This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Efficacy and Safety of Diclofenac Potassium 25 mg Tablet Taken Three Times Daily in Subjects With Acute Joint Pain (NCT01666197), a randomized phase 4 study. The primary outcome is Pain on Movement.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01666197 |
| Phase | Phase 4 |
| Condition | Ankle Sprain |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 100 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Novartis |
| Results posted | Yes |
2. Clinical Question
Population
Subjects with acute ankle sprains and associated acute joint pain. The reported condition is ankle sprain; further eligibility criteria and the characteristics of participants are not reported in the registry record.
Intervention
Diclofenac potassium 25 mg tablet, taken three times daily. The study description frames use as occurring under in-use conditions.
Comparator
Placebo, in a randomized, parallel-group comparison. Other details about the placebo or how treatment was administered are not reported in the registry record.
Primary question
How did the reported mean change in pain on movement at 48 hours, measured on a 100 mm visual analog scale, differ between the diclofenac and placebo groups? The reported contrast is a mean difference of -27.9 mm, with a confidence interval from -34.2 to -21.6 mm.
The primary question concerns a difference between group means, not the response of every individual participant. The endpoint description identifies change from baseline in pain on movement. The registry record gives a mean of 31.3 mm for diclofenac and 59.2 mm for placebo. The comparison is expressed as diclofenac minus placebo, yielding a negative mean difference. On the scale, 0 is anchored as no pain and 100 as extreme pain. The registry record does not state the sign convention used when calculating change from baseline, so the numerical direction of change should be interpreted with that limitation in mind.
The study was designed to compare diclofenac with placebo in acute ankle sprains. The posted results give a group-level contrast at 48 hours, but do not describe the distribution of individual responses, the proportion of participants meeting a threshold for improvement, or outcomes at other times. Those questions are distinct from the primary comparison of average scores.
3. Trial Design
This completed phase 4 study was randomized, placebo-controlled, and parallel-group. The registry record lists quadruple masking, while the official title describes the study as double-blind. These are different descriptions in the record; which specific groups of people were masked is not reported in the registry record. The randomized allocation and masking descriptions establish the intended design features, but do not by themselves show how allocation concealment or masking were implemented.
The study compared diclofenac potassium 25 mg tablets taken three times daily with placebo among subjects with acute ankle sprains. The stated aim was to evaluate efficacy and safety under in-use conditions, particularly with regard to pain relief. Enrollment was 100. The reported outcome summaries include 50 participants in the diclofenac group and 50 in the placebo group. The registry record does not clarify whether those outcome denominators equal the number randomized, the number treated, or the number included in a particular analysis.
The recorded start was 2012-08, and primary completion was 2013-01. The sponsor was Novartis, and the status is completed. The registry record does not report the study sites, eligibility details, allocation procedure, treatment adherence, concomitant care, or a protocol document. It also does not give a detailed account of the schedule of assessments beyond the primary endpoint timeframe of 48 hours.
A parallel-group trial assigns participants to a group and compares outcomes between the groups, rather than having each participant receive both treatments in sequence. Randomization is intended to reduce systematic differences between groups at the start of a trial, although the registry record does not provide baseline characteristics with which to assess balance. Placebo control gives a comparison condition, but the content of the placebo and practical details about its use are not reported. The record describes the broad design and treatments, while leaving several operational features unspecified.
