IV Iron for the Anemia of Traumatic Critical Illness: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for IV Iron for the Anemia of Traumatic Critical Illness (NCT01180894), a randomized na study. The primary outcome is RBC Transfusion.

2. Clinical Question

The central statistical question is how precisely the observed difference between groups estimates a difference in transfusion occurrence in the trial population. The registry reports the group counts, an unadjusted risk difference, an interval around that estimate, and an unadjusted p-value. These describe the posted data; they do not by themselves establish why the groups differed or whether the observed pattern would recur in another study.

The trial is listed as completed, with enrollment of 150. Its official title describes a multicenter, randomized, double-blind comparison, while the masking field records quadruple masking. The registry record does not report additional detail about participating centers or the populations included at each center.

3. Trial Design

This was a randomized, parallel-group comparison of iron sucrose and placebo. The registry records quadruple masking; the official title describes the comparison as double-blind. It does not specify which participants, clinicians, outcome assessors, or other personnel were masked, so the practical meaning of the masking entry cannot be determined from the record.

The iron sucrose arm is described as receiving 100 mg IV TIW. The placebo arm is described as normal saline. More detailed information about allocation procedures, treatment duration, adherence, permitted co-interventions, and the timing of transfusions is not reported in the registry record. The record lists Denver Health and Hospital Authority as sponsor.

The primary outcome was a count of participants who underwent red blood cell transfusion during 42 Days. The outcome is binary at the participant level: each participant either had a transfusion recorded during the stated timeframe or did not. The posted result lists 47 of 75 participants in the iron sucrose arm and 55 of 75 in the placebo arm. The registry also lists secondary outcomes for iron-deficient erythropoiesis, infection, and the number of participants who died. The posted results include infection and death measures, but do not include a posted result for iron-deficient erythropoiesis.

The registry lists enrollment of 150 and status as completed. The start is recorded as 2011-06, and primary completion as 2013-09. These registry dates do not establish when each participant entered or completed follow-up. The registry record does not report the original sample-size justification, the planned analysis population, detailed follow-up procedures, or a statistical analysis plan. It records no reported analyses.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as RBC Transfusion, measured over 42 Days.

The primary endpoint counts participants who underwent red blood cell transfusion during 42 Days. It is a participant-level event outcome: the count reflects whether a participant experienced at least one qualifying transfusion during the timeframe, rather than the total number of transfusions given. The registry’s endpoint description is “The number of participants who underwent RBC transfusion.” It does not report further rules for what counted as a qualifying transfusion or how the outcome was ascertained.

Transfusion is relevant to the trial’s stated question because the registry describes the study as testing whether intravenous iron supplementation improves anemia and reduces the need for red blood cell transfusion. A count of participants with the event provides a direct group-level description of how many experienced this outcome during follow-up. It does not, by itself, explain the clinical circumstances of each transfusion or indicate how anemia changed over time.

The posted counts are 47 participants in the iron sucrose group and 55 in the placebo group. Because the groups have the same reported size, the statistical comparison can be expressed as a difference in the proportions with a transfusion. The record also reports a risk ratio, an odds ratio, an interval for the risk difference, and an unadjusted p-value. These are alternative ways of describing the between-group pattern; they are not separate outcomes.

The registry record does not report a threshold for transfusion, a hemoglobin-based transfusion rule, or whether decisions were standardized across centers. Such details would help readers understand how the endpoint was generated, but should not be inferred from the outcome label alone.

7. Results Posted in the Registry

• Iron Sucrose: 62.7% (47/75) versus 73.3% (55/75) on control; risk difference -10.7 percentage points (95% CI -25.5 to 4.2), risk ratio 0.85 (0.68–1.07); unadjusted two-proportion z-test p = 0.161.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Infection

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Iron Sucrose: 2.3% (1/44) versus 1.9% (1/52) on control; risk difference 0.3 percentage points (95% CI -5.4 to 6.1), risk ratio 1.18 (0.08–18.35); unadjusted two-proportion z-test p = 0.905.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Iron Sucrose and the control. The interval gives the range of effects that remain compatible with the data.

