Examining the Role of Improved NSAID Management in Treating Dysmenorrhea and Bladder Pain: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Examining the Role of Improved NSAID Management in Treating Dysmenorrhea and Bladder Pain (NCT03697720), a na phase 4 study. The primary outcome is Change in Menstrual Pain.

2. Clinical Question

The central question is about change over time within the study group, not a difference between people assigned to naproxen and people assigned to another treatment or to no treatment. A within-person comparison can describe whether reported pain scores differed between the two diary periods. Without a concurrent control group, however, such a change cannot by itself distinguish an intervention effect from other explanations for change over time.

The broader study aims also concerned whether bladder pain sensitivity changed after reduced menstrual pain experience over six months. The brief summary describes quantitative sensory tests and EEG measures as tools for examining sensory sensitivity mechanisms. The registry record does not report numerical findings for those aims. The primary outcome identified in the record is change in menstrual pain, so the bladder-related aims should not be treated as evidence of a reported bladder pain result.

3. Trial Design

The registry record describes a completed Phase 4, single-group study with an enrollment of 26. Its intervention was naproxen, and the arm description specifies naproxen 500mg starting just before and during menses. Allocation is recorded as NA, masking as none, and the model as single group. These details describe a study without a randomized, masked comparison between treatment groups.

The primary outcome was change in menstrual pain. The record describes comparing the worst menstrual pain score in a diary collected over 6-8 months with the worst pain score in a baseline pretreatment diary. The outcome is continuous: it is a score on a 0 through 10 Numeric Rating Scale. The record identifies the summary measure as a mean and the dispersion measure as a standard deviation.

The study description gives a wider scientific context. It aimed to examine whether optimized naproxen use would improve pain reports from baseline, and whether bladder pain sensitivity and measures of sensory processing changed in association with menstrual pain experience. Those aims do not establish that each measure was a primary endpoint or that each result was reported. The registry record lists two outcome measures and two analyses, but does not report enough detail in the available outcome information to characterize the additional measure or the corresponding analysis.

Because there is no separate control group, the central design contrast is between a participant's baseline and later pain report, rather than between treatment assignments. The registry record does not report a detailed protocol for treatment adherence, the timing of individual assessments beyond the stated timeframe, or the statistical analysis plan. Such details should not be inferred from the single-group design or from the stated study aims.

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: Some participant data were missing due to attrition

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 Change in Menstrual Pain, measured over 6-8 months.

The primary endpoint is change in menstrual pain, measured as the worst menstrual pain score recorded in a diary. The registry describes a Numeric Rating Scale from 0 through 10, where 0 means no pain and 10 means worst pain imaginable. The score at the 6-8 months diary period is to be compared with the baseline pretreatment diary score.

A pain rating is a patient-reported measure of symptom intensity. A diary can capture ratings across the menstrual pain period rather than relying only on a later general recollection. Using the same scale at baseline and follow-up makes the scores interpretable on a common scale. The endpoint focuses specifically on worst menstrual pain, not on every aspect of pain, daily functioning, bladder symptoms, or sensory testing.

In general, a mean summarizes the average score or average change across participants, while a standard deviation describes how much individual scores vary around that mean. A mean change alone does not show how consistent changes were among participants. The registry record identifies the endpoint type and summary measures but does not report the numerical baseline value, follow-up value, mean change, standard deviation, confidence interval, or p-value. The direction and size of the observed change therefore cannot be evaluated from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary endpoint as a continuous pain score and names the mean and standard deviation as the summary statistics. It describes a comparison of a baseline pretreatment diary score with a later diary score. The specific estimator, test, confidence interval method, and model used for that comparison are not reported in the registry record. The methodological explanations below are general and do not assert that a particular method was used in this study.

What does a mean change describe?

In general, a mean change is the average of participant-level differences between follow-up and baseline, when such paired observations are available and that is the chosen analysis. Its sign depends on the subtraction convention. For a pain scale on which higher scores mean worse pain, the direction of a change can be meaningful, but a numerical estimate and its definition are needed to establish that direction. The registry record does not report a mean change or state the sign convention used in an analysis.

A mean can be useful because it condenses many individual observations into one central summary. It can also hide variation: some participants may have larger changes, smaller changes, or changes in the opposite direction. The standard deviation describes the spread of observed scores around a mean; it is not the same as the uncertainty in the estimated mean. A confidence interval, when reported, conveys uncertainty about an estimated quantity under the assumptions of the method. It does not show the range within which most individual participants' scores fall.

Why does the within-person structure matter?

For a baseline and follow-up comparison, scores from the same participant are related. In general, an analysis that accounts for pairing uses that relationship and can differ in precision from treating the two sets of scores as unrelated. The registry describes a baseline-to-follow-up comparison, but it does not say whether the analysis used paired differences, another repeated-measures method, or a different approach. It also does not report the correlation between the two measurements. No particular paired analysis should therefore be attributed to the study.

