Coordinated Oral Health Promotion (CO-OP) Chicago: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Coordinated Oral Health Promotion (CO-OP) Chicago (NCT03397589), a randomized na study. The primary outcome is Parent-reported Tooth Brushing Frequency.

2. Clinical Question

This is a behavioral intervention question, rather than a question about a drug or procedure. The stated aim is to assess oral-health promotion delivered through community health workers in medical clinics, Women, Infants and Children (WIC) centers, and family homes. Those settings are part of the intervention context; the registry record does not report separate outcome estimates for each setting.

The primary measure concerns a reported behavior, not a clinical examination of dental caries. Parent report can capture how often brushing occurs in everyday life, while also depending on what parents remember and report. The record does not describe a specific recall period, response options, threshold for a favorable response, or validation process. Consequently, the question is clear at a broad level, but the precise outcome contrast cannot be reconstructed from the registry information.

3. Trial Design

NCT03397589 is a completed, randomized, parallel-group behavioral trial sponsored by the University of Illinois Chicago. The registry lists an enrollment of 420. The record describes a single-masked design, but does not identify who was masked or explain how masking was maintained. It does not report the randomization procedure, allocation concealment, or the unit used to assign participants or sites.

The intervention arm was offered community health worker services. Workers trained in oral health were assigned to half of the sites, and participants at those sites were offered four in-person visits and follow-up phone calls over 12-months. Families could choose the location for visits. The wait-list control arm received usual care; after final data collection at one year, participants and sites in that arm were to be offered the services. The registry does not describe the content of usual care or report how many participants received each component of the intervention.

The study addresses dental caries in children, health behavior, and healthcare disparities. Its listed primary outcome, however, is parent-reported tooth-brushing frequency at 12-months post-randomization. The record identifies no study phase beyond NA. The recorded start date is 2018-01-20, primary completion date is 2020-08-20, and status is COMPLETED.

Although the record gives the overall enrollment and arm-specific safety denominators, it does not give the number analyzed for the primary outcome. It also does not report participant flow, withdrawals, protocol deviations, or an analysis population definition. These details matter when assessing how closely the reported outcome data represent the randomized groups.

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

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 Parent-reported Tooth Brushing Frequency, measured over 12-months post-randomization.

The primary endpoint is parent-reported tooth-brushing frequency for children, assessed at 12-months post-randomization. Parents are asked how often the child's teeth are brushed. The registry classifies the outcome as a count of participants, but does not provide the response categories or explain how the frequency response is converted into a participant count. It also does not specify whether the comparison uses a threshold, a particular frequency category, or another summary.

The measure is relevant to the study's stated focus on promoting oral-health behavior. Brushing frequency is a behavior families can report, and the intervention is intended to promote oral health through community health worker contact. In general, a behavioral endpoint can help assess whether an intervention is associated with a change in the targeted behavior. It is not the same as a direct clinical measure of dental caries or oral health status.

Parent report has practical value, but is also subject to recall and reporting limitations. The registry record does not describe the question wording beyond asking how often the child's teeth are brushed, the recall period, response choices, or procedures to reduce reporting error. It does not report an endpoint definition that would permit a single comparison to be interpreted as a change in frequency. The outcome's several categories or time points were not reduced to one comparison in the available analysis information, and no primary-outcome result is reported.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The record identifies a randomized, parallel-group design with single masking. In general, random assignment is intended to make comparison groups similar, on average, with respect to measured and unmeasured characteristics at the time of assignment. This supports a causal interpretation when the allocation process is sound, outcomes are measured appropriately, and the analysis respects the assignment. The registry does not describe the randomization method, concealment, or the unit of assignment, so these design features cannot be evaluated in detail.

What does the parallel design imply?

In a parallel design, participants are assigned to a group and the groups are followed over the study period. The intervention group was offered community health worker services, while the wait-list control group received usual care and was to be offered services after final data collection. General statistical comparisons in this design estimate differences between groups at a defined outcome assessment. The registry identifies the intended primary assessment as 12-months post-randomization, but does not report the endpoint data or analysis estimate.

What does masking tell us?

Single masking means that the record identifies one masked party, but it does not say who that party was. In general, masking can reduce the influence of expectations on care, reporting, or outcome assessment, depending on who is masked and what procedures are used. Behavioral interventions may be difficult to conceal from participants and workers because the intervention involves visits and calls. The record does not explain whether participants, outcome assessors, or analysts were masked, so the potential role of masking in this trial cannot be assessed further.

How should a count outcome be understood?

