Mobile Health Intervention to Identify Early Responders to Treatment in Adolescent Obesity: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Mobile Health Intervention to Identify Early Responders to Treatment in Adolescent Obesity (NCT03561597), a na na study. The primary outcome is Proportion of Patients Triaged to the Low Risk Weight Management Clinics.

2. Clinical Question

The question is about whether the intervention pathway can identify participants for low-risk clinic triage, rather than about a treatment effect relative to a control group. The registry also lists secondary objectives concerning BMI z-score, metabolic profile, feasibility, fidelity, and other possible predictors of poor response. Outcome listings include weight changes, BMI z-score, %BMIp95, feasibility, fidelity, and attrition, but the outcome results are not reported in the registry record. The description therefore establishes the intended focus, but not the observed pattern of triage or changes in clinical measures.

3. Trial Design

The registry identifies this as a completed pilot study of a mobile health intervention to identify early responders to treatment in adolescent obesity. The design is listed as single group, with allocation recorded as NA and masking as none. Enrollment is listed as 40. The listed intervention is behavioral and is named Mobile health intervention; its arm is titled Mobile health application.

The registry description proposes a staged approach to adolescent obesity management and frames mobile health as a community-based option. It describes a brief intervention by a Weight Management Clinics nurse coordinator followed by the Kurbo Program. The primary objective focuses on triage to low-risk Weight Management Clinics after the brief intervention and completion of 4 program sessions. The objective describes this work over a 12 month recruitment period, while the primary outcome timeframe is listed as 6 month. The record does not explain how these time references relate to each other.

The record lists a start date of 2018-04-10, a primary completion date of 2019-10-21, and a status of completed. The dates and status describe the registry entry; they do not establish when each participant was recruited, how long each participant was followed, or whether every planned assessment was completed. Those details are not reported in the registry record.

Secondary outcomes cover feasibility, fidelity, attrition, weight change at 3 and 6 months, BMI z-score changes, and %BMIp95 change from baseline to 6 months. The registry lists 54 outcome measures and 0 analyses. A comparator group, allocation procedure, and masking procedure are not reported as features of this single-group record. The registry does not report a protocol-level statistical plan, sample-size justification, or details of how participants were selected for the primary endpoint analysis.

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:

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 Proportion of Patients Triaged to the Low Risk Weight Management Clinics, measured over 6 month.

The primary endpoint is titled “Proportion of Patients Triaged to the Low Risk Weight Management Clinics.” It is listed in units of participants and described as a count of participants. Its stated aim is to examine triage after a brief intervention by a nurse coordinator and completion of 4 Kurbo Program sessions. The registry lists the timeframe as 6 month.

In general, a proportion expresses the number of people meeting a defined outcome relative to a specified group. For interpretation, the group used as the denominator needs to be clear, as does the rule for deciding that a participant was triaged to the low-risk clinics. Neither the analyzed denominator nor the operational criteria for low-risk triage are reported in the registry record. Although the outcome title uses the word “proportion,” its listed unit and parameter describe a participant count; the registry does not provide the numerical result or clarify the reporting format.

The endpoint is relevant to the stated triage objective because it concerns placement within the proposed care pathway after the mobile health intervention. It is not, by itself, a comparison of outcomes between intervention and control groups: the study is listed as single group. Nor does the endpoint establish whether later weight or metabolic outcomes differed by triage status. Those questions would require results and analysis details that are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a single-group design estimate?

A single-group study observes participants who receive the intervention pathway without a concurrent comparison group. In general, it can describe outcomes within that group, provided the outcomes, denominators, and analyses are reported. It cannot separate the intervention's contribution from other influences on outcomes as directly as a randomized comparison can. Changes over time may be described, but a before-and-after pattern alone does not establish what would have happened without the intervention.

For this study, the registry identifies a single group and no allocation. The primary question is whether participants were triaged to low-risk Weight Management Clinics after the nurse-coordinator intervention and Kurbo sessions. The registry record does not report the primary result or an analysis comparing outcomes across different triage pathways.

What does a participant proportion require?

In general, a proportion is based on a numerator and a denominator: the numerator counts participants meeting an outcome, and the denominator defines the participants among whom that outcome is assessed. The interpretation depends on having a consistent outcome definition and a clearly specified eligible group. If participants have missing outcome information, the handling of those participants can affect both the denominator and the interpretation.