There may also be more than one diary observation contributing to a period's score. The endpoint description refers to the worst score from the baseline pretreatment diary and to the worst score from a diary over 6-8 months. The exact diary aggregation procedure and rules for incomplete diaries are not reported in the registry record. In general, choices about which observations form a participant's endpoint affect the quantity being summarized.

What does a confidence interval add?

In general, a confidence interval presents a range of values compatible with an estimate under the statistical method and its assumptions. A narrower interval indicates greater precision for that estimate than a wider interval, but interpretation also depends on the outcome scale and the study question. A confidence interval does not remove bias from missing observations or from the absence of a control group. No confidence interval for the primary outcome is reported in the registry record, so the uncertainty around the outcome estimate cannot be described.

A p-value, when used, measures how unusual data at least as inconsistent with a specified null hypothesis would be under the assumptions of a statistical test. It is not the probability that the null hypothesis is true, nor does it measure the clinical importance of a result. A p-value alone would not describe the size of a change or its precision. The registry record does not report a primary outcome p-value or the test used, so significance testing cannot be reconstructed from the information recorded.

How should the planning assumptions be read?

The registry record describes sample-size planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The illustrations are described as planning for a stated fraction of the observed effect and as giving participants per arm for non-time-to-event outcomes. These assumptions describe hypothetical planning scenarios, not the single-group design of this completed study. The record does not report the numerical planning outputs in the information, and they should not be read as observed power or as evidence about the precision of the actual outcome analysis.

In general, a planning calculation asks what sample size would be needed under specified assumptions about an effect, variability, allocation, and statistical procedure. Its answer depends on those assumptions. A planning illustration based on an observed effect is not an independent confirmation that the effect is real, and a hypothetical two-arm calculation does not turn a single-group study into a two-arm trial. No sample-size justification for the actual study design is reported in the registry record.

What statistical details are unavailable?

The record does not report the exact analysis population, the number contributing paired diary data, the model or test, any adjustment variables, the treatment of outliers, or the missing-data method. It does not report a numerical primary outcome estimate or an uncertainty interval. These omissions prevent independent evaluation of whether the analysis followed a prespecified plan, whether assumptions were checked, or how sensitive findings might be to analytic choices. General statistical concepts can explain what such methods would mean, but cannot fill in methods or results that are not reported in the registry record.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Primary Dysmenorrhea")
n   <- c(19)
m   <- c(4.1)
sp  <- c(2.4)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Primary Dysmenorrhea  19  4.100  2.400  2.943  5.257

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists two outcome measures and two analyses, and identifies change in menstrual pain as the primary outcome. It does not describe the other outcome measure in enough detail to establish its role, nor does it report a hierarchy of hypotheses, a multiplicity adjustment, or a plan for interpreting multiple tests. Whether and how multiplicity was addressed is not reported in the registry record.

In general, testing multiple outcomes or analyses can increase the chance of at least one apparently unusual result when each test is considered separately. A prespecified primary outcome can help distinguish the central question from other analyses, while an adjustment or a clearly stated interpretation plan can address multiple testing. These are general principles; they do not indicate that a particular issue affected this study. The record does not provide p-values or numerical results with which to assess multiplicity in practice.

The primary endpoint description explicitly notes that some participant data were missing due to attrition. The number of missing observations, their timing, reasons, and distribution across outcome periods are not reported in the registry record. The method used to handle missing diary data, including whether an analysis used complete pairs, imputation, or another method, is also not reported. Missingness can affect both the number of observations contributing to an estimate and the interpretation of that estimate. In general, results may be biased when the likelihood of missing data is related to unobserved outcomes, but the record does not establish that this occurred.

The enrollment of 26 does not establish the endpoint analysis population. The number with complete baseline and follow-up records and the criteria for inclusion in each analysis are not reported. No intention-to-treat, per-protocol, or other analysis-population designation is reported in the registry record. As a result, neither the extent of attrition nor the robustness of the primary outcome analysis can be evaluated from the recorded information.

12. 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 safety summary lists a Primary Dysmenorrhea group with 26 at risk for serious adverse events, 0 serious adverse events, 26 at risk for other adverse events, and 1 other adverse event. It also records 0 deaths. The registry record does not list serious adverse event terms, and it does not describe the other adverse event.

These are counts in the record, not estimates of comparative risk. With a single group and no control arm, the counts cannot show whether the intervention caused an event or whether event frequency differed from another treatment. The record does not report event severity beyond the serious-versus-other categorization, timing, duration, outcome, or causal assessment for the one other event. It also does not provide enough detail to assess how adverse events were solicited or classified.

A zero count for serious events or deaths in this group does not establish that such events are impossible or that the intervention is free of risk. It describes only what the registry reports for the study group. The safety summary should be read alongside the limited information on event definitions and follow-up, rather than as a comprehensive safety assessment.

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

The study addresses a question about change in menstrual pain during a period of naproxen use, with pain assessed using a 0 through 10 Numeric Rating Scale. It also reflects an interest in possible links between menstrual pain and bladder pain sensitivity. Those questions are relevant to understanding symptom measurement and sensory mechanisms, but the registry record does not report numerical outcome findings for the primary endpoint or the broader aims.