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
| Stage | Diclofenac Potassium 25 mg Tablet | Placebo |
|---|---|---|
| STARTED | 50 | 50 |
| COMPLETED | 50 | 50 |
| NOT COMPLETED | 0 | 0 |
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.
| Characteristic | Unit | Diclofenac Potassium 25 mg Tablet | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 50 | 50 | 100 | |
| Age, Continuous | Years | 30.7 (SD 13.4) | 33.2 (SD 12.2) | 32.0 (SD 12.9) |
| Sex: Female, Male: Female | Participants | 23 | 24 | 47 |
| Sex: Female, Male: Male | Participants | 27 | 26 | 53 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 50 | 50 | 100 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Region of Enrollment: Germany | participants | 50 | 50 | 100 |
6. Primary Endpoint
The registry lists the primary outcome as Pain on Movement, measured over 48 hours.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | mm |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is pain on movement, reported as change from baseline at 48 hours. It is measured on a 100 mm visual analog scale, with 0 anchored as no pain and 100 as extreme pain. A visual analog scale converts a participant’s position along a continuum into a numerical score, allowing the average score or change in score to be compared across groups. The registry record identifies the endpoint as a mean and reports standard deviations for each group.
Pain on movement is relevant to the stated study question because the trial focused on acute ankle sprains and pain relief. Measuring change from baseline is intended to account for each participant’s starting score when describing subsequent pain. However, the registry record does not give baseline group means or specify whether the change was calculated as the 48-hour score minus baseline or baseline minus the 48-hour score. That missing sign convention matters when translating the numerical direction into a description of improvement.
The endpoint is continuous: its values can take a range of positions on the scale rather than representing only categories such as improved or not improved. A mean comparison describes average group outcomes, but does not show how many participants experienced a particular degree of change. No secondary outcomes are posted in the registry record.
7. Results Posted in the Registry
- Diclofenac Potassium 25 mg Tablet: mean 31.30 versus 59.20 on control; difference -27.90 (95% CI -34.20 to -21.60), standardized effect d = -1.73; z-test p = <0.001.
Mean difference: Diclofenac Potassium 25 mg Tablet
95% CI: -34.20 to -21.60
Recalculated from the posted summary statistics
8. Statistical Interpretation
At 48 hours, the reported mean pain-on-movement change was 31.3 mm in the diclofenac group and 59.2 mm in the placebo group. The unadjusted recalculated mean difference, expressed as diclofenac minus placebo, was -27.9 mm. Its confidence interval extends from -34.2 to -21.6 mm, and the unadjusted p-value is <0.001. These values describe the posted group-level contrast on the stated scale; they do not describe the result for every participant.
The negative sign indicates that the diclofenac group’s reported mean was lower than the placebo group’s mean under the comparison’s stated ordering. Because the endpoint is described as change from baseline but the direction used to compute change is not specified, the registry record does not establish from the endpoint description alone whether a lower change value corresponds to a larger reduction in pain. The scale anchors identify the meaning of scores, but do not resolve the sign convention for change.
The standard deviation was 18.8 mm in the diclofenac group and 12.8 mm in the placebo group. Standard deviation describes the spread of individual values around a group mean. It is not the uncertainty in the mean difference; the confidence interval addresses uncertainty in the estimated contrast. The group summaries give some information about variability, but not the full distribution of scores or changes. In particular, they do not identify outliers, skewness, or how much the groups’ individual values overlap.
The unadjusted p-value is evidence against a statistical model in which there is no group difference, assuming the analysis and its assumptions are appropriate. It is not the probability that the null hypothesis is true, nor a measure of how important a difference is to participants. The confidence interval also conveys uncertainty about the mean contrast; its endpoints are both negative. Neither the p-value nor the interval establishes clinical importance, which would require context such as a meaningful-change threshold. Such a threshold is not reported in the registry record.
The comparison is a recalculated unadjusted result from the posted summary statistics, and the record reports no discrepancy. A detailed sponsor analysis is not posted: the number of analysis records is 0. The recalculated comparison therefore should be understood as a summary-statistic estimate, not as a substitute for an unavailable detailed analysis report. The registry record does not provide adjusted estimates, a prespecified statistical analysis plan, or analysis-population definitions.
These results concern one endpoint at 48 hours in this completed trial. They do not establish how scores differed at other time points, how durable any difference was, or how findings apply outside the participants represented in the trial. The record also lacks detail about missing outcome data and participant characteristics, so the extent to which the reported summaries represent all randomized participants cannot be determined from the registry record.
