A Prospective Multi-center Study on Total Hip Arthroplasty With E1: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Prospective Multi-center Study on Total Hip Arthroplasty With E1 (NCT01883492), a randomized na study. The primary outcome is Polyethylene Wear Between Immediate Postoperative and 2 Year Postoperative Period.

2. Clinical Question

3. Trial Design

The registry describes a prospective, multicenter, randomized study of total hip replacement with E1. It lists a parallel-group model and single masking. The record does not identify who was masked, so the masking description does not establish whether participants, clinicians, assessors, or another group were unaware of assignment. The trial concerns hip osteoarthritis and compares two femoral head materials while using an E1 highly crosslinked polyethylene liner in both described arms.

The registry lists enrollment of 153 and identifies Zimmer Biomet as the sponsor. The study start date is 2013-03-11, and the primary completion date is 2019-02-06. Its status is terminated. The phase is listed as NA, and the record describes device interventions, including a femoral stem, acetabular cup, and acetabular liner.

The primary outcome concerns x-ray-based vector wear through the 2-year postoperative period. The endpoint population is described as participants with an available x-ray at the 2-year follow-up visit. The outcome summaries list 57 participants for the Biolox delta head group and 63 for the CoCr head group. Those are the reported group sizes for this outcome, not a complete account of participant flow through the study. Reasons for unavailable imaging, withdrawal, or missing follow-up information are not reported in the registry record.

Secondary outcomes include Harris Hip Score and WOMAC Osteoarthritis Index assessments at postoperative follow-up visits. The registry does not report the original sample-size justification, detailed allocation procedures, or a full statistical analysis plan. It also does not report why the study was terminated. These omissions limit what can be inferred about the intended design and conduct beyond the listed randomized, single-masked, parallel-group description.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Participants, whose x-ray taken at 2 year follow-up visit being available.

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 Polyethylene Wear Between Immediate Postoperative and 2 Year Postoperative Period, measured over Immediate postoperative and 2 year postoperatively.

The primary endpoint is mean polyethylene wear between the immediate postoperative period and the 2-year postoperative period. The registry defines wear as vector movement, calculated from the difference in femoral prosthetic head positions on x-rays at those time points. It is reported in millimeters as a mean with a standard deviation. The endpoint is based on participants whose 2-year follow-up x-ray was available.

In general, a change in component position on imaging can be used to quantify movement over time. The registry describes this endpoint as a measured value with no lower or upper limit and notes that it can be negative. A negative result therefore remains a possible measured value under the registry's definition; it should not automatically be interpreted as an error or as a value that has been truncated at zero.

The comparison addresses whether the mean measured wear differs between the Biolox delta and CoCr head groups when each is paired with the E1 liner. The posted summaries report a mean of 0.42 millimeter for the Biolox delta group and 0.15 millimeter for the CoCr group. This imaging measure is distinct from the clinical scores reported as secondary outcomes. It describes a radiographic change over the specified period and does not by itself summarize symptoms, function, or every aspect of the clinical course.

7. Results Posted in the Registry

• CoCr Head: mean 0.15 versus 0.42 on control; difference -0.27 (95% CI -0.60 to 0.06), standardized effect d = -0.30; z-test p = 0.108.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Harris Hip Score at 6 Month Follow-up Visit

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • CoCr Head: mean 92.61 versus 92.67 on control; difference -0.06 (95% CI -2.98 to 2.86), standardized effect d = -0.01; z-test p = 0.968.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between CoCr Head and the control. The interval gives the range of effects that remain compatible with the data.

Harris Hip Score at 1 Year Follow-up Visit

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • CoCr Head: mean 94.52 versus 95.23 on control; difference -0.71 (95% CI -2.99 to 1.57), standardized effect d = -0.11; z-test p = 0.543.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between CoCr Head and the control. The interval gives the range of effects that remain compatible with the data.

Harris Hip Score at 2 Year Follow-up Visit

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • CoCr Head: mean 96.28 versus 96.15 on control; difference 0.13 (95% CI -1.89 to 2.15), standardized effect d = 0.02; z-test p = 0.900.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between CoCr Head and the control. The interval gives the range of effects that remain compatible with the data.

