Unintentional Overfeeding of Formula Fed Infants: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Unintentional Overfeeding of Formula Fed Infants (NCT02701868), a registered phase not stated study. The primary outcome is Focus Group Recommendations to Improve Infant Formula Preparation Instructions.

2. Clinical Question

The study's rationale concerns the possibility that powdered formula preparation practices could result in overfeeding. The registry summary notes that formula-fed infants experience greater weight gain in the first year of life and proposes unintentional overfeeding from over-scooping as a possible contributor. That rationale is not itself a trial result. The clinical question addressed by the primary outcome is about participants' recommendations for improving instructions, rather than a measured clinical outcome such as infant weight gain.

3. Trial Design

The registry record describes a completed, two-phase study titled “Unintentional Overfeeding of Formula Fed Infants,” sponsored by Pennington Biomedical Research Center. It records enrollment of 171. The study began in 2016-07 and had a primary completion date of 2017-04. The conditions listed are Childhood Obesity and Infant Development.

In Phase 1, up to 40 individuals were to take part in focus groups at Pennington Biomedical Research Center. The description anticipates approximately six groups, each with 5-10 participants, conducted at the Pennington Biomedical Demonstration Kitchen over approximately 3 months. The focus groups assessed how participants read and understood powdered infant formula package preparation instructions and solicited recommendations for improvement. The primary outcome is explicitly limited to Phase 1 participants.

Phase 2 was designed to test revised instructions against the instructions on product packaging. Its description says that up to 150 individuals who did not participate in Phase 1 would be recruited. The registry lists Phase 2 Standard Instructions and Phase 2 Modified Instructions as separate arms. Although the study description uses a comparison, the allocation method is not stated. The record therefore does not support treating the arms as a randomized, like-for-like comparison.

The enrollment figure and the planned recruitment limits describe different record entries; the registry does not explain their relationship. It also does not report the actual recruitment, participation, or completion counts for each phase beyond the safety-group counts. The record indicates that the study is completed, but completion status alone does not supply outcome results or details of the analyses used.

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

Analysis population for the primary outcome, as defined in the registry: The focus groups were only completed for Phase 1 participants. This outcome measure does not apply to Phase 2 participants who did not participate in focus groups and provide infant formula preparation instructions.

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 Focus Group Recommendations to Improve Infant Formula Preparation Instructions, measured over Day 1.

The primary outcome is “Focus Group Recommendations to Improve Infant Formula Preparation Instructions.” It is measured as the percentage of focus-group participants reporting specific recommendations, with a timeframe of Day 1. The description says that five focus groups provided primary recommendations. The measure concerns participants' reported recommendations about the reading and comprehension of powdered infant formula package preparation instructions. It does not measure infant feeding behavior, formula intake, weight gain, or a clinical diagnosis.

A percentage is a way to describe how frequently a particular response occurs within a defined group. For this outcome, interpretation depends on knowing which participants form the denominator and which recommendation or response is being counted. The registry identifies the unit as the percentage of focus-group participants and says that specific recommendations are summarized. It does not provide the recommendation categories, their observed percentages, or the corresponding counts in the outcome description available in the record.

Using participant recommendations is relevant to the formative purpose of Phase 1: identifying aspects of instructions that may be difficult to read or understand and gathering suggestions for improvement. Such feedback can inform a later test of revised instructions, but it is not evidence by itself that the revised wording changes preparation behavior or infant outcomes. The registry states that this endpoint does not apply to Phase 2 participants, who did not take part in the focus groups. Numerical results for this primary outcome are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods describe how observations are converted into estimates and how uncertainty is assessed. In this study, the primary outcome is a percentage of focus-group participants reporting specific recommendations. A descriptive percentage can summarize how often a recommendation was reported, but interpretation requires a clear response category and denominator. The registry identifies the outcome unit and the focus-group population, but it does not report the specific recommendation categories or their observed values.

What would a descriptive percentage tell a reader?

In general, a percentage expresses a part relative to a defined whole. For a focus-group recommendation, the denominator could be the participants whose responses were collected for that recommendation, and the numerator would be those reporting it. The record describes the outcome as a percentage of focus-group participants but does not provide the underlying counts or clarify whether each participant could report more than one recommendation. Without the response definitions and data, the reported measure cannot be reconstructed or checked from the registry information.

Focus-group feedback is also not automatically equivalent to a population estimate. General statistical reasoning distinguishes qualitative or formative feedback, which can identify perceived problems and suggestions, from a probability-based estimate intended to represent a broader population. The registry record describes focus groups for evaluating instruction comprehension; it does not report a sampling scheme that would justify treating the participants' recommendations as representative of all caregivers or formula users.

How should a comparison be interpreted?

