Loteprednol Etabonate Versus Vehicle for the Treatment of Inflammation and Pain Following Cataract Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Loteprednol Etabonate Versus Vehicle for the Treatment of Inflammation and Pain Following Cataract Surgery (NCT01010633), a randomized phase 3 study. The primary outcome is Resolution of Anterior Chamber Cells (ACC)..

2. Clinical Question

3. Trial Design

The registry describes a randomized, double-masked, parallel-group phase 3 trial. It lists loteprednol etabonate and its vehicle as the two study conditions. The posted enrollment is 406, with 203 participants listed in each arm for the primary outcome. The trial status is completed.

The study began in 2009-11, and primary completion is recorded as 2010-06. Bausch & Lomb Incorporated is listed as the sponsor. These registry entries describe the design and record history; they do not give a full account of the conduct of the trial.

Randomization means allocation to study conditions is determined by a chance-based process rather than being selected by the participant or investigator. In general, this can reduce systematic differences between groups at the start of a trial. The registry record does not report the randomization sequence method, how allocation was concealed, or whether any stratification was used.

Double masking indicates that the registry classifies the trial as masked at two levels, but the record does not specify which people were masked or how masking was maintained. Parallel-group design means the listed arms are separate treatment groups rather than a crossover sequence. Details of follow-up beyond the primary outcome visit, treatment adherence, and discontinuation are not reported in the registry record.

The primary endpoint concerns study eyes with complete resolution of anterior chamber cells, assessed at Visit 5 on postoperative day 8. The registry identifies the intent-to-treat population for this outcome. It does not report the trial’s sample-size justification, the protocol’s full statistical plan, or any planned interim analyses.

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.

Before assignment: 406 participants eligible for cataract surgery were enrolled in the study (safety population). 397 participants completed the study.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intent to treat (ITT) population

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 Resolution of Anterior Chamber Cells (ACC)., measured over Visit 5 (Postoperative day 8).

The primary endpoint is the number of study eyes with complete resolution of anterior chamber cells at Visit 5, on postoperative day 8. The registry defines complete resolution as Grade 0. Anterior chamber cells are described as an accumulation of white cells in aqueous, assessed by investigators using a slit lamp and graded on a scale from 0 to 4, where Grade 0 means no cells. The outcome is listed in eyes, and the stated analysis population is intent to treat.

This measure captures a specific sign of postoperative inflammation at a specified visit. In general, a clearly defined clinical measure can make a comparison more interpretable by tying the result to an observable finding, an assessment procedure, and a time point. Here, the endpoint focuses on whether the specified Grade 0 state was reached; it is not a complete measure of every aspect of inflammation, pain, recovery, or safety.

The registry also lists resolution of anterior chamber cells among secondary outcomes, while its summary describes the broader purpose as comparing safety and efficacy for postoperative inflammation and pain. The primary endpoint does not itself report pain, and the available registry entries do not establish how every other outcome was defined or analyzed. The endpoint therefore answers a focused question about complete resolution of this clinical sign at the recorded visit, rather than all possible questions about postoperative outcomes.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry reports a Chi-squared method for the primary comparison and labels its parameter as a mean difference in final values. It reports a value of 14.3, a 95% confidence interval from 5.7 to 22.9, and p < 0.001. The record does not provide a fuller statistical specification explaining how the labeled parameter relates to the count outcome. The interpretation should therefore distinguish the reported analysis from any alternative analysis that might be considered for such data.

What does a Chi-squared comparison do?

As a general statistical explanation, a Chi-squared test can assess whether observed categorical counts are compatible with a null model of no association or no difference, depending on the test formulation. It evaluates how far the observed pattern is from what the null model would predict, relative to the variability expected under that model. The test does not, by itself, express the size of a difference in a directly interpretable clinical unit; an effect estimate and an interval are useful for that purpose.

The registry lists a binary endpoint: an eye either has the specified complete resolution or it does not. The posted values give the count meeting the endpoint in each arm, but do not provide the complementary outcome counts or a detailed analysis dataset. The record does not state whether the reported Chi-squared calculation used a particular continuity correction, a particular handling of missing observations, or another implementation choice. Those details are not reported in the registry record.

How should the estimate and interval be read?

