SMILE: Clinical Trial to Evaluate Mindfulness as Intervention for Racial and Ethnic Populations During COVID-19: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for SMILE: Clinical Trial to Evaluate Mindfulness as Intervention for Racial and Ethnic Populations During COVID-19 (NCT06242080), a randomized na study. The primary outcome is Change From Baseline to Post-Intervention in the Generalized Anxiety Disorder-7 Scale.

2. Clinical Question

The study's stated aims also include assessing stress, quality of life, autonomic measures, and intervention sustainability. The posted primary outcome is specifically change in GAD-7 score from baseline to the post-intervention assessment at 8 weeks. These results therefore address one part of the broader research question. The registry record lists 398 participants enrolled, while the primary outcome results are based on smaller groups with valid, uploaded measurements at both time points. The record does not explain the relationship between total enrollment and the participants represented in the primary results.

3. Trial Design

This is a randomized, single-masked, parallel-group trial with three groups: MTIA intervention, MAPP intervention, and wait-list control. The registry record identifies the phase as not applicable. It lists the University of North Carolina, Chapel Hill as sponsor, an enrollment of 398, and a status of terminated. The recorded study start is 2024-05-13 and the primary completion date is 2025-05-27. The reason for termination is not reported in the registry record.

The study description identifies adults who self-identify as African American, Black and/or Latino, with clinically significant anxiety, as the intended study population. The MTIA approach is described as instructor-administered, while MAPP is described as self-administered through an app. The wait-list control group was to complete study assessments without receiving the mindfulness intervention during its research role. Both mindfulness approaches are described as organized around an 8-week program. The full intervention details are not reported in the registry record.

The primary assessment compares change in GAD-7 score from baseline to week 8. The analysis population is described as participants with valid, uploaded data at both baseline and week 8. The overall group comparison is reported using ANOVA. The displayed arm summaries contain 24 participants for MTIA, 16 for MAPP, and 31 for wait-list control. These outcome counts differ from the total enrollment, but the reasons for missing or unavailable outcome data are not reported in the registry record.

The record lists 37 outcome measures and 16 analyses. The listed secondary outcomes include autonomic activity, parasympathetic activity, vagal efficiency, and COVID-19-related stress. The available record does not report the original sample-size justification, detailed randomization procedures, masking procedures, or a complete statistical analysis plan. It also does not describe why the study was terminated.

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: Of the 398 individuals who signed informed consent, 196 confirmed eligibility, completed enrollment procedures and were randomized.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Data are reported for all participants with valid, uploaded data available at both Baseline and Week 8.

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 Change From Baseline to Post-Intervention in the Generalized Anxiety Disorder-7 Scale, measured over Baseline, 8 week.

The primary endpoint is change from baseline to the 8-week assessment in the Generalized Anxiety Disorder-7 scale, or GAD-7. This is a seven-item self-report questionnaire about the frequency of anxiety over the prior 2 weeks. Each response is scored from 0, meaning not at all, to 3, meaning nearly every day; the items are summed to produce a total score from 0 to 21. Higher scores indicate greater anxiety symptoms.

Using change scores focuses the comparison on how reported symptoms shifted over the intervention period, rather than on the end-of-period score alone. The study description says the among-group differences in change scores are compared by ANOVA. The posted results give mean change and standard deviation for each group. The mean changes are -4.0 for MTIA, -3.0 for MAPP, and -2.0 for wait-list control. Because higher GAD-7 scores indicate more symptoms, a negative change represents a reduction in reported score within a group. These within-group changes do not, by themselves, establish that the intervention groups changed differently from control.

GAD-7 is used as a patient-reported symptom measure, not as a direct assessment of every clinical or functional outcome. The endpoint description does not report a threshold for interpreting a change as clinically important. The registry record also does not report how missing or invalid questionnaires were handled beyond defining the primary outcome population as participants with valid, uploaded data at both assessments.

7. Results Posted in the Registry

• "MTIA" Intervention: mean -4.00 versus -2.00 on control; difference -2.00 (95% CI -4.98 to 0.98), standardized effect d = -0.37; z-test p = 0.188.
• "MAPP" Intervention: mean -3.00 versus -2.00 on control; difference -1.00 (95% CI -3.63 to 1.63), standardized effect d = -0.21; z-test p = 0.457.

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.

