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 Hepatitis C-Video vs. Brochure Education Delivery (NCT04204447), a non-randomized na study. The primary outcome is Improvement in Scores on HCV Knowledge Questionnaire.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04204447 |
| Phase | NA |
| Condition | Hepatitis C |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 176 |
| Arms in the primary outcome | n/a |
| Lead sponsor | State University of New York at Buffalo |
| Results posted | Yes |
2. Clinical Question
Population
Patients on opiate replacement therapy with a history of hepatitis C were the intended population. The registry record describes a 25-item hepatitis C knowledge assessment but does not give further eligibility criteria or a detailed description of the enrolled population.
Intervention
Participants in the video intervention were asked to watch an educational video about hepatitis C. The study description identifies interactive video education as the approach under investigation.
Comparator
Participants in the brochure intervention were asked to read an educational brochure about hepatitis C. The comparison concerns the delivery format for education, rather than a treatment for hepatitis C.
Primary question
The primary question is whether knowledge-assessment scores changed after education and at 1 mo. follow up, and how the score changes compare between the video and brochure groups. The registry record names improvement in scores on the HCV Knowledge Questionnaire as the primary outcome, but does not report the observed scores or a comparison of changes.
The registry record frames the study around information retention and medical decision making in patients on opiate replacement therapy with a history of hepatitis C. The assessment is intended to capture correct responses to questions arising from the educational material. As the allocation was non-randomized, any observed difference between groups would need to be interpreted as an association in this study, not automatically as an effect caused by the education format. The record does not report enough outcome data or analysis details to determine whether scores changed, whether the groups differed, or how precise any comparison was.
3. Trial Design
This was a prospective, non-randomized, parallel-group study comparing hepatitis C education delivered by video with education delivered by brochure. The registry record lists no masking. The recorded enrollment was 176, and the study status is completed. The study started on 2019-11-27, with primary completion on 2020-10-31. The sponsor is State University of New York at Buffalo.
The intervention descriptions specify that participants in one group were asked to watch an educational video and participants in the other were asked to read an educational brochure. The record does not report how participants were assigned to those groups, whether allocation depended on participant or site characteristics, or whether the groups were recruited in the same way. Because allocation was non-randomized, baseline differences between groups may be relevant when interpreting a comparison. The record does not report baseline characteristics that would allow those differences to be assessed.
The primary outcome was scheduled at pre-intervention, immediate post-intervention, and 1 mo. follow up. The registry record describes one primary outcome measure, but lists no analyses and gives no numerical outcome results. It therefore does not establish whether all enrolled participants completed each assessment, how many contributed outcome data at each time, or whether the planned time points were analyzed as repeated observations.
The safety record lists 86 participants at risk in the video group and 90 in the brochure group. These figures sum to the recorded enrollment of 176, but they are safety denominators and do not by themselves describe the number with available questionnaire scores at each time point. The registry record does not state a randomization procedure, masking procedures, a statistical analysis plan, or a sample-size justification. Those design details should not be inferred from the study title or from the fact that the study is marked completed.
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 | Brochure Intervention | Video Intervention |
|---|---|---|
| STARTED | 90 | 86 |
| COMPLETED | 83 | 81 |
| NOT COMPLETED | 7 | 5 |
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 | Brochure Intervention | Video Intervention | Total |
|---|---|---|---|---|
| Participants analysed | 90 | 86 | 176 | |
| Age, Continuous | years | 43 (SD 11) | 41 (SD 12) | 42 (SD 11) |
| Sex: Female, Male: Female | Participants | 55 | 51 | 106 |
| Sex: Female, Male: Male | Participants | 35 | 35 | 70 |
| Race (NIH/OMB): Other race – American Indian or Alaska Native | Participants | 1 | 0 | 1 |
| Race (NIH/OMB): Other race – Asian | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Other race – Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Other race – Black or African American | Participants | 12 | 1 | 13 |
| Race (NIH/OMB): Other race – White | Participants | 76 | 74 | 150 |
| Race (NIH/OMB): Other race – More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Other race – Unknown or Not Reported | Participants | 1 | 11 | 12 |
6. Primary Endpoint
The registry lists the primary outcome as Improvement in Scores on HCV Knowledge Questionnaire, measured over Pre-intervention, Immediate post-intervention, and 1 mo. follow up.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | Improvement in scores |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is described as improvement in scores on the HCV Knowledge Questionnaire. It is a continuous measure: the assessment contains 25 items, with one point for each correct answer, and scores range from 0 to 25. The record states that the questions arise directly from the information contained in the video and that an increase in score indicates more correct responses. The assessment has no subscales.
