Functionally-tailored Oral Care Intervention for Community-dwelling Older Adults With Dementia and Their Caregivers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Functionally-tailored Oral Care Intervention for Community-dwelling Older Adults With Dementia and Their Caregivers (NCT04238520), a randomized na study. The primary outcome is Person With Dementia: Oral Hygiene.

2. Clinical Question

3. Trial Design

The registry describes a randomized, single-masked, parallel-group trial of two behavioral interventions. One arm received the Functionally Tailored Oral Care Intervention, and the other received a Control Intervention. The record identifies Xi Chen as the sponsor and lists the study as completed. It records a start date of 2020-04-22 and primary completion on 2023-08-04. The phase is listed as NA.

The study concerns community-dwelling people with dementia and their caregivers. The brief description presents intervention development as an aim and describes a staged program intended to tailor oral-care rehabilitation to the person’s functional abilities while providing caregiver skills training. It describes a 4-week intervention with 8 modules, including modules for environmental changes, caregiver cueing, and oral-care techniques. These are features described in the study aims; the registry record does not identify the specific modules received by participants in the randomized comparison.

The brief description also frames the evaluation as a randomized controlled trial and mentions an aim involving 40 pairs. The registry’s enrollment is 26. The record does not explain the relationship between the aim’s stated number of pairs and the enrollment listed for the completed study, so these figures should not be treated as interchangeable measures of planned and observed enrollment.

The primary outcome is person-level oral hygiene, measured as percentage change in plaque scores between baseline and 3 months. The posted arm summaries list 7 people in control and 19 in the intervention group. Separately, the outcome description says 18 people completed, comprising 5 in control and 13 in the intervention group. The record does not explain why the arm summary counts differ from the completion counts or specify the analysis population used for the reported means. Allocation concealment, the masking role, and further design 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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The percentage change in plaque scores between baseline and 3 months was compared between the PWD in the control group and PWD in the study group. 26 PWD (7 in the control and 19 in the study group) with completed data at the baseline. A total of 18 PWD (control group=5 and study group=13) completed the study with data on this outcome measure.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: 26 pairs of participants with dementia (PWD) and their family caregivers (FCG) (Total=52 participants) were enrolled into the study at the baseline. A descriptive analysis was completed for PWD and FCG, respectively.

6. Primary Endpoint

The registry lists the primary outcome as Person With Dementia: Oral Hygiene, measured over Baseline and 3 Months.

The primary outcome is the percentage change in plaque scores between baseline and 3 months for people with dementia. Plaque was assessed using the Debris Index (DI) of the Oral Hygiene Index. The record describes the DI as a scale from 0 to 3: lower values indicate no debris, while higher values indicate more soft debris on the tooth. It also identifies this measure as a plaque score.

A change measure can describe how an outcome shifts over a follow-up period relative to its starting value. The study description uses percentage change to assess oral hygiene over time and compares that measure between the control and intervention groups. This is the stated rationale for using the outcome; the registry does not provide further justification for selecting percentage change rather than another summary of the plaque score.

The posted summaries give a mean percentage change of 29.6 with a standard deviation of 32.9 for the control arm, listed with n=7. For the intervention arm, the mean is 37.3 with a standard deviation of 23.4, listed with n=19. These summaries describe the arm-level data as posted; they do not by themselves quantify the uncertainty in the between-group contrast.

The outcome description says that 18 participants completed, whereas the posted arm summaries list 7 and 19. The registry record does not clarify this difference or state whether the means use baseline participants, completers, or another analysis population. The direction represented by positive percentage change is not defined in the record, so the means alone do not establish whether a larger value corresponds to better or worse oral hygiene.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies this as a randomized trial with single masking and a parallel-group model. Randomization is intended, in general, to make treatment groups comparable on average at the point of allocation. It does not ensure identical groups in a small study, nor does the design label alone reveal how randomization was generated or concealed. Those details are not reported in the registry record. The record also does not specify who was masked.

What do the arm summaries describe?

