Gabapentin for Postop Pain After SSLF: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Gabapentin for Postop Pain After SSLF (NCT03123861), a randomized phase 4 study. The primary outcome is Pain During Normal Activities (Surgical Pain Scale Item 2).

2. Clinical Question

The clinical question is whether postoperative pain scores at seven days differ between participants assigned to gabapentin and those assigned to placebo after vaginal sacrospinous ligament fixation for apical pelvic organ prolapse. The registry describes overall pain during normal activities as the primary outcome and also records gluteal pain during normal activities and worst pain as secondary outcomes.

3. Trial Design

The registry describes a randomized, quadruple-masked, parallel-group phase 4 trial. It is marked completed, with enrollment of 45. The study start date is 2017-06-01 and the primary completion date is 2020-07-25. The sponsor is University of North Carolina, Chapel Hill.

The planned comparison was gabapentin versus placebo after vaginal sacrospinous ligament fixation. The intervention description specifies 300 mg of gabapentin for the first 3 postoperative days, followed by 300 mg twice a day for an additional 11 days. The placebo group was to take placebo for 2 weeks after surgery. Both groups were to receive standard-of-care pain medications, and participants were to be followed for 6 weeks after surgery.

The registry’s primary endpoint population is participants who underwent the surgery and had follow-up data at 7 days. The posted primary outcome summaries include 19 participants in the gabapentin group and 20 in the placebo group. Those endpoint counts are not the same as the adverse-event risk counts; the reason for the differing analysis populations or denominators is not reported in the registry record.

Randomization and masking describe features of the intended comparison, but the registry record does not describe the methods used to generate or conceal the assignment sequence or how masking was maintained. It also does not report the original sample-size justification, details of any interim analyses, or a full statistical analysis plan. Those omissions limit what can be inferred about the planned analysis beyond the design and outcome descriptions recorded.

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 who underwent sacrospinous ligament fixation surgery with follow-up data 7 days after surgery

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 Pain During Normal Activities (Surgical Pain Scale Item 2), measured over 7 days after surgery.

The primary endpoint is pain during normal activities, measured with item 2 of the Surgical Pain Scale at 7 days after surgery. The item asks about average pain during normal activity over the last 24 hours. The registry describes a scale from 1 to 10, with 10 representing the most intense or worst pain. The posted results summarize this continuous measure using a mean and standard deviation for each group.

This kind of patient-reported measure is used to capture pain in an everyday activity context, rather than only pain under a particular test condition. In general, the mean describes the group’s average score, while the standard deviation describes how spread out individual scores are around that average. Neither measure tells how any one participant felt, and group averages do not show the full distribution of responses.

The seven-day assessment is an early postoperative time point. Although the planned follow-up period was 6 weeks, the primary endpoint described in the registry is specifically the score at 7 days. Results at this time point should therefore be interpreted as evidence about the recorded measure at that time, not as a summary of the entire follow-up period or of pain at later times.

7. Results Posted in the Registry

• Gabapentin: mean 1.60 versus 3.20 on control; difference -1.60 (95% CI -2.92 to -0.28), standardized effect d = -0.75; z-test p = 0.018.

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.

Gluteal Pain During Normal Activities

• 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:
  • Gabapentin: mean 2.10 versus 3.40 on control; difference -1.30 (95% CI -2.68 to 0.08), standardized effect d = -0.59; z-test p = 0.066.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Gabapentin and the control. The interval gives the range of effects that remain compatible with the data.

Worst Pain (Surgical Pain Scale Item 4)

• 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:
  • Gabapentin: mean 2.40 versus 4.00 on control; difference -1.60 (95% CI -3.20 to 0.00), standardized effect d = -0.63; z-test p = 0.050.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Gabapentin and the control. The interval gives the range of effects that remain compatible with the data.

Across the posted secondary pain outcomes, the group means follow a consistent descriptive direction: the gabapentin group has lower mean scores than the placebo group. This pattern is broadly aligned with the direction of the primary comparison. It does not resolve the discrepancy between the sponsor’s reported primary analysis and the unadjusted recalculation, and it should not be treated as independent confirmation of the primary result.

