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 IVIG Versus Placebo for the Treatment of Patients With Severe C-Diff (NCT00177970), a randomized phase 4 study. The primary outcome is 1) Normalization of WBC's.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00177970 |
| Phase | Phase 4 |
| Condition | Clostridium Difficile-associated Diarrhea (CDAD) |
| Allocation | Randomized |
| Design model | Single Group |
| Masking | Double |
| Enrollment | 14 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Pittsburgh |
| Results posted | Yes |
2. Clinical Question
The trial asked whether adding intravenous immunoglobulin G (IVIG) to usual medications for severe Clostridium difficile-associated diarrhea and colitis would be associated with better clinical and laboratory outcomes than adding a normal saline placebo. The registry describes eligible patients as unresponsive to standard antimicrobial therapy. It proposed random assignment to IVIG or placebo, with both groups continuing their usual medications for the condition.
The planned primary question concerned normalization of the white blood cell count (WBC) during the study. The registry described a normal WBC count as 3.8-10.0/CMM. The study summary also anticipated that the IVIG group would have fewer stools per day (< 3 per day) than the placebo group. These statements describe the study’s planned questions, not observed findings.
Other questions concerned abdominal pain or tenderness, antibody measurements, neutrophil count, body temperature, and length of hospital stay. The study planned to assess these outcomes during follow-up that included daily monitoring until discharge. The registry record lists Clostridium difficile-associated diarrhea as the condition and describes severe disease in the trial title and summary.
Population
Patients with severe Clostridium difficile-associated diarrhea or colitis who were described as unresponsive to standard antimicrobial therapy. The registry lists enrollment as 14.
Intervention
A single dose of IVIG at 400 mg/kg, infused over 4-6 hours, in addition to usual medications for the condition.
Comparator
A normal saline infusion as placebo, also alongside usual medications.
Primary question
Whether WBC normalization during the study differed between the IVIG and placebo groups. No comparative outcome results are reported in the registry record.
3. Trial Design
The registry classifies the study as phase 4, randomized, and double-masked. Its description says eligible patients would be randomly assigned to receive IVIG or a normal saline placebo, with usual medications continued in both groups. IVIG was planned as a single dose of 400 mg/kg over 4-6 hours. The summary describes close monitoring during infusion and daily monitoring until discharge.
The registry lists an enrollment of 14. The study summary, written as a plan, anticipated enrolling approximately 40 patients over a period of two years. It names UPMC Shadyside Hospital, McKeesport Hospital, and St. Margaret's Hospital as planned recruitment sites. The listed start is 2003-10, and primary completion is listed as 2008-04. The current status is TERMINATED; the registry record does not report why the study was terminated.
There is an inconsistency in the design metadata: the registry labels the model SINGLE GROUP, while the trial description specifies random assignment to two intervention groups. These entries cannot be reconciled from the registry record. The study is therefore best described using both details, without assuming which model label reflects the intended or implemented analysis.
The registry lists University of Pittsburgh as sponsor. It describes collection of vital signs, CBC, stool C. difficile cytotoxin assay, and stool counts before and after therapy. These are planned procedures in the summary; the record does not establish which procedures were completed for enrolled participants. It also does not report actual treatment allocation, adherence, duration of follow-up for individual participants, or the number of participants completing follow-up.
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 | IVIG | Placebo |
|---|---|---|
| STARTED | 0 | 0 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: No results available record destroyed due to age of study. no publications
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
Population: No results available record destroyed due to age of study. no publications
| Characteristic | Unit | IVIG | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 0 | 0 | 0 | |
| Age, Categorical: <=18 years | Participants | — | — | — |
| Age, Categorical: Between 18 and 65 years | Participants | — | — | — |
| Age, Categorical: >=65 years | Participants | — | — | — |
| Sex: Female, Male: Female | Participants | — | — | — |
| Sex: Female, Male: Male | Participants | — | — | — |
| Region of Enrollment: United States | participants | — | — | — |
6. Primary Endpoint
The registry lists the primary outcome as 1) Normalization of WBC's, measured over during the course of the study.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The registered primary endpoint is normalization of WBC during the course of the study. The record describes the normal range as 3.8-10.0/CMM but does not give a numerical endpoint estimate, a time-specific assessment, or a definition of how normalization was to be summarized across participants. No results are available in the registry record.
