Effect Of Meloxicam Versus Placebo In Mainland Chinese Patients With Osteoarthritis Of The Knee: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effect Of Meloxicam Versus Placebo In Mainland Chinese Patients With Osteoarthritis Of The Knee (NCT01430559), a randomized na study. The primary outcome is The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Total and the 3 Subscales Scores (Pain, Stiffness and Physical Function) at Screening 1 by Using a Paper Worksheet and a Personalized Electronic LogPad System (E-diary).

2. Clinical Question

3. Trial Design

The trial record describes a randomized, double-blind, placebo-controlled, multicenter, parallel-group study of meloxicam in mainland Chinese subjects with osteoarthritis of the knee. Its listed phase is NA, and its status is completed. Pfizer is identified as the sponsor. The record gives the enrollment as 408.

The study began on 2011-10-24, and primary completion is recorded as 2013-03-27. The placebo arm description specifies 2 Placebo capsules once a day for 12 weeks. Meloxicam is listed as a drug intervention, and the safety groups identify the active treatment as Meloxicam 15 mg; a corresponding dosing schedule for that arm is not reported in the registry record.

The stated purpose had two parts: to validate the Western Ontario and McMaster Universities Osteoarthritis Index, or WOMAC, in mainland Chinese patients with knee osteoarthritis, and to evaluate meloxicam versus placebo for reducing osteoarthritis symptoms in that population. The listed primary outcome focuses on WOMAC measurement at Screening 1, with scores obtained using a paper worksheet and a personalized electronic LogPad system. The record also lists changes in WOMAC scores, patient global assessment and quality-of-life measures among secondary outcomes.

Although randomization and masking are recorded, details such as the randomization procedure, allocation concealment, and how masking was maintained are not reported in the registry record. Nor is the protocol’s sample-size justification reported. These omissions limit what can be concluded about the operational details of the design from the registry record alone.

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: This study comprised of a Screening Period prior to Treatment Period. During Screening, 52 healthy participants and 356 participants with osteoarthritis (OA) were included in validation analysis set (total enrollment=408), 293 out of the 356 OA participants were assigned randomized to treatment, and 6 of these randomized participants did not receive actual treatment.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Validation Analysis Set (VAS) - all OA participants who were non-screen failure at Visit 1 (Screening 1) and returned for Visit 2 (Screening 2); and all enrolled healthy participants. Here, n=number of evaluable participants for each specific category.

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.

Population: Full Analysis Set (FAS): all randomized participants who received at least 1 dose of study medication.

6. Primary Endpoint

The registry lists the primary outcome as The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Total and the 3 Subscales Scores (Pain, Stiffness and Physical Function) at Screening 1 by Using a Paper Worksheet and a Personalized Electronic LogPad System (E-diary), measured over Screening 1 (Visit 1: Days -21 to -14).

The primary outcome is the WOMAC total score and its pain, stiffness and physical-function subscale scores at Screening 1, measured using a paper worksheet and a personalized electronic LogPad system, or E-diary. WOMAC asks about pain and stiffness in the index knee and difficulty with daily tasks during the past 48 hours. The registry describes the subscales as means of their component question scores. Pain, stiffness and physical function range from 0 to 10, with higher values indicating worse status; the total ranges from 0 to 240, with higher values indicating a worse health condition.

WOMAC is used to capture related but distinct aspects of knee osteoarthritis symptoms and function. Comparing the instrument’s administration formats can inform whether the measure is usable in the population studied. The stated validation objective makes this measurement question central: the primary outcome is not a treatment-change endpoint, but a set of scores recorded at screening. The registry record does not report the statistical criterion for deciding whether the paper and electronic assessments are sufficiently comparable, or numerical results for that assessment.

