Immersive Virtual Reality Intervention for Non-Opioid Pain Management: A Randomized Controlled Trial: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Immersive Virtual Reality Intervention for Non-Opioid Pain Management: A Randomized Controlled Trial (NCT02887989), a randomized na study. The primary outcome is Pain Intensity Ratings (NRS).

2. Clinical Question

The registry describes a randomized controlled trial of a virtual reality intervention versus a control intervention using television content. Both groups received their assigned room-based content as an adjunct to pain medication, rather than as a replacement for medication. The clinical question therefore concerns the comparison of these two approaches within the study’s hospital setting, not virtual reality versus no care.

Pain intensity was recorded by hospital staff as part of usual care. Patients were asked to rate pain on an 11-point numeric rating scale, from 0 for “no pain” to 10 for “worst imaginable pain.” The primary outcome was summarized as a mean before and after intervention and as a time series. The stated assessment period was approximately every 3-4 hours for the period 48 hours pre and post intervention. Further details about how the pre- and post-intervention summaries were constructed are not reported in the registry record.

The main posted comparison gives mean ratings of 4.66 for virtual reality and 4.94 for in-room television. The estimated mean difference, expressed as in-room television minus virtual reality, is 0.28. Its confidence interval includes zero, so the posted estimate is compatible with a range of differences that includes no average difference as well as differences in either direction. These results describe the recorded ratings in this trial; they do not establish what would happen in other patient groups or settings.

3. Trial Design

The registry describes a randomized, parallel-group trial with no masking. One group received virtual reality content and the comparison group received content from the in-room Health and Wellness television channel. The registry lists the study as completed and records enrollment of 140. It does not report how the random sequence was generated, how assignment was concealed, or whether any staff or participants were unaware of the assigned group. The degree to which participants could be masked to these visibly different interventions is not specified.

The intervention descriptions place both approaches in the hospital room and allow their use as needed for pain management for up to 20 days. Both were intended as adjuncts to opioid and non-opioid pain medication. The registry summary states that investigators would follow patients through hospitalization and monitor outcomes during and after their stays, including pain levels, medication requests, and quality of life. The posted primary outcome information concerns pain intensity ratings. Details of the timing and completeness of follow-up for the other outcomes are not reported in the registry record.

The registry gives 61 participants for the virtual reality primary-outcome summary and 59 for the in-room television summary. Those are the group counts attached to the posted mean pain ratings, and they are not the enrollment figure. The relationship between the enrolled group and these outcome-specific counts, including reasons for any unavailable ratings, is not reported in the registry record. Safety information uses a separate stated at-risk count of 70 for each group, so those figures should not be treated as interchangeable with the primary-outcome counts.

The primary outcome was a continuous measure summarized by means and standard deviations. The registry describes pain measurement at three-to-four hour intervals during waking hours, with a standard numeric rating scale. The analysis approach for repeated measurements, the method used to derive the pre/post means, and any adjustment for baseline pain or other factors are not reported in the registry record. The registry lists a secondary outcome of length of stay. It does not report the trial’s original sample-size assumptions or justification, nor does it report an analysis plan detailed enough to establish which analyses were planned before results were known.

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:

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 Intensity Ratings (NRS), measured over Approximately every 3-4 hours for the period 48 hours pre and post intervention.

The primary endpoint is pain intensity measured with a numeric rating scale (NRS). The scale runs from 0, defined as “no pain,” to 10, defined as “worst imaginable pain.” Hospital staff asked participants to rate their pain during usual care at three-to-four hour intervals during waking hours. The stated timeframe is approximately every 3-4 hours for the period 48 hours pre and post intervention.

Pain ratings are a patient-reported measure of the experience the intervention is intended to address. Recording them repeatedly can describe how ratings vary over time, rather than relying only on a single assessment. The registry says that the primary outcome was summarized as pre/post means and in time series. It does not report the precise rule used to select observations for each summary, how missing ratings were handled, or whether the time-series analysis accounted for the correlation among ratings from the same participant.