Secondary outcomes add context about different aspects of pain, including gluteal pain during normal activities and worst pain. The registry also lists daily narcotic use as a secondary outcome, but the posted numeric secondary results described in the record do not include a result summary for that measure. The record identifies four outcome measures and four analyses, while three secondary outcomes are listed; the relationship between these counts and the full analysis set is not further explained.

Unadjusted secondary comparisons carry less weight because multiple outcomes create multiple opportunities for an apparently notable result. General statistical context: when many hypotheses are tested, the chance of at least one result appearing unusual by chance can increase. A multiplicity procedure can address that issue, but the registry record does not report whether any adjustment was planned or applied. The secondary results should therefore be regarded as exploratory unless a fuller analysis plan establishes otherwise.

The consistency of direction across pain measures is worth noting as a pattern, but it does not establish that the observed differences are robust or clinically important. The registry record does not report a threshold for meaningful change on these scales, and there is no reported adjustment that would support treating the secondary analyses as confirmatory. Their interpretation remains conditional on the endpoint definitions, available follow-up data, and the unresolved differences in reported analysis results.

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

• Gluteal Pain During Normal Activities
• Worst Pain (Surgical Pain Scale Item 4)
• Daily Narcotic Use

9. Statistical Interpretation

10. Statistical Methods Explained

The registry describes a two-sided t-test for the sponsor’s comparison. A separate recalculation uses the posted group summaries to estimate an unadjusted difference in means. These approaches address a related question but are not necessarily identical in all analytical details. Because the reported results differ, the sponsor’s own analysis takes precedence for interpreting the trial’s reported inferential result.

What does a difference in means describe?

For a continuous outcome, the difference in means compares the average score in one group with the average score in the other. In this comparison the recalculated contrast is defined as the gabapentin mean minus the placebo mean. A negative estimate means the recorded average score was lower in the gabapentin group. The estimate describes the observed contrast; by itself it does not establish why the groups differed or whether the result would persist in another sample.

The group standard deviations describe variability among the observed scores. A larger standard deviation indicates greater spread around the group mean. General statistical context: variability affects the precision of an estimated difference, because a noisy outcome makes it harder to distinguish a group contrast from ordinary participant-to-participant variation. The registry’s recalculation uses the posted standard deviations rather than assuming that all individuals have scores close to their group average.

What does the t-test assess?

A t-test evaluates how compatible the observed difference is with a null comparison of no mean difference, under the assumptions of the test. A two-sided test allows evidence in either direction; it does not prespecify that one group must have a higher or lower score. The sponsor reports a two-sided t-test and p = 0.09. The unadjusted recalculation reports p = 0.018. The disagreement means these p-values should not be blended or treated as interchangeable. The registry record does not report the full sponsor analysis specification needed to explain the difference.

General statistical context: a p-value is a measure of how unusual the observed data, or data more extreme, would be under a specified null model. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of a difference. The p-value also does not account for all possible design or data-quality limitations.

Why are variability and analysis details important?

The recalculation is based on means, standard deviations, and group sizes, which are summary statistics. It cannot recover individual participant data or check the distribution of scores, outliers, or patterns of missingness. General statistical context: the t-test is often used to compare means, but its interpretation depends on assumptions about the sampling process and the analysis. With limited group sizes, individual observations can have a noticeable influence on means and uncertainty estimates. The registry record does not provide participant-level data or a detailed diagnostic assessment.

Over-dispersion is a general concern for outcomes whose observed variability is greater than a model allows. In that situation, a model can understate uncertainty and give overly narrow intervals or small p-values. The posted endpoint is analyzed as a continuous measure with means and standard deviations; the registry does not report a separate over-dispersion assessment. This concept is not evidence that over-dispersion occurred in this trial.

The interval from the recalculation gives a range of values compatible with the summary-based analysis under its assumptions. A confidence interval communicates uncertainty about the estimated mean difference, whereas the standard deviation describes variation among participant scores. These are different quantities. The registry record does not state the confidence level for the displayed recalculated interval, so no confidence level should be inferred from the available record.

How should the planning calculations be understood?

The posted sample-size planning figures use the observed effect as a starting point and consider smaller fractions of it. They are planning illustrations, not part of the original trial design justification. The record does not report the trial’s own original sample-size assumptions. General statistical context: power is the chance that a planned study will meet a specified statistical criterion when a particular effect is present, under the assumptions used for planning. It depends on the assumed effect, variability, allocation, significance level, and analysis. A planning calculation cannot establish what the completed trial’s power was after observing its results.

