Litramine in Weight Maintenance: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Litramine in Weight Maintenance (NCT01505387), a randomized phase 4 study. The primary outcome is Mean Change in Body Weight From Baseline to End of 24 Weeks.

2. Clinical Question

3. Trial Design

NCT01505387, titled “Litramine in Weight Maintenance,” is registered as a Phase 4, randomized, quadruple-masked, parallel-group, placebo-controlled investigation. In a parallel-group design, participants are assigned to one study arm and followed in that arm rather than switching between treatments. The registry describes Litramine and placebo as dietary supplements. In the Litramine arm, the intervention is a plant-origin fibre complex in tablet form; the placebo is described as identical. Both regimens are listed as 2 tablets 3 times daily, consumed orally after meals.

The registry lists enrollment as 50. The primary outcome results report 24 participants for placebo and 25 for Litramine. Those arm-specific outcome counts do not explain the difference between the registry enrollment figure and the number of primary outcome observations, and the reason is not reported in the registry record. The record lists the study status as completed, with a start date of 2012-01 and primary completion in 2012-09.

The stated purpose was to investigate maintenance of body weight after initial weight loss, over a longer period than a previously studied 12-week intervention described in the registry summary. The present study's stated follow-up for the primary outcome is 24 weeks. Specific eligibility criteria, recruitment setting, details of how initial weight loss occurred, and the timing and schedule of study visits beyond the primary endpoint are not reported in the registry record.

Other recorded outcomes include waist and hip circumference, body mass index, full blood count, and blood pressure. These are secondary measures; no numerical secondary outcome analyses are posted. The record identifies InQpharm Group as sponsor. The randomized design supports a comparison between assigned arms, but interpretation also depends on how participants were analyzed, how missing measurements were handled, and what statistical methods were prespecified. Those details 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:

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 Mean Change in Body Weight From Baseline to End of 24 Weeks, measured over 24 weeks.

The primary endpoint is mean change in body weight from baseline to the end of 24 weeks, measured in kg using a calibrated scale. The registry defines positive change as weight gain and negative change as weight reduction. This endpoint therefore expresses the direction and average magnitude of body-weight change during the stated follow-up, rather than the final body weight alone.

Change from baseline is useful in a randomized comparison because it describes how the measured outcome shifted over follow-up in each arm. Comparing the average changes can show whether the groups had different patterns of change during the study period. The mean represents the average across the participants included in each arm's reported analysis, while the standard deviation describes variation among their measurements. The registry reports both arm means and standard deviations.

The endpoint addresses weight maintenance after initial weight loss as described in the registry summary. It does not, by itself, establish what happened before baseline, explain why an individual participant's weight changed, or provide a complete picture of health or safety. The record does not specify the clinical or operational definition used to classify successful maintenance. It also does not report whether the analysis adjusted for baseline body weight or other characteristics. The endpoint should consequently be read as the reported average change in body weight over 24 weeks, with the comparison and its uncertainty interpreted alongside those reporting limits.

7. Results Posted in the Registry

• Litramine: mean -0.62 versus 1.62 on control; difference -2.24 (95% CI -3.09 to -1.39), standardized effect d = -1.48; z-test p = <0.001.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: body-weight change is measured in kg, and the registry reports the mean and standard deviation in each arm. A mean is the arithmetic average of the measured changes among the participants included in an analysis. A standard deviation describes how dispersed individual measurements are around that arm's mean. It is not the uncertainty around the mean itself, and it does not show the full distribution or identify the range of individual outcomes.

What does the mean difference represent?

The reported comparison is a mean difference for Litramine versus placebo. It expresses the difference between the two arm averages on the original kg scale, so its units remain kg. A negative difference means the average change in the Litramine arm is lower than the average change in placebo under the registry's sign convention. This is a comparison of group averages; it should not be interpreted as the amount by which every participant's weight changed.

The arm means are 1.62 kg for placebo and -0.62 kg for Litramine. The registry reports the mean difference as -2.24 kg. These are posted values and should be used as reported. The registry does not provide a detailed description of the calculation, the statistical test, or any adjustment used to obtain the comparison. The unadjusted p-value is reported as <0.001; the record does not specify the exact test used for this value.

How should the confidence interval be understood?

A confidence interval represents uncertainty in an estimate under a statistical procedure and its assumptions. The interval reported for the mean difference is -3.088 to -1.392 kg. It is attached to the group-level contrast, not to individual participants' weight changes. A narrower interval indicates greater precision for the contrast than a wider interval would, while the endpoints provide a range of estimates compatible with the procedure. The registry does not name the interval construction method, so it is not possible to verify from the record whether it came from a particular model or test.

