Pilot Trial of Mobile Mantram Delivery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Pilot Trial of Mobile Mantram Delivery (NCT05998967), a randomized na study. The primary outcome is Credibility.

2. Clinical Question

3. Trial Design

The registry identifies NCT05998967 as a completed randomized, parallel-group pilot trial. It lists enrollment of 36 and compares two behavioral delivery approaches: self-directed MRP and supported MRP. The official title is “Feasibility and Acceptability of Mobile Mantram Repetition Program for Veterans With PTSD (IVI 22-115),” and the sponsor is the VA Office of Research and Development. The listed phase is NA.

The study began on 2021-12-01, and its primary completion date is 2022-09-30. Masking is listed as none. Thus, the record describes a randomized comparison without masking; it does not report further details about how randomization was generated, whether allocation was concealed, or who knew group assignment during assessment. Those design details are not reported in the registry record.

The primary outcome is credibility on Day 1. The posted group summaries include 17 participants in self-directed MRP and 19 in supported MRP. Secondary outcomes include Mantram Practice, the PTSD Checklist for DSM-5 (PCL-5), the Patient Health Questionnaire Depression Items (PHQ-9), and the Insomnia Severity Index. The numeric secondary summaries shown in the registry record are for Day 28, with 14 participants in each group for the reported measures. Numeric Insomnia Severity Index results are not reported in the registry record.

The study summary describes an interest in how Veterans respond to learning MRP online, either independently or with text or phone support. That aim fits the pilot and feasibility framing, but the record does not report a detailed protocol, recruitment setting, intervention schedule, or criteria for judging feasibility or acceptability. The trial’s original sample-size rationale and planned statistical analysis are also 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.

Before assignment: Participants had a primary clinical complaint of PTSD and an Internet-enabled device

Overall Study

Analysis population for the primary outcome, as defined in the registry: Screened individuals

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 Credibility, measured over Day 1.

The primary endpoint is mean credibility on Day 1. The registry describes credibility as participants’ average perception of the logic, utility, and expected benefit of their assigned treatment. Ratings range from 0, meaning not at all, to 8, meaning very. The reported unit is units on a scale, and the registry summarizes the outcome using a mean and standard deviation.

Credibility is an early appraisal of an intervention, not a measure of symptom change. In a study concerned with the feasibility and acceptability of internet instruction, asking whether participants find the approach logical and potentially useful can describe how the intervention is received. It may help characterize whether the delivery approach seems plausible to participants, but it cannot by itself establish whether participants completed the program, whether symptoms changed, or whether any change was caused by the intervention.

The Day 1 timing matters for interpretation: the primary rating concerns initial expectations rather than a later outcome. The registry does not report the exact point during instruction when the rating was collected or a threshold defining an acceptable credibility score. Nor does it report a separate primary measure of program completion or engagement. These details are not reported in the registry record, so the credibility result should be read as a narrow measure of early perception.

7. Results Posted in the Registry

• Supported MRP: mean 5.23 versus 4.78 on control; difference 0.45 (95% CI -0.53 to 1.43), standardized effect d = 0.30; z-test p = 0.369.

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.

Mantram Practice

• 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:
  • Supported MRP: mean 5.00 versus 4.93 on control; difference 0.07 (95% CI -1.46 to 1.60), standardized effect d = 0.03; z-test p = 0.929.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Supported MRP and the control. The interval gives the range of effects that remain compatible with the data.

PTSD Checklist for DSM-5 (PCL-5)

• 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:
  • Supported MRP: mean 27.71 versus 31.00 on control; difference -3.29 (95% CI -18.38 to 11.80), standardized effect d = -0.16; z-test p = 0.669.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Supported MRP and the control. The interval gives the range of effects that remain compatible with the data.