The interpretation of any planning illustration depends on how well its assumptions represent a future study. In this case, the posted assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set to a stated fraction of the observed effect. The planning figures should therefore be read as conditional illustrations, not as a validated design recommendation. The original protocol’s rationale and any additional design considerations are not reported in the registry record.

11. Confidence Intervals and Precision

The recalculated primary mean difference is -1.6 units, with a confidence interval extending from -2.924 to a value just below zero. The interval conveys uncertainty about the estimated group contrast under the recalculation’s assumptions. Its lower limit is farther from zero than its upper limit, so the range includes both a more pronounced negative difference and a difference close to zero. The confidence level for this interval is not reported in the registry record.

General statistical context: a confidence interval is not a guarantee that the true value lies within the particular interval, nor does it show the range of individual participants’ scores. It describes the uncertainty of an estimate under a statistical procedure. The standard deviations in the group summaries describe variation among scores; they should not be read as confidence intervals for the mean difference.

The recalculated interval does not include zero, while the sponsor’s reported p-value is 0.09. That discrepancy is important to precision as well as to the overall interpretation: the available registry results do not support treating the recalculated interval as the sole account of uncertainty. The sponsor’s analysis is the primary reported analysis, but its interval and effect estimate are not reported in the registry record. Without those statistics and the details of the sponsor’s analysis, the precision of its estimated contrast cannot be assessed from the registry report.

For the secondary outcomes, the recalculated intervals are also relevant to uncertainty, but they do not replace the sponsor-reported analyses or address the issue of multiple outcomes. In general, a range that reaches or crosses zero is compatible with a small or absent mean difference as well as with values in the direction of the point estimate. Intervals should be read as ranges of plausible estimates under the analysis, not as proof that one particular effect is present.

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 sample-size planning figures are expressed as participants per arm for the continuous outcomes in this trial. They are not total event counts. The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The assumed effect is a stated fraction of the observed effect. The original trial’s own design assumptions and sample-size justification are not reported in the registry record.

The 80% power column gives the illustrative number of participants per arm for a planned study to have 80% power under those assumptions and at the stated effect size. The 90% power column gives the corresponding number per arm for 90% power. In general, higher planned power requires a larger study when other assumptions are held constant. The figures are planning illustrations based on this trial’s observed effect, not observed power.

The rows that plan for 100% of the observed effect use the full observed estimate as the target. The rows that plan for 75% or 50% of the observed effect use progressively smaller target effects. Smaller effects are harder to distinguish from chance variation, so the planning calculations require more participants per arm to reach the same power target. For example, in the primary outcome’s planning figures, planning for 75% of the observed effect gives 50 participants per arm for 80% power and 67 participants per arm for 90% power; planning for 50% gives 112 and 150 participants per arm, respectively.

These numbers are sensitive to the assumptions and to the observed effect used as their starting point. They should not be interpreted as proof that a particular future sample size is sufficient. The discrepancy between the sponsor’s analysis and the unadjusted recalculation also counsels against treating the recalculated effect as a definitive planning value. A prospective design would need its own justified target effect and assumptions, which are not reported for the original trial.

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 = -1.600; pooled standard deviation σ = 2.137.
2. n = 2 × (1.96 + 0.842)² × 2.137² / -1.600² = 28.0, rounded up to 28 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 <- -1.6                      # observed difference in means
sigma <- 2.13680741901229                     # 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(3123861)
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 = 28 (80% power), 38 (90% power)
 75% of observed effect: n per arm = 50 (80% power), 67 (90% power)
 50% of observed effect: n per arm = 112 (80% power), 150 (90% power)
power.t.test: 29 
Simulated power at n = 28 per arm: 0.787 (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. Analyses Reported by the Sponsor

The sponsor’s reported primary analysis is a two-sided t-test with p = 0.09. The unadjusted recalculation from the posted group means, standard deviations, and group sizes gives a mean difference of -1.6 units, a confidence interval from -2.924 to a value just below zero, and p = 0.018. These are discrepant results. Under the stated interpretation approach for this registry record, the sponsor’s own analysis takes precedence.

