Emergency Department Outcomes for Patients With Opioid Use Disorder: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Emergency Department Outcomes for Patients With Opioid Use Disorder (NCT04289363), a registered phase not stated study. The primary outcome is Percent of Participants Who Received Emergency Department (ED)-Initiated/Expedited Buprenorphine (BUP).

2. Clinical Question

3. Trial Design

The registry describes a completed study titled Emergency Department Outcomes for Patients With Opioid Use Disorder, sponsored by NYU Langone Health. The recorded start date is 2020-11-25, and the primary completion date is 2022-01-28. Enrollment is 53. The listed intervention is clinical program implementation, a behavioral intervention. The study summary describes a mixed-methods evaluation that triangulates multiple sources of data collected during the parent study and ancillary studies. Its stated focus includes the feasibility, acceptability, sustainability, and impact of an ED-initiated buprenorphine clinical program and implementation facilitation strategy, as well as factors influencing diffusion and effectiveness.

The primary outcome is a percentage measure with a timeframe of up to Month 12. Its population description refers to 1489 adult ED patients identified through retrospective chart review and data matching as having nonmedical opioid use. That analytic population is not the same description as the overall enrollment figure, and the registry record does not explain how the figures relate. The outcome description names the IF and Post-IF periods and then ends with an incomplete period reference; the remaining period definition is not reported in the registry record.

The record lists ED patients and patients identified via chart review, including an arm description focused on administrative and health record data used to assess screening, assessment, and eligibility determination. It does not describe a randomized allocation or a like-for-like control arm. The timing and operational details of data collection, the precise implementation sequence, and the statistical analysis plan are not reported in the registry record. Although the study is marked completed, that status alone does not establish that outcome results or detailed analyses are available.

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.

Before assignment: Certain Outcome Measures of the current study were pre-specified to utilize participants not enrolled in the study. These participants are represented in the "Patients Identified via Chart Review" arm. As these participants were not enrolled in the study, they are not counted in the Protocol Enrollment. Enrolled participants are represented in the "ED Patients" arm.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The overall number of participants analyzed for this outcome measure (n=1489) represents individuals identified via retrospective chart review and data matching for all adult emergency department (ED) patients identified to have nonmedical opioid use presenting to the ED during the IF, Post-IF or Maintenance periods. This outcome was not assessed among participants in the ED patients arm.

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 Percent of Participants Who Received Emergency Department (ED)-Initiated/Expedited Buprenorphine (BUP), measured over Up to Month 12.

The primary endpoint is the percentage of participants who received ED-initiated or ED-expedited buprenorphine, with a timeframe of up to Month 12. The registry defines the numerator as candidates who receive ED-initiated buprenorphine with any disposition, together with candidates who receive ED-expedited buprenorphine and are discharged. Its denominator combines candidates who are discharged with candidates who receive ED-initiated buprenorphine but are not discharged. The registry record does not further explain how candidates are identified, how overlapping categories are handled, or how records with incomplete information are treated.

This measure is used to describe a program-related care process: whether the specified ED patient population received buprenorphine through the listed initiation or expedited pathways. In general, a process percentage can help characterize reach and implementation in a defined setting. It does not by itself establish why the observed rate occurred or what would have happened under a different implementation strategy. Nor does it measure all aspects of subsequent care or patient outcomes. The registry specifies a 95% confidence interval as the measure of dispersion, but reports no endpoint percentage or interval estimate. Consequently, the observed rate and its statistical precision are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a percentage, so its basic statistical interpretation depends on a numerator and a denominator. Here, the registry defines both in terms of candidates’ disposition and receipt of ED-initiated or ED-expedited buprenorphine. A percentage summarizes the frequency of a defined event within a defined group. It is not automatically a rate per unit of time, and it is not necessarily the proportion of every person who entered the ED or every person with opioid-use disorder. The specific eligibility and denominator rules determine the population to which the estimate applies.

What does the confidence interval describe?

A confidence interval is a way to express uncertainty around an estimated quantity. In general, an interval that is more concentrated indicates greater statistical precision under the assumptions used to calculate it; a broader interval indicates more uncertainty. The registry names a 95% confidence interval for the endpoint but does not report its bounds or the method used to calculate it. Therefore, neither the estimated percentage nor its precision can be assessed from this record. A confidence interval also does not correct for bias in how patients were identified, how records were selected, or how the outcome was defined.

Why does the denominator matter?

