Assessing Home Food Environment and Diabetes Self-management Among Adult Type 2 Diabetes Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Assessing Home Food Environment and Diabetes Self-management Among Adult Type 2 Diabetes Patients (NCT03039569), a non-randomized na study. The primary outcome is Self-Care Activities: Healthy Eating.

2. Clinical Question

3. Trial Design

This was a completed, non-randomized, parallel-group study of adults with type 2 diabetes. The registry describes 79 participants, with 40 assigned to text messaging and 39 to a measurement-only control group. Because allocation was non-randomized, the groups may have differed in relevant ways before the intervention. The record explicitly cautions that the arms are not a like-for-like control comparison.

The planned intervention consisted of three messages each week for three months (12 weeks). Messages addressed nutrition education and diabetes self-management, including strategies concerning food choices and the home food environment, self-management skills, and cardiovascular disease risk perception and knowledge. The control group did not receive text messages. The study is described as using a quasi-experimental design; masking was none.

The primary outcome was self-care activities related to healthy eating, measured at three months. The registry describes assessing differences in outcome variables from baseline to the 12-week follow-up between the groups, using the Proc Glimmix procedure. The record does not report the specific covariates, model specification, or assumptions used for that procedure. It also does not report numerical estimates for the primary outcome, uncertainty intervals, or a p-value.

The registry lists secondary outcomes concerning self-reported hemoglobin A1C, concern about cardiovascular disease events, total carbohydrate, and moderate or vigorous physical activity. Results for these outcomes are not reported in the registry record. The study is marked completed, but completion does not itself establish what the outcome findings were.

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: Treatment effects were evaluated by assessing the differences in the outcome variables from baseline to the 12-week follow-up between participants in the intervention group and the control group using Proc Glimmix procedure.

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 Self-Care Activities: Healthy Eating, measured over Three months.

The primary endpoint was self-care activity related to healthy eating. It was described as an average of summary scores across four self-reported healthy-eating items, referring to days over the last seven days. The measurement was expressed in days per week, with a stated range from 0 days to 7 days. The registry gives three months as the timeframe.

This endpoint represents reported behavior rather than a laboratory measurement or a direct assessment of food consumption. A days-per-week measure can make a recurring behavior interpretable in everyday terms: it describes how frequently participants reported engaging in the activities covered by the items. Averaging several related items can provide a summary measure of a broader behavior category, though the record does not describe the individual items or how their scores were combined in detail.

The registry says treatment effects were evaluated by comparing changes from baseline to the 12-week follow-up between the intervention and control groups. That approach focuses on change over time and contrasts the groups’ changes, rather than relying only on a single follow-up value. The numerical change estimates and their precision are not reported in the registry record, so the size and direction of the primary endpoint result cannot be described.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a non-randomized, parallel-group comparison. In a parallel design, participants are assigned to one group and outcomes are compared across groups. Here, the groups were text messaging and measurement-only control. Because allocation was not randomized, observed differences between groups may reflect participant characteristics or other factors as well as the intervention. This is a general limitation of non-randomized comparisons, and the registry specifically warns that the arms are not a like-for-like control comparison.

What does a change comparison mean?

The primary outcome description says the evaluation compared changes from baseline to the 12-week follow-up between the intervention and control groups. In general, a change comparison considers how an outcome moves over time within each group and then contrasts those changes. It is intended to address change over the study period rather than simply comparing follow-up values. The registry does not report the numerical changes or the resulting between-group estimate, so the comparison cannot be quantified from the registry record.

The record identifies the Proc Glimmix procedure for evaluating treatment effects. This identifies a statistical procedure, but not the full model. The registry does not report the specific model terms, covariates, treatment of repeated measurements, or assumptions used. Those details matter because different modeling choices can affect estimates and uncertainty. The model description alone is not enough to reconstruct the analysis.

What does a standard error describe?

The primary outcome is characterized as a least-squares mean with a standard error. In general, a least-squares mean is a model-based mean estimate, potentially reflecting adjustment or averaging defined by the fitted model. A standard error describes the estimated sampling variability of an estimate under the model. It is not a measure of how much individual participants vary, and it is not by itself a confidence interval. The numerical least-squares means and standard errors are not reported in the registry record.