9. Statistical Methods Explained
What does a mean difference describe?
A mean difference compares the average outcome in one group with the average in another. Here, the comparison is diclofenac minus placebo: the reported group means are 31.3 mm and 59.2 mm, and the resulting unadjusted mean difference is -27.9 mm. The unit remains millimeters because the original endpoint is a score on a millimeter scale. The sign depends on the order of subtraction. A negative value means the first group’s reported mean is numerically lower than the second group’s reported mean; by itself, it does not explain the meaning of change from baseline when the sign convention for change is unspecified.
A mean difference retains the original scale, which can help readers relate the contrast to the endpoint’s measurement range. It is a group-average contrast, not a statement that each participant had a change of that size. Participants can have different scores and changes, and a group mean compresses those individual results into one summary.
Why report standard deviations?
The standard deviations are 18.8 mm for diclofenac and 12.8 mm for placebo. Standard deviation describes how dispersed observations are around their group mean. Larger spread indicates that values are more varied around the average, whereas smaller spread indicates that values are more clustered. It is not a confidence interval and does not directly state how precisely the group mean or difference has been estimated. Precision also depends on the amount of information contributing to the estimate.
The registry record reports 50 participants for each group with the endpoint summaries. It does not give participant-level values or distribution plots in its textual outcome details. Standard deviations alone cannot reveal whether the distributions are symmetric, whether there are unusual values, or how much participants in the groups had similar outcomes.
What does the confidence interval add?
A confidence interval gives a range of values compatible with the observed data under the method used to estimate it. In repeated use of the same procedure under its assumptions, intervals would vary from sample to sample; the interval is not a guarantee that the true effect lies within its particular endpoints. The reported interval for the mean difference runs from -34.2 to -21.6 mm. The confidence level and full interval method are not reported in the registry record.
The interval communicates uncertainty and direction together. Both endpoints are negative, so the reported range does not include zero. That statement concerns the numerical contrast, not whether its magnitude is important to participants. The registry record does not identify a threshold for clinical importance, and the interpretation of the change direction is limited by the missing sign convention.
How should the p-value be understood?
The reported unadjusted p-value is <0.001. In general, a p-value describes how unusual data at least as extreme as those observed would be under a specified null model and statistical assumptions. It is not the probability that the null model is true, and it does not measure the size or practical importance of an effect. The word unadjusted indicates that the value is not presented as adjusted for other variables or for multiple comparisons. The registry record does not describe the full test procedure or a multiplicity plan.
The comparison is a simple unadjusted recalculation from the posted summary statistics. The record reports no discrepancy. The result is presented as a mean difference with a confidence interval, rather than as a detailed model-based analysis. The registry record lists 0 analysis records, so a full statistical analysis report is not available in the record. It does not report whether any prespecified covariate adjustment, sensitivity analysis, or alternative model was used.
What does the standardized contrast mean?
The recalculated standardized mean difference is d = -1.735. A standardized mean difference expresses a contrast relative to a measure of outcome variability, so it has no millimeter unit. The direction follows the ordering of the comparison, with diclofenac first and placebo second. Standardization can help describe the magnitude relative to spread, but it does not replace the original-scale mean difference and does not establish clinical importance. The registry record does not report a threshold for interpreting this standardized value.
Statistical methods rely on assumptions about the outcome and its sampling behavior. For a continuous endpoint, a mean-based comparison is most straightforward when the mean is meaningful and the analysis handles uncertainty appropriately. The registry record does not provide diagnostic checks, participant-level data, or a detailed description of assumptions. General concerns about distribution shape, dependence, and missing values therefore cannot be assessed from the posted summary alone. No evidence of over-dispersion or a count model is reported; those concepts are not central to this continuous mean endpoint.
