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 Pharmacoeconomic Study Assessing the Cost of Chronic Hepatitis C Treatment With Peginterferon Alfa-2b (PegIntron) and Ribavirin (Rebetol) in the Czech Republic (Study P04588)(COMPLETED) (NCT00723632), a registered phase not stated study. The primary outcome is Average Cost Per Participant With Sustained Virologic Response (SVR) Stratified by Weight Category.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00723632 |
| Phase | Phase not stated |
| Condition | Hepatitis C, Chronic, Hepatitis C |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 901 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Merck Sharp & Dohme LLC |
| Results posted | Yes |
2. Clinical Question
Population
Participants with chronic hepatitis C in the Czech Republic were included in the study. For the primary cost outcome, the analysis population was restricted to participants with a completed initial exam form, at least 1 follow-up visit form, a recorded end of treatment, and a recorded sustained virologic response status six months after treatment ended. The number meeting all of these conditions is not reported in the registry record.
Intervention
The treatment under study was the combination of peginterferon alfa-2b, identified as PegIntron, and ribavirin, identified as Rebetol. The registry describes all participants included in the study as receiving this combination; it does not describe separate treatment arms.
Comparator
No like-for-like control group is described. The registry record states that allocation was not stated and identifies the study as not being a randomized comparison. The cost outcomes were instead considered across groups defined by weight category, ribavirin dosage, and prior treatment status.
Primary question
What was the average cost per participant with sustained virologic response, stratified by weight category? The cost measure included specified treatment-related expenses and was expressed in Czech Crown, adjusted for inflation to 2010 values. The record also describes secondary cost outcomes stratified by ribavirin dosage and prior treatment status. Numerical findings for these outcomes are not reported in the registry record.
3. Trial Design
This was a completed, non-randomized study of costs associated with peginterferon alfa-2b plus ribavirin treatment for chronic hepatitis C in the Czech Republic. The registry lists enrollment of 901 participants and describes a single treatment group: all participants included in the study. It does not identify a comparator arm, and allocation is not stated. The registry therefore does not support interpreting the study as a randomized comparison between treatment strategies.
The study objective was to evaluate costs associated with treatment. The cost categories specified in the registry are rescue medication, concomitant therapy, disease monitoring, and medical intervention costs that the treating institution recognized as treatment-related expenses. The study also aimed to evaluate the relationship between therapy-related costs, ribavirin dosing, and participant history. The precise operational definitions of these cost categories and the methods used to assess those relationships are not reported in the registry record.
The primary outcome was average cost per participant with sustained virologic response, stratified by weight category. Secondary outcomes were average cost per participant with sustained virologic response stratified by ribavirin dosage and prior treatment status. The primary outcome timeframe was from enrollment up to 48 weeks for participants with HCV genotype 1, and from enrollment up to 24 weeks for participants with HCV genotypes 2 and 3. The registry defines sustained virologic response as undetectable HCV RNA six months after the end of treatment.
The record lists a start date of 2005-09, primary completion in 2010-12, and completed status. It does not report a randomized allocation procedure, a control group, or a statistical analysis plan. The number of participants included in each outcome stratum and the numerical cost findings are not reported in the registry record.
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 | Peginterferon Alfa-2b and Ribavirin |
|---|---|
| STARTED | 901 |
| COMPLETED | 698 |
| NOT COMPLETED | 203 |
Analysis population for the primary outcome, as defined in the registry: Participants were included in the analysis if all of the following conditions were met: initial exam form was completed; at least 1 follow up visit form was completed; the end of treatment (either according to plan or early) was recorded; and SVR status was recorded six months after treatment termination.
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 | Peginterferon Alfa-2b and Ribavirin |
|---|---|---|
| Participants analysed | 698 | |
| Age, Continuous | years | 38 (18 to 80) |
| Sex: Female, Male: Female | Participants | 300 |
| Sex: Female, Male: Male | Participants | 398 |
6. Primary Endpoint
The registry lists the primary outcome as Average Cost Per Participant With Sustained Virologic Response (SVR) Stratified by Weight Category, measured over From enrollment up to 48 weeks for participants with hepatitis C virus (HCV) genotype 1, and from enrollment up to 24 weeks for participants with HCV genotypes 2 and 3.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Full Range |
| Unit | Czech Crown |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is average cost per participant with sustained virologic response, reported separately by weight category. Sustained virologic response is defined in the registry as undetectable HCV RNA six months after the end of treatment. The endpoint combines a cost measure with a treatment-response classification: it describes total qualifying costs in a group relative to the number of participants in that group who met the response definition.
