In-home Obesity Prevention to Reach Low-income Infants: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for In-home Obesity Prevention to Reach Low-income Infants (NCT03529695), a randomized na study. The primary outcome is Mother BMI.

2. Clinical Question

3. Trial Design

NCT03529695, titled “In-home Obesity Prevention to Reach Low-income Infants,” is registered as a completed randomized, single-masked, parallel-group study. It lists 77 participants as enrolled and names the University of Southern California as sponsor. The record lists the phase as not applicable. The study began on 2018-11-01, reached primary completion on 2023-01-30, and has completed status.

The two behavioral interventions were Standard HVP Curriculum and Obesity Prevention. In the standard-services arm, participants received the standard Healthy Families America home-visitation curriculum from trained home visitors. In the obesity-prevention arm, participants received that standard curriculum with an obesity-prevention enhancement module, also delivered by trained home visitors. The record describes matching families to home visitors based on ethnicity, race and language preferences for the obesity-prevention program. It does not give full intervention schedules or enough detail to reconstruct all delivery procedures.

The study description situates the intervention within weekly, in-home services and describes a goal of evaluating whether integrating an obesity-prevention module affects maternal and infant outcomes. It also identifies maternal diet, physical activity, food insecurity and feeding practices, as well as social-network support, as possible mechanisms of interest. These are study aims, not evidence that a particular mechanism changed.

The registry record lists 22 outcome measures, including maternal BMI and behavioral outcomes such as fruit, vegetable, fried-food, soda and fruit-juice intake frequency, maternal movement frequency, and frequency of infant supervised active movement. It reports zero analyses. Details such as the randomization procedure, allocation concealment, the identity of the masked party, and the statistical analysis plan 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: The enrollment number represents the number of mother-infant dyads.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Some participants did not compete all study assessments.

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: Baseline data obtained for 76 mother-child dyads (152 participants total)

6. Primary Endpoint

The registry lists the primary outcome as Mother BMI, measured over Baseline, 6 months, 12 months.

The primary endpoint is maternal body mass index (BMI), a continuous measure expressed in kg/m^2. The registry record describes it as BMI at each assessment, with measurements scheduled at baseline, 6 months and 12 months. It specifies a mean as the summary measure and standard deviation as the dispersion measure. Some participants did not complete all study assessments.

As a general statistical explanation, a continuous endpoint retains information about the range of measured values rather than reducing observations to a yes-or-no category. Comparing group means can therefore describe differences in average BMI, while standard deviations describe how dispersed individual values are around each group mean. BMI is used in this study as an outcome relevant to its stated focus on obesity prevention in mothers. The registry record does not report a primary-outcome result, a clinically important difference, or an analysis comparing the groups at any assessment.

Because the endpoint is recorded at multiple time points, interpretation would depend on knowing which assessment or trajectory the analysis targeted, how repeated measurements were handled, and which participants contributed observations. Those details and the corresponding estimates are not reported in the registry record. The record’s note about incomplete assessments also means the number of observations contributing at each time point cannot be established from the posted information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record labels the study randomized, single-masked and parallel-group. These labels describe broad design features, but do not supply all the information needed to assess the conduct or analysis. In a randomized study, allocation is intended to create groups that are comparable on average at assignment. That purpose does not guarantee that groups will be identical, especially in a study of limited size, and it does not remove the need to report how randomization was generated and implemented. The sequence-generation method and allocation concealment are not reported in the registry record.

What does a parallel-group comparison mean?

In a parallel-group design, participants are assigned to one intervention group and remain in that group for the comparison, rather than switching between interventions. Here, the two listed groups correspond to standard home-visitation services and standard services augmented by an obesity-prevention module. The registry record does not report detailed allocation counts by arm, so the enrolled total should not be read as an arm-specific sample size. Nor does the record identify which person or group was masked under its single-masked designation.

How should a mean and standard deviation be read?

A mean describes the average value of a continuous measurement in a group. A standard deviation describes the spread of individual observations around that group average. They answer different questions: the mean locates the group’s center, while the standard deviation describes variability among participants. Neither quantity alone is a between-group treatment estimate. To interpret a comparison, readers would need the group summaries together with a direct contrast and its uncertainty. Those primary-outcome results are not reported in the registry record.

What would a confidence interval add?

As a general statistical concept, a confidence interval communicates the precision of an estimate under a specified statistical procedure and its assumptions. A relatively narrow interval indicates greater precision than a wider interval, while the interval’s location describes which effect sizes remain compatible with the analysis. A confidence interval is not a guarantee that the true effect lies within its limits, and it does not establish whether an effect matters clinically. The registry record does not report a confidence interval for maternal BMI.

Why do repeated measurements need an analysis plan?