The posted group means are 4.66 for virtual reality and 4.94 for in-room television, with standard deviations of 2.91 and 3.04, respectively. These summaries describe average recorded ratings and their variability within the groups. A mean does not show the full distribution of individual ratings, and a standard deviation is not a confidence interval for the group mean. The comparison is therefore best read alongside its confidence interval and the registry’s information about the analysis, rather than as a complete account of every participant’s pain experience.

7. Results Posted in the Registry

• In-Room Television: mean 4.94 versus 4.66 on control; difference 0.28 (95% CI -0.79 to 1.35), standardized effect d = 0.09; z-test p = 0.606.

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.

Length of Stay) LOS

• 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:
  • In-Room Television: mean 5.64 versus 5.11 on control; difference 0.53 (95% CI 0.25 to 0.81), standardized effect d = 0.68; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for In-Room Television than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The registry names length of stay as a secondary outcome. Its posted group summaries and comparison describe a pattern in which the television group’s mean is higher than the virtual reality group’s mean, but a separate reported t-test value does not align with the comparison summary. That inconsistency makes the secondary finding harder to interpret as a single coherent result. It should be read as a secondary, uncertain finding, rather than as a basis for overriding the primary pain outcome.

In general, secondary outcomes can add context by examining dimensions beyond the primary endpoint. They do not automatically confirm the primary result, and a difference on a secondary measure does not demonstrate a difference on the primary measure. Here, pain intensity is the primary outcome, while length of stay is listed as secondary. The registry does not report a formal framework for combining these outcomes or a prespecified hierarchy that would explain how much weight the secondary result was meant to carry.

Unadjusted secondary results generally carry less confirmatory weight when researchers examine multiple outcomes or analyses. Each additional test creates another opportunity to observe a result that appears notable by chance, even if no underlying effect exists. A multiplicity adjustment or a prespecified testing sequence can address some of that concern, but such a procedure is not reported in the registry record. There is also an internal reporting inconsistency for this secondary outcome, with the reason not reported.

The record lists three outcome measures and two analyses overall, while only one secondary outcome is named in the posted outcome information. The relationship among these entries is not sufficiently described to determine the complete set of comparisons considered. As a result, the overall pattern should be interpreted cautiously: the primary pain estimate is imprecise, and the secondary information does not resolve that uncertainty. The registry record does not give enough information to establish whether the secondary finding was prespecified or exploratory.

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

• Length of Stay) LOS

9. Statistical Interpretation

10. Statistical Methods Explained

The main outcome is continuous: it is a numeric rating summarized by a mean and standard deviation. A mean describes the average recorded rating in a group, while a standard deviation describes how much individual observations vary around that group average. They answer different questions. In particular, the standard deviation is not the uncertainty of the difference between group means. That uncertainty is reflected in the confidence interval for the comparison.

What does the mean difference represent?

The posted primary contrast is the mean rating for in-room television minus the mean rating for virtual reality. Its estimate is 0.28. With this order, a positive estimate means the television group’s observed mean is higher; a negative estimate would mean the virtual reality group’s observed mean is higher. Stating the contrast direction matters because the sign of a difference depends on which group is subtracted from which. The estimate is a comparison of group averages, not a statement that every participant in one group had a higher or lower rating than every participant in the other.

The registry also gives a standard error for each group mean. A standard error describes the sampling uncertainty of an estimate under the statistical model; it is distinct from the spread of individual ratings. The reported group standard deviations are much larger in scale than the standard errors because the former describe participant-level variation while the latter concern precision of the group mean. The comparison’s confidence interval uses uncertainty in the contrast to show a range of values compatible with the observed data under its assumptions.

How should a confidence interval be read?