The registry states that cost per participant with sustained virologic response was calculated as the ratio of total costs for all participants to the number of participants with sustained virologic response in the given group. This is a group-level ratio. It is not necessarily the arithmetic mean of individual participant costs among those who achieved sustained virologic response. That distinction matters because costs incurred by participants without the response can contribute to the numerator, while the denominator counts participants with the response.
Costs were adjusted for inflation to 2010 values and expressed in Czech Crown. The endpoint is therefore intended to describe treatment-related resource costs in a common price-year basis, rather than to compare clinical outcomes between randomized groups. The registry’s specified cost categories include rescue medication, concomitant therapy, disease monitoring, and medical interventions recognized by the treating institution as treatment-related expenses.
The registry does not report numerical values for the endpoint, the weight categories, or the number of participants with sustained virologic response in each group. The precision and variation of the cost estimates therefore cannot be assessed from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a cost analysis, not a randomized comparison of treatment strategies. It identifies peginterferon alfa-2b plus ribavirin as the treatment received by all participants included in the study, but it does not describe a separate control group or state how treatment allocation occurred. Consequently, the design as reported does not establish a comparative treatment effect. Its stated focus is the cost of treatment and how costs relate to response, weight category, ribavirin dosage, and treatment history.
The primary outcome is a group-level cost ratio: total costs for participants in a given group divided by the number of participants in that group who achieved sustained virologic response. This measure can be useful for describing resource use in relation to a response outcome, but it should not be read as the typical amount spent by an individual participant who achieved sustained virologic response. The numerator includes costs for all participants in the group, according to the registry definition, whereas the denominator counts participants with the response.
Cost values were adjusted for inflation to 2010 values and expressed in Czech Crown. This makes the intended monetary reference period explicit, but the registry does not provide the cost estimates, ranges, group sizes, or response counts needed to assess how large or stable the reported quantities were. No numerical primary or secondary outcome results are reported in the registry record. The record lists 3 outcome measures and 0 analyses, so it does not provide estimates, confidence intervals, or significance tests for the outcomes.
The listed analysis population required records for the initial exam, at least 1 follow-up visit, end of treatment, and sustained virologic response status six months after treatment. Those criteria define who could contribute to the analysis, but the number who met them and the number excluded are not reported in the registry record. If participants with incomplete records differed in costs or response status from those included, the analyzed group could differ from the enrolled group; the record does not report enough information to assess that possibility.
Any statistical interpretation should therefore remain descriptive and limited to the stated cost framework. The record does not permit a judgment about the magnitude, precision, or comparative importance of the costs. Nor does an average cost per response, by itself, establish that one treatment is more efficient than another: that conclusion would require an appropriate comparator and relevant outcome and cost data, which are not reported in the registry record.
9. Statistical Methods Explained
The primary endpoint is defined as a ratio rather than a conventional comparison of participant-level means. The numerator is the total cost for all participants in a given group, and the denominator is the number of participants in that group with sustained virologic response. In general, this kind of ratio expresses group-level resources in relation to the number of people meeting a specified outcome. It does not give the distribution of individual costs, and it can be affected by both the costs accumulated by the group and the number of participants meeting the response definition.
The registry reports the endpoint as a mean and gives full range as its dispersion measure. In general, a mean describes a central value, while a full range describes the span from the smallest to the largest observed value. A range can indicate the spread of observations, but it does not show how observations are distributed within that span. The numerical mean and range for the primary endpoint are not reported in the registry record, so neither the size of the cost measure nor its observed variability can be evaluated.
Stratification means reporting a measure separately across categories rather than combining all participants into a single group. The primary outcome is stratified by weight category. The secondary outcomes are stratified by ribavirin dosage and prior treatment status. In general, stratification can reveal whether a measure varies across clinically or operationally relevant groups, but it does not by itself demonstrate that the grouping characteristic caused any observed difference. Participants in different strata may differ in other ways as well. The category definitions, group sizes, and numerical estimates are not reported in the registry record.
The timeframes vary by HCV genotype: from enrollment up to 48 weeks for genotype 1, and from enrollment up to 24 weeks for genotypes 2 and 3. Sustained virologic response is assessed six months after the end of treatment. These are distinct time references: the outcome observation period is stated by genotype, while the response definition refers to follow-up after treatment ends. The registry does not report further detail about visit schedules, handling of treatment interruptions, or the timing of cost collection within those periods.
