Lap-Band Surgery on Adolescents for Safety and Efficacy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Lap-Band Surgery on Adolescents for Safety and Efficacy (NCT00587301), a na na study. The primary outcome is Percentage of Excess Weight Loss (EWL).

2. Clinical Question

The central question is whether the registered participants who underwent Lap-Band surgery had a measurable change in excess weight by the stated Year 1 endpoint, alongside what safety events were recorded. The endpoint listing specifies a mean and standard deviation, indicating a continuous outcome intended to describe the group’s weight-loss result and its variability. However, the registry record does not include the mean, standard deviation, number assessed at Year 1, or an analysis estimate for that endpoint. Thus the primary question can be identified, but its answer cannot be quantified from the registry record.

The study is prospective and open-label, and it has one study group rather than a randomized treatment comparison. Accordingly, the record can describe outcomes observed among participants receiving the intervention, but it does not provide a concurrent control group for separating treatment-associated changes from other influences over time. The record’s stated aim includes safety and efficacy; that aim is not itself evidence of an outcome. Safety figures are recorded separately and should be interpreted as event counts within the listed group, not as a controlled comparison.

3. Trial Design

The registry identifies NCT00587301 as a prospective, open-label study of Lap-Band adjustable gastric band operations in morbidly obese adolescents ages 14-17. The intervention is listed as a device, and the study model is single-group. Enrollment is recorded as 119. Allocation and phase are both recorded as NA, while masking is NONE. No separate control arm is listed.

These design features matter for interpretation. A prospective study follows participants forward according to its planned observation, but prospective follow-up alone does not establish that a change was caused by the intervention. With a single group, observed changes can be described within that group; there is no concurrent control group in the registry record to provide a like-for-like estimate of what would have happened without the intervention. Open-label status means masking is not part of the recorded design. The record does not report further details about outcome assessment procedures.

The primary outcome is Percentage of Excess Weight Loss (EWL), specified as a mean with standard deviation and measured at Year 1. The record lists 10 outcome measures and includes BMI repeatedly among the secondary outcomes. It reports 0 analyses. Numerical results for the primary endpoint, secondary outcomes, and statistical comparisons are not reported in the registry record.

The study is marked COMPLETED. Its recorded start is 2005-06 and its primary completion date is 2020-07-08. These dates describe the registry timeline; they do not supply individual follow-up durations or establish that every participant contributed data at every endpoint. The registry record does not report the analysis population, participant flow, endpoint-specific follow-up completeness, or a detailed statistical plan. Those omissions limit assessment of how the enrolled group relates to the population contributing to any particular result.

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:

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 Percentage of Excess Weight Loss (EWL), measured over Year 1.

The primary endpoint is Percentage of Excess Weight Loss (EWL), with a Year 1 timeframe. It is specified as a continuous measure summarized by a mean and standard deviation. Excess weight loss expresses weight change relative to an excess-weight reference, rather than simply reporting body weight in its original units. That form can be useful when the clinical question concerns change in excess weight and when participants may begin at different weights.

As a general statistical interpretation, a group mean describes the average endpoint value among the observations included in the analysis. The standard deviation describes the spread of individual observations around that mean. It is not the same as a confidence interval: a confidence interval expresses uncertainty about an estimated quantity, whereas a standard deviation describes variation among observations. Neither statistic can be interpreted fully without knowing the analyzed population and how much outcome data were available.

The record does not report the Year 1 mean, standard deviation, confidence interval, number assessed, or a baseline value for this endpoint. It also does not report how the endpoint was operationally calculated or how missing Year 1 measurements were handled. Therefore, the endpoint’s definition and summary format are identifiable, but its observed magnitude and precision cannot be assessed from the registry record. The endpoint listing should not be mistaken for a numerical result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record specifies a continuous primary endpoint summarized by a mean and standard deviation. It reports no analyses and does not include numerical estimates for the endpoint. The methods concepts below are general explanations of the listed statistical terms; they do not imply that a particular unreported procedure was used in this study.