BMI is listed at baseline, 6 months and 12 months. Repeated observations from the same participant are related, so a statistical method that treats them as unrelated can misrepresent uncertainty. Different approaches may estimate a contrast at a particular visit, a difference in change, or an overall pattern across visits. These are not interchangeable estimands. A complete interpretation would require knowing which contrast was prespecified, how within-participant correlation was handled, whether baseline values were incorporated, and how incomplete records were treated. These details are not reported in the registry record.

What do over-dispersion and distributional assumptions mean?

As a general explanation, over-dispersion arises when observed variability in a data set is greater than a statistical model assumes. If a model underestimates variability, its uncertainty estimates can be too small and its intervals or tests can be misleading. This issue is particularly relevant to some count or binary-outcome models; it is not a finding reported for this study. For a continuous endpoint such as BMI, an analyst would still need to consider the measurement distribution, the pattern of variability, and whether the chosen model’s assumptions are adequate. The registry record does not identify the model or report diagnostic checks.

What do the planning illustrations represent?

The record describes sample-size illustrations based on an observed effect, with two-sided significance level 0.05, equal allocation, and a normal approximation. It says that the effect to detect is a stated fraction of the observed effect and distinguishes participant counts per arm for non-time-to-event outcomes from total event counts for time-to-event outcomes. These are planning illustrations, not observed power and not evidence that the study was designed around those assumptions. The registry record does not report the trial’s own sample-size justification or the resulting illustration values in the registry record for this analysis. An illustration based on an observed effect should not be mistaken for a confirmatory result or a guarantee of future precision.

More broadly, statistical significance and estimation are distinct. A test addresses compatibility with a null hypothesis under assumptions; an estimate and its interval describe magnitude and precision. Neither substitutes for transparent reporting of the outcome data, analysis population and prespecified method. For this study, the record’s design labels and endpoint definition can be described, but the statistical procedure used to analyze the primary outcome is not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome includes measurements at baseline, 6 months and 12 months. The registry record notes that the primary outcome has several categories or time points and was not reduced to one comparison. It lists 22 outcome measures overall and reports zero analyses. These registry entries leave unanswered how the primary endpoint and secondary outcomes were organized into planned hypotheses, which contrasts were primary, and whether any adjustment for multiple comparisons was planned. The multiplicity strategy is not reported in the registry record.

As a general statistical point, assessing several outcomes, time points or contrasts can increase the chance of obtaining at least one apparently unusual result by chance if each is interpreted as an independent confirmatory test. Adjustment methods, hierarchical testing or a clearly designated primary contrast can address different aspects of this issue, but the choice depends on the study’s aims and analysis plan. No such strategy is reported for this trial, so no claim about multiplicity control is warranted.

The primary-outcome population note says some participants did not complete all study assessments. The registry record does not give the number of missing BMI observations at each visit, reasons for missingness, or the analysis population. It also does not describe imputation, likelihood-based methods, sensitivity analyses, or other approaches to incomplete data. As a general explanation, missing-data methods rely on assumptions about why observations are absent; those assumptions affect how estimates should be interpreted. Without the missingness pattern and analysis details, the impact of incomplete follow-up cannot be assessed.

Whether all randomized participants were analyzed in their assigned groups, or whether another population was used, is not reported in the registry record. The allocation and masking labels alone do not answer this question.

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.

Most frequent non-serious adverse event terms

The registry record reports serious adverse events for mothers and children in both intervention groups. For mothers in the Standard HVP Curriculum group, 35 were at risk, with 0 serious events and 2 other events reported as affecting participants. For mothers in the Obesity Prevention group, 42 were at risk, with 0 serious events and 1 other event affecting participants. For children, the corresponding Standard HVP Curriculum group figures were 35 at risk, 0 serious events and 2 other events affecting participants; the Obesity Prevention group figures were 42 at risk, 0 serious events and 1 other event affecting participants. No deaths were reported in any of these four entries.

These are counts as recorded, not evidence that the groups had equivalent safety. The at-risk counts are the denominators listed for each entry; no percentages or comparative safety estimates are reported. The child and mother entries are separate reporting groups and should not be combined to create a new total. The record does not provide event descriptions for the reported non-serious events, event timing, severity details beyond the serious-event classification, or a statistical comparison. Serious-event counts of zero in the posted record should therefore be read narrowly as the reported counts, not as proof that no adverse experiences occurred.

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

The record supports a description of the study’s question and design: it randomized participants between standard home-visitation services and those services with an obesity-prevention enhancement, with maternal BMI identified as the primary outcome. BMI was scheduled for assessment at baseline, 6 months and 12 months. The study was completed and enrolled 77 participants. These details establish what the trial set out to compare, but do not establish what the comparison found.