The design is single group and compares a baseline pretreatment diary with a later diary. In general, this design can describe change among participants with the required observations. It cannot, on its own, establish how much of any change was caused by the intervention, because there is no concurrent control group to show the course over the same period under another condition. Changes over time may have multiple explanations. This is a limitation of what the design can establish, not evidence that any specific alternative explanation occurred.

The absence of a numerical result in the registry record means that no effect magnitude, direction, or precision can be stated. It does not mean that the measured scores were unchanged, that an analysis found no effect, or that the study failed to collect data. The primary outcome description notes some missing participant data due to attrition, but the amount and handling of missingness are not reported. Without a reported estimate and its uncertainty, readers cannot judge how large or consistent any change was.

The safety counts are also limited in scope. The record lists no serious adverse events, one other adverse event, and no deaths in the group, but does not describe the other event or establish causality. Those counts do not support a comparative safety conclusion.

In general, an informative interpretation would consider the outcome estimate, its uncertainty, missing-data handling, and the design together. The registry record provides enough detail to identify the primary question and important design constraints, but not enough numerical outcome information to determine what change was observed. Conclusions about efficacy, lack of efficacy, or a causal effect would go beyond the reported record.

14. Why This Trial Matters Statistically

This trial is statistically notable because its primary question is framed as change within a group over time, while the planning assumptions described in the registry record refer to a hypothetical two-arm comparison. Keeping those distinct prevents a planning illustration from being mistaken for the study's actual design or for evidence of an observed treatment effect. The record describes one group, no masking, and no randomized comparator.

The endpoint also highlights the difference between a scale's definition and a reported result. A 0 through 10 Numeric Rating Scale gives a common framework for recording worst menstrual pain, and the mean and standard deviation identify intended ways to summarize continuous scores. But those details do not reveal the baseline level, the amount of change, participant-to-participant variation, or precision. Without the numerical outcome estimate and an uncertainty measure, the statistical result cannot be evaluated.

Attrition makes the analysis population especially relevant. The registry record notes that some data were missing due to attrition, while leaving the number of complete observations and the missing-data method unreported. For a baseline-to-follow-up question, whether participants have usable data at both time points affects which observations can inform a change estimate. The record does not allow readers to assess how that issue was addressed.

More broadly, the study illustrates why a registry entry's study aims, design description, endpoint definition, numerical results, and analysis details answer different questions. A clearly defined endpoint does not substitute for an effect estimate; a completed status does not establish a reported result; and safety counts in one group are not a comparative assessment. Separating these elements helps readers recognize what the statistical record supports and where uncertainty remains.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main trial-specific limitation is the absence of a concurrent control group. A baseline-to-follow-up comparison can describe within-group change, but it cannot separate intervention-associated change from other changes over time. Allocation is listed as NA, masking as none, and the model as single group. The record therefore does not support a randomized between-group treatment contrast.

The primary outcome is based on participant-reported worst menstrual pain in diaries. Such a score is a defined measure on a 0 through 10 scale, but the registry record does not report diary completion rules, how individual diary entries were combined, or how incomplete diaries were treated. It also does not report the numerical baseline and follow-up summaries or the estimated change. The endpoint's measurement definition is available, but its observed result and precision are not.

The record notes that some participant data were missing due to attrition. It does not report how many observations were missing, why participants left or did not contribute data, whether missingness differed across measurement periods, or how the analyses handled missing data. This leaves the extent and possible implications of attrition unclear.

The enrollment was 26, but the number included in the primary endpoint analysis is not reported. The record also does not report the specific statistical test or model, an analysis population, a prespecified analysis plan, or multiplicity procedures. These gaps make it difficult to assess reproducibility and the sensitivity of conclusions to analytic choices.

Finally, the registry record describes bladder-related and sensory-mechanism aims without reporting their numerical findings in the available outcome information. The safety summary does not describe the one other adverse event or provide comparative data. These limitations constrain conclusions about both the wider aims and safety, in addition to the missing primary outcome result.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Examining the Role of Improved NSAID Management in Treating Dysmenorrhea and Bladder Pain — NCT03697720.
• Registry record last updated 2023-10-18; status last verified 2023-09.
• Results first posted 2023-10-18.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

The registry record describes a completed Phase 4, single-group study of naproxen for dysmenorrhea, with an enrollment of 26. The intervention description specifies naproxen 500mg starting just before and during menses. There was no masking and no separate control group.

The primary endpoint was change in worst menstrual pain, comparing a baseline pretreatment diary with a diary over 6-8 months. Pain was recorded on a Numeric Rating Scale from 0 through 10, and the record identifies a mean and standard deviation as the summary measures. It notes that some participant data were missing due to attrition.

The numerical primary outcome estimate, its uncertainty, the analysis population, and the missing-data method are not reported in the registry record. The broader aims concerned bladder pain sensitivity and sensory measures, but numerical findings for those aims are not reported in the available information. The safety summary lists 0 serious adverse events, 1 other adverse event, and 0 deaths in the group, without describing the other event.