The interval's endpoints are both negative. In the stated comparison, that means the reported interval does not include zero as a possible mean difference. This is an interpretation of the posted interval, not a separate recalculation or a guarantee about the true effect. Confidence intervals depend on assumptions about sampling and the analysis; details such as distributional assumptions, adjustment, and missing-data handling are not reported in the registry record.

What does the p-value contribute?

The reported p-value is unadjusted and listed as <0.001. In general, a p-value measures how incompatible the observed data are with a specified null model, assuming that model and the analysis assumptions hold. A smaller p-value represents stronger evidence against that null model in the context of the test. It does not tell the probability that the null model is correct, the probability that the finding is due to chance, or the practical importance of the estimated difference. Since the exact test and analysis details are not reported, the p-value should be read as the registry's stated unadjusted result.

Multiplicity concerns arise when multiple outcomes or comparisons are analyzed. Testing multiple hypotheses can increase the chance of at least one apparently notable result if no adjustment or prespecified hierarchy is used. The registry lists four secondary outcomes, but it does not post their analyses or report how multiplicity was addressed. The primary comparison's unadjusted p-value should not be described as multiplicity-adjusted.

Why does variation matter?

Variation among participants affects how precisely an average can be estimated. The reported standard deviations are 1.48 kg in placebo and 1.55 kg in Litramine. Standard deviations provide context for the spread of the outcome measurements within the arms. A mean difference can be interpreted alongside these spreads and the sample counts, but the standard deviations alone do not reveal whether the distributions were symmetric, whether there were outliers, or whether model assumptions were satisfied.

Over-dispersion, in general, means that observed variability is greater than a chosen statistical model expects. When a model underestimates variation, its uncertainty estimates can be too small and its confidence intervals too narrow. The posted arm standard deviations do not by themselves establish that over-dispersion occurred. The record does not report diagnostics or model details that would permit such an assessment. This is a general reason to consider variation and model assumptions, not a claim that the trial analysis had this problem.

What can be inferred about the analysis plan?

The registry provides the outcome definition, arm summaries, mean difference, confidence interval, and unadjusted p-value. It does not report the original sample-size justification, the trial's prespecified significance threshold, interim analyses, analysis populations, missing-data methods, or a detailed statistical analysis plan. The planning assumptions attached to the sample-size illustrations are not evidence of the assumptions used to design or analyze the trial. No assumptions about the sponsor's original design should be inferred from those illustrations.

The reported primary outcome counts are 24 for placebo and 25 for Litramine, while the registry enrollment is 50. The record does not explain the difference between these figures. It also does not state whether the analysis included all randomized participants, only participants with observed endpoint measurements, or another group. Randomization describes assignment; it does not by itself identify the analysis population. These distinctions matter because exclusions or missing measurements can affect the interpretation of an arm comparison.

Overall, the posted statistics support a descriptive reading of the mean change and the reported between-arm contrast. They do not permit independent reconstruction of every analytical choice. A transparent interpretation keeps the estimated contrast, its confidence interval, and the unadjusted p-value distinct, while treating unreported methods as unknown rather than filling them in.

10. Confidence Intervals and Precision

The mean difference for Litramine versus placebo is -2.24 kg, and its reported 95% confidence interval runs from -3.088 to -1.392 kg. The estimate is the central reported contrast; the interval describes uncertainty around that group-level estimate under the interval's statistical assumptions. It does not describe the spread of participant-level weight changes. The arm standard deviations, 1.48 kg for placebo and 1.55 kg for Litramine, describe that within-arm variability instead.

The interval is entirely negative, so the reported range of compatible mean differences does not include zero. Its endpoints still leave uncertainty about the precise magnitude of the contrast. The confidence interval should be considered alongside the point estimate, not as proof that one exact value is correct. The registry does not report the method used to construct the interval, so the assumptions behind its coverage cannot be assessed from the record alone.

Precision is influenced by the amount of information available and the variability of measurements. The primary outcome analysis reports 24 participants for placebo and 25 for Litramine. These counts are close but do not explain how they relate to the registry enrollment of 50; the reason is not reported in the registry record. The posted interval is the available uncertainty summary for the comparison. No alternative adjusted interval or sensitivity analysis is reported.

The unadjusted p-value of <0.001 is evidence about compatibility with a null model, not a substitute for the interval. The interval communicates a range of estimated mean differences on the kg scale, while the p-value compresses evidence into a tail probability under a test model. Neither statistic describes the probability that an individual will have a particular outcome. The interval also cannot resolve limitations arising from unreported analysis populations, missing-data handling, or multiplicity.

11. 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 express participants per arm, not total events. They are illustrations based on the observed mean difference and use the assumptions stated for the calculation: a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set as a stated fraction of the observed effect. These are planning assumptions for the illustrations; the original trial design assumptions are not reported in the registry record.