Knowledge scores are used to quantify how many questions a participant answers correctly, rather than relying only on a general impression of whether the information was understood. The scheduled assessments—pre-intervention, immediate post-intervention, and 1 mo. follow up—could describe knowledge before education, shortly afterward, and later. A comparison of score changes between groups could address whether the two delivery formats were associated with different patterns of knowledge scores, provided the analysis appropriately accounts for the study design and available observations.
The registry record does not report the actual mean scores, standard deviations, changes from baseline, or a between-group estimate. It also does not explain exactly how “improvement” was calculated for the primary endpoint or specify which time-point comparison was the main statistical contrast. Consequently, the endpoint definition clarifies what was intended to be measured, but not what the study found.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clinically relevant educational comparison: video versus brochure delivery of hepatitis C information for patients on opiate replacement therapy with a history of hepatitis C. It also specifies a knowledge questionnaire and assessment times. Those details define the intended outcome, but they are not results. No questionnaire scores, group means, standard deviations, changes, between-group estimates, confidence intervals, or p-values are reported in the registry record. There is therefore no posted numerical basis for describing the direction, size, statistical uncertainty, or statistical significance of a knowledge-score comparison.
The study is marked completed, but completion status does not itself show that the primary outcome changed or that one format was associated with a larger change. The record lists 176 enrolled participants and safety denominators of 86 for the video group and 90 for the brochure group. Those denominators do not establish how many questionnaire observations were available at each scheduled assessment. They also cannot substitute for outcome results or for an analysis of change.
Non-randomized allocation matters for interpretation. In general, random allocation is intended to balance measured and unmeasured characteristics across groups on average. Without randomization, group membership may be related to characteristics that also affect knowledge scores or score changes. For example, prior familiarity with hepatitis C or differences in how participants encountered the educational material could be relevant in principle; the registry record does not report whether such factors were measured or adjusted for. This is a general design consideration, not a claim that any particular imbalance occurred in this study.
The record does not report the method used to compare groups, whether baseline scores were incorporated into the analysis, or how observations across the assessment times were handled. A numerical difference, if reported, would need to be interpreted alongside its uncertainty and the analysis method. Without those results, neither the magnitude nor the precision of a group comparison can be assessed. No conclusion that either delivery format produced more knowledge is supported by the registry information available.
Any sample-size planning illustration should be read as a hypothetical planning calculation, not as evidence of an observed effect or as “observed power.” The record describes planning assumptions based on an observed effect, but it does not report the outcome estimates needed to evaluate that effect. Planning calculations cannot replace a reported estimate and its uncertainty. In particular, they do not resolve the limitations associated with non-randomized allocation, unavailable outcome results, or unreported handling of missing observations.
The safety figures are separate from the knowledge endpoint. The record lists zero serious adverse events and zero other adverse events in each group, along with zero deaths. These entries describe what is recorded in the safety portion of the registry; they do not provide evidence about the effectiveness of either educational format. The safety record also does not describe how adverse events were collected or over what period they were assessed.
9. Statistical Methods Explained
The primary outcome is continuous, so a natural descriptive summary would be a mean score with a measure of variability such as a standard deviation. The mean describes the average score in a group, while the standard deviation describes how dispersed individual scores are around that average. The registry record names the mean and standard deviation as the outcome summary, but does not provide either quantity. The score range of 0 to 25 also gives the scale on which any reported mean would need to be interpreted.
What would a change score represent?
In general, a change score expresses how a participant’s measurement differs between specified assessment times. For this study, the record identifies pre-intervention, immediate post-intervention, and 1 mo. follow up as assessment times. A change from pre-intervention to immediate post-intervention would describe the short-term score movement; a comparison involving follow up would address whether scores were maintained or changed later. These are general interpretations of possible contrasts. The registry record does not specify which change comparison was the primary analysis or report any calculated changes.
For a comparison of education formats, a group contrast in change would ask whether the average score movement differed between the video and brochure groups. The estimated contrast would describe the size and direction of the association in the analyzed participants. It would not, on its own, establish that format caused the difference, particularly with non-randomized allocation. The record does not report a group contrast or its statistical method.
Why does the study design matter?
In general, non-randomized groups can differ before an intervention begins. If characteristics related to group assignment also relate to the outcome, a simple comparison may combine differences associated with the format and differences that existed between groups. Adjustment for measured baseline characteristics can sometimes address measured differences, but it cannot guarantee removal of unmeasured confounding. Whether the study measured or adjusted for relevant characteristics is not reported in the registry record. No adjusted or unadjusted estimates are posted.
Repeated observations from the same participant are related rather than independent. In general, an analysis of measurements collected at multiple times should account for that within-person relationship, or define an appropriate change outcome. Treating repeated measurements as unrelated observations can misrepresent uncertainty. The registry record does not say whether repeated-measures methods were used, whether each time point was analyzed separately, or whether the analysis focused on a particular contrast.