The posted registry information does not include primary-outcome values, between-group estimates, confidence intervals or statistical tests. It also reports zero analyses. Therefore, it does not show whether average maternal BMI differed between groups, how large any difference might have been, or how precise an estimate would be. The absence of posted estimates is not evidence that the groups were the same, and it is not evidence that the intervention changed BMI.

The same distinction applies to the study’s secondary outcomes and proposed mechanisms. Outcomes concerning food intake and movement are listed, and the study description identifies maternal and social factors of interest. But no outcome estimates or analyses for those measures are reported. The record does not establish changes in those behaviors or show that they explain any infant outcome.

As a general principle, a randomized comparison can inform an intervention effect when its outcome estimates, analysis methods and limitations are reported and interpreted together. The design label alone cannot supply those results. Incomplete assessments are acknowledged, but their extent and handling are not described, further limiting assessment of precision and potential bias. The registry record also does not report the trial’s statistical analysis plan or sample-size justification.

Accordingly, the defensible conclusion is descriptive: the record documents a completed randomized study with a maternal BMI primary outcome and a home-visitation enhancement, but it does not report the analyses needed to judge the primary comparison. No medical recommendation or claim about treatment effectiveness follows from the available registry information.

13. Why This Trial Matters Statistically

This study illustrates why a registry entry should be read as a record of design and reporting, not automatically as a source of outcome evidence. It clearly identifies a randomized, parallel-group comparison, the two service models, the primary endpoint, and its scheduled assessments. Those details allow readers to understand the intended question and the broad structure of the comparison.

At the same time, the registry record reports zero analyses and no primary-outcome estimates. A defined endpoint is not equivalent to a reported result. Without group summaries, a contrast and measures of uncertainty, readers cannot judge the size or precision of an effect. This distinction is central to statistical interpretation: knowing what was measured does not tell us what the measurements showed.

The trial also raises common design and reporting considerations. A continuous outcome measured repeatedly needs a clearly specified comparison and an approach that accounts for observations from the same participant. Multiple outcomes and time points call for transparent identification of primary contrasts and multiplicity handling. The record lists 22 outcome measures but does not report the relevant analysis details. Incomplete assessments are acknowledged, yet their extent and treatment are not described.

These gaps do not erase the value of the design information. They indicate what can be concluded from this record and what remains uncertain. Distinguishing an intervention’s stated rationale from measured evidence, and registry status from posted analysis, helps prevent a study aim or design label from being mistaken for a result.

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 principal limitation for statistical interpretation is that the registry record does not report primary-outcome results or analyses. No arm-specific maternal BMI means, contrasts, confidence intervals or tests are available in the posted information. The record says the primary endpoint covers several time points and was not reduced to one comparison, leaving the target contrast unclear.

The record acknowledges that some participants did not complete all study assessments, but does not report missing-observation counts by visit, reasons for missingness, or how incomplete measurements were handled. The number of participants contributing to each BMI assessment therefore cannot be established from the record. The enrolled total of 77 does not, by itself, describe outcome-specific sample sizes.

Although the study is identified as randomized and single-masked, random-sequence generation, allocation concealment and the masked party are not reported in the registry record. The full statistical analysis plan, model specifications, analysis population, and approach to repeated measurements are also not reported. The registry lists 22 outcome measures but does not describe a multiplicity strategy or provide analyses for the secondary outcomes.

The intervention descriptions in the registry record are incomplete, so all implementation details cannot be evaluated. The record also does not provide a detailed participant-characteristics breakdown or enough information to assess how closely the enrolled population represents other settings. The planning illustrations described in the record are not a substitute for the trial’s own sample-size justification, which is not reported in the registry record. These limitations constrain evaluation of precision, bias, and generalizability; they do not establish that a particular bias or problem occurred.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: In-home Obesity Prevention to Reach Low-income Infants — NCT03529695.
• Registry record last updated 2024-10-23; status last verified 2024-10.
• Results first posted 2024-10-23.
• 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

NCT03529695 is a completed randomized, single-masked, parallel-group study sponsored by the University of Southern California, with 77 participants enrolled. It compared standard Healthy Families America home-visitation services with the same curriculum plus an obesity-prevention enhancement module. The primary outcome was maternal BMI in kg/m^2 at baseline, 6 months and 12 months, summarized as a mean with standard deviation. Some participants did not complete every assessment.

The record lists 22 outcome measures, reports zero analyses, and does not provide primary-outcome estimates or statistical tests. It reports zero serious adverse events in the listed mother and child groups, alongside counts of other events affecting participants, and no deaths. The extent and handling of missing outcome data, statistical analysis plan, multiplicity approach, and trial-specific sample-size justification are not reported in the registry record. As posted, the record describes the study design and endpoints but does not provide results for the primary comparison.