A confidence interval is a method for expressing estimation uncertainty. In repeated use of the same procedure under its assumptions, intervals constructed in this way would cover the underlying parameter at the stated confidence level. It is not a probability statement that the fixed true value has a particular chance of lying in this one interval. For the primary contrast, the interval crosses zero. Since zero represents no mean difference, the interval does not exclude that possibility. Its negative and positive portions also leave room for differences in either direction, so the direction and size of the underlying difference are not determined precisely by this estimate.

A confidence interval does not account for every possible source of uncertainty. It cannot correct for bias from missing observations, problems in measurement, departures from the planned analysis, or incomplete reporting. Its interpretation depends on the analysis that generated it. The registry does not report enough detail to assess the treatment of repeated measurements, missing ratings, or adjustment for other variables.

What does the p-value add?

The unadjusted primary comparison has p = 0.606. In general, a p-value measures how inconsistent the observed data are with a specified null hypothesis under the test’s assumptions. It does not measure the probability that the null hypothesis is true, the probability that a result occurred by chance, or the probability that an intervention will benefit an individual. It also does not measure clinical importance. The estimate and interval should be considered together with the p-value, the design, and the completeness of the outcome data.

The registry does not list a reported primary analysis method in the posted comparison information. A comparison of means can be analyzed using different approaches, particularly when repeated observations are collected from each participant. The registry describes pain ratings at repeated intervals and says summaries were given as pre/post means and time series, but it does not state the model used to account for the within-participant relationship among ratings. Repeated ratings from one person are generally not independent observations. In general, treating correlated observations as independent can misstate uncertainty; methods for repeated measures can model that correlation. The exact approach used for the posted primary result is not reported in the registry record.

Why can repeated ratings require special handling?

When a measure is collected more than once from the same participant, a participant’s ratings may tend to resemble one another. This is called within-participant correlation. General methods for repeated measures account for that structure rather than treating each rating as if it came from a different person. A time-series presentation can show change over time, but a plot or series of means alone does not establish how the correlation was handled in an inferential test. The registry’s description of collection frequency and pre/post summaries does not specify the statistical model or its assumptions.

The posted primary comparison gives participant counts, group means, standard deviations, standard errors, an estimated contrast, an interval, and an unadjusted p-value. Those summaries allow the reader to see the magnitude and uncertainty reported for the group comparison, but not to reproduce every feature of a repeated-measures analysis. The original data, timing of individual ratings, and analysis specification are not reported in the registry record.

How should the secondary comparison be interpreted?

Length of stay is also summarized as a continuous outcome, using means and standard deviations. The registry posts a mean difference and an unadjusted p-value for the comparison, and it separately records a two-sided t-test with a different p-value. An unadjusted p-value is calculated without a correction for considering multiple outcomes or tests. This can make nominal evidence appear stronger when many hypotheses are examined. More importantly in this record, the two posted inferential values for length of stay are not consistent with one another. The reason is not reported, so the result requires caution rather than an assumption that one entry is authoritative.

General statistical practice distinguishes a prespecified primary analysis from exploratory analyses. A primary analysis can be interpreted in light of the study question and its planned methods; secondary analyses can help describe other aspects of the data but may be more vulnerable to multiplicity and selective emphasis. The registry record does not report enough detail about its analysis plan, outcome hierarchy, or multiplicity handling to determine the intended confirmatory status of the secondary comparison.

The trial’s original sample-size justification and assumptions are not reported in the registry record. Separate planning illustrations use the observed effect and explicit assumptions; they are prospective planning calculations, not evidence that the completed trial had a particular probability of detecting its observed result. The interpretation of those illustrations is described separately. No statistical method can repair missing information about the original design or the analysis populations when those details are absent from the registry.

11. Confidence Intervals and Precision

The primary mean difference is 0.28, with a confidence interval whose lower limit is negative and whose upper limit is positive. The interval therefore crosses zero. This is an important feature of the result: the observed estimate is small and positive under the contrast definition of television minus virtual reality, but the data are compatible with a range that includes no average difference and possible differences in either direction. The interval is not narrow enough to establish the direction of the underlying contrast with confidence.

