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 Total Joint Arthroplasty and Sleep (NCT03968939), a randomized phase 4 study. The primary outcome is Epworth Sleepiness Scale (ESS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03968939 |
| Phase | Phase 4 |
| Condition | Primary Total Hip Arthroplasty, Primary Total Knee Arthroplasty |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 55 |
| Arms in the primary outcome | n/a |
| Lead sponsor | James A. Keeney |
| Results posted | Yes |
2. Clinical Question
Population
Participants undergoing primary total hip arthroplasty or primary total knee arthroplasty were enrolled. The registry record reports an enrollment of 55. For the primary outcome, it notes that the number analyzed at each follow-up was the number of participants who followed up with the research team, reflecting attrition. The numbers followed at each time point are not reported in the registry record.
Intervention
The intervention group received over-the-counter diphenhydramine (25 mg) and oral melatonin (3mg) before bedtime, along with a sleep hygiene education brochure. The registry description calls these sleep aids and education. It does not report adherence to the medications or brochure, or whether participants continued the interventions throughout follow-up.
Comparator
The trial included sleep hygiene education alone and usual care as separate groups. Participants assigned to education received a brochure. The usual-care group did not use sleep education or non-prescription sleep medications to assist with sleep. Thus, the trial’s three groups allow comparisons involving sleep aids plus education, education alone, and usual care; the registry record does not specify one primary pairwise comparison.
Primary question
The clinical question is whether postoperative sleepiness, measured by the Epworth Sleepiness Scale, differs over follow-up among participants assigned to sleep aids plus education, education alone, or usual care after joint arthroplasty. The scale was assessed at baseline and at 2 weeks, 6 weeks, and 12 weeks postoperatively. The registry record does not report group means, standard deviations, or comparative estimates, so it does not establish the direction or precision of any group differences.
3. Trial Design
The registry describes a prospective, randomized, controlled trial with a parallel-group model and double masking. It is listed as Phase 4 and has a status of completed. Enrollment was 55. The listed study dates are 2019-10-01 for the start and 2022-03-01 for primary completion. The sponsor is James A. Keeney.
Participants with primary total hip arthroplasty or primary total knee arthroplasty were assigned among three groups: usual care, sleep hygiene education, or over-the-counter sleep aids combined with sleep hygiene education. The sleep-aid group received diphenhydramine (25 mg) and oral melatonin (3mg) before bedtime and a brochure. The education group received the brochure without the listed sleep medications. The usual-care description specifies no sleep education or non-prescription sleep medication to assist with sleep.
Randomization and double masking are recorded, but the registry record does not report the sequence-generation method, allocation-concealment process, or who was masked. It also does not explain how masking was maintained across groups with visibly different education or medication components. Those details should not be inferred from the design labels alone.
The primary outcome was measured at baseline and at 2 weeks, 6 weeks, and 12 weeks postoperatively. The registry describes follow-up counts as the number of participants who returned follow-up information, due to attrition. It does not report the number with outcome data at each visit. The record lists three outcome measures, but the other outcome measures are not described in the registry record for this analysis.
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 | Control Group (Usual Care) | Sleep Hygiene Education | Over-the-counter Sleep Aids (25 mg Benadryl + 3mg Melatonin) |
|---|---|---|---|
| STARTED | 15 | 26 | 14 |
| COMPLETED | 15 | 26 | 14 |
| NOT COMPLETED | 0 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Due to attrition, the number analyzed at each time point is the number of participants who followed up with the research team
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 | Control Group (Usual Care) | Sleep Hygiene Education | Over-the-counter Sleep Aids (25 mg Benadryl + 3mg Melatonin) | Total |
|---|---|---|---|---|---|
| Participants analysed | 15 | 26 | 14 | 55 | |
| Age, Continuous | Years | 67.77 (55 to 81) | 67.19 (53 to 80) | 66.47 (57 to 75) | 66.71 (55 to 81) |
| Sex: Female, Male: Female | Participants | 6 | 18 | 3 | 27 |
| Sex: Female, Male: Male | Participants | 9 | 8 | 11 | 28 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 14 | 26 | 14 | 54 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 1 | 0 | 0 | 1 |
| Region of Enrollment: United States | participants | 15 | 26 | 14 | 55 |
| Total Joint Arthroplasty (TJA) Cohort: Total Knee Arthroplasty (TKA) | Participants | 9 | 18 | 9 | 36 |
| Total Joint Arthroplasty (TJA) Cohort: Total Hip Arthroplasty (THA) | Participants | 6 | 8 | 5 | 19 |
6. Primary Endpoint
The registry lists the primary outcome as Epworth Sleepiness Scale (ESS), measured over Baseline, 2 weeks, 6 weeks and 12 weeks post-op.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the Epworth Sleepiness Scale (ESS), a subjective measure used in sleep medicine to assess a person’s tendency to become sleepy. It asks participants to rate their chance of dozing in eight situations. Each response is scored from 0 for no chance of dozing to 3 for a high chance of dozing, and the values are totaled to produce a score from 0 to 24. Higher scores indicate a greater chance of experiencing excessive sleepiness.
