Efficacy of a Multimodal Brain Health Intervention for Older African Americans: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy of a Multimodal Brain Health Intervention for Older African Americans (NCT04863378), a non-randomized na study. The primary outcome is Daily Average Steps Recorded by Actigraphy Watch.

2. Clinical Question

3. Trial Design

The registry classifies the SHARP Study as nonrandomized, unmasked, and single-group. Its recorded enrollment is 13, and its status is completed. The study started on 2022-02-01, with primary completion on 2023-06-30. The intervention is behavioral and is named Walking conversational reminiscence. The registry summary describes a multimodal approach involving walking, social engagement, and reminiscence, alongside the use of wearable digital biomarkers.

The intervention population includes Black/African American adults aged 65 or older who are cognitively healthy or mildly cognitively impaired. The registry distinguishes these groups using baseline Montreal Cognitive Assessment scores: 24 or higher for the cognitively healthy group and below 24 for the MCI group. The record also lists community stakeholder interviewees, described as Black/African American adults aged 55 or older who take part in individual interviews about historical landmarks and events relevant to future Oakland walking routes. That group is noninterventional and is excluded from the primary outcome data.

The design does not provide a randomized intervention-versus-control comparison. The healthy and MCI categories describe participant status rather than a stated assignment to treatment and control. Consequently, a difference between those categories, if reported, would not by itself isolate an intervention effect. The registry record does not report additional design details such as allocation procedures beyond the nonrandomized classification, visit schedules, or the analysis plan. Those details are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: Participants of the Community Stakeholder Interviewees group are identified via a consultation between the study team and representatives from UC Davis Alzheimer's Disease Center and the AAMLO

Overall Study

Analysis population for the primary outcome, as defined in the registry: Outcome measure data not collected from participants in the Community Stakeholder Interviewees group

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 Daily Average Steps Recorded by Actigraphy Watch, measured over 24 weeks.

The primary endpoint is Daily Average Steps Recorded by Actigraphy Watch. It is a continuous measure, summarized as a mean with standard deviation, and its timeframe is 24 weeks. Daily steps are recorded using a continuously worn Withings actigraphy watch, described as measuring 24-hour activity or gross motor activity. Outcome-measure data are not collected from the Community Stakeholder Interviewees group.

Step counts offer an objective way to describe recorded activity over time. A mean conveys the average level of the measure for the observations included in an analysis; a standard deviation describes how dispersed those observations are around that mean. General interpretation depends on knowing what observations were included, how days with missing recordings were handled, and whether the mean represents individual participants or pooled daily records. Those analytic details are not reported in the registry record.

The endpoint can describe recorded activity, but its name and measurement schedule do not establish that a change occurred. The registry record does not report the observed mean, standard deviation, baseline-to-follow-up change, confidence interval, or test result. It therefore does not support a numerical conclusion about the direction or precision of the step-count outcome.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean summarize?

For a continuous outcome such as daily step count, the mean is a measure of central tendency: it describes an average across the observations included in an analysis. The registry names the primary measure as daily average steps and specifies the mean as its summary parameter. A mean is most interpretable when the analysis makes clear whether it averages measurements within each participant first, averages all recorded days together, or uses another approach. Those details matter because repeated days from the same person are related observations rather than wholly independent pieces of information. The analysis approach for the primary measure is not reported in the registry record.

The standard deviation describes spread around the mean. It is not the uncertainty in the estimated mean itself. General interpretation separates these concepts: the standard deviation reflects variability among observations, while a standard error or confidence interval would express uncertainty about an estimate under a particular analysis. The registry lists standard deviation for dispersion but does not report an observed value or a confidence interval for the primary endpoint.

Why does repeated measurement matter?

The watch is described as continuously worn, and the outcome is daily steps over 24 weeks. Repeated daily measurements can help describe activity patterns, but measurements from one participant may be correlated across neighboring days. If an analysis treats all days as independent when they are not, its uncertainty estimates can be too optimistic. General methods for repeated measurements account for within-person dependence, for example by modeling participant-level clustering or summarizing each participant before making a group-level estimate. The registry record does not identify which approach, if any, was used.

Wearable measurements can also be incomplete. A watch may not yield a usable reading for every intended day, and participants may differ in the amount of recorded time. General analyses need a prespecified definition of a valid day or participant, a way to handle missing measurements, and clarity about whether summaries use the same observation window for everyone. These rules are not reported in the registry record. No missing-data results or sensitivity analyses are reported there either.

What would a comparison establish?

A randomized comparison is designed to make treatment groups comparable, on average, with respect to factors that could affect the outcome. This registry classifies the study as nonrandomized and single-group, and it does not describe a like-for-like control comparison. Consequently, the listed design does not support the same causal interpretation as a randomized intervention-versus-control trial. Even a measured change over time could be influenced by time trends, changes in participation, or measurement availability. The record does not report a statistical adjustment plan addressing such influences.