The Number of Participants Who Died

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Iron Sucrose: 9.3% (7/75) versus 2.7% (2/75) on control; risk difference 6.7 percentage points (95% CI -0.9 to 14.2), risk ratio 3.50 (0.75–16.30); unadjusted two-proportion z-test p = 0.086.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Iron Sucrose and the control. The interval gives the range of effects that remain compatible with the data.

The registry lists three secondary outcomes: iron-deficient erythropoiesis, infection, and the number of participants who died. Posted results are available for infection and death, while a result for iron-deficient erythropoiesis is not reported in the registry record. Across the available secondary outcomes, the evidence is not uniformly precise: the intervals differ in width, and some comparisons are based on very few events. The pattern should be considered alongside, rather than as a replacement for, the primary transfusion outcome.

Secondary outcomes may help describe other events recorded during follow-up, but they address different questions and timeframes from the primary endpoint. The primary outcome concerns transfusion during 42 Days; the posted secondary infection and death measures use 28 Days. A difference or lack of a clear difference in one endpoint does not determine the result for another, and secondary findings do not explain the primary result unless a prespecified analysis establishes such a relationship. The registry does not report analyses linking these outcomes.

The secondary comparisons are reported as unadjusted. General explanation: when multiple outcomes are tested, the chance of obtaining at least one apparently unusual result can increase if no adjustment or prespecified hierarchy is used. An unadjusted p-value does not account for the number of comparisons. The registry does not report whether multiplicity was considered, whether outcomes had an ordered testing plan, or which secondary outcomes were intended to support confirmatory conclusions.

For those reasons, secondary results are best viewed as descriptive and exploratory in this record. Their interpretation should account for the outcome definitions, follow-up windows, event counts, and uncertainty intervals, not just whether an unadjusted p-value crosses a threshold. They can identify patterns for further study, but they do not independently establish a treatment effect or resolve uncertainty in the primary comparison.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Iron-deficient Erythropoeisis (IDE)
• Infection
• The Number of Participants Who Died

9. Statistical Interpretation

10. Statistical Methods Explained

General explanation: A binary endpoint records whether an event occurred for each participant. For the primary outcome, the event is undergoing red blood cell transfusion during 42 Days. The group counts can therefore be expressed as proportions with the event, and the statistical comparison can describe the difference or ratio between those proportions. The registry gives the event counts, the group sizes, and several effect measures.

What does the risk difference describe?

The risk difference subtracts the event proportion in the comparison group from the event proportion in the intervention group. The posted primary estimate is -0.107. Its negative sign means that the observed event proportion was lower in the iron sucrose group than in the placebo group. The risk difference is an absolute measure on the proportion scale. It is not a count of participants and should not be interpreted as a causal effect without considering the design, conduct, and uncertainty of the trial.

How do the risk ratio and odds ratio differ?

A risk ratio compares the event proportions between groups as a ratio. An odds ratio compares the odds of the event, where odds are the event proportion divided by the proportion without the event. Both are relative measures, but their numerical values are not interchangeable. When an event is common, the odds ratio can differ more from the risk ratio than it would for a rare event. General statistical interpretation should therefore keep the scale in view. The primary risk ratio and odds ratio are posted alongside the risk difference, but the registry does not report a prespecified choice of effect measure in an analysis plan.

What does an interval communicate?

General explanation: an uncertainty interval describes a range of estimates compatible with the data under a statistical procedure and its assumptions. A narrower interval indicates greater precision on that measure; a wider interval indicates less precision. The primary interval for the risk difference extends from -0.255 to 0.042, covering negative and positive values and including no difference. The registry does not state the confidence level or construction method, so no more specific interpretation of its coverage should be assumed.

What does the p-value communicate?

The unadjusted p-value for the primary comparison is 0.161. General explanation: a p-value quantifies how unusual data at least as discrepant as those observed would be under a specified null model and analysis procedure. It is not the probability that the null model is correct. The term “unadjusted” indicates that the reported value is not presented as corrected for multiple comparisons. The registry does not provide the test name, the exact null hypothesis specification, or details about any model diagnostics.