The defined Validation Analysis Set includes OA participants who were not screening failures at Visit 1 and returned for Visit 2, together with enrolled healthy participants. The outcome description notes that the evaluable number can differ by category. Those category-specific counts and the primary outcome estimates are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes the study as randomized, double-blind and parallel group. In general, 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 or reporting. These design features do not by themselves guarantee that all sources of bias were avoided. The registry record does not report the sequence-generation method, allocation concealment procedure, or details of how masking was implemented.

What does the primary outcome measure?

The primary outcome is a continuous measure: WOMAC total and subscale scores at Screening 1. A continuous outcome can take values across a scale rather than being limited to event categories. The record specifies means and standard deviations as the summary format. In general, a mean describes the average score in the analysed group, while a standard deviation describes how spread out individual scores are around that average. Neither summary alone indicates whether the paper and electronic formats agree for individuals.

The three subscales cover pain, stiffness and physical function. Each subscale has a stated range from 0 to 10, and higher scores indicate worse status. The WOMAC total is described as the sum of question scores, ranges from 0 to 240, and also assigns higher values to worse health condition. These scale definitions help interpret score direction, but do not supply an observed result. The record does not report a primary-outcome estimate, its uncertainty, or the method used to assess agreement between assessment formats.

How should estimates and confidence intervals be read?

In general, an estimate summarizes the observed contrast or quantity of interest, while a confidence interval expresses uncertainty around that estimate under the statistical model used. A narrower interval indicates greater precision than a wider interval, but an interval’s interpretation depends on the analysis and assumptions. The registry record does not report a confidence interval for the primary outcome or a treatment effect. No conclusion about the size or precision of either can therefore be drawn in the registry record recorded for this outcome.

For a randomized treatment comparison, an unadjusted difference in group means is a simple summary of separation between group averages. An adjusted estimate may account for specified baseline variables or other model terms. The registry record does not report which covariates, if any, were included in a treatment-effect model. It also does not report whether a primary analysis used an adjusted or unadjusted comparison.

What does the planning illustration represent?

The sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between the two arms and a normal approximation. The illustration varies the effect to detect as a stated fraction of the observed effect. In general, such calculations explore how a hypothetical design might perform under specified assumptions. They are not observed power and do not show the probability that the completed trial detected a true effect. They also do not replace a protocol’s prospective sample-size justification, which is not reported in the registry record.

For continuous outcomes, a planning calculation depends on assumptions about the effect and variation as well as the chosen significance level and power target. If the observed effect is used as the starting point, the result is conditional on that estimate and should not be treated as a reliable forecast for a future study without considering uncertainty and design relevance. The registry record does not report a protocol-based rationale for enrollment or the assumptions originally used by investigators.

Why do analysis populations matter?

The primary outcome description names a Validation Analysis Set, with eligibility tied to screening status and return for the next screening visit, and it also includes enrolled healthy participants. It further notes that the evaluable number can vary by category. This is important because a summary based on one population may not describe the same participants as a treatment comparison based on randomized groups. The analysis population for each reported result, and any missing-data method, are not reported in the registry record.

In general, missing outcomes can affect estimates when the likelihood of missingness is related to participant characteristics or outcomes. Statistical approaches may make different assumptions about unobserved scores, and sensitivity analyses can examine how results change under alternative assumptions. No missing-data procedure or sensitivity analysis is reported in the registry record. The available description is therefore not enough to assess the influence of missing measurements.

Finally, a trial with multiple outcomes, time points and analyses raises the general issue of multiplicity. Testing many hypotheses can increase the chance of at least one apparently noteworthy finding if no adjustment or prespecified hierarchy is used. The registry record lists multiple outcome measures and analyses, but the statistical plan, multiplicity adjustment, and any prespecified testing sequence are not reported. Accordingly, no inference about how multiplicity was handled should be made.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 14 outcome measures and 60 analyses. The stated secondary outcomes include several WOMAC assessments at Weeks 2, 4, 8 and 12, alongside patient global assessment, SF-36 and EQ-5D measures. Multiple outcomes and time points create a general multiplicity concern: when many hypotheses are examined, the chance of an apparently unusual result can increase unless the analysis uses a prespecified strategy to control or interpret that risk.

