Start Treatment and Recovery for Opioid Use Disorder: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Start Treatment and Recovery for Opioid Use Disorder (NCT04505540), a na na study. The primary outcome is Number of Participants With Self-reported Treatment Retention.

2. Clinical Question

In statistical terms, the primary question is descriptive: among participants in the Bridge Clinic group, what count was recorded for self-reported treatment retention at the specified follow-up? Because the registry record does not identify a concurrent comparison group or report the outcome count, it cannot establish a comparative treatment effect from the information recorded. The study’s outcomes also include measures of illicit opioid use, but their results are not reported in the registry record.

3. Trial Design

The record describes a completed, single-group study named “Start Treatment and Recovery for Opioid Use Disorder.” Its official title refers to the effectiveness of a Bridge Clinic following an emergency department-initiated intervention for opioid use disorder. The sponsor is the University of Vermont. The record lists enrollment as 104 and the study status as completed.

The design fields identify a single-group model, allocation listed as NA, and no masking. No randomized allocation or parallel control group is described. The skip note explicitly cautions that the arms are not a like-for-like control comparison. The registry record does not report a protocol-level rationale for selecting this design or explain whether any comparison with an external group was planned.

The intervention is identified as Bridge Clinic, with medication-assisted treatment supervised by an addiction bridge clinic until stabilization in treatment. The study purpose refers to emergency department-initiated buprenorphine/naloxone treatment and evaluation at 1 week, 3 months, and 6 months after treatment initiation. These descriptions establish the general setting and follow-up periods, but details such as eligibility criteria, treatment delivery procedures, clinic attendance requirements, and the definition of stabilization are not reported in the registry record.

The primary outcome is a count of participants with self-reported treatment retention at 1 week. The record also lists six outcome measures overall and three entries titled “Number of Participants With Illicit Opioid Use.” The outcome results and the timing details for those entries are not reported in the registry record.

The record gives a study start date of 2019-09-30 and a primary completion date of 2022-10-31. The phase is listed as NA. The record reports no analyses. It does not describe a statistical analysis plan, sample-size justification, interim analyses, or a prespecified approach to confounding and follow-up. As a result, the posted information supports a description of the study structure, but not a reconstruction of its full conduct or 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.

Baseline

Reasons for not completing this period:

1 Week Eligible to Self-report

Reasons for not completing this period:

1 Week Contacted for Self-report

Reasons for not completing this period:

1 Week Eligible for Urinanalysis

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.

Population: 94 participants were available for analysis after 10 were withdrawn from the study

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Self-reported Treatment Retention, measured over 1 week.

The primary endpoint is the number of participants with self-reported treatment retention, measured at 1 week. Its description defines retention as self-reported enrollment in treatment for opioid use disorder after 1 week. The unit is participants, and the outcome is recorded as a count rather than as a time-to-event measure or a continuous score.

A count can communicate how many participants met a stated outcome definition. For retention, this gives a straightforward summary of reported enrollment at the specified follow-up. It is relevant to the study’s stated aim of evaluating outcomes after treatment initiation, because continued enrollment in treatment is one way to describe engagement at that time. It does not, by itself, establish why a participant remained enrolled, how consistently treatment was received, or what happened after the measurement point.

Self-report is the specified source of the retention measure. The registry record does not report how the question was asked, how the response was verified, how the count was derived, or how participants without a recorded response were handled. It also does not provide the observed count or a denominator for this endpoint. Consequently, the endpoint definition can be described, but its observed frequency and precision cannot be assessed from the registry record.

Because the study has a single group and no identified like-for-like control, the endpoint is descriptive in this record. A count at 1 week would characterize reported retention within the group; without a comparative estimate and its uncertainty, it would not quantify a contrast between treatment strategies.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What kind of outcome is the primary measure?

General statistical explanation: a count outcome records how many participants meet a specified condition. Here, the condition is self-reported enrollment in treatment for opioid use disorder after 1 week. The registry classifies the outcome as a count of participants with an event. That wording describes the data type, not a finding. The observed count and the number of participants assessed for this endpoint are not reported in the registry record, so the count cannot be converted into a rate or proportion from the available information.