Change in Autonomic Activity From Baseline to Post-Intervention as Measured by Heart Period

• 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:
  • "MTIA" Intervention: mean -16.00 versus 5.00 on control; difference -21.00 (95% CI -128.22 to 86.22), standardized effect d = -0.16; z-test p = 0.701.
  • "MAPP" Intervention: mean -64.00 versus 5.00 on control; difference -69.00 (95% CI -139.85 to 1.85), standardized effect d = -0.78; z-test p = 0.056.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between "MTIA" Intervention and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between "MAPP" Intervention and the control. The interval gives the range of effects that remain compatible with the data.

Change in Parasympathetic Activity Baseline to Post-Intervention as Measured by High-frequency Heart Rate Variability (HF-HRV)

• 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:
  • "MTIA" Intervention: mean -0.10 versus -0.40 on control; difference 0.30 (95% CI -0.91 to 1.51), standardized effect d = 0.20; z-test p = 0.628.
  • "MAPP" Intervention: mean -1.00 versus -0.40 on control; difference -0.60 (95% CI -1.68 to 0.48), standardized effect d = -0.44; z-test p = 0.277.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between "MTIA" Intervention and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between "MAPP" Intervention and the control. The interval gives the range of effects that remain compatible with the data.

Change in Vagal Efficiency Baseline to Post-intervention Measured Using HF-HRV and Heart Period Coupling

• 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:
  • "MTIA" Intervention: mean -7.60 versus -1.60 on control; difference -6.00 (95% CI -25.14 to 13.14), standardized effect d = -0.26; z-test p = 0.539.
  • "MAPP" Intervention: mean 6.80 versus -1.60 on control; difference 8.40 (95% CI -5.99 to 22.79), standardized effect d = 0.49; z-test p = 0.253.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between "MTIA" Intervention and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between "MAPP" Intervention and the control. The interval gives the range of effects that remain compatible with the data.

The registry lists a broad set of secondary outcomes, including autonomic activity, high-frequency heart rate variability, vagal efficiency, and COVID-19-related stress. The detailed secondary results include baseline-to-post-intervention comparisons for heart period, HF-HRV, and vagal efficiency. Across these displayed summaries, the direction and size of group contrasts are not consistent: some estimates favor a more negative change in an intervention group, while others favor a more positive change. The corresponding recalculated intervals include zero, and the estimates are based on small outcome groups.

These secondary measures are related to the study's wider aims, but they do not replace the primary GAD-7 endpoint. In particular, autonomic measurements are distinct outcomes and cannot, on their own, establish a difference in reported anxiety symptoms. The primary result is an overall ANOVA p-value of 0.341, with unadjusted pairwise calculations whose intervals include zero. The secondary findings do not change that primary statistical reading.

The record lists 35 posted secondary outcomes, but the available detailed results do not supply a complete set of estimates for all of them. It is therefore not possible to infer a single pattern across every secondary measure. The registry record does not report a multiplicity adjustment plan. When multiple outcomes and comparisons are examined, isolated unadjusted results carry less weight because some may look unusual by chance. The secondary measures are best read as exploratory evidence about the study's broader questions, with attention to their sample sizes, uncertainty, and the incomplete reporting of analysis details.

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

• Change in Autonomic Activity From Baseline to Post-Intervention as Measured by Heart Period
• Change in Autonomic Activity From Baseline to Follow-up as Measured by Heart Period
• Change in Parasympathetic Activity Baseline to Post-Intervention as Measured by High-frequency Heart Rate Variability (HF-HRV)
• Change in Parasympathetic Activity Baseline to Follow-up as Measured by High-frequency Heart Rate Variability (HF-HRV)
• Change in Vagal Efficiency Baseline to Post-intervention Measured Using HF-HRV and Heart Period Coupling
• Change in Vagal Efficiency Baseline to Follow-up Measured Using HF-HRV and Heart Period Coupling
• Change in the COVID-19 Stress Scale Baseline to Post-Intervention
• Change in the COVID-19 Stress Scale Baseline to Follow-up

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: it is a numerical score, and the registry reports group means and standard deviations. A mean describes the central value of the observed changes, while a standard deviation describes how much individual changes vary around that mean. The same mean can arise from quite different participant-level patterns, so the spread matters when judging how precisely the mean is estimated.

What does the overall ANOVA test?

ANOVA is a method for comparing means across groups. In this trial's primary analysis, the registry reports an ANOVA comparison across MTIA, MAPP, and wait-list control. An overall ANOVA asks whether the group means are consistent with a common value or whether there is evidence of some difference among them. It does not, by itself, identify which pair of groups differs. The registry reports p = 0.341 for this overall analysis. A p-value describes how incompatible the observed data are with a specified null model, under the assumptions of the test. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of a difference.

What do the pairwise estimates add?

