Diabetes Prevention Translation: the Healthy Lifestyle Project: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Diabetes Prevention Translation: the Healthy Lifestyle Project (NCT01050205), a randomized na study. The primary outcome is Changes in Weight Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants..

2. Clinical Question

The project addresses whether an adapted version of a lifestyle program can be evaluated in settings outside a large research study. The registry description names a worksite, a primary care practice, and local community centers dedicated to older adults as settings of interest. The clinical question is framed around weight change, while additional outcomes include measures of glucose, insulin, blood lipids, A1c, and systolic blood pressure.

The primary comparison concerns the mean change in pounds between randomized arms. It does not directly answer whether an individual participant will lose weight, nor does the registry result establish what happens after the posted assessment. The available comparison is between immediate and delayed assignment during the specified assessment period.

3. Trial Design

The Diabetes Prevention Translation Project: the Healthy Lifestyle Project is a completed randomized, parallel-group behavioral trial sponsored by the University of Pittsburgh. The registry lists enrollment of 223 participants. The trial started in 2010-09, and primary completion was recorded in 2015-03. Masking is listed as none, and phase is listed as NA.

Before assignment, eligible participants were asked to choose between Group Lifestyle Balance Group and Group Lifestyle Balance DVD. Participants were then randomly assigned to the Current Intervention arm, with immediate intervention, or the Delayed Intervention arm, with intervention delayed until 6 months. The registry does not describe how the choice of format was incorporated into assignment or analysis.

The posted primary weight results include 148 participants in the Current Intervention arm and 75 in the Delayed Intervention arm. These arm counts sum to the enrollment recorded in the registry, but the reasons for the unequal allocation are not reported in the registry record. Outcome-specific counts can differ from the arm counts, and the registry does not give a full account of the reasons for missing measurements.

The primary endpoint is a continuous measure of change in weight from baseline to post-intervention, assessed at 6 months after commencement of intervention. The registry describes an intent-to-treat approach using last observation carried forward when data are missing. Other protocol details, including the original allocation procedure, the trial's planned sample-size justification, and the full 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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intent to treat using last observation carried forward when data are missing.

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 Changes in Weight Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants., measured over Baseline and post-intervention (assessed at 6 months after commencement of intervention).

The primary endpoint is change in weight between baseline and post-intervention, assessed at 6 months after commencement of intervention. Weight is reported in pounds, and the endpoint is summarized as a mean with a standard deviation. The registry describes weighing participants twice on a digital physician's scale on a hard, flat surface. Participants were asked to remove their shoes and stand centered on the scale, looking forward and not touching another surface. They stepped off between measurements; a third measurement was taken if the first two were more than 0.5 pounds apart.

Weight is a continuous outcome: each participant's measurement can take a range of values, rather than fitting into a simple event/no-event category. Change from baseline focuses the comparison on how the measurement shifted over the assessment period. The two randomized arms allow that change to be compared between participants assigned to immediate intervention and those assigned to delayed intervention.

The choice of weight as the primary endpoint identifies the principal outcome used for the main comparison; it does not by itself establish the clinical importance of a particular change. The registry record does not report a threshold defining a meaningful change or a planned interpretation threshold. The posted means describe average change in the analyzed groups, not the amount of change experienced by every participant.

7. Results Posted in the Registry

• Delayed Intervention: mean -1.80 versus -10.40 on control; difference 8.60 (95% CI 6.20 to 11.00), standardized effect d = 0.92; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Changes in Fasting Glucose Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants.

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Delayed Intervention: mean -1.50 versus -1.90 on control; difference 0.40 (95% CI -1.69 to 2.49), standardized effect d = 0.05; z-test p = 0.707.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Delayed Intervention and the control. The interval gives the range of effects that remain compatible with the data.

Changes in Fasting Insulin Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants.

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Delayed Intervention: mean 0.81 versus -0.18 on control; difference 0.99 (95% CI -0.47 to 2.45), standardized effect d = 0.19; z-test p = 0.185.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Delayed Intervention and the control. The interval gives the range of effects that remain compatible with the data.

