Management of Mineral and Bone Disease in Hemodialysis-Calcitriol vs. Paricalcitol: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Management of Mineral and Bone Disease in Hemodialysis-Calcitriol vs. Paricalcitol (NCT01725113), a randomized phase 4 study. The primary outcome is Calcium Levels at Month 3 Post Calcitriol Treatment Initiation.

2. Clinical Question

The comparison is between treatment protocols, not simply between two independent groups assigned to receive one treatment throughout. Each sequence includes both treatments, in opposite orders. That design makes the timing and order of measurements important when interpreting a treatment contrast. The record does not report a numerical treatment comparison, confidence interval, or p-value for the primary endpoint.

Secondary outcomes listed include parathyroid hormone and phosphorus levels, along with the amount of active vitamin D analog used, at month 3 after initiation of each treatment. These outcomes describe other laboratory measures and treatment use; their numerical results are not reported in the registry record. The record therefore establishes the comparison the trial set out to make, but it does not permit a conclusion about the measured differences between protocols.

3. Trial Design

This was a phase 4, randomized, prospective, single-masked crossover study. The registry lists an enrollment of 16 and a status of terminated. The reason for termination is not reported in the registry record. Winthrop University Hospital is listed as the sponsor.

Participants were assigned to one of two treatment sequences. One sequence received an intravenous calcitriol-based protocol for 14 weeks and then crossed over to an intravenous paricalcitol-based protocol for 14 weeks. The other sequence received the same protocols in the reverse order. The registry does not report the method used to generate or conceal the random allocation, who was masked, or whether there was a washout period between treatment periods.

A crossover design allows each participant to receive both treatments, so observations can in principle be compared within the same person. This can account for stable differences between participants. General statistical considerations are that such analyses must also account for treatment order, period, and possible carryover from an earlier treatment. The statistical analysis used for this trial is not reported in the registry record, so it is not possible to determine how these features were handled.

The primary endpoint is described as calcium levels at month 3 after calcitriol treatment initiation, with the timeframe listed as up to month 6. The record also lists outcomes after paricalcitol initiation and a series of parathyroid hormone, phosphorus, and treatment-amount outcomes. The registry lists 8 outcome measures but no analysis results. It does not state how many participants completed both periods or how many contributed data to each endpoint.

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.

Before assignment: Of the 16 enrolled participants, 3 were removed due to screen failure and 1 patient experienced death before the start of study.

Overall Study

Reasons for not completing this period:

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: Baseline characteristics are only available among participants who completed the trial.

6. Primary Endpoint

The registry lists the primary outcome as Calcium Levels at Month 3 Post Calcitriol Treatment Initiation, measured over Up to Month 6.

The primary endpoint is the mean calcium level, measured in mg/dl, at month 3 after calcitriol treatment initiation. Calcium is a laboratory measure relevant to mineral and bone disease, and monitoring it provides information about a biochemical outcome during the treatment protocol. The registry identifies the endpoint as a continuous measure summarized by a mean and standard deviation.

The timeframe is listed as up to month 6. The endpoint title names the month 3 measurement following calcitriol initiation, while the crossover schedule assigns 14 weeks to each treatment period. The registry does not give further detail about the precise assessment visit, acceptable timing window, or how the primary endpoint was defined for participants who began with paricalcitol.

A mean describes the average observed measurement in the analyzed group; a standard deviation describes the spread of individual measurements around that mean. These summaries do not, by themselves, show the difference between treatment protocols or the uncertainty around that difference. A treatment comparison and its precision would require the relevant result and analysis. Neither a numerical mean and standard deviation nor a comparative estimate for the primary endpoint is reported in the registry record.

The endpoint was selected within a study whose stated purpose was to compare safety and effectiveness using revised KDIGO parathyroid hormone targets. The record does not report the rationale for selecting calcium as the primary outcome, a target range, or a criterion for non-inferiority. Those details cannot be inferred from the endpoint name alone.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean and standard deviation describe?

The primary outcome is a continuous laboratory measure, summarized as a mean and standard deviation. General: a mean represents the arithmetic center of measured values, while the standard deviation describes their dispersion. These answer different questions: the mean indicates a typical level in the analyzed observations, and the standard deviation indicates how varied those observations are. Neither quantity alone gives the uncertainty in a comparison between treatments. The registry record does not report the endpoint's numerical summaries.

What would a treatment estimate and confidence interval add?

General: a treatment estimate expresses the observed contrast between treatment conditions in the scale of the outcome, while a confidence interval describes the range of values compatible with the data and the chosen analysis under its assumptions. A narrow interval indicates greater precision than a wide interval. Interpretation depends on the interval's location relative to clinically or scientifically relevant thresholds. No treatment estimate or confidence interval for calcium is reported in the registry record, so the magnitude and precision of a contrast cannot be assessed.