The pairwise figures compare each mindfulness group with the wait-list control. They are recalculations from posted summary statistics and are unadjusted. An estimated mean difference gives the contrast in average change between the two groups; a negative estimate in these comparisons means the intervention group's average change was more negative than the control group's. The estimates are -2.0 for MTIA versus control and -1.0 for MAPP versus control. The associated unadjusted p-values and confidence intervals convey uncertainty about these contrasts. These pairwise calculations are not a replacement for the sponsor's reported omnibus analysis.

Unadjusted means that the pairwise p-values have not been adjusted to account for testing more than one contrast. When many outcomes or comparisons are examined, the chance of encountering a nominally unusual result can increase. The registry record does not report whether a multiplicity plan was used for these comparisons or across the wider set of outcomes. Therefore, isolated unadjusted secondary findings warrant particular caution.

Why do confidence intervals matter?

A confidence interval gives a range of values compatible with the data and the method used to calculate it. It shows the uncertainty around an estimate, not a guarantee that the true value lies in a particular interval. For the two primary pairwise recalculations, the intervals include zero. This is consistent with the corresponding unadjusted p-values not providing strong evidence against a zero-difference model. The width of each interval also shows that a range of effect sizes remains compatible with the observed summaries.

The recalculated contrasts use pooled standard deviations and standard errors derived from the group summaries. A pooled standard deviation combines information about variation across the two groups being compared. Such a summary can be useful for an unadjusted comparison, but it does not incorporate participant-level covariates or any adjustments that might have been used in a full analysis. The registry does not report adjusted primary estimates, covariate handling, or a detailed model specification beyond the ANOVA description.

How should the study structure be understood?

Randomized allocation means the record identifies participants as assigned at random, while a parallel model means the groups are followed as separate arms rather than participants crossing between interventions. Single masking is recorded, but the identity of the masked party and the practical masking procedures are not reported in the registry record. The record does not supply enough detail to assess how allocation was generated or concealed.

For the primary endpoint, valid, uploaded measurements at both baseline and week 8 define the analysis population. The registry does not explain whether participants without those measurements were excluded, whether missing values were imputed, or whether sensitivity analyses were undertaken. These matters can affect interpretation if inclusion in the outcome analysis is related to participants' symptoms or experience of the intervention.

For general statistical context, over-dispersion means that observed variation is larger than a statistical model expects. It can make standard errors and confidence intervals too optimistic if the extra variation is ignored. The primary outcome is analyzed as a continuous score, and the record gives standard deviations, but it does not report an over-dispersion assessment. The posted planning assumptions use a normal approximation; those assumptions are for the planning illustration and are not evidence about the original trial's design or analysis choices.

11. Confidence Intervals and Precision

The primary pairwise estimates are imprecise. The MTIA-versus-control mean difference is -2.0, with a 95% confidence interval from -4.977 to 0.977. The MAPP-versus-control mean difference is -1.0, with a 95% confidence interval from -3.634 to 1.634. Each interval spans zero. This means the posted summaries do not rule out no mean difference, and they also remain compatible with differences in either direction within their respective ranges.

These intervals should be read alongside the small outcome groups: the summaries use 24 MTIA participants, 16 MAPP participants, and 31 controls. When group estimates are based on limited numbers of observations and participant changes vary, uncertainty can remain substantial. The primary outcome standard deviations are 6.0, 4.0, and 5.0. The confidence intervals express uncertainty about between-group mean differences; they are not ranges containing most individual participants' changes.

The overall ANOVA p-value of 0.341 offers a separate, omnibus assessment of the three groups. The pairwise intervals and p-values are recalculated unadjusted comparisons, not confidence intervals reported alongside the sponsor's ANOVA. The registry record does not report an interval for the overall ANOVA result. No interval should be interpreted as proving equivalence or absence of an effect. The posted data leave uncertainty about the size and direction of possible group differences.

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 the continuous-outcome comparisons in this trial; they are not total event counts. The planning illustration assumes a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It sets the effect to detect as a stated fraction of the observed effect. For example, the MTIA comparison gives 117 participants per arm for 80% power and 157 participants per arm for 90% power when planning around 100% of the observed effect. For the MAPP comparison, the corresponding figures are 346 and 463 participants per arm.

The 80% power column gives the number of participants per arm estimated to provide an 80% chance of detecting the assumed effect if that effect is real and the planning assumptions hold. The 90% column gives the number per arm for a higher chance of detecting that same assumed effect. These are planning targets, not descriptions of the number enrolled or analyzed. The displayed planning counts are not the trial's original design justification; that justification is not reported in the registry record.