10. Confidence Intervals and Precision
The reported confidence interval for the mean difference ranges from -34.2 to -21.6 mm, around the point estimate of -27.9 mm. It gives a range of uncertainty for the contrast on the endpoint’s original scale. Because the interval endpoints are both negative, the range is entirely on the negative side of zero under the stated diclofenac-minus-placebo ordering. The exact confidence level and the method used to construct the interval are not reported in the registry record.
Precision is different from the magnitude of an estimate. A confidence interval can be used to judge how narrowly or broadly the data locate a group difference, given the method’s assumptions. It does not tell whether the difference matters to participants. The record does not state a clinically meaningful difference threshold, so clinical importance cannot be inferred from the interval alone.
Each group has a reported denominator of 50 for the endpoint. The standard deviations are 18.8 mm for diclofenac and 12.8 mm for placebo. These values describe spread among observations, while the interval describes uncertainty in the estimated group contrast. The registry record does not provide participant-level information, baseline distributions, missing-data details, or the confidence-interval method, limiting independent assessment of how the estimate was constructed.
The p-value is reported as <0.001, which is consistent with the interval lying away from zero under conventional testing approaches, although the full analysis procedure is not described. Precision should therefore be read alongside the endpoint definition and the limitations in analysis reporting. A numerically precise estimate does not establish generalizability or clinical relevance.
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.
| Effect to detect | Participants per arm, 80% power | Participants per arm, 90% power |
|---|---|---|
| 100% of the observed effect | 6 | 7 |
| 75% of the observed effect | 10 | 13 |
| 50% of the observed effect | 21 | 28 |
The planning figures are participants per arm, not total events. They are hypothetical planning illustrations based on the observed mean difference, not the trial’s own original design assumptions. The assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. The original trial’s sample-size justification and design assumptions are not reported in the registry record.
For planning for 100% of the observed effect, the illustration gives 6 participants per arm for 80% power and 7 participants per arm for 90% power. For planning for 75% of the observed effect, it gives 10 participants per arm for 80% power and 13 participants per arm for 90% power. For planning for 50% of the observed effect, it gives 21 participants per arm for 80% power and 28 participants per arm for 90% power.
In general, power is the chance that a planned study will detect an effect of the size specified by its assumptions, if that effect is present and the assumptions hold. The 80% and 90% columns describe different target probabilities of detecting the assumed effect; they are not results observed in this trial. A smaller effect is harder to distinguish from random variation and therefore needs more participants under otherwise similar assumptions. These values are not observed power.
The planning curve should be read as a visual version of the same relationship between assumed effect size and required participants per arm under the stated assumptions. It does not show the number actually enrolled or prove that the original trial was planned using these values. The registry record reports enrollment of 100, with outcome summaries for 50 participants in each group, but its own sample-size justification is not reported.
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 z1−α/2 = 1.960) and the desired power (z1−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
- Observed difference Δ = -27.900; pooled standard deviation σ = 16.082.
- n = 2 × (1.96 + 0.842)2 × 16.0822 / -27.9002 = 5.2, rounded up to 6 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 <- -27.9 # observed difference in means
sigma <- 16.0822883943797 # 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(1666197)
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 = 6 (80% power), 7 (90% power)
75% of observed effect: n per arm = 10 (80% power), 13 (90% power)
50% of observed effect: n per arm = 21 (80% power), 28 (90% power)
power.t.test: 6.3
Simulated power at n = 6 per arm: 0.769 (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 record lists one outcome measure and no posted secondary outcomes. The primary outcome is pain on movement at 48 hours. It also lists 0 analysis records. The lack of posted secondary outcomes does not establish that the study collected no other measurements; it means additional outcomes are not reported in the registry record. The record does not describe a prespecified hierarchy of outcomes or a multiplicity adjustment plan.
Multiplicity arises when several outcomes, time points, subgroups, or analyses are tested. In general, conducting more tests can increase the chance of at least one apparently unusual result even when no true effects exist. Whether that concern applies to unposted analyses cannot be assessed from this record. The reported p-value is unadjusted, and no adjustment procedure is reported.