The recalculation is a simple comparison of summary statistics. It is useful for describing what follows from those posted summaries, but it cannot reproduce analysis choices that are not recorded, use participant-level data, or determine why the two results differ. The registry record does not report the sponsor’s effect estimate, confidence interval, or enough analytical detail to reconcile the discrepancy. The sponsor’s p-value alone also does not quantify the size of the estimated difference or its precision.

Accordingly, the recalculation should be treated as an unadjusted check rather than a replacement for the trial’s reported analysis. It is not appropriate to choose between the results on the basis of which is more favorable. The record leaves the reason for the discrepancy unresolved, and that uncertainty should remain part of any reading of the primary finding.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary pain outcome and several secondary outcomes. It reports an outcome-measure count of 4 and an analysis count of 4, and lists three secondary outcomes. The record does not explain how those counts correspond to the full set of planned outcomes or analyses. It does not report whether a multiplicity adjustment was planned or used, or which outcome was intended to be confirmatory beyond the endpoint marked primary.

Multiplicity matters because testing several outcomes can make at least one result look more unusual by chance, even if there is no true difference for any outcome. General statistical context: prespecifying a primary endpoint and using an appropriate analysis plan can help control how multiple results are interpreted. Without a reported plan or adjustment, secondary p-values should be considered unadjusted and should not be treated as if each were the only test conducted.

The registry defines the primary endpoint population as participants who underwent surgery and had follow-up data at 7 days. The posted endpoint group summaries include 19 participants in the gabapentin arm and 20 in the placebo arm. Enrollment is 45. The record does not explain the difference between these counts, report the extent or reasons for missing primary outcomes, or describe how missing data were handled. It does not say whether an intention-to-treat, per-protocol, or other analysis population was used.

Random assignment supports a comparison of groups, but missing outcomes can affect how representative the analyzed participants are of those randomized. General statistical context: if missingness is related to participants’ outcomes or treatment assignment, complete-case summaries may not preserve the balance intended by randomization. The registry record does not provide the information needed to assess that possibility. It also does not report sensitivity analyses for missing data.

The sponsor’s primary p-value and the simple recalculation differ. The registry record does not provide enough analysis detail to determine whether multiplicity, missing-data handling, covariate adjustment, or another specified method contributes to that discrepancy. These uncertainties should be kept distinct rather than attributing the difference to a particular cause.

16. 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 5% reporting threshold.

Most frequent non-serious adverse event terms

The adverse-event record reports no serious adverse events in either group. The serious-event risk count is 21 for gabapentin and 22 for placebo, with zero affected in each group. Deaths are recorded as zero in both groups. These figures describe the adverse-event records and denominators as posted; they do not establish that no unrecorded events occurred.

For other adverse events, the record lists 2 affected participants in the gabapentin group and 0 in the placebo group among the corresponding risk counts of 21 and 22. The record does not provide event descriptions in the posted summary or explain whether the events were considered related to study medication. The other-adverse-event counts should not be conflated with serious adverse events.

The adverse-event denominators differ from the primary outcome group counts. The registry record does not explain why these analysis populations differ, so the figures should be interpreted within their own recorded denominators. With no event detail or additional context, these counts alone do not establish comparative safety or support conclusions about the frequency or nature of all possible harms.

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

The posted results describe pain scores at 7 days after surgery among participants with follow-up data. The group means are lower in the gabapentin arm than in the placebo arm for the primary pain measure, and the simple summary-based recalculation estimates a negative mean difference. This is an account of the observed data and the recalculated comparison, not a medical recommendation or a conclusion that treatment does or does not work.

The registry’s own reported primary analysis gives p = 0.09, while the unadjusted recalculation gives p = 0.018 and an interval that does not include zero. Because these results differ, the sponsor’s own analysis takes precedence. The available record does not include enough detail to explain the discrepancy, and the sponsor’s effect estimate and interval are not reported. That leaves meaningful uncertainty about how the primary result should be quantified.

The results do not establish the effect at later time points, even though the planned follow-up was 6 weeks. Nor do the seven-day summaries establish an effect for people outside the described study population or for procedures excluded by the eligibility description. The registry does not report a threshold for a clinically meaningful difference on the scale, so statistical estimates alone cannot establish whether the observed contrast would be important to patients.