The endpoint denominator is not described simply as all identified candidates. It combines candidates who are discharged with candidates who receive ED-initiated buprenorphine and are not discharged. The numerator also distinguishes ED-initiated receipt with any disposition from ED-expedited receipt among discharged candidates. These definitions make the endpoint specific to the program’s operational pathway. In general, changing inclusion criteria or the handling of disposition can change the meaning of a percentage, even when the numerator is described in similar terms. The registry record does not provide further rules for categorizing repeat visits, incomplete records, or candidates with unclear status.

The population description cites retrospective chart review and data matching. Such sources can support analysis of care processes across records, but their interpretation depends on the completeness and consistency of documentation and matching. These are general considerations, not reported findings about the quality of this study’s data. The registry record does not report validation procedures, missing-record rates, deduplication rules, or the handling of conflicting information. It also does not fully state the final period included in the outcome population description.

How should the design shape interpretation?

The study summary describes mixed methods and triangulation across multiple data sources, and the record identifies an implementation evaluation rather than a randomized comparison. In general, triangulation can bring different forms of evidence to bear on questions about implementation, but it does not make distinct data sources equivalent or remove the need to explain how each source was analyzed. The statistical analysis plan, qualitative analytic approach, and integration procedures are not reported in the registry record. No causal effect can be inferred from a percentage alone, particularly without a stated randomized comparison or a reported adjustment strategy.

The record includes sample-size planning assumptions for an illustration: a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect specified as a fraction of the observed effect. It also distinguishes planning outputs for time-to-event outcomes from those for other outcomes. These are planning conventions, not evidence of the study’s original design or observed power. The registry record does not report the numerical observed effect used for the illustration, a numeric planning estimate, or a protocol-based sample-size justification. Because the study is not described as a randomized comparison and no two-arm allocation is stated, those illustrative assumptions should not be read as a description of the actual implementation evaluation.

In general, percentage estimates may be affected by clustering if outcomes from the same site, clinician, or patient are correlated. Over-dispersion, meaning more variability than a simple statistical model assumes, can also make standard errors and confidence intervals too narrow if it is ignored. These are general methodological considerations, not established features of this analysis. The registry record does not report whether clustering, repeated presentations, over-dispersion, or other model assumptions were assessed or addressed. It also does not describe an adjusted model, covariates, or a method for comparing implementation periods.

The registry lists eight outcome measures and names several secondary measures, including receipt percentages under alternative definitions and changes in reported drug-use days and overdose events. For multiple outcomes, general statistical practice may require attention to the number and priority of tests, since examining many results can increase the chance of at least one apparently notable finding. No multiplicity strategy or hierarchy is reported. Since no outcome estimates are reported, there is no basis for evaluating the magnitude, precision, or consistency of findings across those measures.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Patients Identified Via Chart Review")
n      <- c(1489)
events <- c(587)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Patients Identified Via Chart Review  1489  587  39.4  36.9  42.0  37.0  41.9  37.0  41.9

11. Multiplicity, Missing Data and Analysis Populations

The registry lists eight outcome measures. Among the named secondary outcomes are percentages of discharged, non-admitted, and other participants receiving ED-initiated buprenorphine; a measure of ED-initiated or expedited receipt; and changes in reported days of opioid or other drug use and self-reported opioid-related overdose events. The record does not state how these outcomes were prioritized relative to one another or whether any statistical adjustment for multiple comparisons was planned. In general, examining several outcomes can increase the chance of chance findings, so a prespecified hierarchy or multiplicity approach can help readers interpret a family of tests. The registry record does not report such an approach.

Missing-data methods are not reported in the registry record. It does not explain how incomplete administrative records, missing outcome fields, unavailable follow-up assessments, or participants with uncertain eligibility were handled. The record also does not state whether the primary percentage uses only complete records or applies any imputation or sensitivity analysis. These omissions matter because the denominator and the observed percentage can depend on how missing or ambiguous records are treated.

The primary outcome population is described as 1489 individuals identified through retrospective chart review and data matching, while overall enrollment is 53. The record does not reconcile these figures or specify how they relate to the study’s analysis populations. The complete population description and final period label are not reported in the registry record. It also does not identify a per-protocol, intention-to-treat, or other analysis population. No analysis entries or numerical outcome results are reported, so the handling of analysis populations cannot be evaluated.

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

The primary measure is intended to describe a defined aspect of ED program implementation: receipt of ED-initiated or ED-expedited buprenorphine under the endpoint’s stated numerator and denominator rules. If reported, it would describe the frequency of that process among the specified candidates in the relevant records and timeframe. It would not, on its own, establish that the implementation strategy caused a change in receipt, since the registry does not describe a randomized comparison or a like-for-like control group.