The registry records the outcome as a mean with standard deviation, assessed at baseline and at 2 weeks, 6 weeks, and 12 weeks postoperatively. A mean describes the group’s average score, while a standard deviation describes how dispersed individual scores are around that average. Reporting both can help readers distinguish a group’s average symptom level from the variability among participants.
Repeated assessment makes it possible to describe sleepiness at multiple points in recovery, rather than relying on one follow-up measurement. However, the registry record does not report the ESS means or standard deviations at any time point, nor a group contrast over time. It therefore does not show how the scores changed or how precisely any differences between groups were estimated.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the ESS as the primary outcome and specifies assessment at baseline and at 2 weeks, 6 weeks, and 12 weeks postoperatively. It also states that the number analyzed at each time point depended on participants who followed up. These details establish what was intended to be measured and how follow-up availability affected the analyzed counts, but they are not outcome results.
ESS means and standard deviations by group and time point are not reported in the registry record. Comparative effect estimates, confidence intervals, and p-values are also not reported in the registry record. The record lists zero analyses. Consequently, the statistical evidence does not allow readers to assess the direction, magnitude, or precision of differences among sleep aids plus education, education alone, and usual care. No conclusion about comparative benefit or lack of benefit can be drawn from the information recorded.
A mean difference, if reported, would describe the average separation in ESS scores between groups or time points. A confidence interval would indicate the range of values compatible with the data and the analysis assumptions; narrower intervals generally indicate greater precision. A p-value, if reported, would describe how unusual data at least as incompatible with a specified null hypothesis would be under that hypothesis and the test assumptions. None of these statistics can be reconstructed from enrollment and design information alone.
The study enrolled 55 participants, but the number contributing ESS data at each follow-up is not reported in the registry record. This matters because incomplete follow-up can reduce precision and can also affect interpretation if participants with missing measurements differ systematically from those observed. The available record does not describe missing-data assumptions or methods, so the extent to which attrition may have influenced an analysis cannot be evaluated.
The safety figures record zero serious adverse events, zero other adverse events, and zero deaths in each group, with the group-specific numbers at risk reported in the safety entry. These are descriptive counts, not proof that the interventions have no risk. They do not provide a comparative estimate with uncertainty, and the record does not describe how adverse events were collected or classified beyond the listed categories.
In short, the registry supports a description of the study design, planned outcome, follow-up schedule, and recorded safety counts. It does not provide the endpoint data or analyses needed to quantify a treatment contrast. Interpretation should remain limited to those design and reporting details.
9. Statistical Methods Explained
The design labels describe the broad structure of the trial. Randomized allocation means assignment was intended to use a chance-based process, which can help balance both measured and unmeasured baseline characteristics on average. The registry record does not report the specific randomization method or concealment procedures, so the details and implementation cannot be assessed. A parallel-group model means participants are assigned to a group and the groups are followed alongside one another. The double-masking label indicates that masking was intended, but the record does not state which people were masked or how masking was maintained.
What does a mean and standard deviation describe?
The ESS is a continuous score, and the registry specifies a mean and standard deviation as its summary. The mean is the arithmetic average of the recorded scores in a group at a given time point. The standard deviation describes how much scores vary around that average. These summaries answer different questions: the mean describes the group’s average score, while the standard deviation describes dispersion among participants. Without the reported means, standard deviations, and corresponding analyzed counts, neither the average scores nor their variability can be interpreted.
General statistical explanation: a group mean is not the same as an individual participant’s score, and a difference between means does not show that every participant experienced a similar change. The distribution of scores and the way missing observations are handled can also affect how well a mean represents the data. The registry record does not report distributional diagnostics or an alternative summary method.
How should repeated measurements be understood?
The ESS was scheduled at baseline and at 2 weeks, 6 weeks, and 12 weeks postoperatively. Repeated measurements can describe the course of an outcome over follow-up, but observations from the same participant are related rather than independent. General statistical methods for repeated measurements account for this within-participant correlation when estimating group patterns or differences over time. The registry record does not report which analytical method, if any, was used to account for repeated measurements. It also does not report a particular time point as the sole comparison of interest or a model for change from baseline.
When groups are assessed at baseline and later visits, analysts may compare follow-up values, changes from baseline, or overall patterns across time. These approaches answer related but not identical questions and can rely on different assumptions. The registry record does not identify the chosen estimand, specify whether baseline adjustment was planned, or report an analysis model. It would therefore be inappropriate to attribute any one approach to the trial.
