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 A Clinical Trial of Oral Versus IV Iron in Patients With Chronic Kidney Disease (NCT00830037), a randomized phase 4 study. The primary outcome is Mean Rate of Decline in mGFR in the Two Groups - Oral and IV Iron.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00830037 |
| Phase | Phase 4 |
| Condition | Chronic Kidney Disease, Iron-deficiency Anemia |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 136 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Indiana University |
| Results posted | Yes |
2. Clinical Question
Population
The registry describes patients with chronic kidney disease and iron-deficiency anemia. Its summary refers to mild to moderate chronic kidney disease, but further eligibility criteria and the characteristics of participants enrolled are not reported in the registry record.
Intervention
The intervention was intravenous iron. The registry lists the intervention as IV Iron; details such as the preparation, dose, schedule, and duration are not reported in the registry record.
Comparator
The comparator was oral iron, listed as Ferrous Sulfate. The registry does not give further information about dose, schedule, duration, or treatment adherence.
Primary question
The main question was whether the modeled rate of decline in measured glomerular filtration rate differed between the intravenous-iron and oral-iron groups. The registry summary describes a hypothesis that intravenous iron could be associated with a more rapid decline, but the posted result is an estimated between-group difference with uncertainty, not a demonstration of a causal mechanism.
The registry identifies this as a randomized, parallel-group comparison in people with chronic kidney disease. It reports an enrollment of 136 and lists chronic kidney disease and iron-deficiency anemia as conditions. The outcome was measured as a slope in milliliters per minute per 1.73 square meters per year, with the endpoint timeframe described as baseline and 2 years. The primary outcome description says the group slopes were adjusted for baseline log urinary protein/creatinine ratio. Proteinuria is also listed as a secondary outcome.
The clinical question is therefore specific: how did the modeled kidney-function slopes compare between the two assigned iron approaches in this trial? The result does not by itself resolve broader questions about all intravenous or oral iron regimens, all people with kidney disease, or outcomes beyond those recorded.
3. Trial Design
The registry record describes a phase 4, randomized, open-label, parallel-group trial. The listed interventions were IV Iron and Ferrous Sulfate, with arm titles of IV Iron and Oral Iron. The allocation was randomized, and masking was listed as none. The registry does not describe the randomization procedure, any allocation concealment, or steps taken to limit measurement or analysis bias.
Enrollment was 136. The reported primary-outcome arm counts were 67 for IV Iron and 69 for Oral Iron. These counts describe the posted outcome groups; details about the analysis population, exclusions, withdrawals, and whether every randomized participant contributed data are not reported in the registry record.
The recorded start was 2008-08, primary completion was 2014-11, and status is listed as terminated. The reason for termination, the timing of termination relative to recruitment or follow-up, and whether the planned follow-up was completed are not reported in the registry record. The registry does not state the intended sample size or explain how enrollment was determined.
The primary outcome was the mean rate of decline in modeled measured glomerular filtration rate in the oral and intravenous groups, expressed as a slope. The description specifies baseline and 2 years as the timeframe and adjustment for baseline log urinary protein/creatinine ratio. Proteinuria is listed as a secondary outcome. The registry lists 2 outcome measures and 2 analyses, but does not give a complete account of the analysis plan or how the secondary outcome was handled.
Because the trial was open label, participants and trial personnel were not masked according to the registry. That is a feature of the recorded design, not evidence by itself that the outcome measurement was biased. The record does not explain whether laboratory or analytic personnel were masked, or whether any other bias-control procedures were used.
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 | IV Iron | Oral Iron |
|---|---|---|
| STARTED | 67 | 69 |
| COMPLETED | 49 | 50 |
| NOT COMPLETED | 18 | 19 |
Reasons for not completing this period:
| Reason | IV Iron | Oral Iron |
|---|---|---|
| Withdrawal by Subject | 2 | 3 |
| Lost to Follow-up | 1 | 2 |
| Active when terminated by DSMB | 15 | 14 |
Analysis population for the primary outcome, as defined in the registry: Modeled iothalamate mGFR slope (e.g., change from baseline to 2 years) was calculated for each group (IV iron vs. oral iron) after adjustment for baseline log urinary protein/creatinine ratio.