For planning for 100% of the observed effect, the listed requirements are 8 participants per arm for 80% power and 10 participants per arm for 90% power. For planning for 75% of the observed effect, the corresponding figures are 13 participants per arm for 80% power and 18 participants per arm for 90% power. For planning for 50% of the observed effect, the listed figures are 29 participants per arm for 80% power and 39 participants per arm for 90% power.

In plain terms, power is the chance that a planned study will meet its statistical detection criterion if the effect assumed for planning is present and the model assumptions hold. The 80% and 90% columns compare different target chances of detecting the specified effect. The higher target generally requires more participants for a given assumed effect. As the assumed effect gets smaller, more participants are needed to distinguish it from variability with the same target power; the listed figures illustrate that pattern.

These calculations are planning illustrations, not observed power and not evidence that the completed trial was designed around these counts. They use the observed effect as an input, so they should not be read as a retrospective measure of how successful the study was. No original sample-size justification or design calculation is reported in the registry record. The figures do not account for any unreported attrition, analysis choices, or multiplicity considerations.

12. 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 = -2.240; pooled standard deviation σ = 1.516.
2. n = 2 × (1.96 + 0.842)² × 1.516² / -2.240² = 7.2, rounded up to 8 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 <- -2.24                      # observed difference in means
sigma <- 1.5161485359221                     # 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(1505387)
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 = 8 (80% power), 10 (90% power)
 75% of observed effect: n per arm = 13 (80% power), 18 (90% power)
 50% of observed effect: n per arm = 29 (80% power), 39 (90% power)
power.t.test: 8.3 
Simulated power at n = 8 per arm: 0.787 (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.

13. Multiplicity, Missing Data and Analysis Populations

The registry reports one primary outcome: mean change in body weight from baseline to the end of 24 weeks. It also lists waist and hip circumference, body mass index, full blood count, and blood pressure as secondary outcomes. Although the record identifies four posted secondary outcomes, it contains no numerical secondary outcome analyses. Consequently, the available statistical interpretation centers on the primary body-weight comparison.

When a study examines several outcomes or statistical comparisons, the chance of at least one result appearing noteworthy can increase. Statistical approaches to multiplicity can include prespecified testing hierarchies or adjustments, but the registry record does not report whether either approach was used. The primary p-value is explicitly unadjusted. It should not be represented as corrected for multiple testing, and there is no basis in the posted information for determining how the sponsor handled the family of outcomes.

The record does not report an analysis population, such as whether analyses followed randomized assignment or were limited to participants with available endpoint measurements. The primary outcome counts are 24 in placebo and 25 in Litramine, while enrollment is listed as 50. The reason for the difference is not reported in the registry record. This does not establish that a particular participant was excluded or that missing data occurred; it means the record does not explain the relationship between enrollment and the outcome counts.

Missing-data methods are also not reported. Without that information, it is not possible to assess whether missing measurements were omitted, imputed, or handled through another method, or how such choices might affect the estimate. The record does not describe sensitivity analyses to test robustness to missingness. Interim analyses, stopping rules, protocol deviations, and a detailed statistical analysis plan are not reported either.

These omissions do not erase the posted arm summaries or comparison, but they limit independent appraisal of how the analysis was conducted and how broadly the unadjusted primary result should be interpreted. The appropriate reading is to distinguish the reported result from the methods and analyses that remain undocumented.

14. 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's adverse-event figures list 25 participants at risk in each arm. For serious adverse events, the reported number of affected participants is 0 in placebo and 0 in Litramine. For other adverse events, the reported number of affected participants is also 0 in each arm. These entries describe the posted registry counts; they should not be expanded into claims about unrecorded events or about safety beyond the information in this record.

The deaths entries are null for both arms. Death counts are therefore not reported in the registry record, rather than being recorded as zero. The registry also lists no top serious-event terms. That absence does not provide detail about how events were defined, collected, reviewed, or attributed, and those procedures are not reported in the registry record.

These safety counts are distinct from the primary outcome analysis counts of 24 for placebo and 25 for Litramine. The record does not explain the difference between the outcome counts and the 25 participants listed at risk in each safety arm. The figures should be read as registry-reported counts, with no assumption about missing safety information or the reason for any difference in reported denominators.

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

The posted primary result describes mean body-weight change during 24 weeks in a randomized, placebo-controlled comparison. The placebo mean was 1.62 kg, while the Litramine mean was -0.62 kg. The reported mean difference for Litramine versus placebo was -2.24 kg, with a 95% confidence interval from -3.088 to -1.392 and an unadjusted p-value of <0.001. Under the registry's sign convention, the result is a lower average change in the Litramine arm than in the placebo arm.

This finding is about averages in the analyzed arms. It does not mean that every participant in one arm experienced the same direction or amount of weight change, and the record does not provide individual-level outcome distributions. The confidence interval describes uncertainty about the mean contrast, not a prediction interval for an individual's result. The p-value does not measure the probability that the intervention is effective or that the observed contrast is due to chance.