How does a crossover design affect analysis?

General: when participants receive both interventions, measurements from one person are related rather than independent. A crossover analysis can use within-participant information, often improving efficiency when the outcome is stable and period effects are appropriately handled. But the treatment comparison can be affected by sequence, time, or carryover if an earlier intervention influences measurements in a later period. Analysis plans commonly need to account for these design features. The registry describes the two 14-week treatment periods but does not report a washout, a model, or how order and period were handled. It is therefore not possible to say what crossover analysis, if any, was applied.

What does non-inferiority require?

General: a non-inferiority study evaluates whether an intervention is not worse than a comparator by more than a prespecified margin. The interpretation requires knowing the margin, the direction of the contrast, and the confidence interval from an appropriate analysis. A nonsignificant difference alone does not establish non-inferiority. Although the registry describes the study purpose as non-inferiority, it does not report a margin, a statistical plan, or a primary-endpoint result. No non-inferiority conclusion can be reconstructed from the record.

What can be inferred from planning calculations?

The sample-size material is described as a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It is explicitly separate from the trial's own design, and it is not observed power. General: planning calculations explore how many participants might be needed under chosen assumptions; they do not establish what the trial actually enrolled, what effect occurred, or how likely the observed study was to detect an effect after completion. The record does not report the original sample-size justification. The crossover design also differs from a simple equal-allocation parallel-arm setup, so the planning illustration should not be mistaken for a description of the trial's analysis.

Why does over-dispersion matter for event counts?

General: some count outcomes vary more than a simple statistical model expects. This extra variability, called over-dispersion, can make standard errors too small if it is ignored, leading to intervals that are too narrow and tests that are too optimistic. The primary outcome in this study is continuous, not a reported count outcome. The registry record does not describe a count model or an over-dispersion assessment, so this issue is not a reported feature of the primary analysis.

Overall, the registry provides design and endpoint descriptions but not a statistical analysis plan or numerical outcome analysis. It does not identify the estimation method, assumptions checked, handling of missing observations, or inferential procedure used for any outcome. General statistical explanations describe what such methods would mean, not methods confirmed to have been used in this trial.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Calcitriol")
n   <- c(9)
m   <- c(8.78)
sp  <- c(0.332)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Calcitriol  9  8.780  0.332  8.525  9.035

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 8 outcome measures, including the primary calcium outcome and secondary outcomes for parathyroid hormone, phosphorus, and amount of active vitamin D analog used. It does not report a multiplicity strategy, such as a hierarchy for testing outcomes or an adjustment to account for multiple comparisons. When many outcomes are examined, the chance of at least one apparently unusual result can increase; general statistical approaches can control or contextualize that issue. Without reported analyses, the extent of any multiplicity concern in the trial's results cannot be assessed.

Missing-data procedures are not reported in the registry record. It does not state how incomplete measurements, withdrawals, or participants who did not complete both crossover periods were handled. The record also does not report an analysis population, such as whether results were based on all randomized participants or only participants with available measurements. These choices can affect the interpretation of a crossover comparison, particularly if missingness differs by period or treatment sequence.

The registry lists no analysis results. It therefore does not show whether exclusions were made, whether any sensitivity analyses were performed, or whether the analysis followed an intention-to-treat or per-protocol approach. Those details are not reported in the registry record and should not be inferred from the enrollment figure or the adverse-event counts.

12. Safety Results

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

Deaths

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: hematuria (11.1%), pneumonia (11.1%).

The adverse-event entries list 9 participants at risk in each named treatment group. The calcitriol entry records 1 participant affected by a serious adverse event, and the paricalcitol entry records 2. No deaths are recorded in either group, and the entries show 0 affected for other adverse events. These are the counts as listed; the registry does not provide a statistical comparison or uncertainty interval for them.

Hematuria and pneumonia are each listed among the top serious-event terms at 11.1%. The record does not assign those terms to a particular treatment group in the listed terms, nor does it clarify whether the term percentages refer to participants, events, or another denominator. They should therefore be read as registry-reported percentages, not as a comparative risk estimate.

Because this is a crossover study, group labels may refer to treatment exposure rather than two independent groups followed throughout. The record does not explain how the safety denominators were defined across treatment periods or whether a participant could contribute to both groups. The counts are descriptive and, without that detail and an analysis, do not establish a difference in safety between protocols.