Precision concerns how narrowly an estimate is determined, not whether a result is important. A confidence interval that crosses zero does not prove that the groups are equivalent. Demonstrating equivalence would require a prespecified equivalence margin and a design and analysis intended to assess whether the interval lies within that margin. Such a margin is not reported in the registry record. Likewise, the registry does not report a threshold for a clinically important difference in pain ratings, so statistical uncertainty cannot be translated into a judgment about clinical relevance.

The group standard deviations, 2.91 for virtual reality and 3.04 for television, describe substantial variation in the recorded ratings around each mean. This variation means that group averages do not reveal the full range or distribution of individual experiences. The reported outcome counts are 61 and 59, respectively, but the record does not explain why these counts differ from the overall enrollment figure or whether missing ratings affected the analysis. Confidence intervals based on observed summaries cannot show how unobserved outcomes might have changed the estimates.

The repeated collection schedule introduces another consideration. If repeated ratings from an individual are correlated, the precision of an analysis depends on how that dependence is handled. The registry describes repeated ratings but does not report the primary analysis model or missing-data method. Thus, the posted interval gives a useful summary of uncertainty for the stated contrast, while its assumptions and robustness cannot be fully evaluated from 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 sample-size figures are planning illustrations based on the observed effect, not the trial’s original design justification. The trial’s own sample-size assumptions are not reported in the registry record. The illustrations assume a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each row uses a stated fraction of the observed effect as the effect to detect. The figures are participants per arm, not total participants and not total events.

The 80% power column indicates the number of participants per arm that the planning calculation estimates would be needed for an 80% chance of detecting the specified effect under the stated assumptions, if that effect were the true effect and the model assumptions held. The 90% column uses a higher target chance of detection, which generally requires more participants per arm for the same effect. These are design targets, not claims about the probability that the completed study detected an effect after its results were observed.

The rows illustrate the effect-size assumption. Planning for 75% of the observed effect requires more participants per arm than planning for the full observed effect; planning for 50% requires more again. Smaller effects are harder to distinguish from random variation, so more participants are generally needed to achieve the same target power. The displayed values are conditional on the stated assumptions and should not be read as a recommendation for a future study without considering its specific question, design, outcome measurement, and analysis plan.

This is not observed power. Observed power is not a useful substitute for interpreting the estimate and its confidence interval after the data have been collected. The planning figures instead show how the assumed effect size and target power influence a hypothetical design under the listed assumptions. The registry does not report whether those assumptions match the trial’s actual planning process.

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 = 0.280; pooled standard deviation σ = 2.975.
2. n = 2 × (1.96 + 0.842)² × 2.975² / 0.280² = 1,771.7, rounded up to 1,772 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 <- 0.28                      # observed difference in means
sigma <- 2.97460836334033                     # 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(2887989)
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 = 1,772 (80% power), 2,372 (90% power)
 75% of observed effect: n per arm = 3,150 (80% power), 4,217 (90% power)
 50% of observed effect: n per arm = 7,087 (80% power), 9,488 (90% power)
power.t.test: 1772.6 
Simulated power at n = 1,772 per arm: 0.798 (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

Multiplicity refers to the increased chance of finding at least one apparently unusual result when multiple hypotheses, outcomes, time points, or analyses are tested. In general, a study that evaluates more than one outcome can use a prespecified hierarchy, an adjustment to the testing procedure, or a clearly exploratory interpretation. Each approach has different implications for the strength of claims. The registry does not report a multiplicity strategy, a testing hierarchy, or whether the posted p-values were adjusted.

The primary outcome includes repeated pain ratings and a pre/post summary as well as a time-series description. The registry reports the assessment schedule but does not specify which time points or summary formed the inferential primary comparison, or how testing across time was handled. It also lists three outcome measures and two analyses overall, while only one secondary outcome is named. The complete set of planned and conducted analyses, and the relationship between them, are not reported in the registry record. Without that information, the risk of selective emphasis among analyses cannot be assessed.