Patient Health Questionnaire Depression Items (PHQ-9)

• 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:
  • Supported MRP: mean 9.86 versus 11.50 on control; difference -1.64 (95% CI -7.11 to 3.83), standardized effect d = -0.22; z-test p = 0.557.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Supported MRP and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes add descriptive information about practice and symptom measures at Day 28. The overall pattern is not a set of precise, conclusive between-group findings: the posted mean-difference intervals for Mantram Practice, PCL-5, and PHQ-9 all include zero. Their point estimates have different directions and scales, so they should not be combined informally into a single judgment about the intervention. Numeric results for the Insomnia Severity Index are not reported in the registry record.

These findings relate to the primary result by addressing different questions at a later time. Day 1 credibility captures participants’ early expectations about the approach; Day 28 practice and symptom measures describe later reported status. The secondary endpoints therefore provide context, but they do not confirm or overturn the primary credibility comparison. A favorable-looking change on one measure would not by itself establish a general effect across outcomes, especially when the measures represent distinct concepts.

The secondary comparisons are unadjusted, and the registry record does not report whether they were prespecified as confirmatory, how many comparisons were planned, or whether any multiplicity correction was intended. When many outcomes are examined, some apparently notable results can arise by chance even if there is no underlying effect. Without a stated testing strategy, secondary estimates and p-values generally carry less evidential weight than a prespecified primary result and are best treated as exploratory.

Day 28 summaries include 14 participants in each group, compared with 17 and 19 for the primary endpoint. The registry record does not explain the difference in observed group counts or report how missing observations were handled. This limits interpretation of the secondary pattern: differences in who contributes data can affect group summaries, and the record does not establish whether the available participants represent everyone randomized. The secondary results are informative as posted summaries, but their uncertainty, multiplicity, and incomplete reporting call for restraint.

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

• Mantram Practice
• PTSD Checklist for DSM-5 (PCL-5)
• Patient Health Questionnaire Depression Items (PHQ-9)
• Insomnia Severity Index

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: each participant contributes a score on the credibility scale, and the registry reports a group mean with a standard deviation. The mean describes the average score in a group. The standard deviation describes how spread out individual scores are around that group average. It is not the uncertainty in the mean itself; uncertainty about a group comparison is reflected more directly by its confidence interval.

What does the mean difference represent?

The comparison is supported MRP minus self-directed MRP. The posted means are 5.23 and 4.78, and the posted mean difference is 0.45. A positive value means that the supported group’s average is higher; a negative value would mean that the self-directed group’s average is higher. This contrast is expressed in the original scale units, which makes its direction interpretable alongside the 0-to-8 scale. It remains a comparison of group averages and does not describe every participant’s experience.

The posted result is an unadjusted comparison. That means the reported contrast is presented without a reported adjustment for other participant characteristics or other model terms. The registry record does not specify the exact test or model used for the comparison, whether an intention-to-treat population was defined, or whether any covariates were included in the original analysis. Those details are not reported in the registry record. The p-value and confidence interval should therefore be understood as the posted unadjusted summary, not as evidence of an undocumented model.

How should the confidence interval be read?

A confidence interval describes uncertainty around an estimated difference. The primary interval is -0.531 to 1.431. It includes zero, the value representing no difference in group means, and also spans differences in both directions. In general, a wider interval indicates less precision than a narrower one. The interval is not a range that contains every participant’s score, and it does not give the probability that the true difference lies inside its endpoints.

What does the p-value add?

The unadjusted p-value for the primary comparison is 0.369. In general, a p-value measures how unusual data at least as discrepant as those observed would be under a specified no-difference model and its assumptions. It is not the probability that the no-difference explanation is true, and it does not measure the size or practical importance of an effect. Here, it should be read with the estimated mean difference and confidence interval, rather than as a stand-alone verdict.

The registry lists a standardized effect-size estimate, d = 0.297, and a pooled standard deviation of 1.516 for the primary contrast. A standardized effect expresses the mean difference relative to a standard deviation, which can help describe magnitude on a scale that is less tied to the outcome’s original units. It is not a separate endpoint, and it does not remove uncertainty. The registry does not report an analysis interpretation or threshold for judging what size of credibility difference would matter.