When interpreting a count, it matters whether the denominator is everyone enrolled, everyone eligible for follow-up, or only those with an observed response. The record does not specify the denominator or how missing responses were handled for the primary endpoint. The enrollment figure and the safety-group denominator do not establish the primary-outcome denominator.

What does the single-group design allow?

General statistical explanation: a single-group outcome estimate describes the observed experience in that group. A treatment effect is usually expressed through a contrast between outcomes under different treatment conditions. Without a concurrent control group or another defined comparison, a change or outcome within one group cannot by itself show what would have happened under an alternative strategy. This matters because outcomes can reflect influences other than the intervention, including differences in participants’ circumstances or events over follow-up. The registry identifies no like-for-like control comparison, and no comparative effect estimate is reported.

The record states that allocation is NA and masking is none. These entries do not describe randomized allocation or masked outcome assessment. Further details about recruitment, allocation procedures, or outcome-assessment safeguards are not reported in the registry record. The study phase is listed as NA, which does not provide an additional statistical design detail.

How should precision be assessed?

General statistical explanation: an estimate is more informative when its uncertainty is also reported. For a count or proportion, uncertainty depends on the observed result, the number of participants contributing data, and the statistical method. A confidence interval can communicate that uncertainty, but no interval is reported for the primary outcome. There are also no posted primary-outcome estimates or analysis results to assess. Therefore, neither the magnitude of the retention outcome nor its precision can be evaluated from the record.

The record gives an enrollment of 104, but does not show that all enrolled participants contributed to the primary endpoint. The safety group’s 94 participants at risk is specific to the adverse-event reporting fields and cannot be assumed to be the endpoint analysis population. The reasons for any difference in denominators, and the number with missing outcome data, are not reported.

What can be inferred from the posted analyses?

The record lists no analyses. It does not provide a statistical analysis plan, a model specification, adjusted estimates, or a description of hypothesis testing. Thus, no model assumptions or inferential procedures can be checked against the reported results. The outcome is a participant count, but that alone does not establish which statistical method, if any, was used to analyze it.

General statistical explanation: when counts are analyzed across groups or periods, the choice of method depends on the design, the outcome definition, and the data structure. If variability exceeds what a selected model assumes, over-dispersion can make standard errors too small and confidence intervals too narrow unless the method accounts for it. This is a general consideration, not a reported feature of this study. The registry record does not provide model output or enough detail to determine whether over-dispersion was relevant.

How should planning calculations be read?

General statistical explanation: sample-size calculations are planning illustrations based on assumptions about the effect to detect, allocation, significance level, and statistical method. They are not observed trial outcomes and should not be described as observed power. The record describes a planning-illustration approach based on a fraction of an observed effect, with two-sided significance level 0.05, equal allocation between two arms, and a normal approximation. However, this study is identified as single-group, and no sample-size justification or two-arm trial design is reported in the registry record. Any planning figures associated with such assumptions would not constitute evidence that this study had a particular achieved power. The registry record does not report the study’s own sample-size justification.

The assumptions for a planning calculation are not a substitute for the analysis plan. They cannot establish which endpoint was used to determine enrollment, whether any interim analysis occurred, or how the final results were analyzed. Those details are not reported in the registry record.

What does the safety count represent?

The safety information is a descriptive count for the Bridge Clinic group. The record identifies 94 participants at risk, with zero serious adverse events, zero other adverse events, and zero deaths. General statistical explanation: event counts are most interpretable when the record also defines the event categories, the period under surveillance, the ascertainment procedure, and the denominator. Those supporting details are not reported. The counts should therefore be read as registry-recorded values, not as a complete characterization of safety or a comparison with another group.

Overall, the statistical methods that were actually used to analyze outcomes are not reported in the registry record. The study design and outcome definitions support a limited description of what was intended to be measured, but the absent analysis results prevent evaluation of effect size, uncertainty, or model adequacy.