How should uncertainty be assessed?
In general, a confidence interval gives a range of values compatible with the data and the assumptions of the statistical method. Its width reflects precision: a wider interval indicates greater uncertainty about the estimate, while a narrower interval indicates greater precision. A p-value, when used, measures how unusual the observed data would be under a specified null hypothesis and model; it does not measure the probability that a hypothesis is true or the importance of a finding. Neither confidence intervals nor p-values for the primary outcome are reported in the registry record. The absence of these results means that precision and statistical evidence cannot be evaluated.
Standard deviations describe variability among observed scores, whereas standard errors and confidence intervals describe uncertainty in estimated quantities. Those measures answer different questions and should not be treated as interchangeable. The registry record does not provide the values needed to characterize score variability or estimate uncertainty. In general, an estimate should be presented with its scale, the groups and time points compared, the number of observations contributing, and an uncertainty interval when available.
What role does the sample-size illustration have?
In general, a sample-size calculation is a planning exercise. It asks how many participants per arm would be needed under stated assumptions about the effect to detect, significance level, allocation, and statistical approximation. The assumptions recorded for the planning illustration include a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the target effect is described as a stated fraction of the observed effect. Such calculations do not report what happened in the trial. They are not observed power, and they do not show whether an effect was detected. The registry record does not report the study’s own sample-size justification. No planning value should be taken as an observed outcome result.
In general, over-dispersion matters when analyzing count outcomes: it occurs when variability exceeds what a chosen count model expects and can make standard errors too small if ignored. That issue is not directly indicated by this primary endpoint, which is a bounded continuous score rather than a count of events. For a bounded score, the distribution, possible ceiling or floor effects, and suitability of the chosen model may be relevant. The record does not report a distributional assessment or model choice, so no claim can be made about how those features were handled.
Finally, statistical significance and practical meaning are not interchangeable. In general, a small p-value does not establish a large or important difference, while a non-significant result does not establish that groups are equivalent. Interpreting the outcome would require an estimate of the difference, its precision, context for the score scale, and an understanding of the study’s limitations. Those outcome and analysis details are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record identifies one primary outcome measure but does not report a statistical analysis plan, a multiplicity strategy, or analysis results. It does not say which of the scheduled assessment times was designated for the primary comparison, whether comparisons at multiple times were planned, or whether any additional outcomes or subgroup analyses were considered. When several comparisons are examined, the chance of at least one apparently unusual result can increase; in general, a prespecified strategy helps clarify how multiple tests are handled. No such strategy is reported in the registry record.
Missing data are also not described. The record does not report how many participants completed the questionnaire at pre-intervention, immediately after the intervention, or at 1 mo. follow up. It does not explain whether incomplete questionnaires were scored, whether participants with missing observations were excluded, or whether any statistical method was used to address missing data. In general, missingness can affect an estimate when participants with observed outcomes differ in relevant ways from those without observed outcomes. Without counts and methods, the extent and possible implications of missingness cannot be assessed.
The record does not identify an analysis population, such as all enrolled participants or only participants with complete questionnaire data. It does not report whether exclusions occurred or how the analysis population related to the safety denominators. No outcome analyses are listed. Thus, the reported enrollment and safety counts should not be interpreted as the number of participants included in every primary-outcome analysis.
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 |
|---|---|---|---|
| Video Intervention | 0 | 86 | 0.0% |
| Brochure Intervention | 0 | 90 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Video Intervention | 0 of 86 |
| Brochure Intervention | 0 of 90 |
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 |
|---|---|
| Video Intervention | 0 of 86 |
| Brochure Intervention | 0 of 90 |
The safety record lists the video group with 86 participants at risk and the brochure group with 90 participants at risk. It records 0 serious adverse events, 0 other adverse events, and 0 deaths in each group. These are registry entries for safety outcomes; they are not estimates of questionnaire scores or effects of education on knowledge.
A zero count in the registry means that no events of that type are recorded for the listed group in this record. It does not, by itself, establish that no events occurred outside the reporting or observation process. The registry record does not describe how adverse events were defined, elicited, verified, or monitored, nor does it give a safety observation period. The listed denominators also do not indicate whether every participant completed every knowledge assessment.
These figures should therefore be read narrowly as the posted safety counts. They do not establish a comparative safety advantage, and they do not answer the primary educational question. No further inference about the safety of either educational format follows from the entries alone.
12. What the Result Does, and Does Not, Mean
The registry record establishes what the study set out to compare and how it intended to measure knowledge: video education versus brochure education, with a 25-item HCV knowledge assessment scheduled before intervention, immediately afterward, and at 1 mo. follow up. The score ranges from 0 to 25, with one point for each correct answer. The record also identifies the study as non-randomized and completed.