Changes in Fasting Lipids (Total Cholesterol) Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants.

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Delayed Intervention: mean -0.50 versus -2.50 on control; difference 2.00 (95% CI -4.29 to 8.29), standardized effect d = 0.09; z-test p = 0.533.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Delayed Intervention and the control. The interval gives the range of effects that remain compatible with the data.

The registry identifies additional outcomes covering fasting glucose, fasting insulin, total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, A1c, and systolic blood pressure. The posted secondary results include comparisons for fasting glucose, fasting insulin, and total cholesterol. Their estimates and intervals are displayed with the primary result, but they address distinct measures and should not be treated as substitutes for the primary weight endpoint.

Across those secondary comparisons, the estimates are small relative to the variability in the measured changes, and the intervals include zero. Their unadjusted p-values do not indicate a clear between-arm separation for these measures in the posted summaries. This broad pattern does not contradict the primary weight comparison: different endpoints can show different patterns, and the weight finding does not imply that every metabolic or cardiovascular measure must change similarly.

Secondary results generally carry less interpretive weight than a designated primary outcome, particularly when several outcomes are examined. Without a reported multiplicity procedure, the chance of encountering an apparently notable result across multiple comparisons is not accounted for by an unadjusted p-value. The registry does not report a hierarchy for the secondary outcomes, a correction method, or a complete analysis plan. The reported secondary summaries should therefore be considered descriptive and exploratory rather than independent confirmation of the primary comparison.

The registry lists 11 secondary outcomes as posted, while the numerical comparison details available in the record cover only a subset. For outcomes without posted comparison details, the corresponding estimates and uncertainty are not reported in the registry record. No conclusions about those unreported numerical results can be drawn from the outcomes' titles alone.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Changes in Fasting Glucose Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants.
• Changes in Fasting Insulin Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants.
• Changes in Fasting Lipids (Total Cholesterol) Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants.
• Changes in Fasting Lipids (Triglycerides) Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants.
• Changes in Fasting Lipids (HDL Cholesterol) Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants.
• Changes in Fasting Lipids (LDL Cholesterol) Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants.
• Changes in A1c Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants.
• Changes in Systolic Blood Pressure (BP) Between Baseline and Post-intervention (Assessed at 6 Months After Commencement of Intervention) Compared to Delayed Intervention Participants.

9. Statistical Interpretation

10. Statistical Methods Explained

What is being compared? The primary outcome is continuous weight change, expressed in pounds. Each arm's mean describes its average change from baseline to the post-intervention assessment. The between-arm mean difference compares those averages. The reported contrast uses delayed-arm change minus current-arm change, so its positive direction corresponds to a less negative average change in the delayed arm than in the current arm.

What does the standard deviation describe? A standard deviation describes how dispersed individual measurements are around the group mean. It is not the uncertainty in the mean itself, and it is not a range containing every participant. The posted standard deviations for weight change are 10.1 pounds in the current arm and 7.8 pounds in the delayed arm. General explanation: greater spread means individual changes vary more widely around the average. The registry reports means and standard deviations, rather than participant-level distributions.

How was the contrast obtained? The displayed comparison is a simple unadjusted recalculation from the posted summary statistics. It compares group means without adjustment for additional covariates. This differs from a fully described sponsor analysis, which is not listed in the registry record. No discrepancy is flagged for the primary comparison. If a sponsor's own analysis differs from a recalculation, the sponsor's analysis takes precedence; the available record does not present such a conflict.

What does the confidence interval convey? A confidence interval gives a range of values compatible with the data and the calculation's assumptions, expressing uncertainty around the estimated mean difference. The primary interval is 6.199 to 11.0 pounds. General explanation: a narrower interval indicates greater precision, while a wider interval indicates more uncertainty. The interval is not a guarantee that the true value lies within it, and it does not capture every source of uncertainty, such as uncertainty from unreported analysis choices.