The registry record does not report a statistical analysis plan, multiplicity adjustment, hierarchy of outcomes, or rules identifying which analyses were confirmatory. It is therefore not possible to determine whether reported analyses, if any, were treated as primary, exploratory or adjusted for multiple testing. No treatment estimates or p values for the listed primary or secondary outcomes are reported in the registry record.

The primary-outcome population is described as a Validation Analysis Set that includes eligible OA participants who returned for the second screening visit and enrolled healthy participants. The definition also notes that evaluable numbers vary by category. The registry record does not report category-specific evaluable counts, the analysis population used for the treatment comparison, or how participants with missing measurements were handled.

In general, complete-case analysis, imputation and model-based approaches rely on different assumptions about missing data. Those assumptions can affect both the estimate and its precision. The registry record does not report the chosen method, reasons for missing observations, or sensitivity analyses. These omissions prevent assessment of how missingness and analysis-population choices may have influenced the findings.

11. 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: angina unstable (0.7%), asthenia (0.7%), haemoglobin decreased (0.7%), platelet count decreased (0.7%), red blood cell count decreased (0.7%).

The safety record lists serious adverse events for 2 of 143 participants at risk in the placebo group and 0 of 144 at risk in the meloxicam 15 mg group. Other adverse events are listed as 0 of 143 and 0 of 144, respectively. These figures are counts within the groups identified in the safety record; they are not estimates of comparative treatment effect and do not show how event timing or duration was handled.

The record also lists OA participants not randomized, OA participants randomized but not treated, and healthy participants in separate safety groups. Their serious and other adverse-event counts are recorded as zero, with group sizes stated in the record. Those groups are not the randomized placebo-versus-meloxicam comparison and should not be combined with it when interpreting the treatment contrast.

Several serious-event terms are listed at 0.7% each: Angina unstable, Asthenia, Haemoglobin decreased, Platelet count decreased, Red blood cell count decreased and Weight decreased. The registry record does not clarify the group attribution or event-level basis for these percentages. Death counts are not reported in the registry record. Because event counts are limited and contextual details are absent, these safety figures describe what the record lists, rather than establishing a comparative safety conclusion.

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

The trial addresses two related but distinct questions. One concerns whether WOMAC can be used in mainland Chinese patients with knee osteoarthritis, including assessment with paper and electronic formats. The other concerns the effects of meloxicam compared with placebo on osteoarthritis symptoms. The stated primary outcome is a screening assessment of WOMAC total and subscale scores; it is not a reported change-from-baseline treatment contrast.

The posted record provides useful definitions of the WOMAC scales and identifies the intended population and measurement formats. However, it does not report the primary outcome estimates or their uncertainty. Without those results, the measurement comparison cannot be judged from the registry record. Likewise, the listed secondary outcomes identify measures and assessment times, but numerical results for them are not reported in the registry record.

The record’s safety figures show the adverse-event counts recorded for the listed groups. They do not, on their own, quantify a reliable between-group difference or establish the likelihood of events over a specified follow-up period. The listed serious-event terms and percentages also lack treatment-group attribution in the registry record. These limits mean that the safety description should remain descriptive.

Nothing in the available record establishes that meloxicam did or did not reduce symptoms. A treatment-effect conclusion would require relevant group estimates, a measure of uncertainty and an understanding of the prespecified analysis and missing-data handling. Those details are not reported in the registry record. The listed planning assumptions cannot fill this gap: a sample-size illustration is a design calculation, not an observed treatment result or evidence of achieved power.

The appropriate interpretation is therefore bounded. The record identifies a randomized, double-blind, placebo-controlled study, defines a WOMAC-focused primary measurement outcome and reports selected adverse-event counts. It does not provide enough numerical outcome evidence to assess the primary validation question or the meloxicam-versus-placebo symptom comparison.