The registry record provides group denominators with the primary outcome summaries, but it does not report the analysis population definition. It is therefore not clear from the record whether the summary follows an intention-to-treat, per-protocol, or other approach. The number randomized, treated, and included in the outcome analysis is not separately described beyond enrollment of 100 and reported endpoint groups of 50 each.
Missing-data methods are also not reported in the registry record. There is no description of how absent 48-hour measurements were handled, whether any participants withdrew, or whether sensitivity analyses considered missing outcomes. Missingness can affect interpretation if the availability of measurements relates to participants’ outcomes or treatment group. Without details on completeness and handling, the extent of any such concern cannot be assessed.
The record does not report a statistical analysis plan, covariate-adjusted estimates, subgroup analyses, interim analyses, or methods for handling protocol deviations. Those features should not be assumed to have been used or omitted in the conduct of the trial solely because they are not described. Their status is not reported in the registry record.
14. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Diclofenac Potassium 25 mg Tablet | 0 | 50 | 0.0% |
| Placebo | 0 | 50 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 2% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Diclofenac Potassium 25 mg Tablet | 1 of 50 |
| Placebo | 3 of 50 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Diclofenac Potassium 25 mg Tablet | Placebo |
|---|---|---|---|
| Headache | Nervous system disorders | 0 of 50 | 2 of 50 |
| Rhinorrhoea | Respiratory, thoracic and mediastinal disorders | 1 of 50 | 0 of 50 |
| Feeling hot | General disorders | 0 of 50 | 1 of 50 |
For serious adverse events, the reported number affected is 0 among 50 participants at risk in the diclofenac group and 0 among 50 participants at risk in the placebo group. These are counts from the registry record; they do not show that no adverse event of any kind occurred. The record also lists other, non-serious adverse events affecting 1 participant in the diclofenac group and 3 participants in the placebo group.
Counts should be read with their group denominators and with attention to the type of event being counted. A zero count means no affected participants were recorded for that category in the posted data; it does not prove that the underlying risk is zero. The registry record does not provide the serious-event terms, and no top serious-event terms are listed. Death counts are not reported in the registry record.
The safety figures do not establish comparative safety on their own. The record does not describe event definitions, timing, severity details beyond the serious versus other distinction, follow-up completeness, or how events were collected. No interpretation about treatment choice should be based on these counts alone.
15. What the Result Does, and Does Not, Mean
The posted primary outcome summaries show a lower numerical mean change in pain on movement for diclofenac than for placebo at 48 hours: 31.3 mm compared with 59.2 mm. The unadjusted recalculated difference is -27.9 mm, with a confidence interval from -34.2 to -21.6 mm and an unadjusted p-value of <0.001. The estimate is a group average on a 100 mm scale, not an individual-level prediction.
The sign convention for change from baseline is not reported in the registry record. Although the scale anchors define low and high pain scores, they do not explain whether the reported change subtracts baseline from follow-up or follow-up from baseline. That limits a direct verbal interpretation of the direction as improvement or worsening. The numerical group contrast and its ordering remain clear, but the endpoint’s change coding is not.
The result does not establish clinical importance because no meaningful-change threshold is reported. Statistical evidence against a no-difference model and clinical importance are separate questions. Nor does a mean difference reveal how many participants experienced a large change, little change, or a change in the opposite direction. Individual participant results and responder outcomes are not reported.
The finding applies to the primary outcome at the reported 48-hour timeframe in the participants represented by the registry summaries. It does not provide evidence about outcomes at other times, longer-term effects, or people outside the study population. Eligibility criteria and participant characteristics are not reported, and analysis-population and missing-data details are unavailable.
The safety record lists no serious adverse events in either group, alongside other adverse events affecting 1 participant with diclofenac and 3 with placebo. These small reported counts and the lack of detailed event information do not establish that one treatment is safer. The registry results describe what was posted for this trial, rather than providing medical advice or a complete account of benefits and harms.