What does a mean describe?

For a continuous outcome, the mean is an average across the observations included in the analysis. It provides a compact description of the group’s central outcome value. The mean does not show the full distribution: different sets of individual values can produce the same mean. It can also be influenced by unusually high or low observations. For an endpoint reported as percentage of excess weight loss, the mean would describe the average percentage among the participants whose data were included, assuming the endpoint had been measured and analyzed as specified.

The population contributing to the mean is important. Enrollment is not automatically the same as the number included in an endpoint analysis. Some participants may not have an outcome measurement at the relevant time, but whether that occurred and how it was addressed are not reported in the registry record. Without an endpoint-specific denominator and missing-data information, the group represented by a mean cannot be fully characterized.

How does a standard deviation differ from a confidence interval?

A standard deviation describes how spread out the observed values are around their mean. A relatively narrow spread indicates that individual values cluster more closely around the average; a wider spread indicates more variation. The standard deviation is about variation in the data, not directly about the precision of the estimated mean.

A confidence interval is a general way to express uncertainty about an estimate. It depends on the estimate’s uncertainty and on a stated confidence level. A confidence interval around a mean is not a range expected to contain a particular proportion of individual participants’ values; that is a different kind of interval. The registry record does not report a confidence interval for the primary endpoint, so the precision of its mean cannot be assessed from the posted registry information.

What does a single-group design permit?

In a single-group study, an outcome can be described among participants who received the intervention. If baseline and follow-up results are available, a within-group change may also be described. Such a change is not the same as a treatment effect estimated against a concurrent comparator. Without a control group, time trends, measurement conditions, changes in other care, and other factors cannot be separated from the intervention’s possible contribution through a randomized comparison.

Here, the registry lists a single group and no separate comparator. It does not report numerical baseline or Year 1 primary endpoint results, so even a within-group change cannot be quantified from the registry record. General cautions about single-group interpretation apply regardless of whether a change is large or small: description of an observed result and estimation of a causal contrast are different statistical tasks.

Why does analysis population matter?

An analysis population defines which participants contribute to a particular estimate. For example, an analysis could be based on all enrolled participants, those who received the intervention, or those with an observed endpoint. These choices can lead to different interpretations, especially when some measurements are unavailable. The registry record does not report the analysis population for the Year 1 endpoint or the number of participants with data for it. The enrollment count alone does not identify the endpoint denominator.

Missing data also require explicit treatment. An analysis may use only observed outcomes, apply a model that accommodates incomplete observations under assumptions, or use another prespecified strategy. Each approach relies on assumptions about why data are missing and what information is available. The registry record does not report a missing-data method or the extent of missingness. It is therefore not possible to determine from the record whether missing outcomes were excluded, imputed, or handled in another way.

What can a sample-size planning illustration show?

As a general matter, a sample-size calculation estimates how much information a future study may need to detect a target effect under stated assumptions. The registry’s planning-illustration description names a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and a target effect expressed as a fraction of an observed effect. For non-time-to-event outcomes, the description defines the result as participants per arm for a stated power level; for time-to-event outcomes, it describes total events.

These are planning assumptions, not findings from the registered single-group study. The registry does not report an observed primary endpoint effect or numerical planning results. A planning illustration cannot establish that the study achieved a particular power, and it is not observed power. The stated two-arm allocation assumption also differs from the single-group design recorded for this study. A sample-size illustration under different assumptions should not be treated as a substitute for a trial’s prespecified design or analysis plan.

Why do multiplicity and outcome selection matter?