In general, a confidence interval describes the range of effect estimates that are reasonably compatible with the observed data and the statistical model used to form the interval. Its endpoints reflect sampling uncertainty as well as the model’s assumptions. A narrower interval generally indicates more precision than a wider one, while the interval does not account automatically for bias, outcome misclassification, missing-data assumptions, or selective reporting.

The sponsor-reported interval is 5.7 to 22.9 at the 95% confidence level. Its interpretation depends on the scale and construction of the reported mean difference, which are not explained further in the registry record. The point estimate and interval should be reported as the sponsor’s analysis states them, rather than silently relabeled as a risk difference or another effect measure. No unit for the comparison estimate is given beyond the parameter description.

What does the p-value communicate?

As a general explanation, a p-value measures how unusual data at least as incompatible with a specified null model would be if that model and the test assumptions held. A small p-value can be evidence against that null model, but it is not the probability that the result occurred by chance, nor the probability that a treatment has no effect. It does not measure clinical importance and does not indicate whether the analysis plan was appropriate.

The registry reports p < 0.001. That threshold should not be rewritten as an exact p-value. The record does not report whether this test was adjusted for other outcomes or analyses, nor does it provide a full prespecified statistical analysis plan. Without that context, the result should be understood as the reported test for this endpoint, not as a complete account of all inferential decisions in the trial.

Why can count outcomes require care?

General statistical methods depend on the form of the outcome and the question being asked. A binary endpoint can be analyzed through group proportions, a difference between proportions, a ratio measure, or a model that adjusts for covariates. Each method has assumptions and produces an estimate on a different scale. An analysis of counts may also need to account for the number of observations contributing to each arm and for any missing or ineligible observations.

Here, the registry describes the outcome as a number of eyes and gives the number of participants listed for each arm, while its reported inferential parameter is called a mean difference in final values. The registry does not explain the relationship among those descriptions. A recalculated comparison is not available for this count outcome in the registry record. That means a reader should not infer a newly calculated estimate from the posted counts or treat the sponsor’s result as if it had been independently reproduced.

Over-dispersion is a general concern when count data vary more than a simple model expects. In such cases, standard errors can be too small if the model understates variability, making intervals too narrow and tests too optimistic. This endpoint is a count of eyes meeting a binary condition rather than a general event-rate outcome, and the registry does not report an over-dispersion assessment or a count-model specification. The concept is relevant as a reminder that model choice must match the outcome, not as a claim that over-dispersion affected this trial.

What can be concluded about planning calculations?

The registry record does not report the trial’s original sample-size justification, target effect, or power calculation. Any planning illustration based on the observed effect is a hypothetical scenario, not a record of the trial’s design rationale and not observed power. In general, planning calculations describe how many participants per arm might be needed under stated assumptions about the effect to detect, significance level, allocation, and statistical approximation. Their results depend on those assumptions and should not be treated as evidence that the completed trial had a particular probability of success.

The stated planning assumptions describe a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect expressed as a fraction of the observed effect. These are planning conventions, not findings from the clinical comparison. The registry does not provide additional planning estimates in the registry record for this explanation. Such scenarios cannot resolve questions about outcome definitions, analysis populations, multiplicity, missing data, or the clinical importance of the endpoint.

10. Analyses Reported by the Sponsor

The registry’s reported inferential result is the sponsor’s own analysis: a Chi-squared comparison, described as a mean difference in final values of 14.3, with a 95% confidence interval from 5.7 to 22.9 and p < 0.001. The posted arm values are 62 and 33 eyes with complete resolution, with 203 participants listed in each arm for the endpoint.

No recalculated two-arm comparison is available for this count outcome in the registry record. The record identifies the values as missing or not estimable for that type of recalculation. There is therefore no independent recalculated estimate to compare with the sponsor’s result, and no basis for claiming that the two analyses agree or disagree. The sponsor’s reported estimate should be presented as the inferential result, while the group counts remain descriptive information.

The registry does not give enough detail to reconstruct the analysis or clarify the scale of the parameter label beyond its description as a mean difference in final values. Readers should avoid interpreting the reported value as a different effect measure without supporting information. Further details about the sponsor’s analysis specification are not reported in the registry record.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists three outcome measures and one secondary outcome, described as resolution of anterior chamber cells. It reports two analyses. These record-level counts do not reveal the complete set of outcomes, time points, or statistical tests considered during the trial, nor do they establish which analyses were prespecified. The full protocol and statistical analysis plan are not reported in the registry record.

