction is essential when translating a clinical-trial result into a precise statistical statement.

Finally, the record shows how interpretation depends on transparency beyond headline results. The registry lists secondary outcomes, but numerical results for some are not reported; it does not report a detailed multiplicity or missing-data strategy. Recognizing these omissions helps separate what the posted primary result supports from what remains unresolved.

18. 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 primary outcome is measured over Day 0 to Day 28, so the posted result pertains to a short timeframe. Longer-term outcomes are not reported in the registry record. The primary endpoint is a composite z-score with a specific direction and interpretation; it does not encompass every aspect of ADHD symptoms, functioning, or participant experience.

The comparator is another active digital intervention. Consequently, the result does not directly compare AKL-T01 or AKL-T09 with no intervention or usual care. The registry describes quadruple masking but does not identify the masked roles or provide details that would allow readers to assess how masking was implemented or whether it was maintained.

Although the primary population is identified as all randomized participants, the registry record does not report how missing observations were handled, why outcome-specific counts differ, or whether sensitivity analyses were conducted. It also does not report a detailed statistical analysis plan, model specification, multiplicity adjustment, or clinical-importance threshold. Those omissions restrict assessment of robustness and practical meaning.

The available secondary numeric results cover three ADHD-RS outcomes; numeric results for other listed secondary measures are not reported in the registry record. The registry’s safety counts provide limited detail about event types, timing, and causal attribution. Finally, the findings are from children ages 8 to 12 years old in this study and should not be assumed to describe other populations or settings.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Software Treatment for Actively Reducing Severity of ADHD — NCT02674633.
• Registry record last updated 2020-08-14; status last verified 2020-08.
• Results first posted 2020-07-24.
• 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.

22. Record Summary

The registry record describes a completed randomized, quadruple-masked, parallel-group study of AKL-T01 (EVO Multi) and AKL-T09 (EVO Words) in pediatric participants ages 8 to 12 years old with ADHD. Enrollment was 348. The primary endpoint was change in TOVA API from Day 0 to Day 28 in the intent-to-treat population.

The posted primary comparison reports mean changes of 0.93 and 0.03, respectively, and a mean difference of -0.9 for AKL-T09 relative to AKL-T01. The unadjusted p-value is 0.009, and the reported confidence interval lies below zero. Numeric ADHD-RS secondary comparisons have confidence intervals including zero; numeric results for other listed secondary outcomes are not reported in the registry record.

Serious adverse event counts and deaths are reported as zero in both groups. The registry does not report the original sample-size justification, detailed analysis plan, missing-data methods, or multiplicity procedure.