The comparison statistics are described as unadjusted re-calculations from posted summary statistics. The discrepancy field is false, so there is no recorded conflict with a sponsor analysis that would take precedence. This does not mean the re-calculation is a substitute for a full trial analysis. Summary-level re-calculation cannot adjust for participant characteristics or reproduce analyses that require individual-level data.

The record contains no reported analyses. It does not describe an intention-to-treat or per-protocol analysis, how participants with missing outcomes were handled, whether any covariates were included, or whether there were interim analyses. These absences limit what can be inferred about the analytic strategy. The registry’s outcome counts and comparative statistics can still be described as posted, but they do not reveal the full data-processing pathway.

For binary outcomes, the number of events and the number of participants with outcome information affect precision. General explanation: fewer observed events or a small analyzed group can make relative estimates especially uncertain, as illustrated by the wide intervals for some secondary outcomes. This is not over-dispersed count data: the endpoint is a participant-level event indicator, not a repeated event count. The registry does not report whether participants could experience multiple transfusions, and the posted endpoint counts participants with a transfusion rather than transfusion episodes.

Randomization is intended to make assigned groups comparable on average, while masking can reduce some forms of differential treatment or assessment. Those general design features do not guarantee balance in a particular trial or eliminate every source of bias. The registry identifies randomization and quadruple masking but provides no methods details sufficient to assess sequence generation, concealment, masking success, or outcome adjudication.

11. Confidence Intervals and Precision

The primary risk-difference estimate is -0.107, with a posted interval from -0.255 to 0.042. The interval spans negative and positive values, so it includes both a lower and a higher observed event proportion in the iron sucrose group relative to placebo, as well as no difference. This makes the direction and size of the underlying difference uncertain. The interval is relatively broad on the risk-difference scale, indicating limited precision for distinguishing among those possibilities.

General explanation: an interval is a range of values compatible with the data under a specified statistical method. It does not guarantee that the true value lies within its endpoints, and it is not a range of individual participant outcomes. The registry record does not report the confidence level or interval method. The posted limits should therefore not be described as a particular confidence interval level unless that information is documented elsewhere in the record.

The relative measures also have intervals that include their no-difference values: the risk ratio is 0.855 with limits 0.685 and 1.067, and the odds ratio is 0.610 with limits 0.305 and 1.221. The choice of measure affects the scale and interpretation, but the uncertainty is evident on each scale. The unadjusted p-value of 0.161 is consistent with the fact that the risk-difference interval includes no difference, though the registry does not report enough methodological detail to establish how the interval and test were constructed.

Precision should not be confused with clinical importance. A broad interval can leave materially different effects compatible with the data, while a narrow interval can estimate a small effect precisely. The registry does not provide a threshold for a clinically important difference in transfusion occurrence. Consequently, the statistics alone cannot define which values within the interval would matter to patients or clinicians.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are illustrations based on the observed effect, not the original trial design. The assumptions listed are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The figures show participants per arm for 80% power and participants per arm for 90% power; they are not total sample sizes. The stated effect to detect is a specified fraction of the observed effect. For time-to-event outcomes, the convention would instead be total events, but the outcomes are not time-to-event planning figures.

The 80% power column gives the number of participants per arm in a hypothetical study that, under the listed assumptions and effect size, would have an 80% chance of detecting that effect at the stated significance level. The 90% column uses the same general idea but targets a higher chance of detection. Neither column describes the probability that the completed trial’s result is correct.

Planning for 100% of the observed effect uses the full observed contrast as the target. Planning for 75% or 50% of the observed effect uses smaller target effects. Smaller effects are harder to detect, so the required number of participants per arm increases as the target effect gets smaller. The estimates are sensitive to the observed effect and should not be treated as established requirements for a future study, particularly when the observed estimate is uncertain.