The primary measure is continuous: percentage change in plaque scores. A mean summarizes the average observed value in an arm, while a standard deviation describes how spread out individual values are around that arm’s mean. The control summary is mean 29.6 and standard deviation 32.9, with n=7 listed. The intervention summary is mean 37.3 and standard deviation 23.4, with n=19 listed. These summaries are useful for describing the observed distributions, but they do not report the uncertainty of a contrast between groups.

A standard deviation and a standard error have different meanings. A standard deviation describes variability among observations. A standard error describes uncertainty in an estimated quantity, such as a mean or treatment contrast, under a statistical model. A confidence interval is a range of values compatible with the data and model at a stated confidence level; it communicates estimation uncertainty. No confidence interval or standard error for the primary contrast is reported in the registry record.

Why is a between-group estimate important?

For a randomized comparison, the central effect estimate would ordinarily express the contrast between the intervention and control groups on the chosen outcome. The record does not report that contrast, its confidence interval, or a test result. The arm means alone cannot show whether the observed numerical separation is distinguishable from sampling variability. Nor can the registry summaries establish that any separation was caused by the intervention.

General statistical interpretation also depends on the outcome’s scale and construction. The DI itself is described as ranging from 0 to 3, with higher values indicating more soft debris. The analyzed outcome is percentage change in that score, but the registry record does not specify the formula, sign convention, or handling of a zero baseline value. Those details matter to the meaning and distribution of percentage changes. They should not be inferred from the scale description.

What does variation tell us?

Observed spread can be important when the outcome varies substantially among participants. Greater variability generally makes it harder to estimate a group mean or contrast precisely, all else being equal. The standard deviations posted for this outcome describe within-arm variation. Without a reported contrast and confidence interval, however, they do not provide a complete measure of precision for the comparison. Distributional details, such as skewness or influential observations, are not reported in the registry record.

In general, over-dispersion means that data vary more than a statistical model assumes. If a model underestimates variability, its uncertainty estimates may be too small. This concept is relevant when selecting and checking a model, but the registry record does not report a model for the primary outcome or evidence about over-dispersion. It would therefore be inappropriate to claim that over-dispersion was present or that any particular adjustment was used.

What can sample-size planning show?

In general, a sample-size calculation illustrates how many participants might be needed to detect a specified effect under stated assumptions, including an error rate, allocation scheme, and model. The record’s stated planning approach refers to a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the detectable effect expressed as a fraction of the observed effect. Such an illustration is a planning exercise, not a measure of power observed after a trial. The registry record does not provide an estimable two-arm comparison for this continuous endpoint, and the relevant planning values are not reported in the registry record.

A post hoc calculation based on an observed effect would not show the probability that the trial correctly detected an effect. The observed effect is itself uncertain, especially when the available data are limited. A confidence interval around the treatment contrast is more directly informative about the range of effects compatible with the data. No such interval is reported for this primary outcome.

What analysis details remain unclear?

The registry gives no primary analysis method, adjustment strategy, or statistical test. The number of analyses is listed as 0, which does not supply a method or result for the primary comparison. The registry record does not report whether the analysis was intention-to-treat, based on completers, adjusted for baseline values, or otherwise defined. It also does not report an interim analysis or a prespecified statistical analysis plan.

The primary outcome description presents both baseline counts and completion counts, while the arm summaries list the baseline group sizes. This mismatch leaves the denominator for the posted means unclear. Missing-data handling can affect estimates if outcomes are unavailable for some participants, particularly when missingness is related to the outcome or group. General methods include analyzing observed cases, imputing missing values, or using model-based approaches, but none should be attributed to this trial without documentation. The registry record does not report the reasons for missing data or how missing outcomes were handled.

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("Control - PWD", "Interventional - PWD")
n   <- c(7, 19)
m   <- c(29.6, 37.3)
sp  <- c(32.9, 23.4)
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  Control - PWD  7  29.600  32.900  -0.827  60.027
CARM  Interventional - PWD  19  37.300  23.400  26.022  48.578

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one secondary outcome, Dyadic Relationship, and reports 3 outcome measures in total. It does not provide a multiplicity strategy for interpreting results across outcomes or analyses. In general, examining several outcomes can increase the chance of finding at least one apparently unusual result by chance. Prespecified outcome hierarchies or adjusted testing procedures can address that issue, but whether either approach was used is not reported in the registry record. The number of analyses is listed as 0; this does not clarify the analytic plan or how results across measures were handled.