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 | IV Iron | Oral Iron | Total |
|---|---|---|---|---|
| Participants analysed | 67 | 69 | 136 | |
| Age, Continuous | years | 63.2 (SD 10.7) | 67.8 (SD 11.5) | 65.5 (SD 11.3) |
| Sex: Female, Male: Female | Participants | 17 | 15 | 32 |
| Sex: Female, Male: Male | Participants | 50 | 54 | 104 |
| Race/Ethnicity, Customized: Black | participants | 27 | 18 | 45 |
| Race/Ethnicity, Customized: Hispanic | participants | 2 | 0 | 2 |
| Race/Ethnicity, Customized: White | participants | 38 | 51 | 89 |
| eGFR | ml/min per 1.73m2 | 34.3 (SD 10.2) | 34.7 (SD 10.0) | 34.5 (SD 10.0) |
| Proteinuria: High proteinuria stratum (≥3g/g) | participants | 9 | 9 | 18 |
| Proteinuria: Low proteinuria stratum (<3g/g) | participants | 58 | 60 | 118 |
6. Primary Endpoint
The registry lists the primary outcome as Mean Rate of Decline in mGFR in the Two Groups - Oral and IV Iron, measured over Baseline, 2 years.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Slope (ml/min per 1.73m2 per year) |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was the mean rate of decline in modeled measured glomerular filtration rate, or mGFR, in the IV Iron and Oral Iron groups. The outcome was expressed as a slope in milliliters per minute per 1.73 square meters per year, with measurements described at baseline and 2 years. A slope represents a rate of change over time rather than a single kidney-function measurement at one visit.
The record says mGFR was assessed through plasma clearance of iothalamate. It describes an IV bolus, serial blood sampling after injection, measurement of iothalamate by high-performance liquid chromatography, and calculation of clearance using a two-pool model and validated pharmacokinetic software. The resulting modeled mGFR slope was calculated for each group after adjustment for baseline log urinary protein/creatinine ratio.
Using a rate of change can address whether the groups followed different average trajectories over the stated observation period. It also requires assumptions about how the repeated measurements are modeled and which observations contribute to the slope. Those analytic details are not fully reported in the registry record. The endpoint is a measure of kidney-function change; it is not itself a measure of symptoms, quality of life, or every possible consequence of chronic kidney disease. Proteinuria was listed separately as a secondary outcome.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The reported group slopes were -4.0 for IV Iron and -3.6 for Oral Iron. The unit attached to the primary endpoint is slope in milliliters per minute per 1.73 square meters per year. The registry also reports a mixed models analysis with a mean difference (net) of -0.35, a 95% confidence interval from -2.9 to 2.3, and p = 0.79.
The estimate is the analysis's central value for the between-group comparison. Its confidence interval indicates the range of values compatible with the data under the analysis and its assumptions. That interval includes values on either side of zero, so the posted estimate does not precisely distinguish a difference favoring either group. The interval also spans effects that could matter in either direction; the registry does not define a threshold for clinical importance. The p-value is not a probability that the null hypothesis is true, nor does it establish that the groups are equivalent.
The arm-level slopes and the mixed-model contrast are distinct reported quantities. The outcome description says the slopes were adjusted for baseline log urinary protein/creatinine ratio, and the analysis is identified as mixed models. The registry does not supply sufficient model details to reconstruct the contrast from the arm values or fully explain how the estimate was obtained. The reported estimate and interval should therefore be read as the registry's analysis, not replaced by a subtraction of the displayed arm slopes.
The result is uncertain in a statistical sense: the confidence interval is broad relative to its central estimate and includes no between-group difference. That does not show that the treatments have identical effects. It means the posted analysis does not pin down the direction or size of a between-group effect with precision. The result also cannot establish the proposed oxidative-stress or inflammatory pathway; those mechanisms are described in the trial summary, but no corresponding measurements or findings are included in the posted primary result.
The registry status is terminated, but it does not state why the trial ended or whether termination affected follow-up or analysis. That context matters when considering how complete the outcome data are, and it is not possible to infer it from the status alone. The analysis population, missing-data handling, and any prespecified decision criteria are also not reported in the registry record.