The primary outcome is described as a count of participants, and the outcome type is classified as binary. In general, a binary outcome records whether each participant meets a defined condition or category. A comparison may then summarize the number meeting that condition in each group, along with uncertainty. Here, the registry does not state the binary threshold or category used for tooth-brushing frequency. It also notes that the primary outcome has several categories or time points and was not reduced to one comparison. Without those details and an analysis result, no group contrast can be interpreted.

Why do analysis choices matter?

In general, an analysis plan specifies the outcome definition, comparison, statistical model, handling of repeated or clustered observations, and approach to missing data. If participants are recruited through sites, outcomes may be correlated within sites; statistical methods may need to account for that dependence. The registry describes workers assigned to half of the sites, but does not state whether the assignment unit was the site, whether clustering was incorporated, or how the analysis handled it. These methods are not reported in the registry record.

The record also does not specify whether the primary analysis followed randomized assignment regardless of intervention receipt, or used another analysis population. Such choices affect the interpretation of a randomized comparison. The numbers enrolled and at risk for safety reporting should not be treated as the primary-outcome analysis denominators in the absence of reported outcome counts.

What do the planning assumptions represent?

The stated planning illustrations use a two-sided significance level of 0.05, equal allocation between the arms, and a normal approximation. The effect to detect is a stated fraction of the observed effect. These are planning assumptions for illustrative sample-size calculations, not a description of the trial's original design justification. The sample-size illustrations are not observed power and do not demonstrate that the study detected an effect. The registry does not report its own sample-size justification, or an analysis linking a primary-outcome estimate to those planning assumptions.

In general, power is a design-stage probability of detecting an effect of a specified size under stated assumptions. It does not measure the probability that a result is true, and calculating power after observing results does not replace reporting the estimate and its confidence interval. Because the registry does not provide a single primary-outcome comparison, the planning assumptions cannot be used to infer a result. The sponsor's own analysis would take precedence if it differed from a simple recalculation, but no sponsor analysis is reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The record lists two outcome measures, and identifies parent-reported tooth-brushing frequency as the primary outcome. It also indicates that the primary outcome includes several categories or time points and was not reduced to one comparison. No analysis is listed. Therefore, the registry record does not show which contrast, category, or time point would be treated as the primary statistical test, nor whether any adjustment for multiple comparisons was planned or used.

In general, testing multiple outcomes, categories, or time points can increase the chance of at least one apparently notable result arising by chance. Prespecified primary comparisons and appropriate multiplicity methods can help make interpretation clearer. The registry does not report a multiplicity strategy, so it is not possible to judge how the multiple outcome components were addressed. This absence does not establish that no such strategy existed outside the record.

Missing-data information is also not reported. The record gives overall enrollment and safety denominators, but does not provide primary-outcome denominators, the amount or pattern of missing outcome data, reasons for missingness, or imputation and sensitivity-analysis methods. In general, missingness can affect an estimate if participants with observed data differ systematically from those without data. The degree of that concern cannot be assessed without outcome follow-up and missingness details.

The analysis population is not defined in the registry record. It is not stated whether the primary comparison was intended to include all randomized participants, only those with observed outcomes, or another set. The record likewise does not describe protocol deviations or intervention receipt in a way that would clarify how participants were handled analytically. As a result, the reported design cannot be connected to a reported primary-outcome analysis.

11. 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 reports serious adverse event figures separately for the community health worker and wait-list control arms. In the community health worker arm, 0 serious events were reported among 211 participants at risk; in the wait-list control arm, 0 serious events were reported among 209 participants at risk. The record also lists 0 deaths in each arm. No serious event terms are listed.

These counts describe the serious-event reporting recorded in the registry. They do not show the primary tooth-brushing outcome, and they should not be used to infer whether the behavioral intervention changed oral-health behavior. The record lists 0 other affected participants in each arm as well, but the available information does not provide event descriptions or further safety detail.

In general, a zero count means that no events of the specified type were recorded in the listed observation group; it does not prove that the underlying risk is absent. Interpretation depends on how events were defined, collected, and followed, and on the completeness of reporting. The registry record does not describe safety surveillance procedures or provide additional event-level information. These figures should therefore be read as the posted counts, not as evidence that no adverse event could occur.

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

The registry record supports a description of a completed randomized trial evaluating community health worker oral-health promotion for families with children aged 0 to 3. It identifies the intervention, the wait-list usual-care comparator, and parent-reported tooth-brushing frequency at 12-months post-randomization as the primary outcome. These details clarify what the trial set out to assess.