These figures are not observed power. They are planning illustrations, not a retrospective assessment of the completed trial’s power. The trial’s own original sample-size assumptions, target effect, and justification are not reported in the registry record. The posted planning figures therefore cannot establish whether the study was designed to detect a particular clinically important difference.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.733; treatment proportion p₁ = 0.627; average p̄ = 0.680.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.6597 = 1.2930.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.6554 = 0.5516.
4. n = (1.2930 + 0.5516)² / (-0.1067)² = 299.0, rounded up to 300 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
p0 <- 0.733333333333333                          # control proportion
p1 <- 0.626666666666667                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(1180894)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 300 (80% power), 400 (90% power)
 75% of observed effect: n per arm = 521 (80% power), 697 (90% power)
 50% of observed effect: n per arm = 1,143 (80% power), 1,530 (90% power)
power.prop.test: 299 
Simulated power at n = 300 per arm: 0.803 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry identifies one primary outcome and three secondary outcomes. It posts comparative statistics for the primary transfusion outcome, infection, and death, but does not post a result for iron-deficient erythropoiesis. The record does not report a multiplicity adjustment, a hierarchy among outcomes, or a plan specifying which comparisons were confirmatory. The secondary p-values are unadjusted, so they should not be read as if they were corrected for testing several outcomes.

Multiplicity matters because repeated statistical testing can increase the chance of observing a seemingly notable result even when none of the tested effects is real. General explanation: prespecifying a primary outcome and controlling how secondary comparisons are interpreted can help distinguish confirmatory evidence from exploratory findings. The registry’s primary outcome is identifiable, but the complete testing plan is not reported. It is therefore not possible to determine from the record whether the posted comparisons correspond to all planned tests.

Missing outcome information is also not described. The primary outcome lists 75 participants in each arm, while the infection outcome lists 44 in the iron sucrose arm and 52 in the placebo arm. The registry does not explain why the infection denominators differ, whether these participants had complete follow-up, or how missing outcome data were handled. No reason should be inferred from the difference in listed group sizes.

The registry does not report the analysis population, such as whether participants were analyzed according to randomized assignment, treatment received, or another rule. It also does not report participant flow, exclusions after randomization, protocol deviations, imputation, sensitivity analyses, or methods for handling withdrawal. These omissions make it difficult to assess whether the posted outcome groups represent all randomized participants and whether missingness could affect the comparisons.

The record lists no reported analyses and contains no detailed statistical analysis plan. The posted summary statistics can be interpreted on their own terms, but conclusions about prespecification, multiplicity control, missing-data assumptions, and analysis populations remain limited.

15. Safety Results

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

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: mortality (9.3%).

The adverse-event record lists serious adverse events affecting 7 participants in the iron sucrose group and 2 in the placebo group. Each arm lists 75 participants at risk for serious adverse events. Other adverse events are recorded as affecting 0 participants in each group, with 75 at risk in each arm. These are descriptive counts; the registry does not provide an adjusted comparison or a causal analysis of the differences.

The serious adverse-event listing includes “Mortality” with 9.3%. This term-level percentage is presented in the registry’s serious-event information, but the record does not explain its calculation or how it relates to the participant-level adverse-event counts. The adverse-event field for deaths is null in both groups; null should not be interpreted as zero. Separately, the secondary outcome reports the number of participants who died within 28 Days.

Serious adverse-event counts and the secondary death outcome are not necessarily interchangeable measures. The record does not report event definitions, seriousness criteria, attribution to treatment, timing, or whether participants could have more than one serious event. These figures should therefore be read as reported safety information, not as proof that an intervention caused or prevented an adverse event.

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

The registry’s primary result is an estimated lower proportion of participants with a transfusion in the iron sucrose group than in the placebo group. The estimate is accompanied by an interval that includes no difference and values on either side of it. The unadjusted p-value is 0.161. Together, these statistics indicate uncertainty about the size and direction of the underlying group difference; they do not establish that iron sucrose reduces transfusion or that the groups are equivalent.

A non-significant p-value is not evidence that an effect is absent. It can arise when an effect is small, when estimates are imprecise, or under other circumstances. Conversely, an observed difference in group counts does not by itself demonstrate a treatment effect. Randomization supports a comparison, but the registry does not provide enough detail about outcome handling, missing data, analysis populations, or trial procedures to evaluate every possible source of uncertainty.

The endpoint concerns whether a participant had a transfusion during the stated period. It does not show the number of transfusions, the severity or duration of anemia, or the clinical reasoning behind each transfusion. The registry’s summary does not report a transfusion threshold or a detailed anemia trajectory. The stated trial purpose also included improving anemia, but the posted primary outcome is transfusion occurrence; it should not be treated as a direct measure of every aspect of anemia.