Those details do not establish what the study found. Numerical score results and analyses are not reported in the registry record. It is therefore not possible to say whether scores increased, whether changes differed between groups, how large any difference was, or how precisely it was estimated. The record does not support a conclusion that video education was superior, inferior, or equivalent to brochure education.
Even if a group difference were reported elsewhere, the non-randomized allocation would remain important when interpreting cause and effect. In general, differences between groups may reflect participant characteristics or other factors associated with allocation, as well as the education format itself. Whether those factors were measured or accounted for is not reported. A completed study status does not resolve this issue or substitute for a statistical analysis.
The stated endpoint concerns correct answers on a knowledge questionnaire. It does not directly measure clinical decisions, hepatitis C treatment uptake, infection outcomes, or long-term health outcomes. The record’s broader interest in medical decision making should not be treated as evidence that those outcomes were measured. The primary outcome description is limited to questionnaire scores.
The safety record lists zero serious adverse events, zero other adverse events, and zero deaths in each group, but these entries do not answer the educational comparison. They should be interpreted as recorded safety counts with the reporting limitations described in the registry record. Overall, the available information describes the study question, design, outcome definition, and safety entries, but does not provide the outcome evidence needed to judge the comparative knowledge results.
13. Why This Trial Matters Statistically
This study is statistically interesting because it asks whether the way health information is delivered is associated with measured knowledge, while using repeated assessments to describe knowledge over time. A questionnaire with one point per correct answer provides a defined score rather than an unstructured impression of learning. The scheduled pre-intervention, immediate post-intervention, and 1 mo. follow up assessments make timing part of the question: a short-term score change and a later score pattern are not necessarily the same estimand.
The non-randomized design also highlights a central distinction in clinical research: a difference between groups is not automatically a causal effect. In general, randomization is intended to reduce systematic baseline differences, while non-randomized comparisons require careful attention to how groups were formed and what factors may influence both allocation and outcome. The registry record does not report the allocation process or adjustment methods, so the limits of causal interpretation are especially important.
The record also illustrates why a well-defined endpoint is not enough to assess evidence. Interpretation requires the actual group results, the comparison being estimated, the analysis population, and measures of uncertainty. Those outcome and analysis results are not reported in the registry record. Without them, the statistical question remains specified but unanswered in the posted record.
Finally, the study provides a useful distinction between planning and evidence. A sample-size planning illustration depends on assumptions and is not a substitute for observed estimates, uncertainty, or an analysis of the data. Statistical planning can inform a study’s design, but only reported outcome results can describe the observed knowledge scores. This distinction is particularly useful when a completed-study record contains a defined outcome but no posted analysis 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 most consequential limitation of the registry record is that it does not report the primary-outcome values or statistical analyses. There are no group means, standard deviations, score changes, between-group estimates, confidence intervals, or p-values. The direction, size, and precision of any difference in knowledge scores therefore cannot be assessed from this record.
The study used non-randomized allocation and no masking. The registry record does not describe how participants entered the video or brochure group, whether baseline characteristics differed, or whether any measured factors were adjusted for. As a result, a causal interpretation of any possible group difference would require caution. The record does not provide the information needed to assess the extent of confounding.
Although three assessment times are specified, the record does not state which time-point comparison defined the primary analysis or how repeated measurements were handled. It also does not report the number of participants with outcome data at each time, how missing observations were treated, or which participants were included in the analysis. The safety denominators should not be assumed to represent the outcome-analysis population at every time point.
The registry record does not report a statistical analysis plan, a sample-size justification, or methods for handling multiplicity. It also does not report detailed eligibility criteria or baseline participant characteristics. These omissions limit assessment of the study’s intended estimand, the comparability of groups, and the applicability of any possible findings. The educational endpoint is a knowledge score; the record does not report clinical decision outcomes or downstream health outcomes as measured results.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Hepatitis C-Video vs. Brochure Education Delivery — NCT04204447.
- Registry record last updated 2024-09-19; status last verified 2024-04.
- Results first posted 2024-09-19.
- 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
NCT04204447 is a completed, prospective, non-randomized, parallel-group study of hepatitis C educational delivery. It compared an educational video with an educational brochure among patients on opiate replacement therapy with a history of hepatitis C. The recorded enrollment was 176; masking was listed as none.
The primary outcome was improvement in HCV Knowledge Questionnaire scores, based on a 25-item assessment ranging from 0 to 25, measured pre-intervention, immediately afterward, and at 1 mo. follow up. The registry record does not report outcome values or statistical analyses, and it does not report methods for missing data or multiplicity. The safety record lists 0 serious adverse events, 0 other adverse events, and 0 deaths in each group. The record defines the study question and endpoint but does not provide the results needed to assess the comparative knowledge-score findings.