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("Bridge Clinic")
n      <- c(93)
events <- c(51)
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  Bridge Clinic  93  51  54.8  44.2  65.2  44.7  64.6  44.7  64.6

11. Multiplicity, Missing Data and Analysis Populations

The record lists six outcome measures, including three entries with the title “Number of Participants With Illicit Opioid Use.” The primary endpoint is self-reported treatment retention at 1 week. The repeated secondary-outcome titles do not, on their own, specify the distinct assessment times, definitions, or analysis procedures for each entry. Those details are not reported in the registry record.

Multiplicity arises when several outcomes or comparisons are analyzed, because the chance of obtaining at least one apparently notable result can increase as more tests are considered. General statistical explanation: researchers may address this through prespecified outcome hierarchies or statistical adjustment, depending on the study aims and analysis plan. The registry record does not report a multiplicity strategy, a hierarchy among secondary outcomes, or inferential results for these outcomes. It is therefore not possible to assess how multiplicity was handled or whether it affected interpretation.

Missing-data procedures are not reported. The record does not state how participants who missed follow-up, declined to respond, or had incomplete outcome information were handled. It also does not provide endpoint-specific denominators or the number of missing observations. These omissions prevent assessment of whether the recorded outcomes represent all enrolled participants or only a subset with available data.

Analysis populations are not described for the primary outcome. The population field for that outcome is blank, and the record does not identify an intention-to-treat, per-protocol, or other analysis population. The enrollment figure of 104 is not necessarily the number contributing to each measure. The 94 participants listed as at risk for safety outcomes should not be treated as the denominator for the retention or illicit opioid use outcomes.

The record reports no analyses, so there is no posted account of exclusions, missing-data sensitivity analyses, or outcome-specific models. These details are not reported in the registry record.

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.

The Bridge Clinic safety entry lists 94 participants at risk. It records zero serious adverse events, zero other adverse events, and zero deaths for that group. These values are counts in the registry record; they are not comparative estimates because no control group is identified.

The safety denominator is not the same as the enrollment figure of 104. The reason for the difference is not reported in the registry record. The 94 participants at risk apply to the safety entry and should not be assumed to represent the number assessed for the primary retention outcome or for every other outcome.

General statistical explanation: a zero recorded event count is not equivalent to proof that the underlying risk is zero. Its interpretation depends on how events were defined, actively sought, documented, and attributed, as well as on the observation period and completeness of follow-up. The registry record does not report those details, nor does it list serious adverse event terms for this group.

The adverse-event counts therefore describe what was recorded in the registry, rather than providing a complete evaluation of safety or a comparison of risks across treatments. The registry record does not report an analysis of adverse events or uncertainty intervals around the counts.

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

The record describes a completed, single-group study focused on a Bridge Clinic following an emergency department-initiated intervention for opioid use disorder. It defines the primary outcome as the number of participants who self-reported enrollment in treatment after 1 week. This establishes what the primary measure was intended to capture, but the registry record does not report its observed value.

As a result, the posted results do not quantify treatment retention at the primary follow-up. They also do not provide a confidence interval, a p-value, or another measure of uncertainty for that endpoint. The three listed illicit opioid use outcomes have no reported results in the record. The study summary mentions evaluation at 1 week, 3 months, and 6 months, but outcomes at those follow-up times are not reported in the registry record.

The safety entry records zero serious adverse events, zero other adverse events, and zero deaths among 94 participants at risk in the Bridge Clinic group. These counts can be stated as recorded, but the registry does not report enough information about event definitions or surveillance to interpret them as a complete account of safety. They also do not provide a comparison with another treatment group.

What the record does not establish is equally important. A single-group study with no like-for-like control comparison cannot, from its within-group outcomes alone, distinguish the effect of the intervention from other influences. The record does not report a randomized comparison, an adjusted treatment effect, or an analysis that accounts for differences in participants or follow-up. It therefore does not provide a causal estimate comparing Bridge Clinic care with an alternative.

General statistical explanation: a study can be informative about feasibility, implementation, and outcomes observed in a group, while still being unable to estimate a causal contrast. The distinction is between describing outcomes and attributing those outcomes to a particular intervention. Here, the registry’s design information permits the former in principle, but the missing outcome results limit even that description. The information recorded cannot establish whether retention was high or low, whether opioid use changed, or whether outcomes differed from those under another approach.