The secondary results provide additional descriptions but have their own limitations, including unadjusted comparisons, differing follow-up windows, and uncertainty around estimates. No result for iron-deficient erythropoiesis is reported in the registry record. Serious adverse-event data are descriptive and do not establish causation.

In short, the posted results describe what happened in the recorded groups and quantify uncertainty around the primary comparison. They do not prove benefit or lack of benefit, establish safety, or settle what would happen in other settings. The registry record does not report a threshold for clinical importance, so the statistical estimates cannot alone determine whether any possible effect would matter in practice.

17. Why This Trial Matters Statistically

This trial illustrates why a group difference and a treatment conclusion are not the same thing. The primary estimate is negative on the risk-difference scale, reflecting a lower observed transfusion proportion in the iron sucrose group, but its interval includes no difference and extends in both directions. A single point estimate can appear more definite than the evidence warrants; reading the estimate together with its interval gives a fuller account of uncertainty.

The example also shows why different effect measures matter. Risk difference, risk ratio, and odds ratio express a comparison on different scales. They may tell a consistent directional story while differing in magnitude and interpretation. Readers should identify the scale before judging what an estimate means, and should avoid treating relative measures as absolute changes.

Secondary outcomes and safety counts highlight another statistical issue: a trial can generate several comparisons, and unadjusted results do not account for that multiplicity. Outcomes with few observed events can also produce wide uncertainty intervals. Such findings can be informative as descriptions, yet still be weak grounds for firm conclusions when the analysis plan and multiplicity handling are not reported.

Finally, planning illustrations based on the observed effect should not be mistaken for the original design or for evidence about the completed trial’s power. The registry does not report the original sample-size justification. Separating retrospective outcome estimates from prospective planning assumptions is essential to interpreting the record accurately.

18. 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 important details about the trial methods and outcome measurement unreported. It does not give full eligibility criteria, participant characteristics, allocation procedures, masking procedures, treatment duration, adherence, or the operational rules for deciding when a transfusion occurred. These details would help assess how the trial was conducted and how broadly the findings might apply.

The record does not report a statistical analysis plan, original sample-size assumptions, analysis populations, interim analyses, adjusted analyses, or methods for missing data. It lists no reported analyses. The posted comparisons are unadjusted, and the record does not say whether the secondary outcomes were planned as exploratory or confirmatory. The confidence level and construction method for the posted intervals are also not identified.

The infection outcome has different listed group sizes from the primary outcome and the death outcome. The reason for this is not reported in the registry record, so the difference cannot be attributed to missingness, eligibility, or any other cause. The registry also does not post a result for iron-deficient erythropoiesis despite listing it as a secondary outcome.

Safety information is limited to reported counts and a serious-event term with a percentage. The record does not provide event-level detail, attribution, or enough information to reconcile the term-level listing with the separately reported death outcome. These limitations restrict interpretation of both efficacy and safety and should prevent stronger claims than the posted summaries support.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: IV Iron for the Anemia of Traumatic Critical Illness — NCT01180894.
• Registry record last updated 2018-02-05; status last verified 2018-01.
• Results first posted 2017-01-20.
• 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.

22. Record Summary

The registry describes a completed, randomized, parallel-group comparison of iron sucrose and placebo for anemia in critically ill trauma patients. It lists enrollment of 150, quadruple masking, and a primary outcome of participants who underwent red blood cell transfusion during 42 Days.

The primary outcome counts are 47 of 75 participants in the iron sucrose group and 55 of 75 in the placebo group. The risk-difference estimate is -0.107, with an interval from -0.255 to 0.042 and an unadjusted p-value of 0.161. The interval includes no difference, leaving meaningful uncertainty about the underlying contrast.

Secondary infection and death outcomes are posted; a result for iron-deficient erythropoiesis is not reported in the registry record. The record does not report the original sample-size justification, statistical analysis plan, analysis populations, or missing-data methods. The available statistics support a description of the posted results, not a definitive causal or clinical conclusion.