Evaluating Muscle Weakness Improvement With Lorcaserin in ICU: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluating Muscle Weakness Improvement With Lorcaserin in ICU (NCT02523690), a randomized phase 1, phase 2 study. The primary outcome is Change in Handgrip Strength as Measured by Hand Dynamometer.

2. Clinical Question

The trial asks whether lorcaserin, compared with placebo, is associated with a change in handgrip strength among critically ill patients being studied in relation to ICU-acquired weakness. The registry describes the study as evaluating safety and efficacy in critically ill patients recovering from critical illness. Muscle weakness and sepsis are listed conditions; the record does not report more detailed eligibility criteria or say that every participant had sepsis.

The outcome is intended to describe short-term change in a measurable aspect of muscle strength. The registry also lists changes in manual muscle strength measured by the Medical Research Council score and changes in quadriceps strength measured by handheld dynamometry as secondary outcomes. The posted record gives a small pilot-trial result, not a definitive answer about effects in a broader ICU population. It does not report an adjusted comparison, a confidence interval, or a statistical test for the primary endpoint.

3. Trial Design

The registry describes a randomized, quadruple-masked, parallel-group pilot trial in Phase 1 and Phase 2. The trial compared lorcaserin with placebo. In both arms, the assigned treatment was administered as a single dose on day 1 and day 3. The registry lists enrollment as 5 and identifies 3 participants in the intervention arm and 2 in the control arm in the posted primary outcome results.

The recorded start is 2015-12, and primary completion is listed as 2017-12. The study status is terminated. The reason for termination is not reported in the registry record, so the status alone does not explain why the trial ended or whether the decision was related to recruitment, feasibility, safety, or results.

Random allocation is intended to reduce systematic differences between treatment groups, while masking is intended to limit the influence of treatment knowledge on care, assessment, and reporting. These design features do not ensure that groups will be similar in a very small trial, nor do they remove uncertainty from sparse outcome data. The registry identifies the design as parallel, meaning the intervention and control arms are separate groups rather than sequential conditions assigned to the same participants.

The record does not report the randomization procedure, allocation concealment method, details of who was masked, or whether masking was maintained. It also does not describe a sample-size justification or provide a full statistical analysis plan. Those details should not be inferred from the labels for trial phase, masking, or allocation.

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

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 Change in Handgrip Strength as Measured by Hand Dynamometer, measured over Baseline and 2 to 6 hours after administration of 30mg lorcaserin/placebo.

The primary endpoint is change in handgrip strength measured with a hand dynamometer. The registry describes the underlying measurement as handgrip strength in kilograms, compared with age- and sex-matched population norms and expressed as percent of predicted strength. Higher values are described as better. The recorded timeframe is baseline and 2 to 6 hours after administration of 30mg lorcaserin or placebo.

A hand dynamometer provides a quantitative measure of grip force. Expressing the measurement as a percent of predicted strength places an observed grip measurement in relation to population norms matched for age and sex, as specified in the registry description. A change measure focuses on how the recorded endpoint differs from baseline over the stated assessment period, rather than only describing a single measurement.

As a general statistical point, a continuous strength measure can retain gradations in performance rather than reducing outcomes to categories. Its usefulness depends on consistent measurement, a clearly defined timing window, and complete outcome recording. The registry does not report the precise calculation used to derive the change values, the handling of measurements outside the stated assessment window, or whether results were adjusted for baseline strength. Those details are not reported in the registry record.

The endpoint is a measurement of strength, not by itself a direct measure of recovery, function in daily activities, or long-term clinical status. The posted primary result should therefore be read as a short-term strength outcome, within the assessment timing specified by the registry.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as a continuous measure and reports a mean and standard deviation for each arm. The following concepts explain how such summaries are generally read. They do not imply that an unreported analysis was performed in this trial.

What does a mean describe?

In general, a mean is a measure of the center of a set of observations. It gives a compact description of the values recorded for an arm, but it does not show the individual observations or their full distribution. A mean can be affected by unusually high or low observations, especially when there are few observations. The means reported for this trial are 0.67 for the intervention arm and 1.75 for the control arm. They are descriptive summaries, not a treatment-effect estimate with quantified uncertainty.

What does a standard deviation describe?

In general, a standard deviation describes how spread out observations are around their mean. A smaller standard deviation indicates that observations are more tightly clustered, while a larger one indicates greater spread. It is not a measure of how certain the mean is, and it does not directly express uncertainty about a contrast between arms. The registry reports standard deviations of 2.93 in the intervention arm and 1.06 in the control arm. Because group sizes are very small, these spread estimates should themselves be read cautiously.

A standard deviation also does not reveal the shape of the observations. It cannot show whether values are symmetric, skewed, or influenced by an unusual observation. With sparse data, summaries can conceal important features of the underlying measurements. Individual-level values and distributional details are not reported in the registry record.

What would an uncertainty interval add?

In general, a confidence interval expresses uncertainty around an estimated quantity, such as a mean or a difference between groups, under a stated statistical method. It provides a range of estimates compatible with the observed data and method; it is not a guarantee that the true value lies within the calculated range. A confidence interval for a treatment contrast would help readers assess both the range of effects compatible with the data and the precision of the estimate. The registry does not report confidence intervals for this primary outcome.