The record gives group counts for the primary pain summaries, but does not state the analysis population, whether participants were analyzed according to randomized assignment, or how missing observations were handled. It does not report how many participants had incomplete outcome data, why observations might be missing, or whether any imputation or sensitivity analysis was used. These omissions matter because the interpretation of a randomized comparison depends not only on group assignment but also on how participants and their outcomes enter the analysis.

The registry lists safety at-risk counts of 70 per group, whereas the primary outcome summaries list 61 and 59. These may reflect different analysis or reporting populations, but the reason for the difference is not reported. It would be inappropriate to assume that either set of counts represents the analysis population for every outcome. Details on exclusions after randomization, protocol deviations, and outcome-specific missingness are not reported in the registry record.

The record also does not describe any interim analyses, stopping rules, or the original statistical analysis plan. Their presence or absence cannot be inferred from the posted results. The absence of these details in the registry limits assessment of whether the reported outcomes and analyses correspond to prespecified choices. It does not, by itself, establish that analyses were inappropriate; it means their conduct cannot be evaluated from the record alone.

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.

The registry reports safety figures separately from the primary-outcome counts. It lists 70 participants at risk in each group. No serious adverse events and no other adverse events are recorded for either group. The registry lists 1 death in the virtual reality group and 0 in the in-room television group. These are descriptive counts; the record does not state whether any death or other event was judged related to the assigned intervention.

The at-risk figures differ from the group counts attached to the primary pain ratings. The reason for that difference, and whether the safety population was defined differently from the efficacy population, are not reported in the registry record. The safety counts should therefore not be substituted for the outcome-specific group counts or combined with them.

Zero recorded adverse events does not prove that no adverse events occurred beyond the observation and reporting captured by the registry. The record does not provide event descriptions, timing, severity beyond the serious/non-serious categories, or attribution assessments. It also does not provide enough information about safety follow-up completeness to assess whether all relevant events were observed. The death count alone does not establish a causal connection to either intervention.

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

The primary result is a comparison of mean pain ratings in the groups assigned to virtual reality and in-room television. The estimated mean difference is 0.28 in the direction of higher ratings in the television group, and the confidence interval crosses zero. The unadjusted p-value is 0.606. Together, these statistics indicate that the posted primary estimate is uncertain and does not distinguish clearly between no average difference and differences in either direction.

This is not evidence that the approaches are equivalent. Equivalence requires a prespecified margin defining differences small enough to be considered practically equivalent, together with an analysis designed to evaluate that claim. The registry does not report such a margin. Nor does the result establish that either approach is superior. The confidence interval and test do not provide a precise estimate of the direction or magnitude of any underlying difference.

The observed group means are averages of recorded ratings, not predictions for an individual patient. Ratings were collected as part of usual care and were summarized from repeated measurements. The registry does not specify in sufficient detail how all repeated observations were analyzed or how missing ratings were treated. Those limitations affect how confidently the reported summaries can be interpreted as estimates for the full randomized groups.

The registry describes the interventions as adjuncts to opioid and non-opioid medication. Consequently, the comparison concerns virtual reality room content versus television content within that context; it is not a comparison of medication with no medication, or of virtual reality with absence of all supportive care. The record does not report enough detail to determine how use of the assigned content, medication exposure, or other care varied across participants.

The secondary length-of-stay entries are not fully consistent with one another, and the registry does not report how multiple outcomes or analyses were handled. That secondary information therefore does not remove the uncertainty in the primary pain comparison. The trial results are specific to the patients, setting, interventions, outcome collection, and analysis captured in the record. They do not alone establish effects in other settings or populations, and they do not support medical advice.