For a continuous endpoint, an analysis might estimate a mean at a particular time, a change over time, or a difference between defined groups. Each answers a different question. A test statistic or p-value, if reported, would address compatibility with a specified statistical null under model assumptions; it would not express the size or practical importance of an effect. A confidence interval would add information about precision. None of these primary-outcome estimates is reported in the registry record, and the record lists zero analyses.

How should planning illustrations be read?

In general, a sample-size calculation asks how many participants would be needed under specified assumptions to detect a chosen effect with a stated error rate and power. It is a planning illustration, not an observed result and not evidence that a study had a given probability of success after completion. The registry’s planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect defined as a fraction of the observed effect. The stated convention is participants per arm for non-time-to-event outcomes. These assumptions do not change the design actually recorded as nonrandomized and single-group.

The planning illustration is based on an observed effect, but no observed primary-outcome effect is reported in the registry record. Numerical planning outputs are therefore not discussed in the registry information available for interpretation. Such values, when displayed elsewhere, should be read only as conditional planning estimates under their assumptions, not as observed enrollment requirements, observed power, or evidence of efficacy. No further statistical methods, model specifications, interim analyses, or sample-size justification are reported in the registry record.

10. Confidence Intervals for Each Arm

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

R code and output

arm <- c("Cognitively Healthy Walkers", "Mildly Cognitively Impaired (MCI) Walkers")
n   <- c(4, 5)
m   <- c(2570, 1140)
sp  <- c(1000, 1030)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Cognitively Healthy Walkers  4  2570.000  1000.000  978.777  4161.223
CARM  Mildly Cognitively Impaired (MCI) Walkers  5  1140.000  1030.000  -138.914  2418.914

11. Multiplicity, Missing Data and Analysis Populations

The registry lists five outcome measures and zero analyses. It identifies Daily Average Steps Recorded by Actigraphy Watch as the primary outcome, but the record does not report results for that measure or the other listed outcomes. It also does not report a statistical plan describing how multiple outcomes or repeated tests would be handled. Whether multiplicity adjustments were planned or applied is not reported in the registry record.

Multiplicity matters when several outcomes, time points, or subgroup comparisons are tested. In general, conducting multiple tests can increase the chance of observing a nominally unusual result even when no underlying effect exists. A prespecified hierarchy, adjustment method, or clear distinction between primary and exploratory analyses can help readers interpret that risk. No such approach is reported, so no claim can be made about how any multiplicity was controlled.

The outcome description specifies a 24-week timeframe, but the registry does not report the analysis population, the number of participants contributing primary-outcome data, the completeness of watch recordings, or rules for handling missing days or missing follow-up. The record says outcome-measure data were not collected from community stakeholder interviewees. It does not otherwise detail exclusions, withdrawals, or analysis populations. Those items are not reported in the registry record.

Missing-data methods affect both the estimate and its uncertainty. General approaches may use available observations, model missingness, or examine how conclusions change under alternative assumptions. Each depends on assumptions about why data are missing. Without the analysis population, completeness information, and stated method, readers cannot assess whether the reported endpoint—if results become available—represents all eligible participants or a subset with usable recordings. No missing-data sensitivity analysis is reported in the registry record.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

The registry lists safety figures separately for the cognitively healthy participants, MCI participants, and community stakeholder interviewees. For the cognitively healthy group, 4 were at risk for serious adverse events and 0 were affected; 4 were at risk for other adverse events and 0 were affected. For the MCI group, 5 were at risk for serious adverse events and 0 were affected; 5 were at risk for other adverse events and 0 were affected. For community stakeholder interviewees, 4 were at risk for serious adverse events and 0 were affected; 4 were at risk for other adverse events and 0 were affected. The registry lists 0 deaths in each group.

These figures describe the registry’s recorded counts, not a guarantee that an event is impossible. A zero affected count means no event was recorded in the stated category among the group listed as at risk in this record. With a small study enrollment, the counts provide limited information about uncommon events. The record does not give event-specific details because no serious adverse event terms are listed, and it does not report further details about collection or adjudication of adverse events. These safety entries should be read as descriptive registry data rather than as a comparative safety analysis.

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

The registry record establishes what the SHARP Study was designed to examine: a multimodal behavioral intervention involving walking, social engagement, and reminiscence, with wearable activity measurement among cognitively healthy and MCI participants. Its primary endpoint is daily average steps over 24 weeks, summarized as a mean with standard deviation. The record also describes a noninterventional community stakeholder group that contributes qualitative input about future walking routes and does not contribute primary outcome data.