As general clinical-trial context, a laboratory endpoint can provide a defined measure of a biological state and may be easier to assess consistently than a subjective symptom. WBC normalization could therefore serve as a marker of clinical course in this study. A laboratory measure is not, by itself, a complete account of symptoms, recovery, or other patient outcomes. Its interpretation depends on the timing of measurement, the rules for handling repeated values, and how the endpoint is compared between groups. Those details are not reported in the registry record.
The study summary also names stool frequency as an expected outcome, including a target of fewer than 3 stools per day, but that is not the registered primary endpoint title. It should not be substituted for the WBC endpoint when describing the primary question. The record does not report whether the planned stool or WBC outcomes were analyzed or what values were observed.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record does not contain outcome results for the primary endpoint or the secondary outcomes. It states that results are unavailable because the record was destroyed due to the age of the study, and it notes no publications. Consequently, no treatment-group contrast, estimate of uncertainty, or conclusion about the observed pattern of outcomes can be drawn from the posted results. This absence of results is not evidence that the groups had similar outcomes or that there was no effect.
The enrollment listing is 14, while the summary anticipated approximately 40 participants. The registry does not explain the difference between this planned enrollment and the listed enrollment, and it does not report how many participants were assigned to each group or included in any outcome analysis. The study status is TERMINATED, but the reason for termination is not reported in the registry record. These registry entries limit what can be inferred about the conduct and completeness of the trial; they do not establish why enrollment was lower than planned or whether that affected any result.
The registry identifies WBC normalization as the primary outcome and lists several other outcome areas, including abdominal pain or tenderness, antibody measurements, neutrophil count, body temperature, and hospital stay. Listing these outcomes does not show that they were measured or analyzed. The record contains no analysis entries. It also does not provide outcome counts, summary statistics, confidence intervals, or p-values for any comparison.
As general statistical context, a comparison between randomized groups is most informative when accompanied by an effect estimate and a measure of its precision. A confidence interval describes a range of effect values compatible with the data and analysis assumptions; it does not establish that the treatment caused an effect or that an effect is clinically important. Neither an effect estimate nor a confidence interval is reported for this trial, so there is no precision assessment to interpret.
Any sample-size illustrations associated with the record should be understood as planning calculations rather than evidence about the trial’s results. The stated assumptions describe two-sided significance level 0.05, equal allocation, a normal approximation, and an effect defined as a stated fraction of an observed effect. The record does not report the trial’s original sample-size justification, and the illustrations do not restore missing outcome data or establish observed power.
9. Statistical Methods Explained
Several statistical concepts help explain what the registry record can and cannot establish. The concepts below are general; they do not describe analyses confirmed to have been conducted for this trial. The registry reports no analysis entries and no outcome results.
What random assignment is intended to do
In general, random assignment allocates participants to intervention groups using a chance-based process. When implemented as planned, it can reduce systematic differences in participant characteristics between groups, on average. It does not guarantee that groups will be identical, especially in a small trial, and it does not remove the need to report how assignment was carried out or how participants were analyzed. The record says assignment was randomized but does not describe the sequence-generation method, allocation concealment, or the allocation actually achieved.
What masking contributes
Double masking generally means that more than one relevant party is unaware of treatment assignment, which can reduce the influence of expectations on care, outcome assessment, or reporting. The registry classifies the study as double-masked and describes a placebo infusion. It does not specify which parties were masked, whether masking was maintained, or whether the placebo matched the IVIG infusion in all relevant respects. Those details are not reported in the registry record, so the classification alone cannot establish how masking operated in practice.
How the primary endpoint could be analyzed
WBC normalization is described as a status measured during the study, with the stated normal range of 3.8-10.0/CMM. As general statistical context, an endpoint recorded as normalized or not normalized is categorical. A group comparison could be expressed as a difference or ratio in the proportion meeting the endpoint, with an uncertainty interval. If WBC values were collected repeatedly, analysis would also need to specify which measurement or time point determined the endpoint, or how repeated measurements were handled. The registry does not report an analysis definition, a measurement schedule for the primary endpoint, or results from such an analysis.