Rows planning for 75% or 50% of the observed effect assume smaller differences to detect than the 100% row. Smaller effects are harder to distinguish from random variation, so they require more participants per arm under the same planning assumptions. The count also varies between the two comparisons because the observed effects and variability used in the illustrations differ.

These figures are a planning illustration based on the observed effects, not observed power. They do not show the probability that the completed trial's findings are true, and they do not revise the interpretation of the reported ANOVA or confidence intervals. The original sample-size assumptions and justification are not reported in the registry record.

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 = -2.000; pooled standard deviation σ = 5.457.
2. n = 2 × (1.96 + 0.842)² × 5.457² / -2.000² = 116.8, rounded up to 117 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 <- -2                      # observed difference in means
sigma <- 5.45651765374771                     # 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(6242080)
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 = 117 (80% power), 157 (90% power)
 75% of observed effect: n per arm = 208 (80% power), 279 (90% power)
 50% of observed effect: n per arm = 468 (80% power), 626 (90% power)
power.t.test: 117.8 
Simulated power at n = 117 per arm: 0.800 (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. Analyses Reported by the Sponsor

The sponsor's reported primary analysis is an ANOVA across all three groups, with p = 0.341. That is the registry's own overall analysis and takes precedence over the pairwise recalculations as the reported sponsor result. It addresses the overall group comparison, not either intervention-versus-control contrast in isolation.

The recalculated contrasts use the posted means, standard deviations, and group sizes to estimate unadjusted differences between each mindfulness group and the wait-list control. They give p = 0.188 for MTIA versus control and p = 0.457 for MAPP versus control. These are separate, unadjusted pairwise calculations, not the sponsor's ANOVA result. The overall test and the pairwise tests answer related but different questions, so their p-values need not match.

The registry does not report the detailed model specification for the ANOVA, whether covariates were included, or a multiplicity adjustment. The recalculations are therefore useful for reading the posted summaries, but they should not be described as a reproduction of the sponsor's full analysis. There is no reported discrepancy between the posted summary statistics and the recalculations.

15. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when a study evaluates multiple outcomes, time points, or group contrasts. As the number of statistical tests increases, the chance of at least one apparently notable result can rise even if there are no true effects. This does not mean that every finding from a study with multiple outcomes is false. It means that individual unadjusted p-values should be interpreted in the context of how many questions were examined and whether the analysis plan identified a primary comparison in advance.

The record lists 37 outcome measures and 16 analyses, and it identifies a primary GAD-7 endpoint. The posted pairwise recalculations are unadjusted. Whether the sponsor applied any multiplicity adjustment, which outcomes were considered confirmatory, and how the analyses were prioritized are not reported in the registry record. The overall ANOVA and the pairwise recalculations also test different hypotheses; the pairwise p-values should not be treated as though they were the sponsor's overall result.

The primary outcome population includes participants with valid, uploaded data at both baseline and week 8. The displayed group sizes are 24, 16, and 31, while total enrollment is 398. The registry record does not report the number of missing primary measurements by group, reasons for missingness, handling of incomplete questionnaires, or use of imputation. It does not state whether analyses included all randomized participants, whether there was a per-protocol population, or whether sensitivity analyses assessed the effect of missing data.

Missing outcome data can affect interpretation if the participants with complete measurements differ systematically from those without them. Without information about missingness and the analysis populations, the possible direction or size of such bias cannot be assessed. The record also does not describe a full statistical analysis plan, detailed model assumptions, or adjustment for baseline characteristics. These omissions limit evaluation of whether the posted analysis followed a prespecified plan and how robust the results are to alternative analytic choices.

16. 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 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports zero serious adverse events in each group: 0 among 65 participants at risk in MTIA, 0 among 65 at risk in MAPP, and 0 among 66 at risk in the wait-list control group. It also reports zero deaths in all three groups. No serious adverse event terms are listed.

These figures describe the recorded serious events during the registry's stated safety reporting period; the record does not give further detail on event definitions, ascertainment, or duration of safety follow-up. Zero reported serious events does not establish that no events occurred outside the recorded reporting scope, nor does it establish that risks are absent.

The safety denominators differ from the smaller group counts used for the primary outcome. The registry record does not explain the denominator differences. It also lists other, non-serious adverse events, but those counts should not be conflated with the serious-event figures. The safety results are a description of recorded events, not a statistical comparison demonstrating equivalence between groups.

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

The posted primary outcome results show that mean GAD-7 scores decreased from baseline to week 8 in all three groups. The decreases were numerically larger in the MTIA and MAPP groups than in the wait-list control group, but the statistical comparisons do not establish that these between-group differences are distinguishable from zero. The sponsor-reported overall ANOVA has p = 0.341, and both recalculated intervention-versus-control confidence intervals include zero.