The findings also do not settle questions about missing outcome data, multiplicity, or analysis populations. The secondary pain results provide descriptive context but carry less weight without a reported multiplicity plan. The adverse-event figures are limited to the recorded counts and denominators and cannot establish the absence of other harms. Taken together, the record is a basis for understanding what was measured and reported, with important limitations in how fully the analysis and its uncertainty are documented.

18. Why This Trial Matters Statistically

This trial illustrates why an analysis cannot be interpreted from a single p-value or group difference alone. The registry includes a randomized comparison, group means and standard deviations, a sponsor-reported test, and a separate unadjusted recalculation. The recalculated estimate is informative about the posted summaries, but its disagreement with the sponsor’s test makes it essential to keep the reported analysis and the recalculation distinct.

The example also shows that precision and statistical evidence are related but not interchangeable. A mean difference describes the size and direction of a contrast, while an interval describes its uncertainty under a specified method. A p-value summarizes evidence relative to a null model; it does not measure clinical importance. Here the sponsor’s interval and effect estimate are not reported, which limits assessment of its estimate’s precision.

Several common design and interpretation questions remain open in the record: the original sample-size rationale, the treatment of missing outcomes, the analysis population, and adjustment for multiple outcomes. These are not minor details. They help determine how strongly a randomized comparison can be interpreted and how much weight to give secondary findings. Their absence is a useful reminder that a completed trial record may still leave key statistical assumptions undocumented.

Finally, the planning illustrations show how assumptions about the target effect influence future sample-size requirements. Smaller effects require more participants per arm to achieve the same planned power under the stated assumptions. Such illustrations are most useful when their assumptions are justified prospectively, rather than selected after seeing the observed result.

19. 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 a self-reported pain score at one early postoperative time point. The registry record does not report a clinically meaningful-change threshold for the scale, so the practical importance of the numerical difference cannot be determined from the score summaries alone. Although follow-up was planned for 6 weeks, the primary result described is at 7 days, and the posted record does not supply a longitudinal account of the outcome across follow-up.

The analyzed primary outcome population is described as participants with follow-up data, and its group counts are 19 and 20. The registry does not explain why these counts differ from the enrollment figure of 45, give reasons for unavailable outcomes, or report missing-data sensitivity analyses. The adverse-event denominators are different again, without an explanation of the populations used. These differences limit assessment of whether the posted summaries represent all randomized participants.

The registry gives a sponsor-reported p-value but does not report the corresponding effect estimate or confidence interval. The summary-based recalculation conflicts with that reported analysis, and the record does not include the details needed to reconcile them. The sponsor’s analysis therefore takes precedence, but its magnitude and precision cannot be fully assessed from the reported statistics.

The eligible population is specific: English-speaking women planning vaginal sacrospinous ligament fixation, subject to the listed exclusions. The record does not establish how findings apply beyond that population. It also does not report the original sample-size justification, a complete statistical analysis plan, multiplicity handling, interim-analysis details, or the method used to address missing data. These limitations are specific to the information documented for this trial and should not be replaced by assumptions about the protocol.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Gabapentin for Postop Pain After SSLF — NCT03123861.
• Registry record last updated 2020-10-26; status last verified 2020-09.
• Results first posted 2020-10-26.
• 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.

23. Record Summary

The registry record describes a completed, randomized, quadruple-masked, parallel-group phase 4 trial comparing postoperative gabapentin with placebo after vaginal sacrospinous ligament fixation. Enrollment is 45. The primary outcome is mean pain during normal activities at 7 days after surgery, measured with item 2 of the Surgical Pain Scale.

The posted primary group means are 1.6 for gabapentin and 3.2 for placebo. A simple unadjusted recalculation estimates a mean difference of -1.6 units, with p = 0.018. The sponsor’s reported two-sided t-test gives p = 0.09; the results are discrepant, and the sponsor’s own analysis takes precedence. The registry does not report the sponsor’s effect estimate or confidence interval.

Secondary pain summaries follow a broadly similar descriptive direction, but multiplicity handling is not reported. The record also does not report the original sample-size rationale, missing-data methods, or full analysis populations. Serious adverse events and deaths are recorded as zero in both groups, with other adverse events reported in 2 participants in the gabapentin group and 0 in the placebo group.