Multiplicity is a general statistical issue that arises when several outcomes, time points, subgroups, or comparisons are tested. If each is assessed separately without adjustment, the chance of at least one apparently notable result can increase. Adjustment methods and prespecified outcome hierarchies can address aspects of this issue, but the registry record does not state whether any multiplicity procedure was planned or used. The reported p-value should therefore be read as the result for the specified primary comparison, not as evidence that the full family of analyses was controlled.

The primary outcome names the intent-to-treat population. In general, an intent-to-treat analysis aims to preserve the randomized group assignment when evaluating outcomes. The registry does not report how missing primary outcome data were handled, whether all randomized participants contributed to this endpoint, how protocol deviations were treated, or whether a different analysis population was also used. The arm counts list 203 participants per group, but those figures alone do not resolve how missing observations or exclusions were handled.

Missing-data assumptions matter because an analysis may be affected if the probability of an outcome being unobserved is related to the outcome itself or differs by group. This is a general concern, not a claim that missingness occurred or biased the result in this trial. The registry record does not report missingness by arm, reasons for missing assessments, imputation methods, sensitivity analyses, or the handling of participants without a Visit 5 assessment.

These gaps limit assessment of how robust the reported comparison is to analysis choices. They do not invalidate the sponsor-reported result, but they mean that the available record does not permit a complete audit of outcome selection, multiplicity control, or missing-data handling.

12. 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 5% reporting threshold.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: cystoid macular edema (0.5%), bronchitis (0.5%), heart failure (0.5%).

The registry lists serious adverse events for 1 participant in the loteprednol group and 2 participants in the vehicle group, with 203 participants at risk listed for each group. It lists 0 other adverse events in each group. These figures describe the registry’s reported safety counts; they should not be treated as a full safety profile or as a direct measure of comparative risk without the analysis details and context.

The record lists cystoid macular edema, bronchitis, and heart failure among the top serious adverse event terms, each shown as 0.5%. It does not identify the group assignment for each listed term or provide enough detail to reconcile these term-level percentages with the group-level serious-event counts. The meaning of the term-level percentage denominator is not further explained in the registry record.

In general, serious adverse event counts summarize events meeting a seriousness definition, but event counts and participant counts are not interchangeable when a participant can have more than one event. The registry does not provide event narratives, timing, causality assessments, or a fuller account of how serious events were classified. Death figures are not reported in the registry record. The posted safety figures are therefore descriptive and do not establish a causal relationship or a complete comparison of harms.

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

The result concerns a particular endpoint: complete resolution of anterior chamber cells, defined as Grade 0 on the slit-lamp assessment, at Visit 5 on postoperative day 8. The posted counts are 62 in the loteprednol arm and 33 in the vehicle arm, with 203 participants listed for each arm. The sponsor’s reported comparison is 14.3, with a 95% confidence interval from 5.7 to 22.9 and p < 0.001.

These findings describe the registry’s recorded comparison for that endpoint and visit. They do not, by themselves, answer whether postoperative pain differed between groups, how outcomes changed over time, or whether other measures of inflammation showed the same pattern. They also do not establish the overall balance of benefits and harms. Those broader conclusions would require the relevant outcome data and fuller study details, which are not reported in the registry record.

Statistical evidence and clinical importance are distinct. In general, a small p-value can indicate incompatibility with a specified null model while leaving the practical importance of the effect unresolved. A confidence interval conveys uncertainty around an estimate under its model, but it cannot account for all potential sources of bias or uncertainty in the study. The registry does not report a threshold for a clinically important difference for this endpoint.

The record identifies a randomized and double-masked design, which are features intended in general to support a fair comparison and reduce some sources of bias. However, details needed to assess implementation, adherence, missing outcomes, and analysis choices are not reported. The endpoint is also limited to the recorded assessment and population; it should not be generalized automatically to other settings, outcomes, or follow-up periods.

Accordingly, the result is evidence about the recorded primary endpoint under the sponsor’s reported analysis. It is not proof of a broader clinical effect, a statement about an individual patient, or a complete account of safety. Interpretation should keep the endpoint definition, visit, estimate, interval, and unreported analysis details together.