In general, a confidence interval combines an estimate with information about its uncertainty to give a range of values compatible with the analysis and its assumptions. A narrow interval indicates greater precision than a wide interval, but the interval does not resolve bias from non-random allocation, measurement error, or missing data. No confidence interval for the primary result is reported in the registry record.

Why does allocation matter?

Randomization is a design method that can reduce systematic baseline differences between groups, on average. With non-random allocation, the groups can differ at the outset in factors associated with the outcome. Statistical adjustment can address measured factors included in a model, but cannot automatically account for unmeasured factors or poorly measured variables. The registry does not report the covariates used in the primary analysis, so the degree of adjustment cannot be assessed.

The outcome itself is self-reported, based on four healthy-eating items referring to the prior seven days. General limitations of self-report include recall error and differences in how participants understand or report behaviors. The registry does not describe checks for these issues. The outcome is a behavioral summary and should not be conflated with the separately listed dietary and clinical measures.

How should planning illustrations be read?

In general, sample-size calculations are planning exercises that estimate how many participants may be needed to detect a specified effect under stated assumptions. The registry’s planning assumptions describe a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect expressed as a fraction of the observed effect. These illustrations do not represent observed outcomes, and they are not observed power. The registry record does not report a trial-specific sample-size justification or numerical outcome results from which to assess the study’s precision.

Over-dispersion is a general issue that can arise when outcome variability exceeds what a model assumes. If present and not accounted for, uncertainty estimates can be too small, making results appear more precise than they are. The registry does not report whether over-dispersion was assessed or how it was handled; the primary endpoint is described as a continuous measure, and no further model diagnostics are reported.

Finally, statistical significance and practical importance are distinct concepts in general. A p-value, when available, addresses compatibility with a null model under specified assumptions; it does not measure the size or importance of an effect. An estimate and its uncertainty are needed to judge magnitude and precision. Neither a primary estimate nor a p-value is reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and multiple secondary outcomes, including self-reported hemoglobin A1C, cardiovascular disease concern, total carbohydrate, and moderate or vigorous physical activity. It reports 12 outcome measures, but does not describe a multiplicity adjustment, a hierarchy among secondary outcomes, or a strategy for interpreting multiple comparisons. These details are not reported in the registry record.

In general, testing many outcomes can increase the chance of at least one apparently unusual result even when no corresponding effect exists. A prespecified outcome hierarchy or multiplicity procedure can help frame interpretation. Because neither the numerical results nor a multiplicity strategy is reported, the registry record does not support conclusions about the overall pattern of outcomes.

The record describes baseline and 12-week follow-up assessment but does not report the amount or pattern of missing outcome data, how missing values were handled, or the number of participants included in each analysis. The analysis population is not reported in the registry record. Group assignment counts should therefore not be assumed to equal outcome-specific analysis counts.

The record lists zero analysis entries, although the primary outcome description names the Proc Glimmix procedure. It does not report whether analyses were adjusted, whether any interim analyses occurred, or how the statistical analysis plan was specified. These matters are not reported in the registry record. Without outcome estimates and missing-data details, the completeness and robustness of the primary comparison cannot be evaluated.

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 2% reporting threshold.

The registry reports zero serious adverse events in this discussion-messaging group and zero in the control group. It also reports zero participants affected by other adverse events in each group, and zero deaths in each group. The record gives 40 participants at risk in this discussion-messaging group and 39 in the control group for the listed adverse-event categories.

These figures describe the events recorded in the registry; they do not establish that no event occurred outside the recorded data or that the intervention is free of risk. In general, zero recorded events does not demonstrate absence of risk, particularly when the available observation and reporting information is limited. The registry does not report further safety details, event definitions, or the method used to collect adverse-event information. No serious adverse-event terms are listed.

The safety figures should be read separately from the primary behavioral outcome. They do not provide evidence about changes in healthy-eating activity or the secondary outcomes, and they do not resolve the limitations of non-randomized allocation.

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

The registry record establishes that the study examined a text-message education intervention and a measurement-only control group among adults with type 2 diabetes. The intervention was designed to address nutrition, diabetes self-management, physical activity, and cardiovascular disease risk awareness. The primary endpoint concerned self-reported healthy-eating activity at three months, described as an average across four items and expressed in days per week.

The record does not report numerical primary outcome results. It therefore does not show how much either group changed, whether the groups differed, or how precise an estimated contrast might be. It also does not report results for the listed secondary outcomes. These omissions do not establish that there was no effect or that an effect was present; they mean the registry record does not provide the estimates needed to assess either possibility.