The registry names Harris Hip Score and WOMAC Osteoarthritis Index outcomes at postoperative follow-up visits, including 6 months, 1 year, 2 years, and 3 years. The posted numerical summaries in the available record cover Harris Hip Score at 6 months, 1 year, and 2 years. Across those summaries, the group means are close, and the unadjusted comparisons do not resolve a clear difference. The registry does not report numerical summaries for the remaining listed secondary outcomes in the material available for this analysis.

These clinical-score measures address a different aspect of follow-up from the primary imaging endpoint. The primary outcome measures vector movement on x-rays, while the secondary score outcomes describe patient-reported or clinical assessment domains as named in the registry. Similar patterns across the posted Harris Hip Score summaries may provide context, but they do not validate the imaging result or establish that the groups are equivalent on either type of measure.

The secondary estimates carry less evidential weight because several outcomes and follow-up times are listed, creating multiple opportunities to observe an apparently notable result by chance. In general, multiple testing increases the chance of false-positive findings unless the analysis plan accounts for it. The registry record does not report a multiplicity adjustment or a prespecified hierarchy for interpreting secondary outcomes. The posted secondary comparisons are unadjusted recalculations, and reported sponsor analyses are not listed.

The record lists 12 secondary outcomes as posted, but the registry does not provide a complete sponsor analysis for them. Without a stated testing strategy and fuller results, secondary findings are best treated as descriptive and exploratory context rather than as independent confirmation of the primary outcome. No claim about the unreported WOMAC or 3-year results can be made from the record.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Harris Hip Score at 6 Month Follow-up Visit
• Harris Hip Score at 1 Year Follow-up Visit
• Harris Hip Score at 2 Year Follow-up Visit
• Harris Hip Score at 3 Year Follow-up Visit
• WOMAC Osteoarthritis Index at 6 Month Follow-up Visit
• WOMAC Osteoarthritis Index at 1 Year Follow-up Visit
• WOMAC Osteoarthritis Index at 2 Year Follow-up Visit
• WOMAC Osteoarthritis Index at 3 Year Follow-up Visit

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: each participant contributes a measured vector-wear value in millimeters, and the group summaries are means with standard deviations. The comparison is the difference between the CoCr head mean and the Biolox delta head mean. In general, a mean difference preserves the outcome's original units, which makes its direction and scale interpretable in millimeters. Here, the posted mean difference is -0.27 millimeter.

What does the standard deviation describe?

In general, standard deviation describes how dispersed individual measurements are around their group mean. It is not the same as a standard error or a confidence interval. The primary-outcome standard deviations are 1.08 millimeters for the Biolox delta group and 0.7 millimeter for the CoCr group. A large spread relative to the difference in means means that participant-level measurements vary substantially in relation to the group contrast. The standard deviation alone does not show whether that variation comes from a few extreme measurements, a broad distribution, or another pattern; distributional detail is not reported in the registry record.

How should the mean difference be read?

The comparison is oriented as CoCr minus Biolox delta. The group means are 0.15 millimeter and 0.42 millimeter, respectively, and the resulting posted contrast is -0.27 millimeter. The sign indicates the direction of the observed contrast under that ordering. It is not a clinical judgment about which group is preferable. In general, a difference in means is a summary of group averages and does not imply that each participant in one group had a lower measurement than each participant in the other.

What does the p-value contribute?

The posted p-value is unadjusted and equals 0.108. In general, a p-value describes how compatible the observed data are with a specified null model, under the assumptions of the statistical test. It is not the probability that the null hypothesis is true, nor does it measure the probability that the result will replicate. Because the registry record does not report a sponsor analysis or its testing procedure, the unadjusted p-value associated with the recalculated comparison should not be treated as a complete account of the trial's statistical analysis.

The p-value also does not convey the range of group differences compatible with the data. The confidence interval gives that complementary perspective: the interval for the primary mean difference crosses zero, so the record does not resolve the direction of the underlying difference with precision. General statistical interpretation considers the estimate, its interval, the outcome scale, and the study context together rather than using the p-value alone.

Why does variability matter?