The registry states that costs were adjusted for inflation to 2010 values and expressed in Czech Crown. In general, inflation adjustment places costs from different periods on a shared price-year basis, making values more interpretable over time. It does not, by itself, address differences in how resource use was measured or which expenses were counted. The stated scope includes rescue medication, concomitant therapy, disease monitoring, and medical intervention costs recognized by the treating institution as treatment-related. The record does not report unit-cost sources, valuation procedures, or whether any costs outside those categories were included.
There are no numerical outcome analyses reported in the registry record. It therefore gives no confidence intervals, hypothesis tests, or estimates of associations between costs and ribavirin dosing or participant history. In general, a confidence interval describes a range of values compatible with the data under the assumptions of the method; its width reflects statistical precision. Without reported estimates and intervals, precision cannot be judged. The registry also does not report whether the cost data were modeled, transformed, or adjusted for differences among participants.
The record includes a sample-size planning illustration based on a stated fraction of an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Such an illustration is a hypothetical planning calculation, not evidence about the study’s achieved power or the precision of its cost results. It is also not a description of the trial’s own design: the registry characterizes the study as not a randomized comparison and describes all included participants in one treatment group. Numerical planning outputs and a numerical observed effect are not reported in the registry record. The stated assumptions should not be read as proof that two comparable arms existed or that the study was designed around those assumptions.
In general, over-dispersion occurs when observed variability is greater than a statistical model assumes. It can make standard errors and inferential conclusions unreliable if a model does not account for it. Cost data can be heterogeneous, but the registry record does not report a distributional model, a diagnostic assessment, or a method for handling over-dispersion. No claim about the presence or absence of over-dispersion can therefore be made for this analysis.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 3 outcome measures: the primary cost outcome stratified by weight category, and secondary cost outcomes stratified by ribavirin dosage and prior treatment status. It reports 0 analyses. Numerical estimates and inferential results for these outcomes are not reported in the registry record. The record does not describe a multiplicity adjustment, a hierarchy for testing outcomes, or a prespecified distinction between confirmatory and exploratory analyses. Without such information and without reported tests, the effect of multiple comparisons on statistical inference cannot be assessed.
The primary analysis population was defined by completion of the initial exam form, completion of at least 1 follow-up visit form, a recorded end of treatment, and a recorded sustained virologic response status six months after treatment. These requirements make the endpoint dependent on having the relevant records. The number of enrolled participants meeting all criteria, and the number excluded for each reason, are not reported in the registry record. It is therefore not possible to determine how much information was available for the cost analyses or whether the analyzed population represented all 901 enrolled participants.
The registry does not report how missing cost information, missing response status, or incomplete forms were handled. It also does not describe imputation, sensitivity analyses, or an analysis population other than the stated eligibility criteria for the endpoint. In general, missing-data methods matter because conclusions can depend on whether missingness is related to costs, response, or participant characteristics. No assumptions about the reasons for missing records or their effect on results can be made from the registry record.
The number of participants in each weight, dosage, or prior-treatment category is not reported. That information would be important for interpreting the stability of stratum-specific estimates. The record also does not report whether participants contributed to more than one category or how category boundaries were defined.
11. What the Result Does, and Does Not, Mean
The registry record establishes the study’s stated purpose and cost definitions, but it does not provide numerical findings. It describes an analysis of costs associated with peginterferon alfa-2b plus ribavirin treatment, with cost per participant with sustained virologic response considered across weight categories and, for secondary outcomes, ribavirin dosage and prior treatment status. Costs were intended to include specified treatment-related expenses and were adjusted for inflation to 2010 values.
Because outcome estimates are not reported in the registry record, the size of the average cost per participant with sustained virologic response is unknown from this record. The same applies to the full range, any differences across strata, and the precision of those estimates. The record does not provide confidence intervals or other measures that would show how uncertain the estimates are. It also does not report the numbers of participants with sustained virologic response in the relevant groups.
The outcome should be understood as a cost-to-response ratio at the group level, not as the cost experienced by a typical participant who achieved sustained virologic response. It does not, by itself, show how costs were distributed among individuals, which cost categories contributed most, or whether costs differed between participants with and without sustained virologic response. The registry does not report those details.
The record does not establish a comparative effect of the combination treatment against an alternative. It describes all included participants as receiving the treatment combination and does not identify a like-for-like control group. A descriptive cost measure for a single treatment group cannot establish comparative cost-effectiveness without an appropriate comparator and relevant comparative outcome data. No conclusion about the treatment’s clinical effect or its value relative to another strategy follows from the registry information alone.