14. Why This Trial Matters Statistically

This trial illustrates why interpreting a clinical result requires more than reading a p-value. The endpoint is a clearly described clinical sign: complete resolution of anterior chamber cells, assessed by slit lamp and defined as Grade 0. The registry also specifies the assessment visit and identifies the intent-to-treat population. Those features help clarify exactly what the primary outcome represents.

The record also presents an important statistical reading issue. It gives group counts for a binary clinical state, while the sponsor’s reported parameter is labeled a mean difference in final values. Because no recalculated comparison is available for this count outcome, the counts cannot be used to silently replace or reinterpret the sponsor’s inferential result. Keeping descriptive data and the reported analysis distinct is essential to transparent reporting.

The reported confidence interval complements the p-value by conveying uncertainty around the sponsor’s estimate. Yet neither statistic resolves whether the magnitude is clinically important, because no clinical-importance threshold is reported. Nor does statistical significance establish that all outcomes favor the same direction or that a broader safety profile is characterized. The registry’s limited reporting on missing data, multiplicity, and analysis specifications further illustrates why readers need both results and methods to judge robustness.

More generally, the record shows how trial design features, endpoint construction, analysis choices, and reporting completeness shape interpretation. Randomization and masking are relevant design attributes, but their practical implementation and the handling of incomplete outcomes are not detailed. Statistical education benefits from separating what the registry documents from what a reader might wish to know. In this trial, the primary comparison is interpretable as a reported result for a specific sign and visit, while the limits of its documentation remain part of the statistical reading.

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 trial-specific details needed for a fuller assessment are not reported in the registry record. These include the eligibility criteria, baseline characteristics, treatment administration schedule, randomization procedure, allocation concealment, and the identities of the people masked. Without these details, the record cannot establish how closely the enrolled participants, treatment delivery, or masking procedures can be assessed.

The primary outcome is defined at a particular visit and focuses on complete resolution of anterior chamber cells. The record does not provide the full distribution of grades, results at other visits, or the complete set of outcome definitions. It also does not report a pain result in the registry record describing the posted analyses, despite pain being part of the study’s stated purpose. Thus, the primary endpoint should not be treated as a comprehensive measure of postoperative recovery.

The sponsor-reported analysis lacks further details on the scale and construction of its mean-difference estimate. No recalculated comparison is available for this count outcome. The record also does not provide a full statistical analysis plan, information on multiplicity control, missing-data handling, protocol deviations, adherence, or sensitivity analyses. These omissions limit independent assessment of the analysis and its robustness; they do not demonstrate that a particular bias occurred.

The safety information is also limited. Serious-event counts are posted, but the registry does not provide event narratives, causal assessments, detailed timing, or the group assignments for the listed serious-event terms. Death figures are not reported in the registry record. These details would be needed for a more complete interpretation of safety.

Finally, the registry does not report the trial’s sample-size justification or threshold for clinical importance. The reported estimate and interval can therefore be described statistically, but the record alone does not establish whether the magnitude is clinically meaningful or how the study was planned to address that question.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Loteprednol Etabonate Versus Vehicle for the Treatment of Inflammation and Pain Following Cataract Surgery — NCT01010633.
• Registry record last updated 2012-01-09; status last verified 2011-12.
• Results first posted 2012-01-09.
• 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 a completed, randomized, double-masked, parallel-group phase 3 trial sponsored by Bausch & Lomb Incorporated. It compares loteprednol etabonate with its vehicle following cataract surgery and lists enrollment as 406. The primary outcome is the number of study eyes with complete resolution of anterior chamber cells at Visit 5, on postoperative day 8, in the intent-to-treat population.

The posted primary outcome counts are 62 for loteprednol and 33 for vehicle, with 203 participants listed in each arm. The sponsor reports a Chi-squared comparison described as a mean difference in final values of 14.3, with a 95% confidence interval from 5.7 to 22.9 and p < 0.001. No recalculated comparison is available for this count outcome. The record also lists serious adverse event counts and selected event terms, but provides limited detail for interpreting them.

The registry does not report a full statistical analysis plan, the trial’s sample-size justification, missing-data handling, or multiplicity procedures. The result is therefore best understood as the sponsor-reported comparison for a specifically defined sign at a specified postoperative visit.