In general, more variable measurements make a group mean less precise when other features of the study are held constant. The standard error reflects uncertainty in a mean estimate and depends on both variability and the number of observations. The primary summaries list 57 participants in the Biolox delta group and 63 in the CoCr group. The recalculated comparison uses the posted means, standard deviations, and group sizes. The registry record does not specify whether the sponsor used covariate adjustment, a particular model, or additional handling of the imaging data.

Over-dispersion is a term generally used when observed variation exceeds what a statistical model assumes. This is relevant when a model's uncertainty estimates depend on assumptions about the distribution of the data. The registry does not report a distributional assessment or an over-dispersion analysis for this continuous endpoint. It is therefore not possible to determine from the record whether such a concern was evaluated. The general point is that a model that understates variability can produce confidence intervals that are too narrow, while a model that accommodates the observed variability can give more realistic uncertainty.

What is and is not reported about the analysis?

The record describes the outcome as a mean with standard deviation and gives the endpoint timeframe and population. It does not report the original statistical analysis plan, a sponsor-reported primary analysis, or the method used to handle missing x-rays. The available comparison is an unadjusted recalculation from the posted summary statistics. This makes it useful for understanding the simple difference between the posted group means, but it cannot reveal whether the trial's planned analysis used other methods.

Randomization is intended in general to make treatment groups comparable on average, including for characteristics that were not measured. It does not ensure that the groups are identical in a particular realized trial, nor does it address bias that might arise after randomization through missing outcomes or analysis choices. Details about random sequence generation, concealment, and analysis by assigned group are not reported in the registry record. The randomized designation is thus important context, but it does not answer every methodological question.

Finally, the primary outcome is restricted to participants with an available x-ray at the 2-year visit. In general, restricting an analysis to observed outcomes can affect interpretation if the reasons outcomes are missing are related to the measurement or group assignment. The record does not describe the extent, reasons, or statistical handling of missing imaging. No assumption about those mechanisms can be made from the posted summaries alone.

11. Confidence Intervals and Precision

The primary mean difference is -0.27 millimeter, with a confidence interval that crosses zero. In general, a confidence interval is a range of estimates compatible with the observed data under the method used to construct it. It conveys uncertainty about the mean difference more directly than the point estimate alone. Because this interval includes zero and extends to values on either side, the posted result does not pinpoint the direction of the underlying group difference.

The interval also matters for considering magnitude. A point estimate is one value drawn from a range of estimates consistent with the data; it should not be treated as an exact measurement of the true effect. The interval allows for a range of possible group differences, and its inclusion of zero means that a zero difference is among the values compatible with the analysis. The registry does not report a threshold for a clinically important difference, so the interval cannot be classified against such a threshold from this record.

Precision depends on the variability of measurements and the amount of information available. The primary summaries list standard deviations of 1.08 millimeters and 0.7 millimeter, with outcome group sizes of 57 and 63. These characteristics contribute to the uncertainty in the comparison. The registry does not report a sponsor analysis or explain whether any additional modeling was used; the interval belongs to the unadjusted recalculation based on the posted summary statistics.

A confidence interval is not a guarantee that the true value lies within its bounds, and it is not a statement that every value inside the interval is equally plausible. In general, its interpretation depends on the statistical method and assumptions. The uncertainty in this result should be read together with the terminated status, the endpoint's available-x-ray population, and the missing-data details that are not reported in the registry record.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm, not total participants and not total events. They use the assumptions stated for the planning illustration: a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The target effect is set to a stated fraction of the observed effect. These are planning illustrations computed from the observed effect, not the trial's own original design assumptions; those original assumptions are not reported in the registry record.

The 80% power column gives the estimated participants per arm for a design with an 80% chance of detecting the assumed effect under the planning assumptions, if that effect and those assumptions were true. The 90% power column gives the corresponding planning figure for a 90% chance. Power is a design property under specified assumptions; it is not a probability that the observed result is correct.

For example, planning for 100% of the observed primary effect gives 175 participants per arm for 80% power and 234 participants per arm for 90% power. Planning for 50% of the observed effect gives 699 participants per arm for 80% power and 936 participants per arm for 90% power. The smaller assumed effect calls for more participants because it is harder to distinguish from ordinary sampling variation. The figures are not observed power for this completed trial, and they do not show what power the original study was designed to achieve.