These limits are about what the registry record reports, not proof that no further analyses or data exist elsewhere. Within the record, the appropriate conclusion is that the study was designed to examine treatment-related costs in relation to sustained virologic response and participant groupings, while the numerical results and key details needed to assess them are not reported.
12. Why This Trial Matters Statistically
This study illustrates why a cost endpoint needs a precise definition. “Average cost per participant with sustained virologic response” might sound like an average among responders, but the registry specifies a ratio with total costs for all participants in a group in the numerator and the number of responders in the denominator. That distinction changes the interpretation: the measure relates group-wide spending to the count of participants reaching the response definition, rather than describing the typical individual cost among responders.
The record also shows why analysis populations are part of an endpoint’s meaning. The primary cost analysis required a completed initial exam form, at least 1 follow-up visit form, an end-of-treatment record, and a response-status record six months after treatment. These requirements define whose information can contribute. Without the number meeting the criteria and an account of missing records, readers cannot assess the coverage or potential selection of the analysis population.
Stratification by weight category, ribavirin dosage, and prior treatment status recognizes that costs may be examined across participant subgroups. Statistically, however, subgroup estimates require clear category definitions and group sizes, and differences between groups are not automatically causal. The registry does not report the numerical subgroup findings or the methods used to account for other differences among participants.
Finally, the study’s non-randomized description matters for interpretation. The registry identifies no like-for-like comparator and does not state an allocation procedure. Cost summaries can describe resource use in the treatment setting, but they cannot establish comparative effectiveness or comparative cost-effectiveness without a suitable comparison and outcome data. The record’s lack of numerical results further limits what can be learned about the magnitude and precision of the cost measures.
13. 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 trial-specific details unavailable. It does not report the numerical primary or secondary cost results, the number of participants with sustained virologic response, or the number analyzed in each stratum. Without these details, neither the magnitude of the estimates nor the extent of uncertainty can be evaluated. Although the primary outcome specifies full range as its dispersion measure, no range values are reported.
The endpoint’s group-level ratio combines total costs for all participants in a group with the number of participants in that group who had sustained virologic response. This construction means the measure is not a participant-level average among responders. The registry does not report participant-level costs or additional summaries that would show how costs were distributed, so the impact of unusually high or low costs cannot be assessed.
The study is described as non-randomized, with allocation not stated and no like-for-like control comparison. The record therefore does not support causal comparisons between treatment strategies. It also does not report the definitions of weight or dosage categories, the details of prior-treatment classifications, or the group sizes needed to judge the stability of stratified estimates.
The cost scope is limited to specified treatment-related expenses, including rescue medication, concomitant therapy, disease monitoring, and medical intervention costs recognized as treatment-related by the treating institution. The registry does not report unit-cost sources, costing procedures, or whether other resource categories were excluded. Generalizability beyond the stated Czech Republic setting cannot be evaluated from the registry information alone.
Finally, the registry does not describe missing-data methods, a statistical analysis plan, or adjustments for multiple outcomes. The outcome population requires several records, but the completeness of those records and the number excluded are not reported. These omissions restrict assessment of potential selection, precision, and analytical choices.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: Pharmacoeconomic Study Assessing the Cost of Chronic Hepatitis C Treatment With Peginterferon Alfa-2b (PegIntron) and Ribavirin (Rebetol) in the Czech Republic (Study P04588)(COMPLETED) — NCT00723632.
- Registry record last updated 2015-10-02; status last verified 2015-10.
- Results first posted 2011-12-20.
- 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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17. Record Summary
The registry record describes a completed study of costs associated with peginterferon alfa-2b plus ribavirin for chronic hepatitis C in the Czech Republic, with enrollment of 901 participants. The primary outcome was average cost per participant with sustained virologic response, stratified by weight category. Secondary outcomes considered ribavirin dosage and prior treatment status.
Sustained virologic response was defined as undetectable HCV RNA six months after treatment ended. The primary cost measure was calculated as total costs for all participants in a group divided by the number of participants in that group with sustained virologic response. Costs were expressed in Czech Crown and adjusted for inflation to 2010 values. The stated cost categories included rescue medication, concomitant therapy, disease monitoring, and medical intervention costs recognized as treatment-related.
The record describes a non-randomized study without a like-for-like comparator, reports 3 outcome measures and 0 analyses, and does not give numerical outcome results. The numbers analyzed, subgroup definitions, missing-data methods, and statistical analysis plan are not reported in the registry record.