Why do the planning illustrations use different assumptions?

The sample-size planning illustrations are explicitly based on the observed effect, not the trial’s original design. They use a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is the stated fraction of the observed effect. In general, over-dispersion—more variability than a model assumes—can make estimates less precise and can reduce the ability to detect a difference. A normal approximation is a simplifying planning method, not a report of the trial’s analysis model.

The displayed planning estimates are sensitive to the assumed effect size. Smaller target effects require more participants to distinguish them from random variation at a given power and significance level. These calculations are planning illustrations only. They are not the original trial’s sample-size justification, and the trial’s own design assumptions are not reported in the registry record.

Finally, a randomized design supports a structured comparison of the assigned groups, but randomization alone does not supply information about missing observations, adherence, or the analysis population. The registry posts smaller group counts for the Day 28 outcomes than for the primary endpoint, without explaining why. How those counts were handled in any formal analysis is not reported in the registry record. These limits matter when interpreting both the estimates and the apparent precision.

11. Confidence Intervals and Precision

The primary mean difference is 0.45 units for supported versus self-directed MRP, with a 95% confidence interval from -0.531 to 1.431. This interval gives a range of values reasonably compatible with the posted estimate under the confidence-interval method used. Because it crosses zero, the data are compatible with no difference as well as with differences in either direction. The estimate alone should not be treated as precise evidence that the groups differ.

The interval’s width reflects substantial uncertainty about the size and direction of the population contrast. It is not a prediction interval for individual credibility scores and does not mean that a particular proportion of participants had scores within those endpoints. The standard deviations of 1.35 for self-directed MRP and 1.65 for supported MRP describe variability among the observed group scores, whereas the confidence interval describes uncertainty around the between-group mean difference.

The group sizes contributing to the primary endpoint are 17 and 19. With these counts, the interval remains broad relative to the point estimate. The registry does not report a prespecified smallest difference that would be important to detect, so precision cannot be judged against a stated practical threshold. Nor does it report a formal equivalence margin. Consequently, the interval cannot support a claim that the delivery approaches are equivalent merely because it includes zero.

The unadjusted p-value of 0.369 is consistent with the interval’s inclusion of zero, but it should not replace interval-based interpretation. The interval makes clear that the data do not pinpoint a single value for the difference. Precision is limited, and the posted result allows a range of interpretations rather than resolving whether a meaningful difference exists.

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, not total events. They apply to a two-arm comparison and should be read as illustrations of the group size needed under stated planning assumptions, not as observed trial enrollment. The assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect targeted is the stated fraction of the observed effect. The original trial’s own sample-size assumptions and justification are not reported in the registry record.

The 80% power column describes the planned chance of detecting the chosen effect if that effect is present, under the planning assumptions and analysis model. The 90% power column uses a higher target chance of detection. Neither column is a statement about what happened in this trial. For the primary credibility contrast, planning for 100% of the observed effect gives 179 participants per arm for 80% power and 239 participants per arm for 90% power. Planning for 75% of the observed effect gives 317 participants per arm for 80% power and 425 participants per arm for 90% power. Planning for 50% of the observed effect gives 713 participants per arm for 80% power and 955 participants per arm for 90% power.

The general pattern is that smaller effects require more participants to detect, while a higher power target also requires more participants under the same assumptions. These are planning illustrations based on the observed effect, not observed power. The pilot’s enrollment of 36 should not be interpreted through those estimates as evidence that the trial had a particular probability of finding a result; the calculations are conditional on the assumed effect and planning method.