The appropriate reading is consequently narrow: the registry describes the intervention and intended measurement, and it records the specified safety counts. The primary and secondary outcome results, their uncertainty, and a comparative treatment effect are not reported in the registry record.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of why design and result availability matter alongside an outcome definition. The primary endpoint is clearly named as a count of participants with self-reported treatment retention at 1 week. Yet the registry record does not give the observed count, its denominator, or an uncertainty estimate. A well-defined measure cannot answer a clinical research question quantitatively when its result is not reported.

The single-group design also shapes what can be learned. A count in one group may describe outcomes among participants who received the Bridge Clinic intervention, but it cannot by itself show how those outcomes compare with another strategy. Since no like-for-like control comparison is identified, causal interpretation is limited even if a within-group result were available.

The record further illustrates the importance of keeping denominators tied to their outcomes. Enrollment is listed as 104, while 94 participants are at risk in the safety entry. The record does not explain that difference, and the safety denominator should not be treated as the denominator for treatment retention. Outcome-specific denominators are needed to understand how many observations support each result.

Finally, the study lists multiple outcome measures but reports no analyses. Without outcome results, missing-data details, or a stated multiplicity approach, readers cannot assess precision or understand how the different outcomes were handled statistically. These are not merely technical details: they determine what conclusions the reported data can support.

The broader statistical lesson is that interpretation depends on the full chain from design, to measurement, to analysis, to reporting. The registry record supplies important design and endpoint descriptions, but does not provide the primary outcome result needed to quantify the central study question.

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.

Several limitations specific to this record constrain interpretation. First, the primary outcome is defined, but its observed count is not reported. The record also does not give an endpoint-specific denominator, so the number of participants contributing data to the retention measure cannot be determined.

Second, the study is single-group, with allocation listed as NA and no masking. No like-for-like control comparison is identified. Any outcomes observed within the Bridge Clinic group would therefore not, on their own, establish what outcomes would have occurred under an alternative strategy. The registry record does not report a comparative estimate or an adjustment for other influences.

Third, enrollment is listed as 104, whereas the safety group lists 94 participants at risk. The reason for this difference is not reported in the registry record. No outcome-specific participant flow or explanation of exclusions is included in the record. The safety denominator cannot stand in for missing denominators for the efficacy outcomes.

Fourth, the outcome information is incomplete for interpretation. The registry lists six outcome measures and three entries titled “Number of Participants With Illicit Opioid Use,” but does not report their results or the timing details for those entries. It also does not provide a missing-data strategy, analysis populations, statistical analysis plan, or multiplicity procedure.

Finally, the adverse-event record gives zero counts but does not describe definitions, surveillance, timing, or completeness. Those counts are not a comparative safety analysis. The registry record’s stated study purpose includes follow-up at 1 week, 3 months, and 6 months, but the primary outcome entry addresses 1 week and outcome results at the stated follow-ups are not reported. These gaps limit both the descriptive conclusions and any broader inference.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Start Treatment and Recovery for Opioid Use Disorder — NCT04505540.
• Registry record last updated 2023-12-11; status last verified 2023-12.
• Results first posted 2023-12-11.
• 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, single-group study sponsored by the University of Vermont, with enrollment of 104. The intervention is Bridge Clinic medication-assisted treatment supervised until participants were stabilized in treatment. The record identifies no like-for-like control comparison and lists masking as none.

The primary outcome is the number of participants self-reporting enrollment in opioid use disorder treatment after 1 week. Its result is not reported in the registry record. The record lists six outcome measures and no analyses. It records zero serious adverse events, zero other adverse events, and zero deaths among 94 participants at risk in the Bridge Clinic safety group.

The registry record does not report the primary outcome denominator, outcome results, statistical analysis plan, missing-data methods, or analysis populations. The study design and posted information support a limited description of the intended measurement and recorded safety counts, but do not provide a quantified treatment effect or comparative conclusion.