The absence of an interval matters because a pair of means alone does not tell readers how much uncertainty surrounds a comparison. The group-level summaries do not support a conclusion about precision equivalent to a formal interval estimate. No interval can be recovered from the registry record without making additional analytical choices, and such a reconstruction would not be the sponsor's reported analysis.

Why is a direct comparison important?

In general, a two-arm trial addresses a comparative question. The relevant estimate is usually a contrast between outcomes under the intervention and control conditions, with an uncertainty measure and, where appropriate, adjustment for design features or baseline values. A comparison might use a model or a prespecified unadjusted method. The registry does not report a primary comparison or model for these results. It specifically indicates that values were missing or not estimable for a two-arm comparison of this continuous endpoint. Therefore, the posted arm summaries should not be presented as an inferential finding.

A p-value, when reported, summarizes how incompatible the observed data are with a specified null model under its assumptions. It does not quantify the size or clinical importance of an effect, and it does not measure the probability that the null hypothesis is true. No p-value for the primary comparison is reported in the registry record. The absence of a p-value is not evidence that the groups are equal; it means the posted record does not provide that test result.

How should the design features be understood?

As a general concept, randomization uses chance to assign participants to treatment groups and can support a fair comparison by reducing systematic allocation choices. In a small study, chance imbalances can still occur. Masking can reduce the influence of knowledge about assignment on treatment, assessment, and reporting, but the registry's quadruple-masking label does not specify which people were masked or whether masking was maintained. A parallel design compares separate randomized groups during the study rather than comparing each participant with themself under different assignments.

These design principles do not remove the need for an appropriate analysis. The registry does not report the randomization method, allocation concealment, baseline comparisons, or an analysis model. It is not possible to infer those details from the design labels.

What do the planning assumptions mean?

The registry's planning illustration is based on the observed effect and states a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. These are assumptions for a planning calculation, not evidence about the trial's achieved power. Any resulting sample-size estimate is a planning illustration, not an observed property of the completed trial and not a retrospective test of whether the trial was adequately powered.

Planning calculations depend on assumptions about the effect, variability, allocation, statistical method, and desired power. When based on an observed effect from a very small study, the estimate can be unstable because the observed effect may not represent the effect expected in a future study. The registry does not report the trial's own sample-size justification, and the planning assumptions should not be mistaken for that justification.

The record gives no statistical analysis for the primary comparison. It also does not report an analysis population, an approach to missing data, or a prespecified strategy for multiple outcomes. General statistical principles can clarify what such analyses would address, but they cannot fill in methods that are not reported in the registry record.

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("Intervention", "Control")
n   <- c(3, 2)
m   <- c(0.67, 1.75)
sp  <- c(2.93, 1.06)
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  Intervention  3  0.670  2.930  -6.609  7.949
CARM  Control  2  1.750  1.060  -7.774  11.274

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 5 secondary outcome entries, including handgrip strength, manual muscle strength measured by the Medical Research Council score, and quadriceps strength measured by handheld dynamometry. Some outcome descriptions appear more than once in the record. The registry also reports 6 outcome measures overall. Multiple outcomes can create a multiplicity issue: when many hypotheses are tested, the chance of at least one apparently notable result can increase. As a general statistical principle, this can be addressed through prespecified outcome hierarchies, adjustment procedures, or cautious interpretation. A multiplicity strategy is not reported in the registry record.

The record lists 0 analyses and says that values were missing or not estimable for a two-arm comparison of the continuous endpoint. It does not report a p-value, confidence interval, analysis model, or adjusted primary comparison. The absence of a reported comparison should not be interpreted as a null result or as evidence that no difference exists.

Missing-data handling and the analysis population are not reported in the registry record. It is therefore unclear whether all randomized participants were included in each outcome analysis, how unavailable measurements were treated, or whether any analysis followed an intention-to-treat principle. The arm counts attached to the primary summaries do not establish completeness for other outcomes or assessment times. No conclusions about missingness mechanisms or their impact can be drawn from the posted information.

The registry does not report a prespecified statistical analysis plan, endpoint hierarchy, or adjustment for baseline measurements. These omissions limit the ability to assess whether the posted outcomes and analyses followed a plan set before data were examined.

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.

The registry reports 0 serious adverse events among 3 participants at risk in the lorcaserin arm and 0 among 2 participants at risk in the placebo arm. It also reports 0 other adverse events among 3 participants at risk in the lorcaserin arm and 0 among 2 participants at risk in the placebo arm. The recorded number of deaths is 0 in each arm. No serious adverse event terms are listed.

These figures describe what was recorded in the registry for the participants at risk. They do not establish that the treatments have no adverse effects. With few participants, the absence of recorded events provides limited information about uncommon events or the range of possible harms. The registry does not report further details about adverse-event definitions, severity grading, event timing, or how events were collected.

Safety findings should be interpreted alongside the small pilot enrollment and the terminated study status. The reason for termination is not reported in the registry record, so it should not be attributed to safety or to any other cause. The posted counts are descriptive and do not provide a comparative statistical safety analysis.