What does the p-value convey? The unadjusted p-value is <0.001. In general, a p-value evaluates how surprising data at least as incompatible with a null comparison would be if the null hypothesis and model assumptions held. It is not the probability that the null is true, a measure of the size of the difference, or a direct measure of clinical importance. Because this is an unadjusted result, it does not account for the family of outcomes that may have been examined.

What is the role of randomization? Random assignment is intended to create groups that can be compared without selecting participants into an arm according to their expected outcome. It supports an intervention-assignment comparison, but does not ensure that every measured or unmeasured characteristic is identical between groups. The registry record identifies randomization but does not report the sequence-generation method, concealment details, or any stratification factors.

How does the missing-data rule enter? The primary population is described as intent to treat, with last observation carried forward when data are missing. This approach carries a participant's last observed measurement forward to represent a later missing value. General explanation: this can preserve participants in the assigned groups, but it relies on an assumption that the carried-forward value is a reasonable substitute for the unobserved value. The registry does not report how many measurements were missing, the timing of missingness, or sensitivity analyses comparing alternative assumptions. The missing-data approach for secondary outcomes is not reported in the registry record.

What is not specified? The registry record does not report the trial's original sample-size justification, detailed statistical analysis plan, interim analyses, covariate-adjustment plan, or a multiplicity procedure. These details matter because they clarify which comparisons were prespecified and how uncertainty across several outcomes was intended to be handled. The unadjusted comparison can describe the posted arm summaries, but it cannot fill in those missing design and analysis details.

11. Confidence Intervals and Precision

The primary mean-difference estimate is 8.6 pounds, with a 95% confidence interval from 6.199 to 11.0 pounds. The interval is entirely on the positive side of zero, consistent with the direction of the posted means under the stated subtraction order. The associated unadjusted p-value is <0.001. These values express the estimate and its sampling uncertainty under the unadjusted calculation; they do not account for unreported modeling choices or multiplicity.

The interval's width gives a sense of precision: it still allows a range of possible differences rather than identifying one exact value. The endpoint values should be interpreted in the same pounds scale as the mean difference. The registry provides no confidence limits for the separate arm means, and no sponsor-reported interval is listed. The interval and p-value are unadjusted recalculations from the posted group summaries.

Precision is also related to variation and the amount of outcome information. The primary arm counts are 148 and 75, and the corresponding standard deviations are 10.1 pounds and 7.8 pounds. These describe the available group sizes and spread; they do not remove uncertainty about the estimate. Outcome-specific sample counts can be smaller than arm enrollment, and the record does not explain all such differences.

Statistical precision is not the same as practical or clinical importance. The registry does not report a threshold for a meaningful weight difference, nor does the interval address how long the observed change lasts. The range describes uncertainty in the mean contrast at the specified assessment, not individual responses or effects at other follow-up times.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm for 80% power and participants per arm for 90% power. They are not total event counts: the event-count convention applies only to time-to-event outcomes, while this continuous outcome uses participants per arm. The figures are illustrations based on the observed effect, not the trial's own original design assumptions.

The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set in turn to 100%, 75%, or 50% of the observed effect. The trial's original sample-size justification and design assumptions are not reported in the registry record.

In plain language, the 80% power column gives the planned number of participants per arm under which the calculation would have an 80% probability of detecting the specified effect if that effect and the assumptions were correct. The 90% power column describes the corresponding planning target for a 90% probability. These are design probabilities under assumptions, not probabilities that the observed result is true. The figures are not observed power.

Planning for a smaller effect requires more participants per arm than planning for a larger effect, because a smaller difference is harder to distinguish from random variation. The listed figures should therefore be read as scenario-based planning illustrations, not as evidence that the trial was designed to detect each scenario or that a particular power level was achieved.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 8.600; pooled standard deviation σ = 9.393.
2. n = 2 × (1.96 + 0.842)² × 9.393² / 8.600² = 18.7, rounded up to 19 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 8.6                      # observed difference in means
sigma <- 9.39279352140494                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(1050205)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 19 (80% power), 26 (90% power)
 75% of observed effect: n per arm = 34 (80% power), 45 (90% power)
 50% of observed effect: n per arm = 75 (80% power), 101 (90% power)
power.t.test: 19.7 
Simulated power at n = 19 per arm: 0.786 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry describes a primary weight outcome and multiple secondary outcomes. It does not report a multiplicity adjustment or a prespecified procedure for controlling the chance of false-positive findings across several comparisons. The p-values accompanying the posted comparisons are unadjusted. This means each p-value addresses its own comparison without incorporating the number of outcomes or analyses considered. General explanation: when many outcomes are examined, isolated nominal findings can occur by chance more often than when a single comparison is evaluated.