When a study assesses multiple outcomes or makes multiple statistical comparisons, the chance of at least one apparently notable result can increase. Statistical methods may address this through a prespecified hierarchy, adjustment, or another approach, depending on the study’s aims. The registry record lists 10 outcome measures and does not report a multiplicity strategy or analysis plan. Because no analyses are reported, the registry does not show how outcomes were selected or whether any adjustment was applied. This is a limitation on interpretation, not evidence that a particular method was or was not used in practice.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Lap-Band")
n   <- c(106)
m   <- c(40.88)
sp  <- c(25.12)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Lap-Band  106  40.880  25.120  36.042  45.718

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 10 outcome measures, including repeated listings of BMI among the secondary outcomes, and reports 0 analyses. It does not report whether outcomes were organized into a prespecified hierarchy, whether multiple comparisons were adjusted, or how the primary endpoint was prioritized in the analysis. When many outcomes are examined, a result can appear notable by chance even when there is no underlying effect; multiplicity methods are one way to address that issue. The registry record does not indicate which approach, if any, was used.

Missing-data handling is also not reported in the registry record. The number enrolled is recorded as 119, but the number with a Year 1 primary endpoint measurement is not reported. No method for handling incomplete follow-up, missing measurements, or withdrawals is listed. Without those details, the reader cannot determine whether an endpoint estimate would represent all enrolled participants or a subset with available measurements, nor assess the assumptions behind any missing-data procedure.

The record does not report the analysis population, detailed statistical analysis plan, or interim-analysis procedures. These are distinct from the study’s stated prospective design and COMPLETED status. Their absence from the registry record means they cannot be used to interpret possible analyses or assess whether all planned outcomes were reported. It does not establish that the investigators did or did not use a particular procedure; those details are simply not reported in the registry record.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: band slippage (10.1%), cholelithiasis (1.7%), port leak (1.7%), pregnancy with abortion (1.7%), abdominal pannus (excess skin) (0.8%).

For the Lap-Band group, the registry lists 119 participants at risk for serious adverse events and 24 affected; it lists 119 at risk for other adverse events and 99 affected. Deaths are recorded as 0. These are descriptive figures for the single listed group. The record does not provide a comparator group, so the counts do not estimate a difference in risk relative to another treatment or to no intervention. Nor do counts alone establish that an event was caused by the device or procedure.

The listed serious-event terms include Band slippage (10.1%), Cholelithiasis (1.7%), Port leak (1.7%), Pregnancy with abortion (1.7%), Abdominal pannus (excess skin) (0.8%), and Band erosion (0.8%). These percentages are reported as registry values; the denominator basis and event-level timing are not reported in the registry record. The terms are descriptive labels, not a complete explanation of severity, duration, management, or attribution. The figures should therefore be read as reported safety information rather than as comparative evidence or a complete account of clinical consequences.

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

The record establishes that a prospective, open-label, single-group study of Lap-Band surgery in morbidly obese adolescents was registered, that enrollment was 119, and that the study is marked COMPLETED. It identifies mean percentage of excess weight loss at Year 1 as the primary endpoint. It also gives descriptive adverse-event counts and selected serious-event terms. These features show what the registry record documents; they do not supply numerical primary endpoint results.

The record does not show the Year 1 endpoint mean, its standard deviation, a confidence interval, or the number assessed. It therefore cannot establish the size or precision of the endpoint result. The stated aim of evaluating safety and efficacy should not be treated as a conclusion about either. Likewise, a completed study does not by itself indicate what its outcomes were.

The single-group design limits causal interpretation. Even if an observed change were available, without a concurrent comparator it could not provide a like-for-like estimate of the outcome under another treatment or without the intervention. The registry record lists no separate control group, and allocation is recorded as NA. The design supports description of the treated group, not a randomized comparison.

The safety figures describe affected participants in the listed group and include 0 deaths as recorded in the registry. They do not show comparative safety, establish causation, or give all the details needed to understand event timing and clinical context. The registry record also does not report endpoint-specific follow-up, missing-data handling, analysis populations, or a multiplicity strategy. Those gaps prevent a full assessment of how the results were generated and how representative they may be.