For the primary outcome, the record says 26 people with dementia had baseline data, with 7 in control and 19 in the study group. It also says 18 completed, with 5 in control and 13 in the study group. The posted arm summaries list n=7 and n=19. The record does not explain how these figures relate or identify which participants contributed to the reported means. It does not give reasons for noncompletion, the amount of missing outcome data at 3 months, or a method for handling missing values.

Analysis populations are not defined. The registry record does not state whether the primary analysis included all randomized participants, only people with observed follow-up data, or another population. It also does not report whether the analysis followed assigned groups regardless of intervention receipt. These distinctions matter because an analysis restricted to participants with complete measurements can describe a selected subset if completion is associated with participant characteristics or outcomes.

General statistical practice is to define the analysis population and missing-data procedures before interpreting an endpoint. Sensitivity analyses can examine whether conclusions depend on assumptions about unobserved outcomes. Neither a missing-data procedure nor sensitivity analysis is reported in the registry record. These omissions limit assessment of how representative the posted arm summaries are of the randomized groups and how robust an estimated comparison would be.

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 counts separately for the control and intervention groups. In control, 5 were listed as at risk for serious adverse events and 5 for other adverse events; 0 serious adverse events, 0 other adverse events, and 0 deaths were recorded. In the intervention group, 13 were listed as at risk for each adverse-event category; 0 serious adverse events, 0 other adverse events, and 2 deaths were recorded.

These are event counts in the registry record, not estimates of comparative risk. The record does not provide descriptions of the deaths, their timing, causes, or whether they were considered related to the intervention. It also does not report how adverse events were collected or adjudicated. The counts therefore should not be interpreted as evidence that the intervention caused or prevented an event.

The safety counts use different at-risk numbers from the primary outcome’s baseline arm summaries, and the safety group sizes match the completion counts described for the outcome. The registry record does not explain the population definitions or whether all events were captured. Zero recorded events in a category means none are listed in the record; it does not establish that the underlying risk is zero.

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

The registry result is a limited descriptive account of plaque-score percentage change between baseline and 3 months. It reports a mean and standard deviation for each group, as well as an inconsistency between the arm counts attached to those summaries and the completion counts in the outcome description. These details can help readers understand what was recorded, but they do not provide a complete treatment-effect analysis.

The reported mean is 29.6 with standard deviation 32.9 in control, and 37.3 with standard deviation 23.4 in the intervention arm. The record does not report a between-group estimate, confidence interval, or p-value. Without those, it is not possible to determine the precision of the comparison or assess the strength of evidence against a no-difference explanation. The numerical values should not be presented as proof of benefit or lack of benefit.

The percentage-change sign convention is also not stated. The DI scale description says higher scores indicate more soft debris, but the registry does not explain how change was calculated or which direction in the percentage-change outcome indicates improvement. A directional interpretation of the arm means would therefore go beyond the information in the record.

Random allocation is a useful design feature for estimating comparative effects, in general, but a design label does not replace a reported analysis. The registry record does not provide enough detail about allocation procedures, masking, analysis population, missing-data handling, or the primary statistical method to evaluate those elements. Nor does it report confidence intervals that would show the range of effect sizes compatible with the observed data.

The record’s safety figures list no serious or other adverse events in either group and 2 deaths in the intervention group. They do not establish causation, comparative safety, or an event rate. The event descriptions and relatedness assessments are not reported in the registry record.

Overall, the available information describes a completed randomized study and posts group-level outcome and safety summaries. It does not establish whether the intervention improved oral hygiene, whether a group contrast was statistically distinguishable from chance variation, or whether the safety counts reflect causal effects. Those conclusions require fuller methods and results than are reported in the registry record.