The record lists no reported analyses for the primary or secondary outcomes. It does not describe whether outcome measures or analysis choices changed from an original plan, and the original statistical analysis plan is not reported in the registry record. This absence limits assessment of whether the posted comparisons follow prespecified choices. It does not establish that analyses were changed or that unreported analyses occurred.

For the primary endpoint, the stated population is intent to treat with last observation carried forward when data are missing. The registry does not report how many participants had missing weights, when values were missing, or whether missingness differed by randomized arm. It also does not report sensitivity analyses using alternative approaches. General explanation: carrying a prior observation forward treats that observation as a stand-in for an unobserved later value, an assumption that may not hold for every participant.

The missing-data handling for the secondary endpoints is not reported in the registry record. Their outcome-specific counts are less than or equal to the primary arm counts in the posted results, but reasons for the differences are not given. The record also does not detail the analysis population for each secondary outcome or explain how participants with incomplete measurements were handled. These omissions limit assessment of the robustness and comparability of the secondary results.

Randomization and the stated intent-to-treat population are relevant to the primary comparison, but they do not resolve uncertainty about missing observations, outcome multiplicity, or unreported analysis choices. Those issues should be kept distinct from the numerical size of the posted weight contrast.

15. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry reports zero serious adverse events among 148 participants at risk in the Current Intervention arm and zero among 75 participants at risk in the Delayed Intervention arm. It also reports zero other adverse events among 148 and 75 participants at risk, respectively. The record lists no serious adverse event terms.

These figures describe the adverse-event counts recorded for the stated groups and risk populations. They do not supply detail about event definitions, collection procedures, duration of monitoring, or whether all participants completed safety follow-up. The death counts are not reported in the registry record. A zero count in the posted results should therefore be read as the recorded count, not as a guarantee that no event occurred outside the recorded assessment or reporting process.

The safety figures are descriptive. They do not provide a detailed comparison of event risk or explain how events were assessed, and they should not be used to infer safety beyond the information recorded for this trial.

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

The posted primary result describes a larger mean decrease in weight in the group assigned to immediate intervention than in the group assigned to delayed intervention during the specified assessment period. The unadjusted mean difference is 8.6 pounds, and its 95% confidence interval is 6.199 to 11.0 pounds. This is a group-level comparison of changes from baseline, not a prediction of an individual's outcome.

The result pertains to an adapted lifestyle intervention studied through immediate versus delayed assignment in the settings described by the registry. It does not establish how the result would differ between Group Lifestyle Balance Group and Group Lifestyle Balance DVD, because the registry does not report format-specific outcomes. It also does not isolate which component of the program might account for the observed contrast.

The posted comparison does not establish the duration of any change after the assessment, because a later follow-up result is not reported in the registry record. It does not establish an effect on diabetes incidence or cardiovascular events: the primary endpoint is weight change, and the registry lists other measured outcomes but does not make weight change interchangeable with those clinical outcomes.

The unadjusted interval and p-value quantify statistical evidence for the posted contrast under the recalculation assumptions. They do not demonstrate that the difference is clinically important; the registry does not report a threshold for meaningful weight change. Nor do the secondary results, which are unadjusted and cover several measures, independently confirm the primary result.

Random assignment supports a comparison by assigned group, but the registry's limited reporting on missing observations, analysis choices, and participant characteristics constrains broader interpretation. The finding should be read as a result for the recorded randomized groups and assessment, not as a guarantee of outcomes in every community or participant population.