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

The posted results describe short-term handgrip-strength outcomes in a small randomized pilot trial comparing lorcaserin with placebo. The registry reports a mean of 0.67 and a standard deviation of 2.93 for the intervention arm, and a mean of 1.75 and a standard deviation of 1.06 for the control arm. These summaries concern the primary endpoint as described in the record: change in handgrip strength expressed as percent of predicted strength, assessed from baseline to 2 to 6 hours after administration.

The record does not report a two-arm statistical comparison, confidence interval, or p-value for this continuous outcome. The arm means cannot establish a treatment effect, its precision, or whether any difference would be clinically important. The standard deviations describe variation among recorded values; they do not provide uncertainty around a treatment contrast.

The results also do not establish longer-term changes in strength, broader physical function, or outcomes beyond the measures listed in the registry. The primary endpoint is a short-term measurement, and the record does not describe follow-up beyond its stated timeframe. The secondary outcome entries do not substitute for an unreported primary analysis.

Randomization and masking are recorded design features, but the registry does not report enough methodological detail to evaluate their implementation. Nor does it report the analysis population, missing-data approach, or reason the study was terminated. Those gaps make it difficult to assess how representative the observed results are or how they should inform future estimates.

The results are best viewed as descriptive information from a pilot trial, not as a definitive estimate of benefit or harm. They do not establish that lorcaserin does or does not improve ICU-acquired weakness. Further interpretation would require complete methods and an appropriate comparative analysis, neither of which is reported in the registry record.

14. Why This Trial Matters Statistically

This trial matters statistically because it illustrates the difference between reporting arm-level summaries and answering a comparative research question. A mean and standard deviation can describe the recorded outcomes in each group, but a randomized trial's central question concerns the contrast between groups and the uncertainty around that contrast. The registry does not report an estimable comparison for the primary continuous endpoint.

The very small arm sizes make precision a central concern. In general, a small dataset offers limited information about the distribution of outcomes and can be strongly influenced by individual observations. A mean may look precise because it is written as a single value, but the number of decimal places does not communicate inferential certainty. The registry's group summaries should therefore be read with their small observed group sizes in mind.

The record also highlights the distinction between planning and observed evidence. A sample-size planning illustration based on an observed effect and stated assumptions is not the same as the trial's original design justification, and it is not observed power. The registry does not report the trial's own sample-size justification. Keeping these concepts separate prevents planning calculations from being mistaken for evidence that the completed study could answer its research question precisely.

Finally, multiple outcomes, missing-data procedures, analysis populations, and prespecified analysis choices affect how results are interpreted. The registry does not report these details. The case therefore underscores that outcome values alone are not a complete statistical report: design information, analysis methods, uncertainty estimates, and transparent reporting are also needed for a rigorous comparison.

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.

The available record has important trial-specific limitations. Enrollment is listed as 5, with 3 participants in the intervention arm and 2 in the control arm for the posted primary results. These small groups provide limited descriptive information and make it difficult to characterize variability or estimate a stable comparative effect.

The registry gives primary outcome means and standard deviations but no confidence interval, p-value, or estimable two-arm comparison. It does not report baseline outcome summaries or an adjusted analysis. The result therefore cannot establish the magnitude or precision of a treatment contrast.

The primary endpoint is assessed in a short window, from baseline to 2 to 6 hours after administration. The registry does not report longer-term results for the primary outcome. It lists 5 secondary outcome entries, with repeated descriptions, but does not provide a reported analysis for them in the registry record for this record.

Further limitations include the absence of reported eligibility details, randomization procedures, allocation concealment, masking implementation, analysis population, missing-data handling, and a multiplicity strategy. The reason for the terminated status is also not reported in the registry record. These omissions limit assessment of the trial's conduct, the completeness of outcome reporting, and the interpretation of the findings.

The posted safety counts are also sparse. Zero recorded events in these small groups cannot rule out uncommon or unobserved adverse events. Overall, the record supports only a cautious descriptive reading of this pilot trial.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Evaluating Muscle Weakness Improvement With Lorcaserin in ICU — NCT02523690.
• Registry record last updated 2020-01-13; status last verified 2019-12.
• Results first posted 2020-01-13.
• 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

The registry describes NCT02523690 as a randomized, quadruple-masked, parallel-group Phase 1 and Phase 2 pilot trial evaluating lorcaserin for ICU-acquired weakness. Participants in the intervention and control arms were scheduled to receive single doses on day 1 and day 3. The study is listed as terminated, and the reason is not reported in the registry record.

The primary endpoint is change in handgrip strength measured by hand dynamometer and expressed as percent of predicted strength, assessed from baseline to 2 to 6 hours after administration of 30mg lorcaserin or placebo. The posted group means are 0.67 for the intervention arm and 1.75 for the control arm; the corresponding standard deviations are 2.93 and 1.06. No inferential comparison is reported for the primary endpoint.

The registry lists 5 secondary outcome entries and reports 0 analyses. Safety summaries record 0 serious adverse events, 0 other adverse events, and 0 deaths in each arm. The results are descriptive and should be interpreted in light of the small arm sizes and the missing analysis and methods details.