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 Observational Study Assessing Chronic Hepatitis C Management in Clinical Practice in Italy (Study P05488 AM1) (NCT00724451), a registered phase not stated study. The primary outcome is Number of Participants Not Eligible for Antiviral Treatment by Reason for Non-eligibility.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00724451 |
| Phase | Phase not stated |
| Condition | Hepatitis C, Hepatitis C, Chronic |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 1128 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Merck Sharp & Dohme LLC |
| Results posted | Yes |
2. Clinical Question
Population
Peginterferon-naïve participants with chronic hepatitis C seen in general clinical practice in Italy. The registry record reports enrollment of 1128, while the primary outcome description refers to 1118 participants.
Intervention
For participants considered eligible for antiviral therapy, treatment was at the physician’s discretion with peginterferon alfa-2a or peginterferon alfa-2b, each in combination with ribavirin, in accordance with approved labeling.
Comparator
No randomized comparator is described. The treatment pathways were not assigned as a like-for-like control comparison, and allocation is not stated in the registry record.
Primary question
At baseline, how many participants were judged not eligible for antiviral treatment, and what reasons did investigators record for that decision?
The study’s stated goal was to elucidate why people with chronic hepatitis C would not be considered eligible for antiviral treatment in common clinical practice. Investigators recorded reasons for not prescribing antiviral treatment. The registry specifically notes that more than one reason could be presented for the same participant, so reason counts should not be read as mutually exclusive categories or as a partition of all non-eligible participants.
The primary outcome concerns treatment eligibility, not whether an antiviral regimen reduced disease or improved another clinical outcome. For participants considered eligible, the record describes physician-directed treatment with either peginterferon alfa-2a or peginterferon alfa-2b plus ribavirin. Because treatment choice was discretionary and the study was observational, any descriptions of participants receiving these regimens do not constitute randomized comparisons of treatment effects.
The secondary objectives concern treatment discontinuation and treatment failure, including the reasons recorded for each. These outcomes address later treatment experience among those treated; the primary question instead describes baseline decisions about eligibility. The registry record does not report a causal question comparing treatment with no treatment.
3. Trial Design
This was a prospective, observational, multicentre study of chronic hepatitis C management in real clinical practice in Italy. The registry lists the study as completed and reports enrollment of 1128. The study ran from 2008-07 to primary completion in 2011-10. The brief summary describes approximately 54 sites in Italy.
Eligibility for antiviral treatment was determined by investigators in the setting of routine practice. The record says that 431 of the 1118 participants were determined to be non-eligible for antiviral therapy by investigator decision. The primary outcome was measured at baseline and records the number of participants not eligible by reason for non-eligibility. More than one reason could be recorded for the same participant.
Participants judged eligible could receive peginterferon alfa-2a or peginterferon alfa-2b with ribavirin, at the physician’s discretion and in accordance with approved labeling. The registry describes the treated participants as peginterferon-naïve participants with chronic hepatitis C. No treatment allocation procedure is stated. The record explicitly cautions that this is not a randomized comparison and that the arms are not a like-for-like control comparison.
The registry lists secondary outcomes for the number of participants who discontinued treatment by reason for discontinuation and the number with treatment failure by reason for failure. The brief summary also identifies defining treatment failure and evaluating reasons for discontinuation as secondary objectives. It lists 3 outcome measures and 0 analyses. Statistical analysis procedures, including a planned approach for comparisons, are not reported in the registry record.
The enrollment figure and the primary-outcome population figure are different: enrollment is listed as 1128, whereas the primary outcome description refers to 1118 participants. The registry record does not explain this difference. These figures should therefore be kept tied to their stated contexts rather than treated as interchangeable denominators.
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 | Participants With Chronic Hepatitis C (CHC) |
|---|---|
| STARTED | 1128 |
| Received Antiviral Treatment | 500 |
| COMPLETED | 326 |
| NOT COMPLETED | 802 |
Reasons for not completing this period:
| Reason | Participants With Chronic Hepatitis C (CHC) |
|---|---|
| Excluded - Prior Use of Peginterferon | 7 |
| Excluded - Hepatitis C Virus Negative | 3 |
| Not Eligible for Treatment | 431 |
| Participant Refused Treatment | 89 |
| Never Started Treatment | 89 |
| Unknown; No Data Sources Available | 9 |
| Physician Decision | 116 |
| Withdrawal by Subject | 45 |
| Investigator + Participant Decision | 13 |
Analysis population for the primary outcome, as defined in the registry: 431 of the 1118 participants were determined to be non-eligible for antiviral therapy by Investigator decision.
