This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Changing Lifestyles for Better Health (NCT00848757), a randomized na study. The primary outcome is Change in Weight.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00848757 |
| Phase | NA |
| Condition | Type 2 Diabetes Mellitus |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 130 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Yale University |
| Results posted | Yes |
2. Clinical Question
Population
Women with pre-diabetes are described in the arm descriptions as the population of interest. The registry lists Type 2 Diabetes Mellitus as the condition, so the record contains a difference between its condition label and its description of the participants. Further eligibility details are not reported in the registry record.
Intervention
The intervention was an intensive lifestyle program. The description says participants were to attend a group program focused on nutritional education, diet, behavior modification, and structured exercise. It was based on the Diabetes Prevention Program “Lifestyle Balance” curriculum, with modifications; details of those modifications are not reported in the registry record.
Comparator
The comparator was usual care. The description says participants would be offered appointments with a medical provider to discuss their diagnosis and diabetes risk, emphasize lifestyle changes, and set individual goals. The record does not describe further details of usual-care delivery.
Primary question
The primary endpoint compares change in weight, in kilograms, from baseline to 12 months. The registry posts a least-squares mean and a 95% confidence interval for each group. It does not post a direct between-group estimate or a test of the difference, so the arm summaries alone do not state the estimated comparative effect or its uncertainty.
3. Trial Design
The registry describes a randomized, parallel-group trial with no masking. It lists an enrollment of 130 and marks the study completed. The listed start is 2009-03 and the primary completion is 2014-07. The registry identifies Yale University as sponsor.
The two groups were intensive lifestyle intervention and usual care control. The posted primary outcome summaries each list 61 participants. The registry record does not explain how the enrollment figure relates to the number of participants in these outcome summaries, or whether any participants were excluded from this particular analysis. That relationship should not be inferred from the counts alone.
The intervention description specifies a group program lasting 12 weeks, including nutrition education, diet, behavior modification, and structured exercise. The comparator description specifies appointments with a medical provider focused on diagnosis, diabetes risk, lifestyle changes, and individual goals. The record does not report the number of sessions in usual care, attendance, adherence, or whether the intervention was delivered as planned.
The listed phase is NA. Further details about allocation procedures, sequence generation, concealment, stratification, and the rationale for the planned enrollment are not reported in the registry record. Randomized allocation can support a fair comparison when implemented and analyzed appropriately, but the registry’s design label alone does not provide these procedural details. The record identifies self-reported physical activity levels as a secondary outcome, but does not post an analysis for that outcome in the information summarized by the registry.
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
| Stage | Intensive Lifestyle Intervention (ILI) | Usual Care Control |
|---|---|---|
| STARTED | 65 | 65 |
| COMPLETED | 61 | 61 |
| NOT COMPLETED | 4 | 4 |
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.
| Characteristic | Unit | Intensive Lifestyle Intervention (ILI) | Usual Care Control | Total |
|---|---|---|---|---|
| Participants analysed | 61 | 61 | 122 | |
| Age, Continuous | years | 43.8 (SD 10.8) | 43.0 (SD 9.7) | 43 (SD 10) |
| Sex: Female, Male: Female | Participants | 61 | 61 | 122 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | participants | 61 | 61 | 122 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Weight, measured over Baseline and 12 Months.
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | kg |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change in weight from baseline to 12 months, measured in kilograms. Weight is a continuous measure: each participant’s value can fall across a range rather than being limited to categories such as improved or not improved. The registry specifies that the posted group result is a least-squares mean, with a 95% confidence interval.
Change from baseline expresses how the measured weight at follow-up differs from the starting measurement. The endpoint description says the change is reported from baseline to 12 months. In the intervention group, the posted mean change is -3.8 kg, with a 95% confidence interval from -4.6 to -3.0. In the usual-care group, it is 1.4 kg, with a 95% confidence interval from 0.6 to 2.2.
As a general statistical point, a continuous outcome can retain more information than converting measurements into broad categories. A confidence interval conveys uncertainty around an estimated group mean; it does not by itself give the uncertainty around the difference between groups. The registry does not report a direct comparative estimate for this endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted summaries describe a negative mean weight change in the intensive lifestyle intervention group and a positive mean weight change in the usual-care group over the baseline-to-12-month period. The respective least-squares means are -3.8 kg and 1.4 kg. Their 95% confidence intervals are -4.6 to -3.0 kg and 0.6 to 2.2 kg. These are group-specific estimates, not a reported estimate of the randomized comparison.
A confidence interval gives a range of values compatible with the data and the statistical model used to calculate it, under the assumptions of that method. It helps communicate precision around an estimate. It is not a range containing every participant’s change, and it is not a guarantee that the true mean lies inside the interval. The registry identifies the intervals as 95% confidence intervals but does not report the model specification or additional details needed to assess how they were calculated.
Although the two group summaries point in different directions, their separate confidence intervals do not substitute for a confidence interval or test for the between-group contrast. A direct comparison accounts for uncertainty in the difference itself. That comparative estimate, its confidence interval, and a p-value are not reported in the registry record. Values needed for a simple unadjusted recalculation of a two-arm comparison are marked as missing or not estimable. No recalculated comparison is therefore presented.