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

The record establishes that the study was designed to compare calcitriol- and paricalcitol-based active vitamin D protocols in hemodialysis patients. It documents randomized treatment sequences, a crossover arrangement, a primary calcium endpoint, secondary laboratory and treatment-use outcomes, and a stated non-inferiority purpose. It also contains limited descriptive serious-event counts.

It does not report the numerical result for the primary endpoint or the secondary outcomes. There is no reported estimate of the calcium contrast, no interval quantifying its precision, and no statistical test result. The record also lacks the non-inferiority margin and analysis details needed to assess the stated objective. These gaps mean that the posted information does not show whether the protocols had similar or different measured outcomes, or how certain an estimate would be.

The adverse-event entries describe counts in treatment-labelled groups, but do not provide a comparative safety analysis. The serious-event terms and percentages are not linked to a specific treatment in the listed terms. No deaths are recorded, but the record does not report follow-up completeness or a broader safety interpretation. Descriptive counts alone cannot settle whether one protocol has a different safety profile.

The findings should not be extended beyond the recorded study population, protocols, endpoints, and observation periods. The record does not provide enough information to assess how representative the enrolled participants were, how the trial ended, or whether the intended crossover analysis was completed. The central statistical point is that a trial's design and outcome definitions are not substitutes for its observed estimates and uncertainty. Those results are not reported in the registry record.

14. Why This Trial Matters Statistically

This trial raises a useful design question for clinical researchers: how should two treatments be compared when each participant receives both in sequence? Crossover designs can make efficient use of within-participant comparisons, because individuals serve as their own comparison. That feature is useful only when the analysis respects the repeated observations and addresses treatment order, period, and possible carryover. The registry describes the sequence structure but does not report how these issues were handled.

The stated non-inferiority purpose also highlights the distinction between failing to find a difference and demonstrating that a treatment is not worse than a comparator by more than an acceptable amount. General: a non-inferiority assessment requires a prespecified margin and an estimate with adequate precision. Neither a margin nor the primary estimate is reported in the registry record. Thus, the design label and purpose alone do not establish an inferential conclusion.

The record also illustrates why outcome definitions and outcome results need to be distinguished. It names calcium as the primary outcome and identifies other laboratory and treatment-use outcomes, but does not report their numerical analyses. Without estimates and uncertainty, readers cannot judge the size or precision of the observed treatment contrasts. The adverse-event counts have a similar limitation: they are descriptive entries, not a comparative analysis.

Finally, a planning illustration is not the same as the original design justification or the completed study's evidential strength. The record says the illustration is based on an observed effect, but supplies no primary result or original sample-size rationale. Treating planning counts as observed power would confuse a hypothetical calculation with evidence from the completed trial.

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.

The record is marked terminated, but the reason for termination is not reported in the registry record. Enrollment is listed as 16, while the safety entries list 9 at risk under each treatment label. The record does not explain whether those entries represent unique participants, treatment-period exposures, or another denominator, so they cannot be reconciled from the available description alone.

Although the study is described as single-masked, the identity of the masked party is not reported. Allocation concealment, a washout period, completion of both treatment periods, and the timing tolerance for the month 3 assessments are also not reported. These details matter for evaluating potential bias and the suitability of a crossover analysis.

The primary calcium outcome has a defined measure and summary type, but no numerical result is reported. The record does not report a non-inferiority margin, analysis model, confidence interval, p-value, missing-data strategy, or analysis population. It also does not report results for the listed secondary outcomes or a plan for handling multiple outcomes.

Safety information is limited to the listed counts and serious-event terms. The registry does not give a detailed accounting of events by period, sequence, or participant, nor an inferential comparison. Taken together, these omissions limit assessment of treatment contrasts, precision, generalizability, and the extent to which the stated study objective was addressed.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Management of Mineral and Bone Disease in Hemodialysis-Calcitriol vs. Paricalcitol — NCT01725113.
• Registry record last updated 2023-11-07; status last verified 2023-10.
• Results first posted 2023-11-07.
• 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.

19. Record Summary

NCT01725113 is a phase 4 randomized, prospective, single-masked crossover study sponsored by Winthrop University Hospital. It compared intravenous calcitriol- and paricalcitol-based protocols in hemodialysis patients, with each treatment period lasting 14 weeks. Enrollment was 16, and the registry status is terminated.

The primary endpoint was mean calcium level at month 3 after calcitriol treatment initiation, measured in mg/dl. The registry lists 8 outcome measures, including secondary parathyroid hormone, phosphorus, and active vitamin D analog use outcomes. Numerical outcome analyses are not reported in the registry record. The record also lists serious adverse-event counts and terms, but does not provide a comparative safety analysis or enough detail to establish the denominators across crossover periods.