In short, the posted primary analysis gives a small negative central estimate, a 95% confidence interval that includes both negative and positive differences, and p = 0.79. These figures describe the comparison under the reported model. They do not establish equivalence, prove the absence of an effect, or demonstrate a clinically important difference.
9. Statistical Methods Explained
The primary outcome combines a longitudinal measure with a between-group comparison. Rather than comparing a single mGFR reading, the endpoint is a modeled slope, intended to represent change over time. The registry describes measurements at baseline and 2 years and reports group slopes, followed by a mixed models analysis of the mean difference (net). The details needed to reproduce the model are not reported in the registry record.
What does a slope represent?
In general, a slope describes the direction and rate of change in an outcome over time. A negative mGFR slope indicates decline in the measured quantity as time progresses within the model's convention. A group-average slope summarizes a modeled trajectory, not necessarily the experience of every participant. The registry reports -4.0 for IV Iron and -3.6 for Oral Iron. Those are group-level results, and they should not be interpreted as identical changes for each person in the group.
Longitudinal outcomes can use information from repeated measurements, but their interpretation depends on how time and observations are represented in the model. General considerations include the timing of measurements, within-participant correlation, and how incomplete follow-up is handled. The registry's endpoint description gives baseline and 2 years as the timeframe and describes a modeled slope, but does not provide enough detail to evaluate these choices or the model assumptions.
What does adjustment mean?
The primary outcome description says that group slopes were adjusted for baseline log urinary protein/creatinine ratio. In general, covariate adjustment estimates a group comparison while accounting for a specified baseline characteristic. The reported contrast is therefore not necessarily the same as a simple comparison of unadjusted group values. The registry does not report the adjustment coefficient, the full model specification, or whether additional covariates were included.
The registry identifies the comparison method as mixed models analysis. In general, mixed models can represent relationships among repeated observations and accommodate variation among participants, depending on how the model is specified. Naming a method does not disclose its full structure. The record does not report the fixed or random effects, covariance structure, estimation method, diagnostic checks, or the precise role of repeated observations in the reported analysis. These omissions limit independent reproduction and detailed assessment of the model.
How should the confidence interval be read?
The reported mean difference (net) is -0.35, with a 95% confidence interval from -2.9 to 2.3. In general, a confidence interval conveys statistical uncertainty around an estimate. A narrower interval indicates greater precision under the analysis assumptions; a wider interval leaves a broader range of effects compatible with the data. This interval includes zero and values in both directions. It therefore does not establish a clear direction for the between-group difference. It is not a range containing 95% of individual participant outcomes.
A confidence interval is not a guarantee that the true value lies within its endpoints, and its interpretation depends on the model and study conduct. It does not describe uncertainty about every aspect of the trial, such as selection bias, missing observations, or measurement error. Those issues require separate information, much of which is not reported in the registry record.
What does the p-value add?
The reported p-value is 0.79. In general, a p-value describes how unusual the observed data, or data more extreme, would be under a specified null model and its assumptions. It is not the probability that the null hypothesis is true. Nor does a large p-value prove equivalence or show that a treatment has no effect. The confidence interval helps convey the range of effect sizes that remain compatible with the analysis; the p-value alone does not communicate that range.
The registry does not identify a superiority, noninferiority, or equivalence margin for this comparison. Without a prespecified margin and an appropriate design and analysis, the result cannot be interpreted as evidence of equivalence. The analysis is categorized as SUPERIORITY OR OTHER in the record, but further detail about the intended hypothesis is not reported.
Why can model results differ from arm values?
The group slopes and the mixed-model mean difference are different summaries. In general, an adjusted model contrast can depend on covariates, repeated observations, and model specification, while arm-level values summarize group results. The registry reports baseline adjustment for log urinary protein/creatinine ratio and identifies mixed models analysis, but does not give enough model detail to reconstruct the contrast. No independently recalculated comparison is reported in the registry record, so the sponsor's model estimate remains the available inferential result.
Over-dispersion is a general concern for count outcomes when variability exceeds what a simple count model assumes. It is not the central issue for this continuous slope outcome, and the registry does not report a count-model analysis for the primary endpoint. The endpoint's main statistical concerns instead include modeling repeated measurements, adjustment choices, precision, and incomplete outcome data. Whether any specific modeling issue affected the result cannot be determined from the posted details.