The study summary mentions stool counts and daily monitoring, but does not specify a statistical model for repeated stool counts or a prespecified summary. Counts can vary more than a simple model assumes. As general context, over-dispersion means that observed variability in counts exceeds the variability expected under a basic count model; accounting for it can affect uncertainty estimates. There is no basis in the registry record to say whether over-dispersion was present or whether a count model was used.
Why estimates need uncertainty measures
As general statistical context, an effect estimate describes the size and direction of a group contrast, while a confidence interval communicates its precision under the analysis assumptions. A wide interval indicates that the data are compatible with a broad range of effects; a narrow interval indicates greater precision, but neither width alone determines clinical importance. A p-value addresses compatibility with a specified null model, not the probability that a treatment works or that the null hypothesis is true. The registry reports none of these results for this trial.
A small amount of enrolled information can leave estimates imprecise, but enrollment alone is not enough to calculate precision. The record lists enrollment as 14, without group allocation, endpoint observations, or analyzed sample sizes. It is therefore not possible to recover a valid treatment contrast or uncertainty measure from the registry entries.
How to interpret planning calculations
The assumptions described for sample-size illustrations use a two-sided significance level of 0.05, equal allocation between arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. These are planning assumptions for illustrative calculations, not evidence about outcomes or the trial's original design rationale. The registry does not report the trial's own sample-size justification. A planning illustration also does not represent observed power: observed power is not a substitute for an effect estimate and its uncertainty after data collection.
The registry record does not include an observed effect estimate from which a reader could assess the clinical or statistical meaning of the trial findings. Because no outcome results are available, sample-size planning assumptions cannot answer whether the trial detected a difference, how large a difference was, or how precisely it was estimated.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary endpoint of WBC normalization and multiple secondary outcome areas: abdominal pain or tenderness, antibody quantity in relation to recovery, correlation between antibody responses measured with ELISA and recovery, neutrophil-count normalization, body-temperature normalization, and length of hospital stay. The study summary also describes stool frequency as an expected outcome. No results are reported for any of these measures.
As general statistical context, evaluating several outcomes can increase the chance that at least one appears notable by chance if all are tested without an appropriate strategy. A prespecified hierarchy, adjustment, or clear distinction between primary and exploratory analyses can help readers understand how multiple comparisons were handled. The registry record does not report a multiplicity plan, analysis hierarchy beyond naming a primary outcome, or any adjustment for multiple testing. It is not possible to determine from the available entries whether such procedures were specified elsewhere or used.
Missing-data methods and analysis populations are also not reported in the registry record. The record does not describe exclusions, withdrawals, missing endpoint values, an intention-to-treat population, or a per-protocol population. Without those details, it is not possible to assess whether the analyzed participants would have matched the randomized groups or how missing observations might have affected an estimate.
The record lists 8 outcome measures and no analysis entries, but provides no outcome-level result data. The number of outcome measures does not establish how many were collected, analyzed, or reported. The reason the record gives for the absence of results is that it was destroyed due to the study’s age; it does not provide a missing-data analysis or a fuller account of the data’s disposition.
11. What the Result Does, and Does Not, Mean
The registry record documents a planned randomized comparison of IVIG with placebo, describes the intended population and procedures, and identifies WBC normalization as the primary outcome. It also gives the listed enrollment, the study dates, and a terminated status. These details characterize the registered study, but they are not evidence of a treatment effect.
No outcome results are available in the registry record. It therefore cannot show whether WBC normalization, stool frequency, abdominal pain or tenderness, antibody measures, neutrophil count, body temperature, or length of hospital stay differed between the groups. It cannot establish the size or precision of any difference, and it cannot support a conclusion that the groups were equivalent. The lack of reported results should not be interpreted as a negative result.
The record’s adverse-event entries list 0 participants at risk and 0 affected in both the IVIG and placebo groups, with deaths recorded as null. These entries do not establish that no adverse events occurred. With no outcome results and no explanation of the adverse-event fields, they should be read as absent or uninformative reporting rather than as evidence of safety.
The planned enrollment of approximately 40 and listed enrollment of 14 are different registry entries, but the record does not explain the discrepancy or report the number assigned to each group. The terminated status does not identify the reason for termination. Neither fact permits an inference about the trial’s findings or why the study ended.