These estimates depend on the observed effect, so they are sensitive to the uncertainty in that effect. If the observed difference is not a reliable guide to a future effect, the resulting planning figures may also be an unreliable guide. The planning display should therefore be read as an illustration of how sample size changes under the stated assumptions, not as a definitive recommendation for a future study.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -0.270; pooled standard deviation σ = 0.901.
2. n = 2 × (1.96 + 0.842)² × 0.901² / -0.270² = 174.6, rounded up to 175 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 <- -0.27                      # observed difference in means
sigma <- 0.900557266269341                     # 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(1883492)
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 = 175 (80% power), 234 (90% power)
 75% of observed effect: n per arm = 311 (80% power), 416 (90% power)
 50% of observed effect: n per arm = 699 (80% power), 936 (90% power)
power.t.test: 175.6 
Simulated power at n = 175 per arm: 0.800 (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.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists multiple secondary outcomes, including Harris Hip Score and WOMAC Osteoarthritis Index measurements at several follow-up times. When multiple outcomes or time points are examined, the chance of at least one apparently notable result can increase. In general, statistical plans can address this through prespecified primary and secondary testing hierarchies or multiplicity adjustments. Such methods and any planned hierarchy are not reported in the registry record. The posted secondary comparisons are unadjusted recalculations, so they should not be interpreted as if a multiplicity strategy had been applied.

The registry does not report a detailed statistical analysis plan, the original sample-size justification, or interim analyses. It does not list sponsor-reported analyses for the outcomes discussed. Consequently, the analysis population, covariate adjustments, handling of repeated measurements, and any decision rules for interpreting multiple outcomes are not reported in the registry record. The record's randomized designation does not by itself answer these analysis questions.

For the primary outcome, the registry describes the population as participants with an available x-ray at the 2-year follow-up visit. It does not report how many participants lacked the relevant imaging, why images were unavailable, or how missing outcomes were handled. In general, missingness can affect an estimate if availability is related to the outcome or differs systematically by group. The available summaries cannot establish whether missingness was unrelated to outcome or treatment group.

The record also does not specify whether the analysis followed assigned groups regardless of treatment received, whether participants were excluded for protocol deviations, or whether other analysis populations were used. These details are not reported in the registry record. The primary comparison should therefore be read as an unadjusted comparison of the posted summaries, not as a fully documented intention-to-treat or per-protocol analysis.

15. 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.

Most frequent non-serious adverse event terms

The registry reports serious adverse events for 0 of 62 participants at risk in the Biolox delta head group and 0 of 67 participants at risk in the CoCr head group. It lists no serious adverse-event terms. Deaths are reported as 0 in each group. These are the counts recorded for the groups and risk denominators specified in the registry; they are not evidence that the true risk is zero.

Other adverse events are listed for 2 of 62 participants at risk in the Biolox delta group and 1 of 67 in the CoCr group. The registry does not provide event terms in the listed safety summary, so the nature, severity, relatedness, and timing of these other events are not reported in the registry record.

In general, zero observed events do not rule out uncommon events, particularly when the available safety information covers a limited number of participants. The registry does not report comparative statistical testing for adverse events or describe how safety follow-up was handled after termination. These counts should be read as recorded observations, not as a complete assessment of comparative safety.

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

The primary summaries show a lower mean vector-wear value in the CoCr head group than in the Biolox delta head group. The unadjusted mean difference was -0.27 millimeter, and its confidence interval crosses zero. The data therefore leave uncertainty about the direction and magnitude of the underlying group difference. The result does not establish that the groups are the same, and it does not establish a reliable difference between them.

The endpoint is a specific radiographic measure: the difference in femoral prosthetic head position between immediate postoperative imaging and the 2-year postoperative period. It is not a complete measure of hip function, symptoms, overall implant performance, or every potential adverse outcome. The registry also reports clinical score outcomes, but their presence does not turn the imaging endpoint into a comprehensive measure of clinical benefit.

