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 Long-term Safety Study of Paricalcitol Injection in Chronic Kidney Disease Patients With Hemodialysis (HD) (NCT00701805), a non-randomized phase 2 study. The primary outcome is The Percentage of Participants With of Hypercalcemia.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00701805 |
| Phase | Phase 2 |
| Condition | Secondary Hyperparathyroidism, Hemodialysis |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 107 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Abbott |
| Results posted | Yes |
2. Clinical Question
Population
People with chronic kidney disease receiving hemodialysis and with secondary hyperparathyroidism were the study population. The registry reports enrollment of 107 participants. The primary endpoint population was all subjects who received at least 1 dose of paricalcitol in this study.
Intervention
Participants received paricalcitol by intravenous injection in one of four dose-regimen groups: 2 µg ± 1 µg, 2 µg ± 2 µg, 4 µg ± 1 µg, or 4 µg ± 2 µg. The study description says treatment was given 3 times per week at dialysis sessions in a dose-titration manner.
Comparator
The registry lists four paricalcitol groups, but no placebo or untreated control group. Allocation was non-randomized, and the registry cautions that the arms are not a like-for-like control comparison. Differences between groups therefore should not be read as randomized treatment effects.
Primary question
The primary safety question was what percentage of participants experienced hypercalcemia during the study. Hypercalcemia was defined by adjusted calcium measurements: at least 1 value above 11.5 mg/dL, or at least 2 consecutive values at or above 11.0 mg/dL. The registry does not report the observed percentage or other primary endpoint results.
This was described as a long-term safety extension following 12 weeks of treatment in the dose-response study M10-309. The extension description says participants would receive treatment for 40 weeks. The primary endpoint timeframe is listed as anytime during the study through Week 53, while its definition refers to measurements during the 52 weeks of the study. Both descriptions are part of the registry record; the record does not explain the difference in wording.
The clinical question is consequently a safety question within an exposed population, not a randomized comparison of paricalcitol with an alternative. The registry also lists outcomes concerning intact parathyroid hormone and alkaline phosphatase, but it does not report their results in the record. Without observed endpoint results, the frequency of hypercalcemia and the precision of that frequency cannot be assessed from the registry record.
3. Trial Design
This was a Phase II, non-randomized, open-label, parallel-group study sponsored by Abbott. The registry records the study as completed and lists enrollment of 107. The study title and descriptions identify chronic kidney disease, hemodialysis, and secondary hyperparathyroidism as the clinical context.
Four paricalcitol dose-regimen groups are listed: 2 µg ± 1 µg, 2 µg ± 2 µg, 4 µg ± 1 µg, and 4 µg ± 2 µg. The descriptions state that the study drug was administered intravenously immediately before completion of hemodialysis, 3 times per week and no more frequently than every other day. They describe an initial dosage administered for 2 weeks, followed by dosage adjustment based on iPTH, adjusted calcium, and phosphorus. The arm descriptions end mid-sentence in the registry record, so further details of the adjustment procedure are not reported in the registry record.
The brief study description characterizes the extension as 40 weeks of dose-titrated treatment after 12 weeks of treatment in the dose-response study M10-309. It identifies the purpose as evaluating long-term safety. The primary endpoint lists a timeframe through Week 53, while its definition refers to 52 weeks; the registry does not clarify that difference.
Because allocation was non-randomized and there was no listed control arm, the four groups should not be treated as randomized equivalents. The registry expressly cautions that the arms are not a like-for-like control comparison. The record does not report how participants were assigned to dose regimens, whether assignment reflected clinical characteristics, or whether any adjustment was made for differences between groups. It also does not report a protocol-based sample-size justification or a statistical analysis plan. These omissions limit what can be concluded about comparative effects, even if group-level results are available elsewhere.
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: One of the 107 subjects withdrew consent before receiving study drug in this study. 106 subjects were treated with study drug. Two of these subjects were not included in the Full Analysis Set for analysis of efficacy because of subject death (n = 1) and withdrawal of consent (n = 1).