17. Why This Trial Matters Statistically

This trial illustrates why a randomized design and a numerical result must be interpreted together with the way outcomes are measured and analyzed. Random allocation is intended to make groups comparable on average, but the registry’s brief design description does not include details about sequence generation, concealment, or analysis population. Those features help readers assess how well the randomized comparison was implemented and analyzed.

The primary endpoint is based on repeated ratings during usual care. Repeated measurement can capture changes over the period of interest, but it also creates an analysis question: ratings from the same person are generally related. Clear reporting of the unit of analysis, repeated-measures method, time points, and handling of missing observations is needed to understand how uncertainty was estimated. The registry describes when ratings were collected and how results were summarized, but does not report those modeling details.

The result also demonstrates why an estimate, confidence interval, and p-value should be read together. A point estimate gives the direction and scale of the observed contrast, while the interval describes uncertainty around it. A p-value alone cannot show clinical importance or establish that an intervention is beneficial. Here the interval includes zero, and the registry does not give a threshold for a clinically important change.

Finally, the length-of-stay entries show the importance of consistency across registry results. A posted comparison and a separately recorded test do not align, and the reason is not reported. That discrepancy is a reporting limitation that constrains interpretation, even though it does not determine which entry is correct. Transparent analysis plans, outcome definitions, missing-data reporting, and consistent numerical results are essential for readers to evaluate a clinical trial.

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 registry record leaves several trial-specific uncertainties. It does not report detailed eligibility criteria, so the boundaries of the intended hospitalized medical and surgical population cannot be assessed. It also does not provide the randomization sequence method or allocation concealment details. The masking status is NONE, but the record does not explain whether outcome assessors or other staff were aware of assignments beyond the intervention’s visible format.

The primary endpoint is described as repeated ratings during waking hours, summarized pre/post and in a time series. The precise construction of the pre- and post-intervention means, the analysis model, and handling of within-person correlation are not reported. Missing-data methods and outcome completeness are also not reported. The primary-outcome counts differ from the overall enrollment figure, but the registry does not explain the difference or identify reasons for unavailable ratings.

The record does not report the original sample-size justification, planned effect size, or the trial’s own statistical assumptions. It also does not report a complete statistical analysis plan, multiplicity handling, interim analyses, or stopping rules. These gaps limit evaluation of whether the reported analyses reflect prespecified choices. This absence of information should not be mistaken for evidence about what investigators did or did not do.

For length of stay, the posted comparison summary and separately reported two-sided t-test p-value do not agree, and the reason is not reported. The registry does not clarify whether the discrepancy reflects different analyses, a transcription issue, or another cause. Safety figures use 70 at-risk participants in each group, unlike the primary outcome counts, without an explanation of the populations. The registry also does not report attribution of the recorded death or detailed event follow-up.

These limitations concern interpretation of the registry record; they do not by themselves demonstrate that the trial was conducted improperly. They identify information needed to assess the reliability, applicability, and completeness of the posted estimates.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Immersive Virtual Reality Intervention for Non-Opioid Pain Management: A Randomized Controlled Trial — NCT02887989.
• Registry record last updated 2018-11-20; status last verified 2018-11.
• Results first posted 2018-11-20.
• 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 completed randomized, parallel-group trial of virtual reality versus in-room television content for hospitalized patients with pain. The interventions were intended for use as needed, for up to 20 days, alongside pain medication. Masking is listed as none.

The primary outcome was pain intensity on an 11-point numeric rating scale, with repeated ratings during usual care. The posted group means are 4.66 for virtual reality and 4.94 for television. The estimated difference, television minus virtual reality, is 0.28; its confidence interval crosses zero, and the unadjusted p-value is 0.606.

Length of stay is listed as a secondary outcome, but the registry’s comparison summary and separate test entry are inconsistent. Safety information records no serious or other adverse events, with 1 death in the virtual reality group and 0 in the television group; attribution is not reported. Details about missing data, analysis populations, multiplicity, and the original sample-size plan are not reported in the registry record.