The primary outcome is titled as a proportion but is listed with the unit Participants and a count parameter. The registry does not state the primary numerator, denominator, triage criteria, or a numerical estimate. These details are necessary for a reader to assess the endpoint's magnitude and precision. They are not reported in the registry record.

How should uncertainty be understood?

General statistical interpretation distinguishes an estimated effect or event frequency from the uncertainty around it. A confidence interval expresses uncertainty under a specified statistical model and analysis. A narrow interval generally indicates greater precision than a wide interval, but precision does not establish that an estimate is free from bias or that it has practical importance. A p-value, when used, describes compatibility between data and a specified null model under assumptions; it is not the probability that a hypothesis is true.

The registry does not report a confidence interval, p-value, or other uncertainty measure for the primary endpoint. It also does not report an inferential analysis of the primary outcome. No conclusion about statistical significance or precision can therefore be drawn from the primary endpoint entry.

What do the planning assumptions mean?

The registry includes assumptions for planning illustrations: a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and a target effect defined as a fraction of the observed effect. Such calculations are hypothetical planning exercises. They are distinct from observed results and do not show the probability that this completed study detected an effect. The record identifies this trial as single group, so an equal-allocation, two-arm illustration does not describe its actual allocation. The numerical planning outputs are not reported in the registry record.

General power calculations depend on the outcome, assumed effect, variability or event frequency, analysis method, and design. If the assumptions do not match a study's design or endpoint, an illustration may not answer the question of how informative the actual study is. A sample-size illustration is not a substitute for a confidence interval around an observed result. No trial-specific sample-size justification or statistical plan is reported in the registry record.

Why can over-dispersion matter?

In general, count outcomes are sometimes modeled with a distribution that assumes a particular relationship between the mean and variability. Over-dispersion means the observed variability is greater than that model allows. If it is ignored, standard errors may be too small and uncertainty may be understated. This is a general concept for count-data analysis; the registry does not report a count model, an over-dispersion assessment, or a statistical analysis for the primary endpoint. The endpoint is listed as a participant count, but that listing alone does not establish what model, if any, was used.

The record lists 54 outcome measures and 0 analyses. This does not identify which measures were analyzed, how they were analyzed, or whether analyses appear elsewhere. Specific choices such as covariate adjustment, model form, handling of repeated measurements, and confidence-interval method are not reported in the registry record.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Mobile Health Application")
n      <- c(40)
events <- c(28)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Mobile Health Application  40  28  70.0  53.5  83.4  54.6  81.9  54.5  81.9

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a broad set of outcomes: feasibility, fidelity, attrition, weight changes, BMI z-score changes, and %BMIp95 change, alongside a primary triage objective. It also lists 54 outcome measures and 0 analyses. The record does not explain how outcome measures relate to each objective, which outcomes were designated for formal testing, or whether any adjustment for multiple comparisons was planned or performed. A multiplicity strategy is not reported in the registry record.

In general, testing many outcomes can increase the chance of at least one apparently notable result, even when each test is interpreted using its own threshold. Adjustment procedures and prespecified hierarchies can address some multiplicity concerns, but the appropriate approach depends on the study's aims and analysis plan. No particular procedure should be assumed for this study. Without a reported analysis plan and results, the relative emphasis placed on the primary and secondary outcomes cannot be assessed.

Missing-data handling is also not reported in the registry record. The outcome listing includes an attrition rate, but the listing does not give the observed attrition result or specify how missing measurements were treated in other outcomes. The record does not state whether analyses used all enrolled participants, only those with complete outcome data, or another analysis population. It also does not report how participants lacking a 6 month triage assessment were handled.

In general, missing outcomes can affect both the denominator of a proportion and estimates of change over time. Interpretation depends on how much information is missing and whether missingness is related to participants' outcomes or characteristics. The registry record does not report these details, so the potential impact of missing data cannot be evaluated.

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

The registry record describes the purpose and broad structure of a pilot mobile health intervention for adolescent obesity. It identifies a single-group study with enrollment of 40 and a primary question about triage to low-risk Weight Management Clinics after a brief nurse-coordinator intervention and 4 Kurbo sessions. The primary outcome timeframe is listed as 6 month, and the record is marked completed.

Those design details do not establish how many participants were triaged, what proportion they represented, or how precisely that proportion was estimated. The primary endpoint result and its uncertainty are not reported in the registry record. Secondary outcomes are listed, but their results are also not reported in the registry record. It is therefore not possible to describe observed changes in weight, BMI measures, feasibility, fidelity, attrition, or metabolic profile from these entries.