The study is described as randomized, but the available record does not report the detailed randomization procedures or analysis plan. Its status is terminated, and the reason is not reported in the registry record. The primary population is limited to participants with an available 2-year x-ray, while the missing-data process is not described. These features matter when considering how far the observed summaries can be generalized.

The results should not be interpreted as evidence that either head material is superior, that they are equivalent, or that one is safer. The posted data support a description of the observed means and uncertainty for the specified imaging outcome. They do not answer questions about unreported outcomes, missing measurements, the reason for termination, or the clinical importance of a particular difference.

17. Why This Trial Matters Statistically

This trial raises a useful statistical distinction between a measured difference and a well-resolved difference. The primary group means are not identical, but the unadjusted confidence interval crosses zero. The point estimate gives the observed direction and size of the contrast; the interval shows that the data do not precisely settle the underlying difference. Both are needed to describe the result responsibly.

The endpoint also illustrates why the measurement definition matters. Vector wear is based on change in femoral head position on x-rays and can be negative under the registry's definition. Treating it as a generic positive-only wear quantity would misrepresent the specified measure. The reported standard deviations further show that the individual measurements vary around the group means, an important part of interpreting a continuous outcome.

The record provides a randomized comparison, but several elements needed to understand the strength of the evidence are not reported: the original design assumptions, sponsor analysis, missing-data handling, and multiplicity strategy. These gaps are especially relevant because the primary analysis population depends on available follow-up imaging and the registry lists multiple secondary outcomes. Statistical interpretation is not just a matter of reading a p-value; it also depends on the population analyzed, uncertainty, and the prespecified analysis framework.

Finally, the planning illustrations demonstrate how required sample size changes when the effect to detect is smaller. They are based on the observed effect and stated general planning assumptions, not the trial's original design. Their value is explanatory: they show the consequences of assumptions, not the probability that this particular study detected a true effect.

18. 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 outcome is restricted to participants with an available x-ray at the 2-year follow-up visit. The registry does not report the extent or reasons for unavailable imaging, participant flow by group, or how missing outcomes were handled. Because availability may affect which observations contribute to the mean, the posted comparison may not represent all randomized participants.

The trial status is terminated, but the reason for termination is not reported in the registry record. The record also does not report the original sample-size justification or the sponsor's statistical analysis for the primary outcome. The presented mean difference and p-value are unadjusted recalculations from summary statistics and should not be mistaken for a documented adjusted trial analysis.

The registry lists a single masking designation but does not identify who was masked. It does not describe random sequence generation, allocation concealment, protocol deviations, or the use of analysis populations. These details would help assess the conduct of the randomized comparison but cannot be inferred from the design labels alone.

There are multiple secondary outcomes and follow-up times, but a multiplicity strategy is not reported. Numerical results are not available in the record for all listed outcomes, including the WOMAC measures and later follow-up summaries. Safety reporting gives event counts but does not describe the nature of the other adverse events or provide comparative testing. These limits constrain conclusions about clinical outcomes and safety beyond the specific counts and summaries recorded.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: A Prospective Multi-center Study on Total Hip Arthroplasty With E1 — NCT01883492.
• Registry record last updated 2020-02-17; status last verified 2020-02.
• Results first posted 2020-02-17.
• 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.

22. Record Summary

The registry describes a prospective, multicenter, randomized, single-masked, parallel-group device study in hip osteoarthritis. It compares an E1 polyethylene liner used with a Biolox delta head against the same liner used with a CoCr head. Enrollment is listed as 153, the sponsor is Zimmer Biomet, and the study status is terminated.

The primary endpoint is mean vector polyethylene wear between immediate postoperative imaging and the 2-year postoperative period, among participants with an available 2-year x-ray. The posted group means are 0.42 millimeter for Biolox delta and 0.15 millimeter for CoCr; the unadjusted mean difference is -0.27 millimeter, with a confidence interval crossing zero and an unadjusted p-value of 0.108.

The registry does not report the reason for termination, the original design assumptions, a detailed analysis plan, or missing-data and multiplicity methods. The available results describe the posted summaries but leave uncertainty about the group difference and important aspects of the trial's analysis.