13. Why This Trial Matters Statistically

This trial is statistically notable because its stated primary outcome is about measurement in a particular population, while its broader study purpose also includes a treatment comparison. Keeping those questions separate is essential. Evidence about how WOMAC scores are collected with paper and electronic formats is not interchangeable with evidence about whether symptom scores change differently between treatment groups.

The outcome definition also illustrates why scale direction and construction matter. WOMAC includes pain, stiffness and physical-function subscales, as well as a total score, and higher scores indicate worse status. The total and subscales are related but not identical summaries. A reader needs the measure’s direction, range and assessment time to interpret any estimate correctly; the registry provides these definitions but not the primary outcome results.

The record describes a Validation Analysis Set with eligibility based on screening status and return for a subsequent visit, and it notes that the evaluable number differs by category. This highlights the importance of defining the analysis population before interpreting averages or treatment contrasts. The record does not report the category-specific counts or missing-data procedures needed to assess the effect of those choices.

Finally, the listing of 14 outcome measures and 60 analyses makes transparent that the study involved a broad set of assessments. In general, multiple endpoints and time points make a prespecified analysis plan important for distinguishing confirmatory results from exploratory findings. Since that plan and any multiplicity strategy are not reported in the registry record, the results cannot be statistically contextualized on that basis. The record is informative about intended measurement and design, but its reported information does not support a numerical conclusion about efficacy or WOMAC format agreement.

14. 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.

A central limitation of the available record is that it defines the primary WOMAC outcome but does not report its numerical results. There is no estimate of paper-versus-electronic score agreement or corresponding measure of uncertainty in the registry record. The primary outcome is recorded at Screening 1, and the record does not state the statistical criterion used to evaluate the measurement formats.

The clinical treatment question is also not numerically resolved by the information recorded. Although the study purpose includes meloxicam versus placebo and the secondary outcomes list changes over follow-up, estimates for those outcomes are not reported in the registry record. The absence of results means the direction, magnitude and precision of any treatment contrast cannot be assessed.

Population details are incomplete for interpreting the primary measure. The Validation Analysis Set definition explains eligibility, but category-specific evaluable counts are not reported. The record also does not describe the analysis population used for each treatment comparison, missing-data handling, or sensitivity analyses. These gaps limit assessment of selection and attrition effects.

Methodological details are not reported for the randomization procedure, allocation concealment, masking implementation, statistical analysis plan, multiplicity handling or protocol-based sample-size justification. The safety record includes limited counts and serious-event terms, but the listed terms’ treatment-group attribution and death counts are not reported. These trial-specific omissions constrain interpretation of both the measurement objective and the treatment and safety questions.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effect Of Meloxicam Versus Placebo In Mainland Chinese Patients With Osteoarthritis Of The Knee — NCT01430559.
• Registry record last updated 2020-12-31; status last verified 2020-12.
• Results first posted 2020-12-31.
• 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.

18. Record Summary

The registry record describes a completed randomized, double-blind, placebo-controlled, multicenter, parallel-group study of meloxicam versus placebo in mainland Chinese patients with knee osteoarthritis. It lists enrollment of 408, sponsor Pfizer, and a study start of 2011-10-24 with primary completion on 2013-03-27.

The primary outcome is WOMAC total and subscale scores at Screening 1, assessed using a paper worksheet and a personalized electronic LogPad system. The outcome description defines the pain, stiffness and physical-function scales and identifies a Validation Analysis Set. The record also lists secondary symptom, patient-assessment and quality-of-life outcomes.

Numerical primary and secondary outcome results, treatment-effect estimates, confidence intervals, p values, analysis-plan details and missing-data methods are not reported in the registry record. Safety counts include serious adverse events in 2 of 143 placebo participants and 0 of 144 meloxicam participants; other adverse events are recorded as zero in both groups. The record supports description of the design and reported counts, but not a numerical conclusion about WOMAC format agreement or treatment effect.