In general, a comparison of outcomes between groups is interpreted through an estimated contrast and its uncertainty. The contrast might be expressed using a measure suitable for the outcome, but the record does not provide the Phase 2 outcome definition or the numerical results needed to identify and interpret such an estimate. It describes standard and modified instructions as arms and says the revised instructions were to be tested for efficacy on infant overfeeding. The allocation method is not stated, and the record specifically does not describe a randomized, like-for-like comparison.

When group assignment is not established as randomized, observed differences may reflect differences between the groups as well as any effect of the instructions. General methods can adjust for measured characteristics, but adjustment cannot automatically remove differences that were not measured or appropriately modeled. The registry record does not report whether adjustment was used, which variables might have been considered, or how any comparison was analyzed. No adjusted or unadjusted estimate is reported.

Confidence intervals are a general way to communicate statistical uncertainty around an estimate. A narrower interval usually indicates greater precision under the chosen model, while a wider interval indicates less precision. An interval does not correct for bias, poor measurement, or an inappropriate analysis. The registry record does not report confidence intervals for the primary outcome or the Phase 2 comparison, so their precision cannot be evaluated from the record.

What do the analysis and planning entries establish?

The registry lists 0 analyses. That entry means no statistical analysis is documented in the record; it does not establish what may have been done outside the registry. The analysis plan, model specifications, handling of repeated observations or focus-group structure, and criteria for selecting results are not reported in the registry record. These details matter because responses from people in the same focus group may share context, and analyses that assume every response is independent may understate uncertainty. This is a general consideration, not a claim about an analysis used in this study.

The record includes planning assumptions for sample-size illustrations: a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. It specifies that time-to-event illustrations give the total number of events under the Schoenfeld approach, while other illustrations give participants per arm. These are planning conventions, not proof that the study used those assumptions. The actual design justification and sample-size calculation are not reported in the registry record.

Planning sizes based on an observed effect are conditional illustrations. They depend on the assumed effect, allocation, significance threshold, model approximation, and other inputs. They should be read as hypothetical planning quantities, not as observed power or evidence that the study had a particular chance of detecting a real effect. In this case, the numerical outcome estimate needed to assess the assumed effect is not reported in the registry record. The stated planning assumptions therefore do not fill the gap in the study's outcome reporting.

Over-dispersion is a general issue when observed variability exceeds what a chosen statistical model expects. If it is ignored, standard errors can be too small and uncertainty can appear narrower than it is. The registry record does not report a model for the outcomes or indicate whether over-dispersion was assessed. It would therefore be inappropriate to say that this issue occurred or that a particular correction was applied.

Overall, statistical methods can clarify how a result was estimated, how uncertainty was handled, and what assumptions support the conclusion. For this study, the registry description identifies the primary measure and a Phase 2 comparison objective, but it does not report the numerical outcome results or analysis details needed for those assessments.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 2 outcome measures and 0 analyses. It describes the primary outcome as focus-group recommendations, but the other outcome's details are not reported in the registry information used for this account. The record does not provide a complete list of hypotheses, comparisons, or analysis populations, so the relationship between the outcomes and any planned claims cannot be established.

Multiplicity is a general concern when multiple outcomes, groups, time points, or statistical tests are examined. The more tests that are considered, the greater the possibility that at least one result may appear notable by chance if no adjustment or prespecified hierarchy is used. Whether an adjustment is needed depends on the scientific questions and analysis plan. The registry record does not report a multiplicity strategy, a hierarchy of outcomes, or a prespecified primary comparison beyond identifying the focus-group outcome as primary.

Missing-data handling is also not reported in the registry record. The record does not say how incomplete questionnaires, missing participant responses, unavailable outcome measurements, or withdrawals were handled. It does not provide outcome-specific denominators or a flow of participants through analysis. Without those details, completeness and the potential influence of missing observations cannot be assessed.

Analysis populations are not described. The registry record does not state whether analyses used all enrolled participants, participants who completed a phase, or another defined group. The Phase 1 outcome is explicitly inapplicable to Phase 2 participants, but the record does not provide a more detailed analysis-set definition. These omissions limit interpretation of both the reported design and any future use of numerical results.

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 adverse-event entries list no serious adverse events, other adverse events, or deaths in any of the three groups. For Phase 1, the record lists 21 at risk for serious events and 0 affected, 21 at risk for other events and 0 affected, and 0 deaths. For Phase 2 Standard Instructions, it lists 75 at risk for serious events and 0 affected, 75 at risk for other events and 0 affected, and 0 deaths. For Phase 2 Modified Instructions, it likewise lists 75 at risk for serious events and 0 affected, 75 at risk for other events and 0 affected, and 0 deaths. No serious adverse-event terms are listed.

These entries describe what the registry reports; they should not be read as proof that an event was impossible or that every possible safety outcome was measured. The record does not provide further information about event-collection procedures, observation periods, definitions, or completeness of reporting. The groups also correspond to different phases and are not documented as a randomized comparison. Thus, the listed zero counts do not support a comparative safety estimate between the Phase 2 instruction groups.