It does not report the primary step-count results. There is no reported estimate of the mean, change, between-group contrast, or uncertainty, and the registry lists zero analyses. Consequently, the posted record cannot establish the magnitude, direction, or precision of any activity change. The study’s stated aims include feasibility, acceptability, and efficacy, but those aims should not be mistaken for reported findings.

The design also limits causal interpretation. The registry classifies the study as nonrandomized and single-group, and does not describe a randomized control comparison. A change observed over time in such a design, if reported, would not by itself show that the intervention caused the change. Other influences and participant-level differences could contribute, and the registry does not report an adjustment plan to address them.

The safety counts are similarly descriptive. The listed groups have zero recorded serious and other adverse events, and zero deaths, but these counts do not establish that risk is absent. The study’s enrollment and the record’s limited safety detail constrain what can be inferred about less frequent events.

The appropriate conclusion is narrow: the registry documents the study design, intervention, intended activity measure, and recorded safety counts, but does not report the outcome analyses needed to assess efficacy or quantify uncertainty. No claim of benefit or lack of benefit follows from the absence of posted estimates.

14. Why This Trial Matters Statistically

This study is statistically notable for combining a behavioral intervention with continuous wearable measurement in a population described as older Black/African American adults, including cognitively healthy and MCI participants. The primary endpoint is concrete and objectively recorded: daily steps measured by an actigraphy watch. The registry also identifies a separate community stakeholder interview group whose qualitative input concerns salient historical landmarks and events for future walking routes. Keeping those roles distinct is important when interpreting both the outcome population and the study design.

The record also illustrates why design labels matter. Nonrandomized and single-group classifications do not support the same causal claims as a randomized control comparison. A mean step count could describe activity, but interpreting a change as an intervention effect would require a design and analysis capable of addressing other explanations for change. The record does not report such an analysis.

Wearable data bring their own statistical considerations. Daily readings may be correlated within a person, and recording completeness may vary. A transparent analysis would explain how repeated days are handled, how valid recordings are defined, and how missing observations affect summaries and uncertainty. Those methods are not reported in the registry record, so readers cannot assess them from the posted information.

Finally, the record highlights the difference between an outcome being named and a result being available. The endpoint and timeframe are specified, yet the registry lists zero analyses and does not report outcome estimates. This prevents readers from evaluating magnitude, precision, or statistical evidence, while still allowing a careful description of the study’s aims, design, and measurement strategy.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main limitation for interpretation is that the registry does not report numerical results for the primary endpoint. There is no posted mean, standard deviation, change estimate, confidence interval, or hypothesis-test result. The registry lists five outcome measures and zero analyses, leaving efficacy, feasibility, and acceptability findings unreported in the record.

The design is classified as nonrandomized and single-group, with no masking and no documented like-for-like control comparison. This limits the ability to distinguish intervention-related change from other explanations. The registry record does not report an adjustment strategy, model specification, or analysis plan that could clarify how such influences were handled.

The endpoint relies on continuously worn actigraphy, but the record does not report completeness of recording, definitions of usable days, participant-level availability, or how missing days were handled. It also does not state whether the analysis accounts for repeated daily observations within participants. Those details are particularly relevant to the precision and representativeness of a mean based on repeated measurements.

Although the record lists cognitively healthy and MCI groups, it does not describe them as randomized treatment and control arms. Their outcomes should not be interpreted as a controlled intervention contrast. The community stakeholder group is noninterventional, has a qualitative role, and is expressly excluded from outcome-measure data.

Safety entries show no recorded serious or other adverse events and no deaths in the listed groups, but the record supplies little event detail and no broader comparative safety analysis. These limitations leave the registry useful for understanding the intended design and measures, but insufficient for judging outcome magnitude, precision, or causal effect.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Efficacy of a Multimodal Brain Health Intervention for Older African Americans — NCT04863378.
• Registry record last updated 2025-01-06; status last verified 2025-01.
• Results first posted 2025-01-06.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

The SHARP Study is recorded as completed, nonrandomized, unmasked, and single-group, with enrollment of 13. It evaluates a behavioral intervention named Walking conversational reminiscence, described as combining walking, social engagement, and reminiscence. The participant groups include cognitively healthy and MCI Black/African American adults aged 65 or older; a separate community stakeholder group provides qualitative input and does not contribute outcome-measure data.

The primary endpoint is mean daily steps recorded by a continuously worn actigraphy watch over 24 weeks, with standard deviation specified as the dispersion measure. The registry lists five outcome measures and zero analyses, but does not report primary-outcome estimates or their uncertainty. Safety listings record zero serious adverse events, zero other adverse events, and zero deaths in each named group. The record supports a description of the study and its intended measurement, but does not provide numerical efficacy results.