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 | Participants With Chronic Hepatitis C (CHC) |
|---|---|---|
| Participants analysed | 1118 | |
| Age, Customized: 18-29 years | participants | 51 |
| Age, Customized: 30-39 years | participants | 119 |
| Age, Customized: 40-49 years | participants | 244 |
| Age, Customized: 50-59 years | participants | 211 |
| Age, Customized: 60-69 years | participants | 263 |
| Age, Customized: 70-79 years | participants | 210 |
| Age, Customized: ≥80 years | participants | 20 |
| Sex: Female, Male: Female | Participants | 541 |
| Sex: Female, Male: Male | Participants | 577 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants Not Eligible for Antiviral Treatment by Reason for Non-eligibility, measured over Measured at baseline.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants judged not eligible for antiviral treatment, grouped by the reason investigators recorded for non-eligibility. It was measured at baseline. The record states that 431 of the 1118 participants were determined to be non-eligible by investigator decision.
This endpoint is useful for describing how treatment eligibility decisions were made in the participating clinical-practice settings. A count by reason can identify the considerations investigators documented when deciding not to prescribe antiviral therapy. That makes the outcome relevant to the study’s stated objective of elucidating reasons for non-eligibility. It does not, by itself, determine whether those decisions were clinically appropriate or whether changing a decision would improve outcomes.
The registry notes that more than one reason could be presented for the same participant. Consequently, reason categories may overlap. Counts for separate reasons cannot be assumed to add up to the total number of non-eligible participants, and a reason count is not necessarily a count of unique people unless the registry explicitly defines it that way.
This is a descriptive eligibility endpoint rather than a treatment-response endpoint. It does not measure antiviral efficacy, treatment failure, or the effect of one regimen relative to another. Those treatment-related topics appear in the study’s secondary objectives, but the registry record does not report analysis methods for them.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The main posted result describes a baseline clinical-practice decision: investigators determined that 431 of the 1118 participants were not eligible for antiviral therapy. The outcome is a count of participants, with reasons recorded for non-eligibility. It should be read as a description of decisions made in the study setting, not as an estimate of treatment benefit or harm.
The registry reports enrollment of 1128, but the primary outcome population is described as 1118. No explanation for the difference is reported in the registry record. The primary outcome result should be interpreted using its stated denominator, 1118; the enrollment count should not silently replace that denominator. The record does not explain whether the difference reflects missing outcome information, exclusions, or another reason, so none of these explanations can be assumed.
Reasons for non-eligibility are potentially overlapping because the registry allows more than one reason for the same participant. A reason-specific count therefore describes how often investigators recorded that consideration; it cannot automatically be treated as a mutually exclusive share of the non-eligible group. The record does not report a statistical analysis of reason counts, uncertainty intervals, or tests of differences between reasons.
The design is prospective and observational, with eligibility decisions and treatment choices made in routine practice. Treatment for eligible participants was at the physician’s discretion. The record states that allocation is not given and that the arms are not a like-for-like control comparison. Therefore, differences between treatment groups, if described elsewhere in the posted results, cannot be interpreted as randomized treatment effects on the basis of this design information alone.
The registry lists secondary outcomes for treatment discontinuation by reason and treatment failure by reason. These outcomes are distinct from the baseline eligibility endpoint. The record does not provide analysis procedures, definitions beyond the stated objectives, or statistical estimates for those outcomes in the registry record described. A reader should not infer a definition of treatment failure or assume how discontinuation reasons were classified.
The posted safety figures list 6 participants affected by serious adverse events among 500 at risk, alongside a separate other-event figure of 169 among 500 at risk. The serious-event terms listed include Anaemia, Neutropenia, Thrombocytopenia, Asthenia, Bronchopneumonia, and Hepatic neoplasm malignant, each reported as 0.2%. These figures are descriptive. The registry record does not provide a randomized comparator or further details sufficient to attribute events to a regimen or distinguish background illness from treatment-related events.
Overall, the data describe investigator-recorded eligibility decisions and selected treatment and safety outcomes in clinical practice. They do not establish why a particular participant was considered ineligible beyond the recorded reason, whether another decision would have been preferable, or whether a treatment caused an observed outcome.