The registry also describes iothalamate clearance measurement and its modeling procedure. In general, a carefully specified measurement and analysis process can help make an endpoint reproducible, but the written description does not replace full analytic details, such as model diagnostics and handling of measurements that are unavailable or unusable. Those details are not reported in the registry record.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| Mixed Models Analysis | Mean Difference (Net) -0.35 | -2.9 to 2.3 | 0.790 |
The registry reports group slopes of -4.0 for IV Iron and -3.6 for Oral Iron, and a separate mixed models estimate of the mean difference (net) of -0.35. The reported 95% confidence interval is -2.9 to 2.3, with p = 0.79. These should be treated as the sponsor's reported analysis results. The registry does not report a separate recalculated comparison that would allow a direct numerical reconciliation with the model estimate.
The quantities need not be interchangeable. The primary outcome description states that group slopes were adjusted for baseline log urinary protein/creatinine ratio, and the comparison method is identified as mixed models analysis. General statistical reasoning allows adjusted model contrasts to differ from simple summaries of group outcomes, but the registry does not provide enough specification to attribute the relationship among these values to any particular modeling choice.
The record does not report a discrepancy between the sponsor analysis and a recalculation. It also does not provide the underlying participant-level observations needed to reproduce the model. Accordingly, the reported mixed-model estimate, confidence interval, and p-value are the available inferential results; the arm slopes provide additional descriptive context rather than a substitute analysis.
11. Multiplicity, Missing Data and Analysis Populations
The registry lists Proteinuria as a secondary outcome and reports 2 outcome measures and 2 analyses. It does not describe a prespecified multiplicity strategy, such as an adjustment of significance thresholds or a hierarchy among outcomes. It is therefore not possible to tell from the registry record whether or how the possibility of multiple statistical comparisons was addressed.
Multiplicity matters in general when several outcomes, time points, subgroups, or analyses are examined: the more opportunities there are to identify a result, the more important it is to understand which comparisons were planned and how interpretation was controlled. The available record does not give a complete list of all analyses that may have been considered, nor does it state whether analyses beyond those posted were conducted. No conclusion about selective reporting can be drawn from that absence alone.
Missing-data handling is also not reported in the registry record. The outcome timeframe is baseline and 2 years, but the record does not state how many participants had usable measurements at each time, how missing measurements were treated, or whether sensitivity analyses were performed. The posted arm counts are 67 and 69 for the primary outcome, but these counts alone do not establish the completeness of longitudinal follow-up or the analysis population.
The record does not state whether all randomized participants were analyzed according to assigned group, whether participants were excluded from the outcome analysis, or whether any alternative analysis populations were used. It also does not describe adherence to the assigned iron approach or how treatment changes were handled. These omissions limit assessment of how the analysis reflects the randomized comparison.
No interim analyses, stopping rules, or sample-size justification are reported in the registry record. The fact that status is listed as terminated does not identify the reason or establish that a particular stopping decision was made. Without that information, the impact of termination on recruitment, follow-up, outcome completeness, or interpretation remains uncertain. A planning illustration based on an observed effect, where available, is not a record of the original design rationale or observed power; the trial's own design justification is not reported.