The posted outcome summaries list 61 participants in each arm. The registry separately lists enrollment of 130, but does not explain the difference between that enrollment figure and the outcome-summary counts. It also does not report how missing weight measurements were handled or which analysis population was used. Those omissions matter when assessing how representative the reported estimates are of all randomized participants.
The registry marks the study completed, but completion status is not itself evidence about the magnitude or certainty of an intervention effect. The results describe the posted group means and their intervals. They do not, on their own, establish a causal comparative effect or support a clinical recommendation.
9. Statistical Methods Explained
The registry describes randomized allocation to a parallel comparison and lists no masking. In a randomized trial, assignment is intended to make groups comparable, on average, with respect to measured and unmeasured characteristics before intervention. Randomization does not ensure that every feature will be balanced in a particular trial, and interpreting the result still depends on how allocation was conducted, how participants were followed, and how outcomes were analyzed. Further details about those procedures are not reported in the registry record.
What does a least-squares mean represent?
A least-squares mean is a model-based estimate of a group mean. In general, such estimates can account for terms included in a statistical model, and may differ from a simple arithmetic average. The registry names the reported quantity as a least-squares mean but does not identify the model terms, adjustment variables, or estimation method. It is therefore not possible to determine from the record what adjustments, if any, underlie the posted estimates. The values should be described as the registry’s reported group estimates rather than as unadjusted raw averages.
How should the confidence intervals be read?
A confidence interval communicates uncertainty about an estimated quantity. In repeated use of a method under its assumptions, intervals constructed at a stated confidence level would cover the underlying quantity at that rate. For an individual result, the interval is best read as a measure of estimation precision, not as a probability statement about the fixed true value. The reported 95% intervals are attached to each group’s mean change. They do not quantify uncertainty in the between-group difference, because that contrast is not posted.
General statistical interpretation also depends on the model and the data. For a continuous endpoint, assumptions may concern the form of the outcome distribution, the model’s fit, and how observations relate to one another. The registry does not report diagnostics or sufficient model details to evaluate those assumptions. No additional assumption should be attributed to the trial without such documentation.
Why is the arm comparison not recalculated?
A between-group estimate requires an appropriate comparison and its uncertainty. The record’s group means and confidence intervals describe each arm separately; separate intervals are not a substitute for the standard error or confidence interval of their difference. The available analysis information is marked as missing or not estimable for a two-arm comparison of this continuous endpoint. Consequently, no unadjusted recalculation is reported. There is also no posted comparative p-value in the registry information summarized for this endpoint.
General explanations of simple recalculation should be kept distinct from the trial’s own analysis. A recalculation from summary statistics, when possible, is unadjusted and may not reproduce a model-based sponsor analysis. In this record, the discrepancy flag is false, but the comparative values are still unavailable for recalculation. The posted arm summaries remain the basis for describing the result; they do not authorize creating a new contrast.
What do the planning illustrations mean?
Any sample-size figures accompanying the results are planning illustrations based on the observed effect under stated assumptions: a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The illustrated effect is a stated fraction of the observed effect. Such illustrations ask how many participants per arm might be needed under those assumptions to detect a selected effect size. They are not observed power, do not describe the trial’s actual design justification, and do not show that the trial had a particular probability of detecting its result.
The trial’s own sample-size justification is not reported in the registry record. Nor are interim analyses, stopping rules, or a detailed statistical analysis plan. These details should not be inferred from the posted outcome summaries or from a planning illustration. General power calculations depend on assumptions about the effect to detect, variability, error rates, allocation, and analysis; they cannot replace documentation of the original design rationale.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary outcome, change in weight, and identifies self-reported physical activity levels as a secondary outcome. It also states that there are six outcome measures, while the listed secondary-outcome information identifies only one secondary outcome. The registry record does not explain this difference or provide a complete account of all outcome measures in the information. It does not report a multiplicity adjustment or describe how multiple outcomes were handled statistically.
As a general matter, when several outcomes or comparisons are tested, the chance of at least one apparently notable result can increase if each is assessed separately. A prespecified testing hierarchy or adjustment can address some multiplicity concerns. The registry record does not state whether such a plan was used, so no particular approach should be attributed to the trial.
The primary group summaries list 61 participants in each arm, whereas the listed enrollment is 130. The registry does not report the analysis population, participant flow, completeness of follow-up, or handling of missing endpoint measurements. It is therefore not possible to determine from this record whether the posted summaries include all randomized participants, only participants with observed measurements, or another defined population.
In general, missing outcomes can affect interpretation if the likelihood of missingness is related to participants’ characteristics or outcomes. Methods such as imputation or sensitivity analyses can be used in some settings, but the registry does not report whether any such methods were used. The missing-data assumptions and their consequences are therefore not assessable from the registry record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Usual Care Control | 0 | 61 | 0.0% |
| Intensive Lifestyle Intervention (ILI) | 0 | 61 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Usual Care Control | 0 of 61 |
| Intensive Lifestyle Intervention (ILI) | 0 of 61 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Usual Care Control | 0 of 61 |
| Intensive Lifestyle Intervention (ILI) | 0 of 61 |
The serious adverse event figures list 61 participants at risk in each group and zero participants affected by a serious adverse event in each group. The figures also list 61 at risk and zero affected for the other adverse-event category in each group, and zero deaths in both groups.