What does a confidence interval add?
General statistical explanation: an estimate gives a best-supported value for a contrast under an analysis, while a confidence interval communicates its uncertainty. A confidence interval is not a guarantee that the true value lies within the interval, nor does it by itself decide whether a difference is clinically important. Interpretation depends on the outcome scale, the contrast being estimated, and the interval’s width and location. No confidence intervals for ESS contrasts are reported in the registry record, so precision cannot be assessed.
A p-value addresses compatibility between the observed data and a specified null hypothesis under the statistical model. It does not measure the size or importance of a difference and does not establish that the null hypothesis is true or false. The registry record reports no p-values or analyses. There is consequently no inferential result to interpret for the primary endpoint.
Why can over-dispersion matter?
General statistical explanation: over-dispersion occurs when the observed variability in data is greater than a model assumes. If a model understates variability, standard errors can be too small and uncertainty intervals can be too narrow. The ESS is recorded as a continuous score summarized by a mean and standard deviation; over-dispersion is not identified as a concern in the registry record, and no model or diagnostic is reported. It should not be assumed either that over-dispersion occurred or that a model was used to address it.
Planning calculations are distinct from trial results. The registry’s planning illustration is described as based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; it varies the effect to detect as a fraction of the observed effect. Those are planning assumptions, not evidence that the trial achieved a particular power. The illustration is not the trial’s own design justification, and the record does not report the trial’s sample-size justification. Because the study has three groups, a calculation that assumes two arms should not be read as a description of the actual three-group allocation or as an observed analysis. The values of the planning illustrations are not reported in the registry record available for this analysis.
10. Multiplicity, Missing Data and Analysis Populations
The primary endpoint was scheduled at multiple time points, and the trial has three groups. That creates more than one possible contrast and more than one possible point at which an outcome difference could be examined. When several comparisons are considered, the chance of at least one apparently unusual result can increase unless the analysis plan addresses multiplicity. General approaches include identifying a primary contrast and time point in advance, adjusting for multiple testing, or treating analyses as exploratory. The registry record does not report a multiplicity strategy, a hierarchy of comparisons, or a single primary pairwise comparison.
The record reports that follow-up counts varied because only participants who followed up with the research team were analyzed at each time point. The numbers with observed outcomes at those visits and the reasons for missing follow-up are not reported in the registry record. Nor does it describe imputation, a likelihood-based approach, sensitivity analyses, or assumptions about the relationship between missingness and ESS scores. Therefore, the impact of missing data on any potential estimate cannot be evaluated.
The analysis population is also not specified. The registry does not report whether participants were analyzed according to randomized assignment, according to the intervention received, or under another population definition. No protocol deviations or adherence summaries are reported in the registry record available for this analysis. These omissions limit assessment of how the randomized design would be reflected in an outcome analysis. They do not establish that a particular method was or was not used outside the registry entry; they mean that it is not reported in the registry record.
11. 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 |
|---|---|---|---|
| Control Group (Usual Care) | 0 | 15 | 0.0% |
| Sleep Hygiene Education | 0 | 26 | 0.0% |
| Over-the-counter Sleep Aids (25 mg Benadryl + 3mg Melatonin) | 0 | 14 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Control Group (Usual Care) | 0 of 15 |
| Sleep Hygiene Education | 0 of 26 |
| Over-the-counter Sleep Aids (25 mg Benadryl + 3mg Melatonin) | 0 of 14 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Control Group (Usual Care) | 0 of 15 |
| Sleep Hygiene Education | 0 of 26 |
| Over-the-counter Sleep Aids (25 mg Benadryl + 3mg Melatonin) | 0 of 14 |
The registry reports zero serious adverse events and zero other adverse events in each of the three groups, and zero deaths in each group. The numbers at risk were 15 in usual care, 26 in sleep hygiene education, and 14 in the over-the-counter sleep-aid group. These are the recorded group counts for the safety categories.
Zero recorded events means that no events in those categories were entered for the listed participants at risk. It does not establish that the true chance of an event is zero, and it does not establish that groups have equivalent safety. With few participants, an event that was not observed may still be compatible with a range of underlying risks. The registry record does not provide uncertainty intervals or a formal comparison of safety between groups.
The record lists no top serious adverse-event terms. It does not report event-collection procedures, severity grading beyond the serious and other categories, or whether events were assessed as related to an intervention. These figures should therefore be read as descriptive registry counts, not as a comprehensive account of all possible harms or a causal safety analysis.