In general, a trial result needs to be interpreted using the observed data, the analysis method, the uncertainty around estimates, and the completeness of follow-up. Those elements are unavailable in this registry record. The appropriate statistical conclusion is limited: the study was registered with a comparative clinical question, but the posted record does not permit an assessment of the observed comparative outcomes.
12. Why This Trial Matters Statistically
This trial is statistically notable because its registry record separates a detailed planned question from an unavailable result. The record describes randomized assignment, masking, an intended placebo comparison, and a laboratory primary endpoint, yet it contains no outcome results or analysis entries. This distinction matters: registration establishes what the study proposed to evaluate, not what the collected data showed.
The registry also contains a design-label inconsistency. It classifies the model as SINGLE GROUP while describing random assignment to IVIG or placebo. Careful reading requires retaining that inconsistency rather than silently choosing one description. Reliable interpretation depends on distinguishing registry metadata from the operational description and acknowledging when the record does not resolve a conflict.
The enrollment information likewise illustrates why planned and listed enrollment should not be conflated. The summary anticipated approximately 40 participants, while the registry lists 14. Without an account of recruitment, allocation, completion, or termination, those entries do not explain what happened. A sample-size calculation cannot substitute for those missing details or recreate unreported results.
As general statistical context, missing trial results limit both effect estimation and evaluation of precision. Without group-level data or a reported contrast, readers cannot judge whether the study was informative, whether estimates were compatible with important differences, or how outcome definitions affected interpretation. This remains true regardless of whether a trial was randomized or masked: design features do not replace outcome reporting.
The record’s value is therefore documentary rather than evidential about comparative efficacy. It identifies intended outcomes and the methods described in the registration, while also making clear that the available record cannot answer the primary statistical question. This is a useful reminder to distinguish a registered hypothesis, a planned design, and an analyzed result.
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 main trial-specific limitation is the absence of outcome data. The registry says no results are available because the record was destroyed due to the age of the study, and it reports no publications. There are no group-level outcome counts or summaries, no treatment-effect estimates, no uncertainty intervals, and no p-values. As a result, comparative outcomes cannot be evaluated.
The record does not explain why the study was terminated or why listed enrollment was 14 when the summary anticipated approximately 40 participants. It does not provide the number randomized to each group, the number completing follow-up, or the number included in analyses. The termination status therefore cannot be assigned a statistical or operational explanation from the available record.
There is also a mismatch between the SINGLE GROUP model label and the description of random assignment to IVIG or placebo. The registry does not resolve this inconsistency. Other design details that would support assessment of validity are not reported, including the randomization procedure, masking details, endpoint assessment schedule, and statistical analysis plan.
The primary endpoint is described as WBC normalization during the study, but the record does not report how repeated measurements were handled or how the outcome was summarized. Secondary outcomes are listed, but the record does not establish which were assessed or analyzed. Missing-data handling, analysis populations, and multiplicity procedures are not reported.
Adverse-event entries show 0 at risk and 0 affected for each group, with deaths listed as null. These fields do not permit a safety assessment. The listed enrollment and outcome-measure count alone cannot resolve the missing results or these reporting limitations.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: IVIG Versus Placebo for the Treatment of Patients With Severe C-Diff — NCT00177970.
- Registry record last updated 2016-10-25; status last verified 2016-09.
- Results first posted 2016-07-15.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
17. Record Summary
NCT00177970 is a phase 4, randomized, double-masked study sponsored by the University of Pittsburgh, comparing IVIG with normal saline placebo for severe Clostridium difficile-associated diarrhea and colitis. The proposed IVIG regimen was a single dose of 400 mg/kg infused over 4-6 hours, alongside usual medications. The registered primary outcome was WBC normalization during the study, with a stated normal range of 3.8-10.0/CMM.
The registry lists enrollment as 14, a start of 2003-10, primary completion of 2008-04, and status TERMINATED. Its summary anticipated approximately 40 participants. The record labels the study model SINGLE GROUP despite describing random assignment to IVIG or placebo.
No outcome results or analysis entries are reported. The registry states that results are unavailable because the record was destroyed due to the study’s age, and notes no publications. The record does not report why the study was terminated or explain the difference between planned and listed enrollment.