Accordingly, the registry record is informative about the study’s design, stated endpoint, and recorded safety categories, but it is not sufficient to quantify the primary outcome or establish a causal treatment effect. No treatment recommendation follows from these registry entries alone.

14. Why This Trial Matters Statistically

This study is statistically instructive because its design and endpoint can be identified even though numerical primary endpoint results are not reported in the registry record. The distinction between a stated outcome and an observed estimate is fundamental: naming a mean percentage of excess weight loss at Year 1 does not tell readers what that mean was, how variable the measurements were, or how precisely it was estimated.

The single-group structure also illustrates the difference between describing outcomes and estimating comparative effects. A prospective follow-up can characterize what was observed among participants in the intervention group, but a single group does not provide a concurrent counterfactual. Without a comparator, changes over time cannot be separated from other influences through a randomized treatment contrast. Recognizing that limit is important when interpreting any before-and-after narrative.

Safety counts raise a related issue. Counts and percentages can describe recorded events, but interpretation depends on the population at risk, event definitions, follow-up, attribution, and comparator information. The registry lists counts for serious and other adverse events and selected serious-event terms, but it does not report enough detail to support a controlled risk comparison. Descriptive safety data are useful, but they answer a different question from comparative safety estimates.

Finally, the record lists 10 outcomes and 0 analyses, while leaving analysis populations, missing-data handling, multiplicity, and the detailed statistical plan unreported. These omissions show why transparent reporting matters: readers need estimates and methods to judge magnitude, precision, completeness, and the possibility of selective emphasis. The record’s design details remain interpretable, but the missing analysis information prevents a full statistical appraisal of the primary outcome.

15. 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.

Several limitations specific to this registry record constrain interpretation. Most importantly, the numerical result for the primary endpoint is not reported in the registry record. The Year 1 mean percentage of excess weight loss, standard deviation, confidence interval, and number of participants assessed are absent. No baseline result or endpoint change estimate is listed. The outcome’s measurement details and calculation procedure are also not reported in the registry record.

The study is single-group, with no separate comparator listed. It therefore lacks a like-for-like control comparison in the registry record. Its open-label design and absence of a masking procedure are recorded, but the record does not explain how outcome measurement or assessment was conducted. The enrolled population is described as adolescents ages 14-17 with morbid obesity; the record does not provide further eligibility details or participant characteristics needed to judge how broadly the findings might apply.

Enrollment is recorded as 119, but the record does not give an endpoint-specific analysis denominator, participant flow, follow-up completeness, or reasons for missing measurements. It does not report which participants contributed to the primary endpoint or how missing observations were handled. These gaps limit assessment of selection and attrition effects.

The registry lists 10 outcomes and 0 analyses, but a statistical analysis plan, multiplicity approach, interim-analysis procedures, and analysis populations are not reported in the registry record. Safety reporting includes counts and selected serious-event terms, but event timing, attribution, and denominator details for the term percentages are not reported. These limitations concern what can be inferred from the registry record; they do not establish what may have been documented elsewhere.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Lap-Band Surgery on Adolescents for Safety and Efficacy — NCT00587301.
• Registry record last updated 2022-03-22; status last verified 2022-03.
• Results first posted 2022-03-22.
• 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.

19. Record Summary

NCT00587301 is a prospective, open-label, single-group study of Lap-Band adjustable gastric band surgery in morbidly obese adolescents ages 14-17. The registry lists enrollment of 119 and identifies the study status as COMPLETED. The primary endpoint is mean Percentage of Excess Weight Loss (EWL) at Year 1, with standard deviation specified as the dispersion measure.

The registry record reports 10 outcome measures and 0 analyses, but does not report numerical results for the primary endpoint, endpoint-specific sample size, a statistical analysis plan, or missing-data and multiplicity methods. The Lap-Band group has 24 participants listed as affected by serious adverse events, 99 by other adverse events, and 0 deaths recorded, with 119 at risk for each category. These are descriptive figures from a single group rather than comparative estimates.