9. Statistical Methods Explained
The primary endpoint is a count, so the basic statistical description is the number of participants recorded in each category. Counts are often useful when the goal is to describe clinical practice: they make the scale of a recorded event or decision concrete. A count alone, however, does not describe how precisely an underlying rate is known. A rate also needs a clear denominator and a defined population. In this study, the primary outcome description identifies 431 of the 1118 participants as non-eligible, while the registry separately lists enrollment of 1128. The reason for the difference is not reported in the registry record.
What does an observational count represent?
In an observational study, researchers record what happens in the settings under study rather than assigning participants to treatments at random. Here, investigators made eligibility decisions in clinical practice, and treatment choice for eligible participants was at the physician’s discretion. The resulting counts describe those recorded decisions and experiences. They do not isolate the causal effect of a treatment from other differences among participants or from clinical decisions that influenced treatment selection.
That distinction matters because participants receiving different regimens may differ in ways related to their care. A randomized design uses assignment procedures to support a different kind of comparison. The registry record explicitly says this study is not a randomized comparison, that allocation is not stated, and that the arms are not a like-for-like control comparison. Therefore, treatment-arm contrasts should not be read as randomized estimates of efficacy.
How should overlapping reasons be handled?
The primary outcome permits more than one reason for non-eligibility to be reported for the same participant. This is a multiple-response structure: an individual can contribute to more than one reason category. In general, counts in such categories need not sum to the overall number of participants, and a category count is not a mutually exclusive portion of the total unless the study says the categories are exclusive. For this study, the record does not provide further rules about how reasons were selected, prioritized, or classified.
Overlapping reasons also affect interpretation of comparisons across categories. A difference between counts may reflect the frequency with which reasons were recorded, but the record does not specify an inferential comparison or an adjustment for overlapping responses. The reasons are best understood as investigator-recorded descriptions rather than independent groups of participants.
What do uncertainty measures add?
In general, a confidence interval describes a range of values compatible with a statistical model and the observed data, reflecting sampling uncertainty under that model. It does not account automatically for all sources of uncertainty, such as selection into a study, measurement differences, or decisions made by clinicians. No confidence intervals or other uncertainty estimates for the primary endpoint are reported in the registry record. There are also 0 analyses listed, so no registry-listed statistical comparison or inferential procedure is available to interpret.
For counts involving events, over-dispersion is a general concern when observations vary more than a simple statistical model assumes. It can make uncertainty estimates too narrow if the model does not accommodate that extra variability. This general issue may matter in clinical data with heterogeneous participants or settings, but the registry record does not state that over-dispersion was assessed or identify a model used for these outcomes.
What do the planning illustrations mean?
Any sample-size calculations associated with the posted results are planning illustrations, not observed power and not evidence of the trial’s original design rationale. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect defined as a stated fraction of the observed effect. For time-to-event tables, the calculation refers to the total number of events; other calculations refer to participants per arm. The record does not report that these assumptions were used to plan this observational study.
Such illustrations answer a hypothetical planning question: under the stated assumptions, what sample size would correspond to a specified target? They do not establish that a study was adequately powered, and they do not turn nonrandomized treatment groups into a valid randomized comparison. The record gives no sample-size justification or protocol power calculation. The registry’s treatment allocation information also makes a two-arm equal-allocation scenario unlike the described physician-directed practice setting.
Why is the endpoint not an efficacy estimate?
The primary outcome is eligibility status and its recorded reasons, measured at baseline. An efficacy estimate would require an outcome that reflects response to treatment and a defined comparison capable of supporting the intended interpretation. The registry lists discontinuation and treatment failure as secondary outcomes but does not report statistical analysis methods for them in the registry record described. No treatment-effect estimate, confidence interval, or hypothesis test is reported for the primary endpoint. Consequently, the count should be interpreted descriptively, without extending it to claims about treatment effects or the quality of treatment decisions.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 3 outcome measures: the primary outcome concerning non-eligibility by reason and secondary outcomes concerning treatment discontinuation by reason and treatment failure by reason. Because the primary outcome allows more than one reason per participant, the reason categories can overlap. The record does not state whether any formal comparisons across reasons or outcomes were planned, or whether multiplicity was addressed. No adjustment method is reported in the registry record.
Multiplicity is a general statistical concern when many hypotheses or comparisons are examined: the chance of finding an apparently notable result can increase if testing is repeated without an appropriate plan. That concern does not imply that formal tests were conducted in this study. The registry lists 0 analyses, and a statistical analysis plan is not reported in the registry record. No p-values or inferential comparisons are described in the registry record for the outcomes discussed.