The endpoint is also not a comprehensive measure of clinical benefit, patient experience, or longer-term outcomes. The study summary refers to feasibility, acceptability, sustainability, and impact, but the primary percentage alone cannot resolve all of those questions. The record lists secondary measures involving drug-use days and self-reported overdose events, but it does not report their results. No conclusion about those outcomes can be drawn from their presence in the registry.

The record does not provide the primary percentage, its 95% confidence interval, or numerical results for the listed secondary measures. It therefore cannot establish whether the measured process was common or uncommon in the analyzed population, how precise an estimate would be, or whether outcomes differed across periods. The 53 enrollment figure and the 1489-person chart-review population describe different quantities in the record, and their relationship is not explained. They should not be used as substitutes for the endpoint denominator.

In general, a confidence interval would communicate uncertainty around an estimate, while the study design and data definitions would shape how far that estimate can be generalized or interpreted causally. Neither uncertainty nor causal attribution can be assessed without the missing results and methodological details. The registry status of completed indicates the study is recorded as completed; it does not itself demonstrate a particular result or establish that the intervention did or did not achieve its aims.

13. Why This Trial Matters Statistically

This study raises a useful statistical distinction between evaluating an implementation process and estimating a treatment effect. The primary measure focuses on whether patients in a specified ED population received buprenorphine through particular pathways. For implementation questions, defining who is eligible, which encounters count, and how discharge status enters the denominator is central to making the estimate interpretable.

The record also describes the use of retrospective chart review and data matching, alongside a mixed-methods evaluation drawing on multiple sources. In general, combining administrative, health-record, and other evidence can help describe different dimensions of implementation. Statistical interpretation still depends on clear population definitions, reliable record linkage, transparent missing-data procedures, and an explanation of how sources contribute to each conclusion. Those details are not reported in the registry record.

The difference between overall enrollment of 53 and the primary outcome population of 1489 illustrates why registry counts need context. Different sources and analytic populations can serve different purposes, but readers need an explicit account of how they relate before using either figure to judge precision or representativeness. The record does not provide that account.

Finally, the absence of reported outcome estimates is consequential: a stated endpoint and confidence-interval plan define what could be assessed, but they do not show the observed result. The registry record identifies an important implementation measurement question while leaving the numerical findings and key analytic details unreported. That distinction prevents planned measurement from being mistaken for evidence about the magnitude or certainty of an outcome.

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.

Several limitations are specific to the available registry description. The primary endpoint estimate and its 95% confidence interval are not reported, and the record lists no analysis entries. As a result, the central statistical finding cannot be assessed. The endpoint description gives a numerator and denominator formula but does not explain candidate identification in operational detail, treatment of repeat presentations, handling of overlapping categories, or the processing of incomplete records.

The relationship between enrollment of 53 and the primary outcome population of 1489 is not explained. Because the outcome population is described as adult ED patients found through retrospective chart review and data matching, it should not automatically be read as the enrolled study population. The record does not clarify the analytic role of each group or provide a complete account of the periods included; its final period reference is incomplete.

The study is not described as a randomized comparison, and allocation is not stated. No like-for-like control comparison is identified. The record also does not report an analysis plan, adjustment methods, site or encounter structure, missing-data approach, multiplicity strategy, or validation of the administrative and health-record data. These omissions limit assessment of precision, potential bias, and the interpretation of differences across periods or groups.

The study summary describes mixed methods, but the registry record does not specify how qualitative and quantitative findings were analyzed or integrated. Adverse-event entries display zeros, but the record does not clarify whether those values represent confirmed absence, lack of recorded events, or another reporting convention. They cannot support a conclusion that no adverse events occurred.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Emergency Department Outcomes for Patients With Opioid Use Disorder — NCT04289363.
• Registry record last updated 2023-07-06; status last verified 2023-06.
• Results first posted 2023-07-06.
• 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.

18. Record Summary

The registry record describes a completed mixed-methods evaluation of an ED-initiated buprenorphine clinical program and implementation facilitation strategy. The registered intervention is clinical program implementation, classified as behavioral. Overall enrollment is 53. The primary endpoint is a percentage of participants receiving ED-initiated or ED-expedited buprenorphine, with a timeframe of up to Month 12 and a specified disposition-based numerator and denominator. Its population description refers to 1489 adult ED patients identified through retrospective chart review and data matching, but the relationship to overall enrollment is not explained.

The record names a 95% confidence interval but reports no primary estimate or interval bounds. It lists eight outcome measures and no analysis entries. A randomized comparison, detailed statistical plan, missing-data procedures, multiplicity strategy, and full analysis-population definitions are not reported in the registry record. Thus, the record documents the evaluation question and measurement framework, but not numerical results from which the primary outcome or its precision can be interpreted.