Overall Study
| Stage | Paricalcitol 2 µg ± 1 µg | Paricalcitol 2 µg ± 2 µg | Paricalcitol 4 µg ± 1 µg | Paricalcitol 4 µg ± 2 µg |
|---|---|---|---|---|
| STARTED | 26 | 29 | 23 | 26 |
| COMPLETED | 23 | 25 | 16 | 22 |
| NOT COMPLETED | 3 | 4 | 7 | 4 |
Reasons for not completing this period:
| Reason | Paricalcitol 2 µg ± 1 µg | Paricalcitol 2 µg ± 2 µg | Paricalcitol 4 µg ± 1 µg | Paricalcitol 4 µg ± 2 µg |
|---|---|---|---|---|
| Withdrawal by Subject | 3 | 1 | 4 | 3 |
| Adverse Event | 0 | 1 | 1 | 0 |
| Missed 7 consecutive doses | 0 | 1 | 0 | 0 |
| Admitted to hospital for 2 weeks | 0 | 0 | 1 | 0 |
| Physician decision, change of therapy | 0 | 0 | 0 | 1 |
| Difficult to travel to dialysis site | 0 | 0 | 1 | 0 |
| Resumption criteria were not met | 0 | 1 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: All subjects who received at least 1 dose of paricalcitol in this 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.
| Characteristic | Unit | Paricalcitol 2 µg ± 1 µg | Paricalcitol 2 µg ± 2 µg | Paricalcitol 4 µg ± 1 µg | Paricalcitol 4 µg ± 2 µg | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 26 | 29 | 23 | 26 | 104 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 16 | 17 | 14 | 16 | 63 |
| Age, Categorical: >=65 years | Participants | 10 | 12 | 9 | 10 | 41 |
| Age Continuous | years | 62.4 (SD 11.89) | 60.3 (SD 12.06) | 58.6 (SD 12.14) | 61.1 (SD 11.91) | 60.6 (SD 11.90) |
| Sex: Female, Male: Female | Participants | 16 | 13 | 6 | 9 | 44 |
| Sex: Female, Male: Male | Participants | 10 | 16 | 17 | 17 | 60 |
| Region of Enrollment: Japan | participants | 26 | 29 | 23 | 26 | 104 |
6. Primary Endpoint
The registry lists the primary outcome as The Percentage of Participants With of Hypercalcemia, measured over Anytime during the study through Week 53.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Percentage of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the percentage of participants with an event of hypercalcemia. The registry defines an event as at least 1 adjusted calcium measurement above 11.5 mg/dL, or at least 2 consecutive adjusted calcium measurements at or above 11.0 mg/dL. The listed timeframe is anytime during the study through Week 53; the endpoint description also refers to measurements during the 52 weeks of the study.
This is a binary participant-level outcome: each eligible participant either met the event definition or did not. A percentage expresses the number of participants meeting the definition relative to the endpoint population. The registry identifies that population as all subjects who received at least 1 dose of paricalcitol in this study. The number of participants meeting the definition and the corresponding percentage are not reported in the registry record.
As a safety endpoint, the measure is intended to capture whether a prespecified calcium pattern occurred during follow-up. Requiring either one measurement above the higher threshold or consecutive measurements at the lower threshold makes the definition depend on both the values and, for the latter criterion, their sequence. The registry does not report details such as the handling of missing calcium measurements or any confirmation procedures beyond the stated definition.
The endpoint describes events observed during exposure and follow-up. By itself, it does not establish that treatment caused an event, and it does not quantify risk relative to an untreated or randomized comparator. The non-randomized design and absence of a listed control group are important when interpreting any percentage.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The available registry entries establish the design, endpoint definition, dose-regimen groups, and selected adverse-event counts. They do not include the observed primary endpoint result, an uncertainty interval, a hypothesis test, or a reported analysis. The number of analyses is listed as zero. Consequently, the frequency of participants meeting the hypercalcemia definition cannot be described from this record, and neither statistical precision nor a between-group difference can be evaluated.
The listed enrollment is 107, while the adverse-event record gives group-specific numbers at risk for serious and other events. These counts describe who was included in those safety summaries; they are not a substitute for the primary endpoint result. The registry does not report the hypercalcemia event count or percentage by dose regimen or for the full endpoint population.
The design also constrains interpretation. Participants were not randomly allocated, and no placebo or untreated group is listed. The registry warns that the arms are not a like-for-like control comparison. Thus, any apparent differences across dose groups could reflect factors other than the dose regimen. The record does not report adjustment methods or information sufficient to determine whether such differences were addressed.
The registry lists serious adverse-event terms, each with a percentage, and group-level counts of participants affected by serious and other adverse events. These are descriptive safety details. The record does not attach the listed serious-event terms to specific groups in the information available, and it does not report a death count. The listed percentages should not be interpreted as comparative estimates or as proof of a causal relationship.