The registry's stated purpose concerns maintaining weight after initial loss, but details of the initial weight-loss period and how it was achieved are not reported in the registry record. The reported endpoint is change from baseline to the end of 24 weeks; it does not describe changes outside that measured period. Longer-term outcomes are not reported. Nor does the primary weight measure answer questions about the other listed outcomes, including waist and hip circumference, body mass index, full blood count, and blood pressure, for which no numerical analyses are posted.

The trial record does not document the original sample-size justification, the statistical analysis plan, analysis populations, missing-data methods, or multiplicity strategy. These gaps limit assessment of design assumptions and analytical robustness. The result should therefore be understood as the posted estimate and uncertainty for this trial's primary comparison, rather than as a complete account of all outcomes, methods, or settings. It does not, on its own, establish what would occur in other populations or under different conditions.

16. Why This Trial Matters Statistically

This trial offers a useful statistical example of how a continuous endpoint can be reported at both the arm level and as a between-arm contrast. The primary outcome includes means and standard deviations for each arm, along with a mean difference, confidence interval, and unadjusted p-value. Keeping these summaries distinct helps readers separate average change, within-arm variability, uncertainty around the comparison, and evidence relative to a null model.

The sign convention matters. Positive values represent weight gain and negative values represent weight reduction, so the negative mean difference for Litramine versus placebo corresponds to a lower average change in that arm. Interpreting the contrast correctly requires attention to the direction of subtraction and to the endpoint's definition. The arm means and estimated difference together make that direction clear without implying that every participant had the average response.

The entry also illustrates why statistical significance and precision should not be conflated. The unadjusted p-value is <0.001, while the confidence interval gives a range of plausible estimates for the group difference under its assumptions. The interval is more directly informative about the magnitude and precision of the contrast. Neither replaces consideration of the sample counts, outcome variability, analysis population, or unreported methods.

Finally, the record names secondary outcomes but does not post their analyses, and it does not report multiplicity handling or missing-data methods. This makes the distinction between a reported primary result and a complete analysis record important. The study can be read for its posted estimates while recognizing that several details needed for a full appraisal of the statistical plan are not reported in the registry record.

17. 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 entry leaves important design and analysis details unspecified. Eligibility criteria, recruitment setting, and the process by which participants experienced the initial weight loss described in the study summary are not reported in the registry record. Those details would help define the population and context to which the outcome pertains. The entry states that the study was randomized and quadruple-masked, but does not identify the roles included in the masking description or report how allocation concealment was implemented.

The registry lists enrollment as 50, whereas the primary outcome results report 24 participants for placebo and 25 for Litramine. The reason those figures differ is not reported. The safety section lists 25 participants at risk in each arm, but the record does not explain how those counts relate to the outcome analysis counts. These differences should be treated as an unresolved reporting detail, not as evidence about participant flow or exclusions.

The original sample-size justification and the trial's own statistical design assumptions are not reported. The available planning illustrations are based on the observed effect and do not document how the trial was designed. The statistical test, confidence-interval method, analysis population, treatment of missing data, and any covariate adjustment are also not reported. Interim analyses and multiplicity procedures are not reported. The registry names secondary outcomes but posts no numerical analyses for them.

Safety reporting is limited to counts for serious and other adverse events; the deaths entries are not reported. The entry does not describe event definitions, collection procedures, or attribution methods. Follow-up in the primary endpoint is stated as 24 weeks, and later outcomes are not reported. These limits constrain interpretation of the posted result to the reported weight-change comparison and the available adverse-event counts. They do not establish that unreported procedures or outcomes had any particular value.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: Litramine in Weight Maintenance — NCT01505387.
• Registry record last updated 2015-06-01; status last verified 2015-05.
• Results first posted 2015-04-03.
• 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.

21. Record Summary

NCT01505387 is a completed, Phase 4 randomized, quadruple-masked, parallel-group, placebo-controlled study sponsored by InQpharm Group. The registry lists enrollment as 50 and describes an investigation of Litramine for maintaining body-weight loss over 24 weeks following initial weight loss. The listed study dates are start in 2012-01 and primary completion in 2012-09.

The primary endpoint was mean change in body weight from baseline to the end of 24 weeks. The reported arm means were 1.62 kg for placebo and -0.62 kg for Litramine. The mean difference for Litramine versus placebo was -2.24 kg, with a 95% confidence interval from -3.088 to -1.392 and an unadjusted p-value of <0.001. The record also lists four secondary outcomes, but no numerical secondary analyses are posted.

For the primary outcome, the registry reports 24 participants in placebo and 25 in Litramine. It reports 0 affected participants for serious and other adverse events in each arm; death counts are not reported. The original sample-size justification, analysis population, missing-data approach, and multiplicity methods are not reported in the registry record.