These counts describe what the registry reports for the recorded safety categories. They do not establish that no events of any kind occurred, that every possible event was collected, or that the groups had identical safety profiles. The record does not list any top serious adverse event terms. Details about event definitions, collection procedures, observation time, severity grading, or relatedness to the intervention are not reported in the registry record.
As a general statistical point, a zero count in a group does not prove that the underlying event risk is zero. The precision of safety estimates depends on the amount and duration of observation and on how events were ascertained. These summaries should therefore be read as registry-reported counts, not as a complete characterization of safety.
12. What the Result Does, and Does Not, Mean
The registry reports a mean change in weight of -3.8 kg for the intensive lifestyle intervention group and 1.4 kg for the usual-care control group, from baseline to 12 months. The corresponding 95% confidence intervals are -4.6 to -3.0 kg and 0.6 to 2.2 kg. These results describe each group’s estimated change; the registry does not report a direct estimate of the difference between groups.
That distinction matters. A randomized trial’s central comparative question concerns how outcomes differ between assigned groups, with uncertainty quantified for that contrast. Group-specific means can be informative, but they do not supply the comparative estimate, its confidence interval, or a significance test. The registry record also does not explain the model behind the least-squares means, the analysis population, or the handling of missing observations.
The record describes women with pre-diabetes in its arm descriptions, while listing Type 2 Diabetes Mellitus as the condition. Eligibility details and the reason for this difference are not reported. The intervention description gives its broad components and duration, but not the full modified curriculum or evidence about adherence and delivery. These limits restrict interpretation of precisely which program was evaluated and to whom the results apply.
Accordingly, the posted data support a description of the two arm-level estimates and their reported precision. They do not, in isolation, establish the size or certainty of a comparative effect, identify the mechanism for any observed change, or justify a clinical recommendation. Interpretation should remain bounded by the information documented in the registry record.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of why group summaries and a direct randomized comparison are different quantities. The registry posts a least-squares mean change and a confidence interval for each arm. Those summaries show the direction and precision of the estimated within-group changes, but they do not report the estimated contrast between the randomized groups. A reader should not treat separate arm intervals as though they were the interval for that contrast.
The record also makes clear that design labels do not answer every methodological question. It identifies randomized allocation and a parallel model, yet further details about sequence generation, concealment, analysis populations, missing outcomes, and the statistical plan are not reported in the registry record. These details are relevant to evaluating how the trial was conducted and how the estimates should be interpreted.
Finally, the enrollment figure and the outcome-summary counts are not reconciled in the registry. The difference cannot be explained from the posted information, so it should be acknowledged rather than resolved by assumption. This is a practical lesson in reading trial records: distinguish reported estimates from unanswered questions, and do not fill methodological gaps with plausible-sounding explanations.
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 does not provide a direct between-group estimate for the primary outcome, a confidence interval for that contrast, or a comparative p-value. It also does not report sufficient information for an unadjusted recalculation. This limits interpretation of the randomized comparison, even though arm-specific estimates and confidence intervals are posted.
The outcome summaries list 61 participants in each arm, while enrollment is listed as 130. Participant flow and the relationship between these counts are not reported in the registry record. The analysis population, missing weight data, follow-up completeness, and missing-data methods are also not reported. These omissions prevent a clear assessment of how the summaries relate to all enrolled or randomized participants.
The registry describes the population as women with pre-diabetes in the arm descriptions but lists Type 2 Diabetes Mellitus as the condition. It does not clarify this difference or report additional eligibility details. The intervention’s broad components are described, but the arm description ends without detailing the modifications to the curriculum. Information about attendance, adherence, and delivery fidelity is not reported.
The record names least-squares means but does not describe the statistical model, adjustment variables, or diagnostic checks. It does not report a sample-size justification, interim analyses, or a detailed statistical analysis plan. The safety summaries provide counts but not further details about event definitions or ascertainment. These record-level limitations leave important aspects of design, analysis, and interpretation unresolved.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Changing Lifestyles for Better Health — NCT00848757.
- Registry record last updated 2022-05-04; status last verified 2022-04.
- Results first posted 2022-03-17.
- 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.
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18. Record Summary
The registry record describes a completed randomized, unmasked, parallel-group trial sponsored by Yale University. It lists enrollment of 130, a start of 2009-03, and primary completion in 2014-07. The arm descriptions concern women with pre-diabetes and compare an intensive lifestyle program with usual care; the registry lists Type 2 Diabetes Mellitus as the condition.
The primary outcome is change in weight from baseline to 12 months. The intensive intervention group’s least-squares mean change is -3.8 kg, with a 95% confidence interval from -4.6 to -3.0. The usual-care group’s mean change is 1.4 kg, with a 95% confidence interval from 0.6 to 2.2. Each outcome summary lists 61 participants. A direct between-group estimate and details about the analysis population and missing data are not reported in the registry record.