12. What the Result Does, and Does Not, Mean
The study addresses a focused statistical question: how ESS scores after primary total hip or knee arthroplasty compare among usual care, sleep hygiene education, and sleep aids combined with education. Randomized assignment and repeated follow-up are relevant design features for evaluating such comparisons. The registry record also identifies the scale and the planned assessment times, making the intended outcome understandable.
However, a design and an outcome definition do not show what happened to participants’ scores. The registry record does not report group-specific ESS results, effect estimates, confidence intervals, or p-values. It therefore cannot show whether scores changed over time, whether groups differed, or how precise a group contrast might be. Neither a favorable nor an unfavorable comparative conclusion is supported by the endpoint information.
The recorded safety entries show zero serious events, zero other events, and zero deaths in each group. Those counts describe what was entered in the registry; they do not demonstrate absence of risk, establish equivalence, or provide a precise estimate of event rates. The limited counts and lack of reported uncertainty or collection details restrict the conclusions that can be drawn.
Planning illustrations, where presented, should be interpreted as hypothetical sample-size calculations under stated assumptions. They are not observed power and are not evidence that an effect was present. The trial’s own sample-size justification is not reported in the registry record. Overall, the available record supports an account of the trial’s question and structure, but not an answer about the comparative effects of the interventions.
13. Why This Trial Matters Statistically
This trial is statistically interesting because it distinguishes a behavioral education approach from a combined approach involving education and non-prescription sleep aids, while also including usual care. That structure makes the choice of comparison important: the combined intervention can be contrasted with education alone, with usual care, or both. Each contrast addresses a different question, and the registry record does not identify one primary pairwise comparison.
The repeated ESS assessments also make the definition of the target comparison important. A contrast at one follow-up visit is not the same as a comparison of change over time or an overall group pattern. A clear analysis plan would ordinarily specify which contrast and time point are primary, how repeated measurements are handled, and how missing follow-up is addressed. Those details are not reported in the registry record, so readers cannot evaluate the intended inferential framework.
The record illustrates why reporting design information is not a substitute for reporting results. Randomization, masking, enrollment, outcome definitions, and safety counts help characterize a study, but effect estimates and uncertainty are needed to evaluate the primary statistical question. Without ESS results or comparative analyses, the magnitude and precision of any differences remain unknown.
Finally, the participant counts recorded for safety and overall enrollment should be considered in light of the limited amount of reported outcome information. The registry notes attrition but does not give analyzed counts at each ESS visit. This makes it difficult to judge precision or representativeness of the follow-up data. The statistical importance of the trial therefore lies both in its three-group, repeated-measures question and in the limits imposed by incomplete reporting of the analysis and results.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The primary limitation for interpretation is that the registry record does not report the ESS group means, standard deviations, or comparative estimates. Without those results, the size and direction of any observed difference cannot be described. No confidence intervals or p-values are reported, and the record lists zero analyses. Statistical significance and precision therefore cannot be assessed.
The study has three intervention groups and several scheduled ESS time points, but the registry record does not identify the primary pairwise contrast or describe how multiplicity was handled. It does not report an analysis model for repeated measurements or clarify whether the comparison concerns follow-up scores, change from baseline, or a group pattern over time. The appropriate interpretation can depend on those choices.
Attrition is acknowledged in the primary outcome description: the number analyzed at each time point is the number who followed up. The actual follow-up counts and reasons for missingness are not reported in the registry record. Missing-data methods and analysis-population definitions are also not reported, limiting evaluation of potential attrition effects and of how participants were included in an analysis.
The record does not report the randomization procedure, allocation concealment, masking details, adherence, or protocol deviations. It also does not report the trial’s sample-size justification. Safety information is limited to group counts for serious and other adverse events and deaths, without reported uncertainty or detail about collection and attribution. These limitations concern what the registry entry reports; they do not establish what may have been documented elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Total Joint Arthroplasty and Sleep — NCT03968939.
- Registry record last updated 2024-07-16; status last verified 2024-06.
- Results first posted 2024-07-16.
- 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.
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18. Record Summary
NCT03968939 is a completed, Phase 4, prospective randomized controlled trial with a parallel-group model and double masking. It enrolled 55 participants with primary total hip or total knee arthroplasty. The three groups were usual care, sleep hygiene education, and over-the-counter diphenhydramine (25 mg) plus oral melatonin (3mg) with sleep hygiene education.
The primary outcome was the Epworth Sleepiness Scale, assessed at baseline and at 2 weeks, 6 weeks, and 12 weeks postoperatively. The registry describes the scale and reports that analyzed counts depended on follow-up, but does not report group outcome values or comparative analyses. Safety entries report zero serious adverse events, zero other adverse events, and zero deaths in each group. The registry record does not report the sample-size justification, analysis methods, multiplicity approach, or missing-data methods.