14. Why This Trial Matters Statistically

This trial raises statistical questions that are common in small randomized studies of behavioral interventions. Outcomes are measured in people with dementia, while the intervention description also emphasizes caregivers and dyads. Keeping the unit of analysis clear matters: the primary outcome is person-level plaque-score percentage change, whereas the registry also lists Dyadic Relationship as a secondary outcome. These measures address different aspects of the intervention and should not be treated as interchangeable.

The reported outcome is a change over time, and its meaning depends on how that change is defined. The DI scale has an explicit interpretation, but the percentage-change formula and sign convention are not stated. Making those definitions clear is important for reproducibility and for interpreting the direction of an observed value. The posted means alone do not resolve that issue.

The relationship between baseline counts, completion counts, and the counts attached to the arm summaries is another central concern. The primary outcome description reports 26 people with baseline data and 18 completions, while the arm summaries list n=7 and n=19. A transparent account of the analysis population and missing observations would help readers understand which data contribute to each estimate.

Finally, effect estimates are most useful when accompanied by uncertainty. Means and standard deviations describe the groups, but a between-group estimate and confidence interval would more directly address the randomized comparison and its precision. The registry record does not report those inferential results. This distinction is especially important when interpreting small studies: a descriptive difference may be compatible with a range of underlying effects, and lack of a reported test is not evidence of no effect.

These statistical considerations do not diminish the value of studying tailored oral-care support. They define what can and cannot be concluded from the currently reported registry information and identify the reporting details needed to assess the comparison rigorously.

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 primary limitation for interpretation is the absence of a reported between-group estimate and its uncertainty. The registry provides arm means and standard deviations but no confidence interval or p-value for the primary comparison. It therefore does not show how precisely the intervention-control contrast was estimated.

The denominator information is not internally clear. The outcome description reports baseline data for 26 people and completion by 18, while the posted arm summaries list n=7 and n=19. The record does not reconcile these counts or identify the population used for the means. Reasons for missing follow-up data, methods for handling it, and sensitivity analyses are not reported in the registry record.

The percentage-change definition is incomplete. The record does not specify the calculation formula or state how to interpret the sign of a change. It describes the DI scale direction, but that is insufficient to infer the direction of the percentage-change summaries. This limits interpretation and reproducibility.

Important design and analysis details are also absent. Although the trial is identified as randomized, single-masked, and parallel-group, the method of sequence generation, allocation concealment, and masking role are not reported in the registry record. The primary statistical method, adjustment for baseline values, analysis population, and prespecified statistical plan are also not reported. The registry does not describe whether interim analyses occurred.

Safety information is limited to group counts. Event descriptions, timing, causes, collection procedures, and judgments about relatedness are not reported in the registry record. The counts should therefore be treated as descriptive entries, not causal safety estimates.

The record’s brief description mentions an aim involving 40 pairs, while enrollment is listed as 26. It does not explain this difference. The phase is listed as NA, and no sample-size justification is reported in the registry record. Together, these gaps restrict assessment of precision, attrition, analysis choices, and how the completed study relates to the aims described.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Functionally-tailored Oral Care Intervention for Community-dwelling Older Adults With Dementia and Their Caregivers — NCT04238520.
• Registry record last updated 2025-04-25; status last verified 2025-04.
• Results first posted 2025-04-25.
• 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 registry describes a completed randomized, single-masked, parallel-group behavioral study of a functionally tailored oral-care intervention and a control intervention for community-dwelling people with dementia and their caregivers. It lists enrollment of 26, a start date of 2020-04-22, and primary completion on 2023-08-04.

The primary outcome is percentage change in plaque scores from baseline to 3 months, measured with the Debris Index of the Oral Hygiene Index. The posted control summary is mean 29.6, standard deviation 32.9, n=7; the intervention summary is mean 37.3, standard deviation 23.4, n=19. The outcome description reports 18 completions, with 5 in control and 13 in the study group, and does not explain the difference in counts.

The registry lists one secondary outcome, Dyadic Relationship, and 3 outcome measures in total. It records no serious or other adverse events and 0 deaths in control; the intervention group has 0 serious or other adverse events and 2 deaths. A primary between-group estimate, confidence interval, p-value, analysis population, and missing-data method are not reported in the registry record.