In general, adverse-event counts are most informative when the event definitions, observation time, and participants under surveillance are clear. The registry supplies group-level at-risk and affected counts, but not those additional details. The figures should therefore be understood narrowly as registry entries, without extending them into a broader conclusion about safety.

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

The record establishes that this completed study had a formative focus-group phase and a planned test of modified formula preparation instructions against standard packaging instructions. Its primary outcome concerns recommendations from Phase 1 participants about improving the readability and comprehension of instructions. The record also identifies overfeeding as the motivation for testing revised instructions in Phase 2.

What the record does not establish is whether any particular recommendation was common, whether the modified instructions changed preparation practices, or whether infant overfeeding differed between the Phase 2 arms. The numerical results for those questions are not reported in the registry record. The outcome description and study rationale should not be treated as evidence of an observed effect.

General interpretation of a trial result requires considering the estimate, its uncertainty, the measurement process, and the design used to make the comparison. Here, the allocation method is not stated, and the record does not report the statistical analyses, comparison estimates, confidence intervals, or p-values. Consequently, neither the magnitude nor the precision of a Phase 2 difference can be judged from the registry description.

The focus-group findings, if reported elsewhere, would address participants' views about the instructions and could help identify opportunities for clearer wording. Such feedback can be useful for developing an intervention, but it is not interchangeable with a test of whether an intervention changes behavior or clinical outcomes. The two phases answer related but distinct questions.

The safety entries report zero serious events, zero other events, and zero deaths in the listed groups. Those counts are limited to what the registry records and do not establish that every type of event was assessed over a fully described observation period. The design and reporting details needed for stronger conclusions are not reported in the registry record.

13. Why This Trial Matters Statistically

This study is statistically interesting because its phases illustrate the difference between developing an intervention and evaluating it. Focus groups can identify concerns about how instructions are read and understood. A later comparison can test whether modified wording is associated with a change in an outcome. The primary focus-group measure and the Phase 2 testing objective are connected in sequence, but they are not the same endpoint or analysis question.

That distinction matters when translating a study rationale into evidence. The registry summary proposes that over-scooping powdered formula may contribute to unintentional overfeeding and describes a test of revised instructions. A plausible rationale motivates research, but it does not establish the size or existence of an effect. The record does not report the numerical results needed to assess the Phase 2 comparison.

The record also illustrates why design details are essential for interpreting group differences. The standard and modified instruction arms are named, but allocation is not stated. General statistical reasoning cautions that group contrasts can reflect factors other than the intervention when allocation does not ensure comparability. Without a documented allocation method and analysis, the strength of any causal interpretation cannot be evaluated.

Finally, the registry distinguishes a primary outcome from a broader study objective but supplies little analysis detail. Knowing the endpoint, denominator, analysis population, missing-data approach, and uncertainty estimates helps readers understand what a result represents. The absence of these details in the registry record is itself important: it limits reproducibility and prevents a quantitative assessment of the study's findings from this record alone.

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 registry record provides a study description but does not report numerical results for the primary outcome. It does not list the specific recommendations and percentages, their underlying counts, or any uncertainty estimates. The description says five focus groups provided primary recommendations, but it does not give the response-level detail needed to assess how recommendations were categorized or summarized.

For Phase 2, the record describes a test of revised instructions against standard packaging instructions, but does not report the outcome definition, observed results, or analysis. Allocation is not stated, and the record does not establish a randomized comparison. The information available therefore cannot support an assessment of comparability between the Phase 2 groups or a causal interpretation of a group difference.

Recruitment and analysis details are limited. The record states enrollment of 171 and gives planned recruitment limits for each phase, but does not explain the relationship between those figures or report detailed participant flow. The analysis populations, outcome denominators, missing-data procedures, and handling of incomplete responses are not reported in the registry record.

The statistical analysis plan, any multiplicity approach, and the rationale for sample size are also not reported. The listed planning assumptions do not establish the methods used for the completed study. The safety entries lack further detail about event definitions, collection methods, and observation periods. These limitations concern what can be concluded from the registry record; they do not establish what information may exist outside it.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Unintentional Overfeeding of Formula Fed Infants — NCT02701868.
• Registry record last updated 2021-01-14; status last verified 2020-12.
• Results first posted 2021-01-14.
• 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 a completed study of powdered infant formula preparation instructions, sponsored by Pennington Biomedical Research Center. It records enrollment of 171, a start date of 2016-07, and a primary completion date of 2017-04. Phase 1 used focus groups to gather recommendations on reading and understanding package instructions. Phase 2 was intended to test modified instructions against standard packaging instructions.

The primary outcome is the percentage of focus-group participants reporting specific recommendations. The record lists 2 outcome measures and 0 analyses, but does not report numerical results for the primary outcome or a Phase 2 comparison. Allocation is not stated. Safety entries list zero serious adverse events, zero other adverse events, and zero deaths in each reported group. Analysis details, missing-data methods, and a multiplicity plan are not reported in the registry record.