In general, a single-group study can provide descriptive information about participants who received an intervention, but it does not by itself establish what outcomes would have occurred under an alternative pathway. This distinction matters for causal interpretation: an observed outcome after participation is not automatically an effect caused by the intervention. The registry does not describe a concurrent comparator or a randomized allocation.

The adverse-event record lists zero counts for serious events, other events, and deaths in the intervention group. That registry entry should be interpreted within the limits of the information recorded; details about event ascertainment and reporting completeness are not reported. Overall, the record supports describing the study's intended triage question and listed design, but it does not support a conclusion about the size, precision, or causal meaning of the primary outcome.

13. Why This Trial Matters Statistically

This study is statistically interesting because its stated objective is a triage question rather than a conventional comparison between treatment groups. It aims to examine whether participants are directed to low-risk Weight Management Clinics after an initial nurse-coordinator intervention and mobile health program. That makes clarity about the triage definition, eligible denominator, and timing central to interpreting the endpoint.

The record also describes a stepped approach to management and proposes early response as a way to inform triage. Evaluating that idea requires more than reporting an outcome title: the decision rule for classifying response and the results for participants must be clear. The registry record does not report the rule, the primary result, or the statistical analysis. The listed secondary outcomes suggest additional domains of interest, including feasibility, fidelity, attrition, and changes in body-size measures, but their results are not reported in the registry record.

The single-group design makes descriptive evidence distinct from comparative evidence. This distinction is important when interpreting a pilot: feasibility and outcome patterns may be informative, but an intervention effect relative to another care pathway cannot be established without a suitable comparison. General statistical principles also make precision important; an estimate without an uncertainty measure can be difficult to interpret, especially when the denominator is not reported.

The registry's planning assumptions use equal allocation between two arms, whereas the study is listed as single group. This contrast illustrates why planning calculations must be read in light of the design to which they apply. Such illustrations are not observed power and do not replace reported outcome estimates. The record's missing analysis details limit assessment of how the triage objective was evaluated.

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.

Several limitations of interpretation arise from the registry entries. First, the primary endpoint is described as a proportion but listed as a participant count. The record does not report the observed count, denominator, criteria for low-risk triage, or an uncertainty estimate. Without these items, the primary outcome's magnitude and precision cannot be assessed.

Second, the study is single group, with allocation NA and masking none. There is no concurrent control group identified in the registry record. Any observed change among participants, if reported elsewhere, could not be interpreted as a controlled contrast based on this record alone. The record does not report a comparison with another triage pathway.

Third, the intervention description is incomplete. It identifies a brief nurse-coordinator intervention and Kurbo sessions, and describes app-based dietary, physical activity, and behavioural-change support, but the remaining arm description is truncated. The registry does not provide further operational detail about delivery or adherence beyond the listed outcome topics of feasibility and fidelity.

Fourth, the record does not report the statistical analysis plan, sample-size justification, analysis populations, missing-data procedures, or multiplicity approach. The 54 outcome measures and 0 analyses do not resolve these omissions. The primary timeframe is listed as 6 month, while the objective also refers to a 12 month recruitment period; the relationship between those timings is not explained. Finally, registry entries listing zero adverse-event counts lack further ascertainment and completeness details. These limitations constrain interpretation of the posted record, rather than establishing that any particular outcome was favorable or unfavorable.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Mobile Health Intervention to Identify Early Responders to Treatment in Adolescent Obesity — NCT03561597.
• Registry record last updated 2021-12-06; status last verified 2018-04.
• Results first posted 2021-12-06.
• 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.

18. Record Summary

The registry record describes NCT03561597, a completed single-group pilot titled “Mobile Health Intervention to Identify Early Responders to Treatment in Adolescent Obesity.” The sponsor is KK Women's and Children's Hospital. The listed enrollment is 40, the start date is 2018-04-10, and the primary completion date is 2019-10-21.

The intervention is a mobile health application, described as the Kurbo Program, following a brief nurse-coordinator intervention. The primary objective concerns triage to low-risk Weight Management Clinics, with a 6 month primary outcome timeframe. Secondary outcome listings include feasibility, fidelity, attrition, weight, BMI z-score, and %BMIp95 measures.

The primary endpoint result, secondary results, statistical analysis details, missing-data methods, and sample-size justification are not reported in the registry record. The record lists 54 outcome measures and 0 analyses. It also lists zero serious adverse events, other adverse events, and deaths for the intervention group, without further reporting detail.