Undiagnosed Hepatitis C Infection in an Urban Hospital: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Undiagnosed Hepatitis C Infection in an Urban Hospital (NCT01957085), a registered phase not stated study. The primary outcome is Point Prevalence of Hepatitis C Infection.

2. Clinical Question

The central question is descriptive: among patients admitted during the study period, how common was hepatitis C infection that had not previously been diagnosed? The brief summary also proposes examining whether undiagnosed infection is associated with age, race, gender, zip code, or type of insurance. Those are planned demographic comparisons, not evidence that any association was found.

The primary endpoint is described as the percentage of subjects who are viremic. Testing was to begin with hepatitis C antibody testing of de-identified leftover samples; samples positive for antibody were then to be tested by polymerase chain reaction. The registry record does not report how many samples were tested, how many were antibody-positive, or how many were viremic. It therefore does not report a numerical answer to the primary question.

3. Trial Design

This was an observational study, not a randomized treatment trial. The registry lists the intervention as “observation only” and describes hospitalized patients as receiving no intervention. The intended data source was leftover serum or plasma collected as part of routine inpatient laboratory work, rather than samples collected through a clinical treatment assignment.

The population was patients admitted to Temple University Hospital. The registry reports enrollment of 366 and a completed status. The study began in 2014-06, and primary completion is recorded as 2015-12. The brief summary describes testing for patients admitted on two separate days, while the primary endpoint timeframe is listed as a single 24 hour period. The record does not explain how those descriptions relate to one another, so the precise sampling schedule is not fully clear.

The planned testing sequence was hepatitis C antibody testing followed, for antibody-positive samples, by polymerase chain reaction testing. The endpoint description says results would be reported as the percentage of subjects who are viremic. The study also planned to compare rates across demographic characteristics, including age, race, gender, zip code, and type of insurance.

Because the record describes one observational group, there is no like-for-like control group and no treatment contrast to interpret. The record does not report a sampling frame beyond the stated hospital admissions, detailed eligibility criteria, or whether every eligible patient had an available leftover sample. It also does not report a protocol for handling unavailable or unusable specimens.

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

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 Point Prevalence of Hepatitis C Infection, measured over Single 24 hour period.

The primary endpoint is titled “Point Prevalence of Hepatitis C Infection.” Its unit is the percentage of total subjects, and the endpoint description specifies that the reported percentage would be the percentage of subjects who are viremic. The timeframe is listed as a single 24 hour period.

Testing was to use de-identified leftover plasma or serum. A hepatitis C antibody test was to be performed first, with polymerase chain reaction testing for samples with a positive antibody result. In general, antibody testing indicates prior exposure to the virus, while polymerase chain reaction testing can identify viral material. The record’s endpoint definition makes the latter evidence of viremia central to the reported prevalence measure; an antibody-positive result alone is not described as the primary endpoint.

Point prevalence is used to describe the proportion of a defined population meeting a condition at a specified time or over a brief measurement period. It is suitable for a descriptive question about the burden of infection among the hospitalized patients tested. It does not, by itself, measure the rate at which new infections arise over time. Although “incidence” appears in the official title, the stated primary endpoint is point prevalence.

The numerical endpoint result, its denominator, and any confidence interval are not reported in the registry record. The record therefore does not establish the observed prevalence or its statistical precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical methods described for this study are limited. The registry record identifies the primary endpoint as a percentage of subjects who are viremic, but it does not report a statistical analysis plan, a confidence interval method, a hypothesis test, or adjustment for demographic covariates. The following explanations are general and do not identify methods as having been used in this study.

What does point prevalence estimate?

In general, a prevalence estimate is a proportion: the number of people in a defined population who meet a case definition divided by the number assessed in that population. For this endpoint, the registry describes the case definition through the testing sequence and specifies viremia as the outcome being expressed as a percentage. The denominator should correspond to subjects with an interpretable result for the endpoint. The record does not report the number tested or clarify how samples without a definitive result would be handled, so the actual denominator cannot be established from the record.

A prevalence estimate describes the population at the time or during the period of measurement. It is distinct from incidence, which generally refers to new cases arising during follow-up. The official title uses “incidence,” but the endpoint itself is explicitly named point prevalence and tied to a single 24 hour period. The endpoint definition, rather than the title alone, determines the measure the registry says was intended.

Why report uncertainty?