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 = 0.450; pooled standard deviation σ = 1.516.
2. n = 2 × (1.96 + 0.842)² × 1.516² / 0.450² = 178.2, rounded up to 179 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 <- 0.45                      # observed difference in means
sigma <- 1.51623566381856                     # 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(5998967)
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 = 179 (80% power), 239 (90% power)
 75% of observed effect: n per arm = 317 (80% power), 425 (90% power)
 50% of observed effect: n per arm = 713 (80% power), 955 (90% power)
power.t.test: 179.2 
Simulated power at n = 179 per arm: 0.802 (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 lists multiple outcomes, including credibility, Mantram Practice, PCL-5, PHQ-9, and the Insomnia Severity Index. It also records 12 outcome measures. Looking across multiple outcomes creates a multiplicity issue: the more comparisons examined, the greater the chance that at least one result may appear unusual by chance alone. A statistical plan can address this by defining primary and secondary questions, specifying which comparisons are confirmatory, and stating whether and how significance levels are adjusted. Such a plan is not reported in the registry record.

The primary outcome is identified as credibility on Day 1, which gives it a distinct role in interpretation. The secondary outcomes are not all interchangeable, and their unadjusted results should not be treated as independent confirmations of one another. The record does not report a testing hierarchy, multiplicity adjustment, or whether the secondary endpoints were exploratory. These details are not reported in the registry record.

The registry record contains no reported analyses. It therefore does not describe an analysis population, such as all randomized participants or only participants with available outcome data. It also does not report a missing-data strategy, an imputation method, or sensitivity analyses. At Day 28, the reported group counts are 14 in each arm, compared with 17 in self-directed MRP and 19 in supported MRP for the primary outcome. The reasons for these different counts, whether they reflect missing measurements or another issue, and the disposition of participants are not reported in the registry record.

The absence of these details does not show that a particular method was or was not used outside the record; it means the record does not permit readers to assess it. Missingness can affect interpretation if participants with recorded outcomes differ from those without them. Likewise, the absence of a reported analysis population makes it difficult to determine precisely which participants contribute to each estimate. These reporting gaps limit assessment of the secondary comparisons and any broader conclusions from the posted results.

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 adverse-event figures are reported separately for the two groups. In self-directed MRP, 0 serious adverse events were reported among 17 participants at risk, and 0 other adverse events were reported among 17 at risk. In supported MRP, 0 serious adverse events were reported among 19 participants at risk, and 1 other adverse event was reported among 19 at risk. No deaths were reported in either group. The registry does not list serious adverse-event terms.

These counts describe events recorded in the registry, not a complete estimate of all possible harms. Zero reported serious events does not establish that serious events are impossible or that the intervention is risk-free. The record does not provide event descriptions for the single other event, the timing or duration of safety monitoring, or further information about how events were collected and classified. Those details are not reported in the registry record.

The denominators are the participants listed as at risk for the adverse-event summaries. They should not be confused with outcome-specific counts or taken to mean that every participant had the same amount of observation. These safety figures are descriptive and limited by the pilot’s size and the information recorded.

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

The result establishes what was observed in this pilot: the Day 1 average credibility rating was 4.78 for self-directed MRP and 5.23 for supported MRP, with a posted mean difference of 0.45 and a 95% confidence interval from -0.531 to 1.431. The interval includes zero and extends in both directions. The record therefore does not provide a precise estimate that settles whether early credibility differs between the two delivery approaches.

It does not show that the approaches are equivalent. Equivalence requires a defined margin for a difference considered sufficiently small, along with an analysis designed to evaluate that margin. Neither an equivalence margin nor an equivalence analysis is reported in the registry record. A nonsignificant unadjusted p-value is not a substitute for that evidence.

It also does not establish that either approach improves PTSD symptoms. Credibility is an early perception measure, and the secondary outcomes are reported at Day 28. The posted PCL-5 and PHQ-9 summaries are not a substitute for a longer-term or fully specified clinical analysis. The registry does not report formal analyses, multiplicity handling, or missing-data methods, and numeric Insomnia Severity Index results are not reported. The record’s evidence is therefore limited to its posted descriptive summaries and comparisons.

The randomized design is relevant because the study compares assigned delivery approaches, but the record does not provide enough detail to evaluate all aspects of conduct and analysis. The pilot framing and modest enrollment make the findings useful as preliminary observations, not a final ranking of the approaches. No claim about treatment benefit, lack of benefit, or individual care follows from these statistics alone.