12. 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 |
|---|---|---|---|
| IV Iron | 37 | 67 | 55.2% |
| Oral Iron | 40 | 69 | 58.0% |
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 |
|---|---|
| IV Iron | 45 of 67 |
| Oral Iron | 47 of 69 |
Most frequent serious adverse event terms
| Event term | Organ system | IV Iron | Oral Iron |
|---|---|---|---|
| General disorders and administration site conditions - other, miscellanous | General disorders | 20 of 67 | 21 of 69 |
| Acute kidney injury | Renal and urinary disorders | 12 of 67 | 15 of 69 |
| Surgical and medical procedures - other, PRBC transfusion | Surgical and medical procedures | 12 of 67 | 12 of 69 |
| Heart failure | Cardiac disorders | 9 of 67 | 9 of 69 |
| Myocardial infarction | Cardiac disorders | 8 of 67 | 8 of 69 |
| Skin infection | Infections and infestations | 7 of 67 | 6 of 69 |
| Renal and urinary disorders - other, end stage renal disease | Renal and urinary disorders | 6 of 67 | 7 of 69 |
| Lung infection | Infections and infestations | 8 of 67 | 4 of 69 |
| Death NOS | General disorders | 6 of 67 | 4 of 69 |
| Cardiac disorders - other, miscellaneous | Cardiac disorders | 5 of 67 | 4 of 69 |
Most frequent non-serious adverse event terms
| Event term | Organ system | IV Iron | Oral Iron |
|---|---|---|---|
| Dizziness | Nervous system disorders | 9 of 67 | 9 of 69 |
| Upper respiratory infection | Infections and infestations | 6 of 67 | 10 of 69 |
| Urinary tract infection | Infections and infestations | 10 of 67 | 4 of 69 |
| Surgical and medical procedures - other, outpatient procedure | Surgical and medical procedures | 7 of 67 | 7 of 69 |
| Fall | Injury, poisoning and procedural complications | 5 of 67 | 6 of 69 |
| Diarrhea | Gastrointestinal disorders | 1 of 67 | 9 of 69 |
| Gastrointestinal disorders - other, stool discoloration | Gastrointestinal disorders | 0 of 67 | 10 of 69 |
| Dyspnea | Respiratory, thoracic and mediastinal disorders | 4 of 67 | 5 of 69 |
| Injury, poisoning and procedural complications - other, traumatic injury | Injury, poisoning and procedural complications | 2 of 67 | 6 of 69 |
| Constipation | Gastrointestinal disorders | 2 of 67 | 5 of 69 |
Serious events with the highest arm-level rate: general disorders and administration site conditions - other, miscellanous (30.4%), acute kidney injury (21.7%), surgical and medical procedures - other, prbc transfusion (17.9%), heart failure (13.4%), lung infection (11.9%).
The registry reports serious adverse events affecting 37 of 67 participants in the IV Iron group and 40 of 69 in the Oral Iron group. It separately reports other adverse events affecting 45 of 67 and 47 of 69, respectively. These are counts of participants recorded as affected, not estimates of the causal effect of either treatment.
The serious-event terms listed include general disorders and administration site conditions - other, miscellanous at 30.4%, acute kidney injury at 21.7%, surgical and medical procedures - other, PRBC transfusion at 17.9%, heart failure at 13.4%, lung infection at 11.9%, and myocardial infarction at 11.9%. The registry does not make clear in the posted information how those percentages were calculated or whether the terms represent mutually exclusive categories. They should be read as reported event information, not added together or treated as independent risks.
Deaths are not reported in the registry record. The record does not provide event timing, severity grading beyond the serious-event classification, relatedness assessments, exposure duration, or a detailed account of how adverse events were collected. Differences in these counts cannot establish that an intervention caused or prevented an event, and the posted figures do not support a complete comparative safety assessment on their own.
13. What the Result Does, and Does Not, Mean
The result describes a randomized comparison of intravenous iron and oral iron on a modeled mGFR slope. The arm-level values were -4.0 and -3.6, and the reported mixed-model contrast was -0.35, with a 95% confidence interval from -2.9 to 2.3 and p = 0.79. The estimate is uncertain: its interval includes zero and effects in either direction. The result therefore does not establish a clear difference between the groups.
It also does not establish that the groups are equivalent. Equivalence requires a defined margin and an analysis designed to assess whether the possible difference is sufficiently small. Such a margin is not reported in the registry record. A non-significant result is not proof that no effect exists, and the confidence interval leaves a range of possible effects compatible with the analysis.
The result applies to the study's recorded population, interventions, endpoint, and analysis. It does not automatically generalize to other iron preparations, schedules, doses, patient groups, or clinical outcomes. The registry summary describes a proposed oxidative-stress and inflammatory mechanism, but the posted primary result concerns mGFR slope. It does not confirm or refute that proposed mechanism because corresponding mechanistic findings are not reported.
The registry lists Proteinuria as a secondary outcome, but no numerical result for it is included in the registry entries. Other outcomes, complete participant characteristics, adherence, and longer-term results are likewise not reported in the registry record. Thus the primary endpoint cannot stand in for every dimension of kidney function or safety.