The record does not report a single primary-outcome comparison or an analysis result. It therefore does not establish whether brushing frequency differed between arms, how large any difference was, or how precisely it was estimated. A completed study status is not a substitute for a posted result, and the absence of a reported comparison should not be interpreted as evidence of no effect or of equivalence.

The endpoint is a parent report of behavior, not a direct clinical assessment of dental caries. Even if a frequency result were available, its meaning would depend on the response categories, outcome definition, missing data, analysis population, and uncertainty. Those details are not reported in the registry record. The record also does not report a clinical outcome estimate that would connect the behavior measure to dental health status.

The intervention involved community health worker visits and follow-up calls, with families able to choose visit locations. The record does not report how much of the offered intervention participants received or whether engagement varied by setting. Thus, it describes the intended delivery model but does not permit assessment of implementation or variation in exposure.

The appropriate conclusion is narrow: the registry describes the trial question and design, but the available primary-outcome information is insufficient to characterize an effect. That distinction preserves the difference between what the study planned to measure and what the registry reports about its results.

13. Why This Trial Matters Statistically

This trial is statistically notable for asking a behavioral question in community settings rather than focusing only on a clinical endpoint. Its intervention was designed for delivery by community health workers through medical clinics, WIC centers, and family homes. The comparison therefore concerns an approach to oral-health promotion that involves people, services, and settings, not simply an isolated treatment exposure.

The design makes clear why the outcome definition and analysis are important. The primary measure is based on parent report, and the registry describes several categories or time points without reducing them to one comparison. For statistical interpretation, readers need to know how reported frequency becomes an endpoint, which time point and contrast are primary, and how uncertainty is estimated. Those elements are not reported in the registry record.

The site-based delivery context also raises a general design consideration. When participants within a site share staff or context, their outcomes may be related. In general, analysis methods should account for such dependence when it is present. The registry does not state the assignment unit or whether site-level clustering was incorporated, so that issue cannot be resolved from the available information.

The record illustrates why a completed trial and an enrollment count are not enough to assess statistical evidence. A meaningful outcome interpretation requires the observed result, its uncertainty, the analysis population, and information about missing data. Without those elements, the study question can be understood, but the evidence for a difference in the primary behavior cannot be evaluated from the registry record.

14. 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 interpreting this trial is that the registry does not report an analyzable primary-outcome comparison. It identifies parent-reported tooth-brushing frequency, but does not specify the response categories, the rule for counting participants, or the contrast used. It also notes that several categories or time points were not reduced to one comparison. No effect estimate or measure of precision is reported.

The registry record does not describe the randomization procedure, concealment, assignment unit, or identity of the masked party. Because the intervention was delivered through sites, the absence of information about site allocation and the handling of possible within-site dependence limits assessment of the statistical design. The record does not state whether the analysis accounted for site-level structure.

Outcome follow-up and missingness are not described. The number enrolled and safety denominators do not establish the number with primary-outcome data. There is no reported analysis population, participant flow, missing-data method, or sensitivity analysis. These omissions prevent evaluation of whether the primary analysis retained the benefits of randomization or how missing observations might affect the result.

The intervention description specifies the offer of visits and calls but does not report uptake, adherence, fidelity, or variation in delivery. The record also does not describe the usual-care content. Consequently, it is not possible to characterize the contrast in services actually received. Finally, no primary-outcome result is reported, so the trial's findings cannot be assessed for magnitude, precision, or multiplicity handling using the registry information.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Coordinated Oral Health Promotion (CO-OP) Chicago — NCT03397589.
• Registry record last updated 2022-10-18; status last verified 2022-10.
• Results first posted 2021-12-09.
• 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.

18. Record Summary

NCT03397589, Coordinated Oral Health Promotion (CO-OP) Chicago, is a completed randomized parallel-group behavioral trial sponsored by the University of Illinois Chicago. The registry lists enrollment of 420 and a single-masked design. The intervention arm was offered oral-health community health worker services; the wait-list control arm received usual care and was to be offered services after final data collection at one year.

The primary outcome is parent-reported tooth-brushing frequency at 12-months post-randomization among children aged 0 to 3. The registry record lists two outcome measures and zero analyses, and does not report a single primary-outcome comparison, effect estimate, or confidence interval. Primary-outcome denominators, missing-data methods, analysis-population details, and the statistical analysis plan are not reported in the registry record.

The safety figures list 0 serious events and 0 deaths in each arm. These are registry-reported counts and do not resolve the missing primary-outcome analysis.