16. Why This Trial Matters Statistically
This trial is statistically informative because its primary outcome is a continuous pain measure and its registry record reports group means, standard deviations, a mean difference, a confidence interval, and a p-value. Together, these summaries distinguish the estimated size and direction of a group-average contrast from the uncertainty around it. The original millimeter scale also keeps the main estimate interpretable in the units used to measure pain on movement.
The record illustrates why endpoint definitions matter. A change-from-baseline measure needs a clear subtraction convention before its sign can be translated into improvement or worsening. The scale anchors alone are not enough to establish the direction of change. This distinction is important even when an estimate is accompanied by a small p-value and an interval that does not include zero.
The trial also shows the difference between a result and a planning calculation. The hypothetical participant requirements use the observed effect and stated planning assumptions; they are not evidence about the power of the completed trial or its original design. The registry record does not report its own sample-size justification, analysis plan, or analysis-population definitions.
Finally, the limited reporting is itself relevant to statistical interpretation. A reader can describe the posted primary comparison and serious adverse-event counts, but cannot assess missing-data handling, the exact analysis procedure, or the extent of other analyses from this record. Clear definitions and fuller analysis reporting are necessary to connect a numerical estimate to its intended interpretation and scope.
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 primary endpoint is described as change from baseline, but the registry record does not state the subtraction convention. This creates ambiguity when translating the sign of the mean difference into a direction of change in pain. Baseline group summaries are not reported, so the change summaries cannot be independently related to starting scores.
The registry record does not describe eligibility criteria or participant characteristics beyond acute ankle sprains. Generalizability to other populations or settings therefore cannot be assessed from these summaries. Although enrollment is 100 and the endpoint groups each contain 50 participants, the record does not separately identify the number randomized, treated, or included in the analysis.
Analysis details are limited. The record lists 0 analysis records and does not report an analysis plan, confidence-interval method or confidence level, covariate adjustment, missing-data handling, or sensitivity analyses. The posted comparison is an unadjusted recalculation from summary statistics. No discrepancy is reported, but participant-level data are unavailable for independent analysis.
The confidence interval and p-value quantify statistical uncertainty under the methods used, but the full methods are not reported. A threshold for clinical importance is also absent. Individual outcome distributions and responder counts are not posted, so the group means and standard deviations cannot show how many participants experienced changes of different sizes.
Safety reporting is similarly limited: serious-event counts are given, but event terms are not listed, and death counts are not reported. Details about event definitions, ascertainment, timing, and completeness are not reported in the registry record. The record’s description of masking also differs between the quadruple-masking field and the double-blind official title, without specifying who was masked.
18. Related Tutorials
19. Related Statistical Calculators
20. Sources
- ClinicalTrials.gov: Efficacy and Safety of Diclofenac Potassium 25 mg Tablet Taken Three Times Daily in Subjects With Acute Joint Pain — NCT01666197.
- Registry record last updated 2014-04-17; status last verified 2014-03.
- Results first posted 2014-03-27.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
21. Record Summary
NCT01666197 is a completed, randomized, phase 4, placebo-controlled parallel-group study sponsored by Novartis. The registry record identifies acute ankle sprain as the condition and lists diclofenac potassium 25 mg tablet taken three times daily and placebo as the study interventions. Enrollment was 100, with 50 participants in each group represented in the primary outcome summaries.
The primary endpoint was change from baseline in pain on movement at 48 hours on a 100 mm visual analog scale. The reported group means were 31.3 mm for diclofenac and 59.2 mm for placebo. The unadjusted recalculated mean difference was -27.9 mm, with a confidence interval from -34.2 to -21.6 mm and p <0.001. The sign convention for change is not reported in the registry record.
Serious adverse events affected 0 participants in each group. The registry record does not provide a detailed analysis plan, missing-data methods, or analysis-population definitions.