17. Why This Trial Matters Statistically

This trial is statistically notable for placing a continuous, patient-level measure within a randomized comparison of immediate and delayed delivery. The primary endpoint is a change score, so interpretation depends on both the direction of within-arm change and the contrast between arms. Reporting the means, standard deviations, sample counts, and an interval allows readers to distinguish the observed average difference from the spread among participants and uncertainty around the estimated contrast.

The result also illustrates why a confidence interval adds information beyond a p-value. The interval gives the scale and range of compatible differences, while the unadjusted p-value addresses evidence against a null comparison under the calculation assumptions. Neither statistic alone determines practical importance, and the registry does not define a threshold for that judgment.

Planning illustrations based on observed effects are useful for discussing how sample requirements change across effect-size scenarios, but they are not substitutes for a trial's original design justification. In this record, the original planning assumptions are not reported. The planning examples therefore help interpret design trade-offs without establishing what the trial was intended to detect.

The registry also illustrates the importance of distinguishing a primary endpoint from a family of secondary outcomes. Multiple measures can provide context, but unadjusted secondary comparisons have less confirmatory value when no multiplicity plan is reported. Finally, the intent-to-treat and last-observation-carried-forward description makes missing-data assumptions visible, while the absence of missingness details shows why an analysis label alone is not enough to assess robustness.

18. 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 does not report detailed eligibility criteria, participant demographics, or how many participants came from each setting. Although the project describes a worksite, a primary care practice, and community centers dedicated to older adults, the posted results do not show whether outcomes differed across settings. Applicability to other populations or delivery contexts therefore cannot be assessed from the record alone.

Participants chose Group Lifestyle Balance Group or Group Lifestyle Balance DVD before randomization, but the record does not give results by chosen format. It also does not report intervention attendance, adherence, implementation fidelity, or the amount of contact participants received. The overall comparison cannot identify whether one delivery format contributed differently to the observed outcome.

The delayed arm was scheduled to receive intervention at 6 months, and the primary result concerns the post-intervention assessment at 6 months after commencement of intervention. The registry does not report later comparative weight outcomes, so persistence beyond this assessment cannot be evaluated from the posted result. The number of participants with missing primary measurements and the details of missingness are also not reported in the registry record, despite the stated use of last observation carried forward.

The between-arm estimate, confidence interval, and p-value are unadjusted recalculations from posted summary statistics. A complete sponsor analysis, covariate-adjustment strategy, original sample-size justification, interim analyses, and multiplicity procedure are not reported in the registry record. The sample-size planning illustrations use the observed effect and stated assumptions; they do not document the original design basis.

Finally, the primary endpoint is weight change. The registry's other outcomes do not establish effects on diabetes incidence, cardiovascular events, or other long-term clinical outcomes. These limitations restrict interpretation to the recorded outcome, comparison, and assessment period.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Diabetes Prevention Translation: the Healthy Lifestyle Project — NCT01050205.
• Registry record last updated 2017-08-25; status last verified 2017-07.
• Results first posted 2017-07-25.
• 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.

22. Record Summary

NCT01050205 is a completed randomized, parallel-group behavioral trial sponsored by the University of Pittsburgh, with enrollment of 223. Participants chose Group Lifestyle Balance Group or Group Lifestyle Balance DVD before assignment to immediate or delayed intervention. The primary outcome was mean weight change from baseline to the post-intervention assessment at 6 months after commencement of intervention.

The posted means were -10.4 pounds in the Current Intervention arm and -1.8 pounds in the Delayed Intervention arm. The unadjusted recalculated mean difference was 8.6 pounds, with a 95% confidence interval from 6.199 to 11.0 pounds and p <0.001. The registry describes an intent-to-treat population using last observation carried forward when data are missing.

Secondary outcomes include glucose, insulin, lipids, A1c, and systolic blood pressure. The record reports zero serious and zero other adverse events in each arm; death counts are not reported in the registry record. Details such as the original sample-size justification, multiplicity procedure, and full statistical analysis plan are not reported in the registry record.