This does not show that the groups were equivalent, because the intervals also include possible differences in either direction. It does not prove that mindfulness approaches have no effect. Conversely, the negative within-group changes alone do not establish an intervention effect: changes observed over time in a group can reflect factors other than the intervention, and the relevant question for this randomized comparison is whether changes differ between groups.

The results also do not establish clinical importance. The registry record does not report a threshold for a clinically important GAD-7 change, and statistical uncertainty is substantial relative to the small outcome groups. The primary analysis is based on participants with valid, uploaded measurements at both time points, rather than the full enrollment. The record does not explain missing outcome data or the reason for termination.

The findings are specific to the posted GAD-7 endpoint, time frame, and analyzed participants. They do not answer every study aim, including durability, sustainability, or associations between COVID-19-related stress and autonomic measures. Those questions require their own appropriately reported outcomes and analyses. The posted data should therefore be read as an uncertain estimate of group differences in anxiety-score change, not as a broad conclusion about the interventions or all populations.

18. Why This Trial Matters Statistically

Statistically, this trial illustrates why a randomized comparison depends on contrasts between groups, rather than on within-group improvement alone. Each group had a negative mean change in GAD-7 score, but the primary question is whether the changes differ across the randomized groups. The registry reports an overall ANOVA and the posted summaries permit unadjusted pairwise recalculations, making the distinction between an omnibus test and pairwise estimates important.

The study also links a self-reported mental health outcome to autonomic measures and COVID-19-related stress. Those are different kinds of measurements and address different parts of the study's aims. Their interpretation depends on clear endpoint definitions, transparent analysis populations, and adequate reporting of uncertainty. The record's smaller primary outcome groups and missing-data details limit how confidently the results can be generalized from analyzed participants to everyone enrolled.

The planning illustrations further emphasize that required sample size depends on the effect one intends to detect. Planning around a smaller effect requires more participants per arm under the stated assumptions. The figures are not a substitute for the original study's design rationale, which is not reported in the registry record. Taken together, the record provides a useful example of how outcome magnitude, precision, analysis populations, and multiplicity all shape interpretation, even when the headline statistical test is straightforward.

19. 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.

A central limitation is the difference between total enrollment of 398 and the much smaller groups represented in the primary outcome summaries. The primary analysis is restricted to participants with valid, uploaded baseline and week-8 data. The registry record does not describe missingness by group, reasons for unavailable measurements, or how incomplete data were handled. This prevents assessment of whether the analyzed participants represent the randomized groups.

The study is marked terminated, but no reason is reported. Without that information, the relationship between termination and recruitment, follow-up, intervention delivery, or analysis cannot be evaluated. The registry also does not report the original sample-size justification or enough detail about the statistical analysis plan to assess prespecification and model choices.

The pairwise comparisons are unadjusted recalculations, and the record does not report how multiplicity was handled across the many listed outcomes and analyses. The overall ANOVA is reported, but detailed model specifications and adjusted estimates are not. The secondary outcome results are incomplete in the available record, so conclusions about the full range of autonomic and stress outcomes are limited.

Finally, the target population is defined broadly by self-identified racial and ethnic groups and clinically significant anxiety, but the registry record does not report detailed demographic composition or further eligibility information in the available description. The intervention descriptions are also incomplete. These reporting limits constrain assessment of who received each intervention, how it was delivered, and how closely the results apply beyond the participants represented in the outcome summaries.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: SMILE: Clinical Trial to Evaluate Mindfulness as Intervention for Racial and Ethnic Populations During COVID-19 — NCT06242080.
• Registry record last updated 2026-05-14; status last verified 2025-09.
• Results first posted 2026-05-14.
• 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.

23. Record Summary

NCT06242080 is a randomized, single-masked, parallel-group study of MTIA, MAPP, and wait-list control for adults who self-identify as African American, Black and/or Latino and have clinically significant anxiety. The registry lists an enrollment of 398 and a terminated status. The primary endpoint is change in GAD-7 score from baseline to week 8 among participants with valid, uploaded data at both assessments.

The registry reports an overall ANOVA p-value of 0.341. Mean GAD-7 changes were -4.0 for MTIA, -3.0 for MAPP, and -2.0 for control. The unadjusted pairwise recalculations have confidence intervals that include zero. The record does not report the reason for termination, the original sample-size justification, or detailed handling of missing outcome data. These results therefore describe uncertain group differences among the participants represented in the posted primary outcome summaries.