For a binary endpoint, an estimate is more informative when accompanied by its denominator and a confidence interval. A confidence interval describes uncertainty around an estimated percentage; it is not a guarantee that the true value lies within the interval. No primary endpoint estimate or confidence interval is reported in the registry record, so precision cannot be judged. A missing p-value is not evidence that a difference was absent: the record lists no analyses, and no result from which to assess a difference is reported.
The posted descriptions also use different wording for the primary endpoint observation period: through Week 53 in the timeframe and during 52 weeks in the definition. This is a reporting detail that could affect interpretation of follow-up, but the registry does not explain it. The study's stated purpose was long-term safety evaluation; the lack of posted primary results means the registry record alone does not establish the observed frequency of the endpoint.
9. Statistical Methods Explained
The registry identifies the primary measure as a percentage of participants with a binary event. The methods needed to interpret such an endpoint begin with a clear event definition, an eligible population, and a follow-up period. The event definition and endpoint population are stated: participants met the endpoint if adjusted calcium crossed the specified threshold pattern, and the population comprised subjects who received at least 1 dose. The timeframe is described both as through Week 53 and as during 52 weeks. How the analysis reconciled those descriptions is not reported in the registry record.
What does a percentage estimate?
For a participant-level binary outcome, the observed percentage represents the share of the analyzed participants who met the event definition. It is descriptive unless paired with a prespecified inferential analysis. A percentage requires both the number of participants with the event and the denominator used. The registry does not report the primary event count or percentage, so neither can be interpreted. The group-level safety counts elsewhere in the record should not be substituted for those missing endpoint data.
A confidence interval is a statistical range that conveys uncertainty around an estimate under the assumptions of the method used. Wider intervals generally reflect less precision, while narrower intervals generally reflect greater precision. The actual interval depends on the event count, denominator, and calculation method. No confidence interval or method for calculating one is reported for the primary endpoint in the registry record. It would therefore be inappropriate to infer precision from enrollment alone.
What can a group comparison establish?
Comparisons between groups require a clear contrast and an analysis that accounts for how participants entered each group. Random allocation can support causal interpretation by balancing measured and unmeasured characteristics in expectation. This study was non-randomized, and the registry explicitly cautions that its arms are not a like-for-like control comparison. The four listed groups are different paricalcitol regimens, not a listed placebo or untreated control. The registry does not report a comparative estimate, confidence interval, test, or adjustment strategy. General statistical principle: without an appropriate design and analysis, differences in observed percentages do not by themselves establish that dose regimen caused a difference.
The record describes a parallel-group model and no masking. These design details indicate that participants were followed in separate regimen groups and that masking was not used. They do not identify how assignment occurred or whether outcome assessment was blinded; further details are not reported in the registry record. For a laboratory-defined endpoint, consistent measurement and follow-up procedures matter. The registry provides the threshold definition but does not report additional measurement procedures.
Why do event definitions and follow-up matter?
The endpoint has two routes to classification: a single adjusted calcium result above 11.5 mg/dL, or at least 2 consecutive results at or above 11.0 mg/dL. The first route depends on one measurement; the second depends on repeated measurements and their order. Missing or irregular measurements could affect the opportunity to meet the consecutive-measurement rule. The record does not explain how missing values, missed visits, or incomplete follow-up were handled. That uncertainty prevents a full assessment of how consistently participants could be classified.
Time-to-event methods are useful when follow-up differs across participants or when the timing of events is central. The primary endpoint is stated as a percentage during a defined study period, not as a time-to-event estimate. The registry does not report a time-to-event analysis for this endpoint. It would be inappropriate to infer one from the timeframe alone.
What do the planning assumptions mean?
The statistical material associated with the record describes planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Such illustrations are prospective planning calculations, not observed results and not evidence that a trial had a particular power. The record does not report the underlying observed effect or the resulting participant counts in the registry record for this analysis. The registry also does not report its own sample-size justification. These planning assumptions should not be mistaken for the study's actual non-randomized allocation or for an analysis of its outcomes.
General statistical principle: a two-sided significance level sets a threshold for interpreting a test under its assumptions; it does not measure the size or importance of an effect. Equal allocation is an assumption in the described planning illustration, not a documented feature of the observed groups. The normal approximation is a calculation method, and its suitability depends on the data and design. Since no primary analysis or event result is reported, none of these planning concepts can fill the gap in the outcome evidence.