The appropriate statistical reading is restrained: the posted mixed-model estimate is centered near zero relative to an interval that spans both directions, and the data do not provide a precise estimate of the between-group difference. The result is not a treatment recommendation and does not establish a clinical benefit or harm.
14. Why This Trial Matters Statistically
This trial matters statistically because it illustrates how a longitudinal clinical endpoint and a model-based comparison answer different questions from a simple comparison of arm summaries. A slope aims to characterize change over time, while the mixed-model contrast estimates a group difference under the model and adjustment described in the registry. Distinguishing these quantities prevents the arm-level values from being mistaken for the full inferential result.
It also illustrates the value of reporting uncertainty alongside an estimate. The mean difference (net) of -0.35 is accompanied by a 95% confidence interval from -2.9 to 2.3 and p = 0.79. The interval makes clear that the available result is compatible with differences in either direction, rather than supporting a definitive claim of no difference. Precision and direction are separate questions from whether a test crosses a conventional threshold.
The record also shows why transparent analysis details matter. Baseline adjustment for log urinary protein/creatinine ratio and use of mixed models are identified, but the full model specification, analysis population, and missing-data procedures are not. Those details are essential to reproducing and evaluating a longitudinal result.
Finally, the registry status is terminated, while the reason and implications are not stated. Readers should avoid treating that status as an explanation for the result. The case underscores a broader statistical principle: a reported estimate must be interpreted with its uncertainty and the limits of the available design and analysis information, rather than as a stand-alone verdict about an intervention.
15. 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.
Several trial-specific limitations of interpretation follow from what is and is not reported. The record describes a randomized, open-label, parallel-group design, but does not give details of the randomization sequence, allocation concealment, or any masking of outcome assessors or analysts. The endpoint includes modeled laboratory measurement, but the record does not state whether those involved in measurement or analysis were masked to group assignment.
The registry identifies a mixed models analysis and adjustment for baseline log urinary protein/creatinine ratio, but it does not provide the complete model specification, assumptions, diagnostics, or the exact analysis population. It also does not report the handling of missing measurements, exclusions, withdrawals, adherence, or treatment changes. These gaps make it difficult to assess how robust the estimate is to analytic choices or incomplete follow-up.
The record lists status as terminated but does not state why the trial ended or whether termination changed the planned recruitment, observation period, or analysis. The original sample-size rationale, any stopping criteria, and any interim analyses are not reported. It is not appropriate to infer these from the status label.
The primary comparison has a confidence interval from -2.9 to 2.3, so uncertainty remains about both direction and size. The registry does not supply a clinical-importance threshold that would help interpret which effects within that interval matter. Nor does it report an equivalence margin.
Safety information is limited to reported counts and listed serious-event terms. Event timing, relatedness, collection procedures, and the meaning of the listed percentages are not fully specified. The record also does not include a numerical Proteinuria result. These limitations constrain interpretation of both efficacy-related and safety-related findings without, by themselves, proving bias or invalidity.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: A Clinical Trial of Oral Versus IV Iron in Patients With Chronic Kidney Disease — NCT00830037.
- Registry record last updated 2016-07-21; status last verified 2016-06.
- Results first posted 2016-07-21.
- 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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19. Record Summary
NCT00830037 is listed as a phase 4, randomized, open-label, parallel-group trial comparing IV Iron with Oral Iron, listed as Ferrous Sulfate. The registry describes patients with chronic kidney disease and iron-deficiency anemia and records enrollment of 136. The trial start is listed as 2008-08, primary completion as 2014-11, and status as terminated.
The primary outcome was the modeled mean rate of decline in mGFR, with a baseline and 2 years timeframe and adjustment for baseline log urinary protein/creatinine ratio. Reported arm slopes were -4.0 for IV Iron and -3.6 for Oral Iron. The mixed models analysis reported a mean difference (net) of -0.35, a 95% confidence interval from -2.9 to 2.3, and p = 0.79.
Proteinuria is listed as a secondary outcome, but a numerical result is not reported in the registry record. The reason for termination, detailed analysis plan, missing-data procedures, and full model specification are also not reported.