In general, an estimate from a sample has uncertainty because another sample from a similar population might yield a different result. A confidence interval expresses that uncertainty in a way that depends on the statistical model and method. The interval does not correct for selection problems, misclassification, or missing specimens; it addresses sampling uncertainty under its assumptions. No interval or method for calculating one is reported in the registry record, so neither the precision of the intended estimate nor the assumptions behind its uncertainty can be evaluated.

For a proportion, analysts may use methods designed for binary outcomes. The choice can matter, especially when the number of outcome-positive subjects is small or the estimate lies near the boundary of the possible range. General statistical practice is to select a method suited to the data and to report both the estimate and its uncertainty. The record does not state which method, if any, was used.

How should demographic comparisons be understood?

The brief summary says that infection rates would be compared across age, race, gender, zip code, and type of insurance. In general, comparisons can be descriptive, such as reporting proportions within categories, or model-based, such as estimating associations while accounting for other measured characteristics. These approaches answer different questions. Unadjusted comparisons describe observed differences between groups; adjusted analyses attempt to distinguish an association with one characteristic from associations involving other variables included in the model. Neither approach, on its own, proves causation.

The registry record does not say whether these comparisons were unadjusted or adjusted, which statistical tests or models were used, how continuous age or zip code was handled, or whether categories were combined. It also does not report estimates, uncertainty intervals, or results for any demographic group. These details are necessary for evaluating the strength and stability of any reported association.

What does multiplicity change?

In general, making multiple statistical comparisons creates more opportunities to observe apparently notable results by chance. A prespecified analysis plan may identify a primary comparison and distinguish it from exploratory analyses; multiplicity procedures may also be used when appropriate. The record names several demographic characteristics as subjects of comparison but does not report a multiplicity plan, a hierarchy of hypotheses, or whether any correction was applied. It is therefore not possible to tell how the results of multiple comparisons, if conducted, were interpreted.

What can planning calculations say?

In general, a sample-size calculation is a planning exercise based on assumptions about the effect to detect, variability, significance level, power, allocation, and analysis method. A calculation using an observed effect is retrospective planning, not evidence that a study had a particular observed power. The record does not report a sample-size justification from the study’s original design. Any planning illustrations associated with the statistical material should be understood as hypothetical planning quantities, not as observed power or as evidence that a difference was found. The record does not provide numerical planning results in the information available for interpretation.

Finally, methods for over-dispersed counts or time-to-event outcomes would not automatically apply to this endpoint: the primary measure is a percentage, not a count rate or time-to-event outcome. General method selection should follow the outcome type and design. The specific statistical methods used for the endpoint and demographic analyses are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry describes a primary prevalence endpoint and proposed comparisons by age, race, gender, zip code, and type of insurance. It does not report whether the demographic comparisons were prespecified as confirmatory analyses, whether they were exploratory, or how multiplicity was addressed. In general, interpreting many comparisons without accounting for the number of tests can make chance findings more likely. No correction method or ordering of hypotheses is reported, so the record does not support conclusions about the statistical status of any demographic result.

Missing-data handling is also not reported in the registry record. The testing plan depends on leftover serum or plasma from routine laboratory work, but the record does not say how many patients had an available sample, how many samples were successfully tested, or how missing and indeterminate results were treated. These details matter because the number enrolled need not equal the number with an evaluable primary endpoint. The record does not report whether missingness was assessed or whether any imputation or sensitivity analysis was performed.

The analysis population is not defined in sufficient detail to determine whether the primary analysis included all enrolled patients, all patients with an available specimen, or only those with a definitive test result. The registry’s enrollment of 366 is recorded, but the endpoint denominator is not. The specific statistical analysis plan, including any interim analyses, is not reported in the registry record. Consequently, the handling of missing observations, analysis populations, and multiple comparisons cannot be verified from the recorded information.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry lists a hospitalized-patient group with 366 participants at risk for serious adverse events and 0 serious adverse events reported. The study is described as observational and observation only, with no intervention. These figures should be read as the serious adverse event summary recorded for the group, not as a comparison between treatments.

A count of 0 in this field means that no serious adverse events are reported in the registry entry for the stated group. It does not establish that no health events of any kind occurred, nor does it show that every possible event was systematically collected. The record does not give event definitions, collection procedures, or further detail about safety follow-up. Deaths are not reported in the registry record.

Because there is no randomized control group and no treatment assignment, these figures cannot estimate a relative safety difference between interventions. The registry entry also does not provide a separate account of non-serious events. The serious-event count is therefore a narrow report of the recorded safety outcome, not a comprehensive account of all clinical events during participation.