Missing-data handling and analysis populations are also not reported in the registry record. The primary outcome description refers to 1118 participants, while enrollment is 1128, and the record does not explain the difference. It does not state whether any participants lacked baseline eligibility information, how incomplete reason entries were handled, or whether any other analysis population was defined. The distinction should remain explicit rather than being resolved by assumption.
Because treatment was assigned at the physician’s discretion and allocation is not stated, the record also does not identify a prespecified intention-to-treat or per-protocol analysis. Those terms should not be inferred from the presence of treatment groups in the study description. The posted information supports a descriptive reading of the reported counts, not a claim about missing-data adjustments or a particular inferential 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 |
|---|---|---|---|
| Participants With Chronic Hepatitis C (CHC) | 6 | 500 | 1.2% |
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 |
|---|---|
| Participants With Chronic Hepatitis C (CHC) | 169 of 500 |
Most frequent serious adverse event terms
| Event term | Organ system | Participants With Chronic Hepatitis C (CHC) |
|---|---|---|
| Anaemia | Blood and lymphatic system disorders | 1 of 500 |
| Neutropenia | Blood and lymphatic system disorders | 1 of 500 |
| Thrombocytopenia | Blood and lymphatic system disorders | 1 of 500 |
| Asthenia | General disorders | 1 of 500 |
| Bronchopneumonia | Infections and infestations | 1 of 500 |
| Hepatic neoplasm malignant | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 1 of 500 |
| Non-hodgkin's lymphoma | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 1 of 500 |
| Cerebrovascular accident | Nervous system disorders | 1 of 500 |
| Hemiplegia | Nervous system disorders | 1 of 500 |
| Polyneuropathy | Nervous system disorders | 1 of 500 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Participants With Chronic Hepatitis C (CHC) |
|---|---|---|
| Anaemia | Blood and lymphatic system disorders | 64 of 500 |
| Asthenia | General disorders | 47 of 500 |
| Neutropenia | Blood and lymphatic system disorders | 23 of 500 |
| Influenza like illness | General disorders | 19 of 500 |
| Pyrexia | General disorders | 19 of 500 |
| Pruritis | Skin and subcutaneous tissue disorders | 14 of 500 |
| Weight decreased | Investigations | 12 of 500 |
| Headache | Nervous system disorders | 12 of 500 |
| Anxiety | Psychiatric disorders | 11 of 500 |
| Insomnia | Psychiatric disorders | 11 of 500 |
Serious events with the highest arm-level rate: anaemia (0.2%), neutropenia (0.2%), thrombocytopenia (0.2%), asthenia (0.2%), bronchopneumonia (0.2%).
The registry lists serious adverse-event figures for the group titled Participants With Chronic Hepatitis C (CHC): 6 affected among 500 at risk. It also lists a separate other-event figure of 169 among 500 at risk. These are descriptive counts, not estimates from a randomized comparison. The record does not provide enough information to attribute the events to a particular treatment or to compare regimens causally.
The listed serious-event terms are Anaemia, Neutropenia, Thrombocytopenia, Asthenia, Bronchopneumonia, and Hepatic neoplasm malignant. Each term is reported as 0.2%. These terms and percentages should be read as registry-reported safety information; the record does not give further details about event timing, severity criteria, recurrence, or how attribution to treatment was assessed.
The at-risk figures and affected figures are not a substitute for a complete safety analysis. The registry record does not report the exposure duration or provide a treatment-specific risk comparison in the registry record described. The serious-event counts therefore describe what was recorded in the stated group, without establishing that treatment caused an event or that the event rate differs from another group.
12. What the Result Does, and Does Not, Mean
The result addresses a practical descriptive question: how often investigators judged participants with chronic hepatitis C to be ineligible for antiviral treatment, and which reasons they recorded. The primary outcome description reports that 431 of the 1118 participants were determined to be non-eligible. Because multiple reasons could be recorded for a participant, individual reason categories may overlap.
This information can characterize decisions made in the participating Italian clinical-practice settings during the study period. It does not show that every clinician used the same criteria, that the listed reasons were exhaustive, or that the decisions represented a single standardized eligibility rule. Those details are not reported in the registry record.
The result does not establish treatment efficacy or comparative safety. This was an observational study, treatment for eligible participants was at the physician’s discretion, and the record states that the arms are not a like-for-like control comparison. The primary endpoint concerns baseline eligibility rather than response to therapy. Any interpretation of treatment outcomes would require outcome-specific information and methods that are not reported in the registry record.