In general, the meaning of a result depends on its endpoint, time point, uncertainty, and analysis context. Here, the clearest conclusion is narrow: the posted Day 1 credibility averages are relatively close, but the uncertainty is substantial and the registry does not resolve the size or direction of a population difference. The later secondary outcomes can inform further study questions, but they do not support a definitive conclusion about symptom outcomes.

17. Why This Trial Matters Statistically

This trial is statistically interesting because it compares two ways of delivering the same named program rather than comparing the program with no intervention. That focus makes the primary question a delivery and acceptability question: do participants’ early expectations differ when instruction is self-directed or supported? The credibility scale provides a direct, though limited, way to describe that initial perception.

The results also illustrate why estimates need to be read together with uncertainty. The primary point estimate is positive, but the confidence interval spans zero and values in both directions. Focusing only on the direction of the observed means could overstate what the data establish; focusing only on a p-value would also obscure the range of compatible differences. The pilot provides an estimate, but not a precise answer.

Planning illustrations based on the observed effect further show how strongly sample-size estimates depend on assumptions about the effect to detect. They are useful for understanding the scale of future planning under specified assumptions, but they are not the original design rationale and do not reveal the trial’s observed power. The record does not report the original justification, reinforcing the distinction between a pilot’s descriptive results and a prospectively designed confirmatory study.

Finally, the record demonstrates the importance of complete reporting. The listed secondary outcomes, differing counts at Day 28, absence of reported analyses, and lack of multiplicity or missing-data details all affect how confidently readers can interpret the pattern. Making those elements explicit would help distinguish exploratory signals from confirmatory evidence. The statistical value of this pilot lies in the questions it helps frame and the uncertainty it makes visible, not in a definitive treatment conclusion.

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.

Several limitations are specific to the posted record. The primary endpoint is a Day 1 self-reported credibility rating, which captures initial expectations rather than program completion or later clinical change. The registry does not report a threshold for an acceptable rating or a separate primary measure of feasibility. Therefore, the endpoint alone cannot establish whether the online program was completed or how much support participants used.

The trial enrolled 36 participants, and the primary summaries include 17 in self-directed MRP and 19 in supported MRP. The Day 28 summaries include 14 in each group. The record does not explain the different counts, provide a participant flow account, or report missing-data methods. It is not possible from the posted record to determine why the numbers differ or how this may affect the summaries.

The record lists no masking and provides no reported analysis details. The method of randomization, allocation concealment, analysis population, covariate adjustment, and exact statistical tests are not reported in the registry record. The registry also does not report a multiplicity plan, and numeric Insomnia Severity Index results are not reported. These omissions constrain assessment of the secondary evidence.

Further information about eligibility, participant characteristics, study setting, adherence, intervention exposure, and follow-up beyond the listed time points is not reported in the registry record. Without those details, it is difficult to assess how broadly the findings may apply or how the delivery approaches were experienced in practice. These limitations reinforce the preliminary, descriptive interpretation of the posted comparisons.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Pilot Trial of Mobile Mantram Delivery — NCT05998967.
• Registry record last updated 2024-03-21; status last verified 2024-03.
• Results first posted 2024-03-21.
• 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

NCT05998967 is a completed randomized, parallel-group pilot of the Mobile Mantram Repetition Program for Veterans with PTSD, sponsored by the VA Office of Research and Development. It compares self-directed internet instruction with supported internet instruction, and masking is listed as none. Enrollment is 36; the listed start date is 2021-12-01 and the primary completion date is 2022-09-30.

The primary outcome is Day 1 credibility. The posted supported-versus-self-directed mean difference is 0.45, with a 95% confidence interval from -0.531 to 1.431 and an unadjusted p-value of 0.369. Secondary summaries are posted for Mantram Practice, PCL-5, and PHQ-9 at Day 28; numeric Insomnia Severity Index results are not reported in the registry record. The record contains no reported analyses, and details of the statistical plan, missing-data handling, and multiplicity approach are not reported.