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

The study addresses a descriptive public-health question: how much viremic hepatitis C infection was present among hospitalized patients tested at an urban hospital. Its planned approach used de-identified leftover samples and a sequence of antibody testing followed by polymerase chain reaction for antibody-positive samples. The primary endpoint was defined as a percentage, making the intended result a point-prevalence estimate rather than a treatment effect.

The record does not report the numerical prevalence result, the endpoint denominator, or a measure of uncertainty. It also does not report the results of the planned demographic comparisons. Thus, the registry entry documents what the study set out to measure, but not the findings needed to quantify infection in the study population or assess the proposed associations.

Even if a prevalence estimate were available, it would describe the tested hospitalized population during the stated measurement period. It would not automatically represent all residents of the surrounding city, all people with hepatitis C, or people in other hospitals. Differences in admission patterns and sample availability could affect which patients are represented; the record does not provide enough information to assess those possibilities.

The observational design also cannot establish that age, race, gender, zip code, or insurance causes infection. Associations can reflect other factors, measurement choices, or the composition of the group studied. The planned comparisons should not be interpreted as causal conclusions, and no such conclusions are reported.

The study’s completed status and enrollment count do not replace outcome reporting. Without the posted endpoint result, its denominator, and uncertainty estimates, the magnitude and precision of the prevalence remain unknown from the registry record.

13. Why This Trial Matters Statistically

This study is statistically important as an example of a question that is primarily about measurement and description rather than comparative treatment efficacy. The target quantity is point prevalence among a defined hospital population. That focus makes the definition of the population, the testing sequence, and the denominator central to interpretation.

The record specifies that antibody-positive leftover samples would be tested by polymerase chain reaction and that the primary result would be the percentage of subjects who are viremic. This distinction matters because a screening result and the endpoint definition are not interchangeable. Clear reporting of the number tested at each stage would allow readers to understand how the final prevalence denominator was reached; those counts are not reported in the registry record.

The study also illustrates why enrollment alone is not enough to judge precision or completeness. The record reports enrollment of 366, but it does not report the number with evaluable samples or the endpoint estimate. Without those details, readers cannot assess how representative the analyzed group was or how much sampling uncertainty remains.

Finally, the proposed comparisons across multiple demographic characteristics raise general questions about multiplicity, confounding, and exploratory analysis. The registry does not report the statistical plan or findings needed to resolve them. For biostatisticians and clinical researchers, the central lesson is to distinguish the stated objective from the evidence actually reported and to interpret a hospital-based descriptive estimate within the population and measurement period that produced it.

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 for interpretation is the absence of reported primary results. No prevalence estimate, numerator, endpoint denominator, or uncertainty interval is reported. The demographic comparisons named in the study summary also have no reported estimates or results.

The population and measurement schedule are not fully clear. The brief summary describes testing patients admitted on two separate days, while the primary endpoint lists a single 24 hour period. The record does not explain whether the endpoint refers to one of those days, both days considered together, or another definition. It also does not provide detailed eligibility criteria or the number of patients with a usable leftover sample.

The testing plan is described, but the record does not report test completion, indeterminate findings, or handling of unavailable specimens. Without these details, the endpoint denominator and potential for selection related to sample availability cannot be assessed. The record also does not describe the demographic categories, statistical models, adjustment variables, or multiplicity approach.

Finally, the study is based on hospitalized patients at one named urban hospital, and the endpoint is a short-period prevalence measure. Any interpretation would need to remain specific to the tested population and period. The registry record does not report enough information to evaluate how closely that population reflects other settings or populations.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Undiagnosed Hepatitis C Infection in an Urban Hospital — NCT01957085.
• Registry record last updated 2020-04-24; status last verified 2020-04.
• Results first posted 2020-04-24.
• 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

NCT01957085, titled “Undiagnosed Hepatitis C Infection in an Urban Hospital,” is an observational study sponsored by Temple University and marked completed. The registry reports enrollment of 366. The study began in 2014-06, with primary completion recorded as 2015-12.

The study aimed to assess undiagnosed hepatitis C infection among hospitalized patients using de-identified leftover serum or plasma from routine inpatient laboratory work. The primary endpoint is point prevalence, expressed as the percentage of subjects who are viremic after antibody testing and polymerase chain reaction testing for antibody-positive samples. The endpoint timeframe is listed as a single 24 hour period, while the brief summary refers to testing on two separate days.

The registry record does not report the primary prevalence result, its denominator, a confidence interval, or the results of the proposed demographic comparisons. It also does not report the specific statistical analysis methods, missing-data procedures, or multiplicity plan.