The study also cannot establish that a different eligibility decision would have produced a better outcome. The counts describe recorded reasons, not the consequences of alternative decisions. They do not show that a reason was medically decisive, preventable, or associated with a later outcome.
Finally, the enrollment count of 1128 and the primary outcome population of 1118 should not be conflated. The registry record does not explain the difference. The result is most accurately stated with the primary outcome denominator as recorded, while acknowledging that the relationship between the two population figures remains unclear.
13. Why This Trial Matters Statistically
This study is statistically notable because its central question is about clinical decision-making rather than a randomized treatment contrast. Many clinical trial summaries focus on whether outcomes differ between assigned groups. Here, the primary endpoint instead counts investigator judgments about antiviral-treatment eligibility and the reasons recorded for those judgments. That distinction determines what the data can answer.
The study’s prospective, multicentre design situates the observations in real clinical practice across approximately 54 sites in Italy. Such a setting can capture how eligibility decisions are documented outside a tightly controlled treatment assignment. At the same time, decisions made in routine care may reflect participant characteristics, clinician judgment, and local practice. The descriptive counts should therefore not be mistaken for estimates of causal effects.
The handling of reasons is also important. Since more than one reason could be reported for the same participant, the categories are not necessarily independent or mutually exclusive. Clear interpretation requires keeping participant counts distinct from reason counts and avoiding assumptions that reason totals partition the non-eligible group.
The record’s differing enrollment and primary-outcome population figures illustrate why denominators matter. A result is interpretable only in relation to the population and outcome definition to which its denominator applies. Since the registry does not explain the difference between 1128 enrolled and the primary outcome population of 1118, it remains an unresolved reporting detail.
Finally, the study highlights the boundary between useful descriptive evidence and a treatment-effect claim. Counts of eligibility decisions and safety events may inform understanding of documented practice, but they do not by themselves establish the effect of a regimen. Recognizing that boundary is essential for biostatisticians and clinical researchers interpreting observational trial records.
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 registry record leaves several study-specific details unresolved. It describes a prospective, observational, multicentre study, but does not report how sites or participants were selected, the operational criteria for eligibility, or whether those criteria were standardized across participating sites. The record identifies investigator decision as the basis for determining non-eligibility but provides no further adjudication procedure.
The relationship between enrollment of 1128 and the primary outcome population of 1118 is not explained. Missing baseline information, exclusions, or another cause cannot be inferred. The record does not report how incomplete outcome records were handled or whether the primary endpoint was available for all enrolled participants.
Reason categories could overlap, and the record does not state whether investigators were required to select from a fixed list, could enter multiple reasons, or used a hierarchy when several reasons applied. Without those details, reason-specific counts may be difficult to compare across sites or interpret as consistently defined categories.
Treatment was at the physician’s discretion for participants considered eligible. Allocation is not stated, and the record cautions that treatment arms are not a like-for-like control comparison. Participant differences and clinical decisions can therefore complicate any treatment-group comparison. The registry does not report adjusted analyses or a method for addressing confounding.
Statistical analysis methods, missing-data procedures, sample-size justification, and analysis populations are not reported in the registry record. The registry lists 0 analyses. The secondary objectives name treatment failure and discontinuation but do not give further definitions or analysis details in the registry record described. Safety information is also limited: event timing, exposure duration, attribution methods, and treatment-specific comparisons are not reported.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Observational Study Assessing Chronic Hepatitis C Management in Clinical Practice in Italy (Study P05488 AM1) — NCT00724451.
- Registry record last updated 2015-09-25; status last verified 2015-09.
- Results first posted 2012-10-31.
- 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
NCT00724451 is a completed prospective, observational, multicentre study of chronic hepatitis C management in real clinical practice in Italy. The registry reports enrollment of 1128, study start in 2008-07, primary completion in 2011-10, and approximately 54 sites.
The primary outcome counts participants judged not eligible for antiviral treatment by investigator-recorded reason at baseline. The record states that 431 of the 1118 participants were determined to be non-eligible and allows multiple reasons for the same participant. Eligible participants could receive peginterferon alfa-2a or peginterferon alfa-2b with ribavirin at the physician’s discretion.
Secondary outcomes concern treatment discontinuation and treatment failure by reason. The registry lists 3 outcome measures and 0 analyses. It does not report statistical analysis procedures, explain the difference between enrollment and the primary outcome population, or describe a randomized treatment comparison. The posted results should therefore be interpreted as descriptions of clinical-practice decisions and recorded outcomes, not as randomized estimates of treatment effects.