Even if a numerical group difference were available, the non-randomized design would require careful interpretation. Group differences could be related to factors other than the text messages. The registry cautions that the arms are not a like-for-like control comparison, and the record does not report enough model detail to assess how measured differences were addressed.

The primary measure is self-reported behavior, not a direct clinical measure. Its interpretation is limited to the reported healthy-eating activities captured by the four items. It should not be treated as interchangeable with dietary intake, hemoglobin A1C, or cardiovascular risk. Those are separate outcomes, and their numerical results are not reported in the registry record.

The appropriate conclusion is descriptive: the registry records the study design and intended outcome assessment, but does not provide numerical findings from which to judge the size, direction, precision, or clinical meaning of the primary comparison.

13. Why This Trial Matters Statistically

This study is statistically notable because it evaluates a behavioral education approach using a non-randomized comparison. Such designs can be useful for examining interventions in real-world settings, but causal interpretation is more difficult when allocation is not random. Differences between groups may predate the intervention, and adjustment can address only factors that are measured and appropriately modeled.

The primary endpoint also illustrates the distinction between a directly observed clinical measure and a self-reported behavioral summary. The measure captures reported frequency across healthy-eating activities, while the registry separately identifies outcomes such as self-reported hemoglobin A1C and total carbohydrate. Keeping these outcomes conceptually distinct helps prevent a behavioral change from being mistaken for a clinical change.

Reporting an outcome estimate together with its uncertainty is essential to statistical interpretation. The registry describes the endpoint and names an analysis procedure, but does not report numerical primary results or precision estimates. As a result, readers cannot assess the magnitude or direction of the estimated comparison from the registry record.

The record also illustrates why analysis populations and missing-data reporting matter. Assignment counts are available, but outcome-specific denominators and missing-data methods are not reported. Without that information, readers cannot determine how much of the assigned sample contributed to each endpoint or whether missing observations could influence estimates.

These features make the record informative about the question and design, but limited as a source of evidence about the observed treatment contrast. Statistical interpretation depends not only on the planned intervention and outcome, but also on transparent estimates, uncertainty, and analysis details.

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 trial-specific limitation is non-randomized allocation. The registry itself cautions that the intervention and control groups are not a like-for-like comparison. Potential baseline differences may complicate interpretation, and the record does not report enough information about adjustment to assess how those differences were addressed.

The primary outcome is self-reported and summarizes four healthy-eating items referring to the prior seven days. It may not capture all aspects of diet or home food availability. The registry does not report the wording of the individual items, validation information, or the detailed scoring procedure beyond describing an average of summary scores.

Numerical results for the primary and secondary outcomes are not reported in the registry record. The primary estimate, standard error, confidence interval, p-value, and outcome-specific analysis counts are unavailable. This prevents assessment of effect direction, magnitude, precision, and completeness of outcome data.

The statistical description names Proc Glimmix but does not specify the full model, covariates, or assumptions. Missing-data methods, analysis populations, multiplicity procedures, and interim analyses are not reported in the registry record. These omissions limit reproducibility and make it difficult to assess the robustness of any intended comparison.

The intervention description specifies text-message content and schedule, but the registry does not report adherence, message receipt, or engagement with linked educational materials. Those details would help characterize the intervention actually received, but cannot be assessed from the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Assessing Home Food Environment and Diabetes Self-management Among Adult Type 2 Diabetes Patients — NCT03039569.
• Registry record last updated 2019-06-19; status last verified 2019-06.
• Results first posted 2019-06-03.
• 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 describes a completed, non-randomized, parallel-group study of adults aged 30 years or older with type 2 diabetes. The intervention group received planned text-message education three times weekly for three months (12 weeks); the control group received no text-message intervention and was described as measurement-only.

The primary outcome was self-care activity related to healthy eating, measured at three months as an average across four self-reported items and expressed in days per week. The registry describes assessing change from baseline to the 12-week follow-up using the Proc Glimmix procedure.

Numerical primary and secondary outcome results, uncertainty estimates, missing-data methods, and outcome-specific analysis counts are not reported in the registry record. The record reports zero serious adverse events, zero other adverse events, and zero deaths in both groups. Because allocation was non-randomized, the registry cautions that the groups are not a like-for-like control comparison.