What is not available?
The registry lists 11 outcome measures and zero analyses. It does not report primary endpoint results, a statistical analysis plan, multiplicity procedures, missing-data methods, or a protocol-based sample-size rationale. No recalculated estimates can be checked against sponsor analyses because no such primary result is present. General statistical principle: when outcomes are numerous, testing many hypotheses can raise the chance of false-positive findings unless multiplicity is addressed. Whether and how that issue was handled in this study is not reported in the registry record.
10. Exact Estimates for Each Arm
No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.
| Arm | Participants | Events | Observed % | Clopper-Pearson 95% CI | Wilson 95% CI | Bayesian 95% credible interval |
|---|---|---|---|---|---|---|
| Paricalcitol 2 µg ± 1 µg | 27 | 11 | 40.7% | 22.4% to 61.2% | 24.5% to 59.3% | 24.5% to 59.4% |
| Paricalcitol 2 µg ± 2 µg | 30 | 19 | 63.3% | 43.9% to 80.1% | 45.5% to 78.1% | 45.4% to 78.2% |
| Paricalcitol 4 µg ± 1 µg | 23 | 14 | 60.9% | 38.5% to 80.3% | 40.8% to 77.8% | 40.6% to 77.9% |
| Paricalcitol 4 µg ± 2 µg | 26 | 17 | 65.4% | 44.3% to 82.8% | 46.2% to 80.6% | 46.0% to 80.6% |
R code and output
arm <- c("Paricalcitol 2 µg ± 1 µg", "Paricalcitol 2 µg ± 2 µg", "Paricalcitol 4 µg ± 1 µg", "Paricalcitol 4 µg ± 2 µg")
n <- c(27, 30, 23, 26)
events <- c(11, 19, 14, 17)
for (i in seq_along(n)) {
ci <- binom.test(events[i], n[i])$conf.int # Clopper-Pearson exact interval
cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i]) # Bayesian, uniform Beta(1,1) prior
wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}
ARM Paricalcitol 2 µg ± 1 µg 27 11 40.7 22.4 61.2 24.5 59.3 24.5 59.4
ARM Paricalcitol 2 µg ± 2 µg 30 19 63.3 43.9 80.1 45.5 78.1 45.4 78.2
ARM Paricalcitol 4 µg ± 1 µg 23 14 60.9 38.5 80.3 40.8 77.8 40.6 77.9
ARM Paricalcitol 4 µg ± 2 µg 26 17 65.4 44.3 82.8 46.2 80.6 46.0 80.611. Multiplicity, Missing Data and Analysis Populations
The registry lists 11 outcome measures, including the primary hypercalcemia measure and several secondary measures concerning iPTH and alkaline phosphatase. It lists zero analyses. Results for the primary and secondary outcomes, statistical tests, and confidence intervals are not reported in the registry record.
Multiplicity arises when several outcomes or comparisons are examined. General statistical principle: the more hypotheses tested, the greater the chance that at least one result appears statistically notable by chance, unless the analysis plan addresses that issue. The registry does not report whether outcomes were tested jointly, whether an order of testing was specified, or whether any multiplicity adjustment was planned. No claim about the study's actual multiplicity handling can therefore be made.
The record identifies the primary endpoint population as participants who received at least 1 dose. It does not report an analysis population for secondary outcomes or explain how participants with incomplete follow-up were handled. Methods for missing endpoint measurements, discontinuations, or missing safety data are not reported in the registry record. For the consecutive-measurement component of the hypercalcemia definition, missing measurements could affect whether the event can be classified; the record does not describe an approach to that situation.
The enrollment count and group-specific safety counts do not reveal the number with observed primary endpoint data. Without outcome denominators and missing-data methods, the extent and possible impact of incomplete data cannot be assessed. The registry also does not report an intention-to-treat population or a per-protocol population. These analysis-population labels should not be inferred from the stated endpoint population.
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 |
|---|---|---|---|
| Paricalcitol 2 µg ± 1 µg | 8 | 27 | 29.6% |
| Paricalcitol 2 µg ± 2 µg | 6 | 30 | 20.0% |
| Paricalcitol 4 µg ± 1 µg | 6 | 23 | 26.1% |
| Paricalcitol 4 µg ± 2 µg | 4 | 26 | 15.4% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Paricalcitol 2 µg ± 1 µg | 27 of 27 |
| Paricalcitol 2 µg ± 2 µg | 30 of 30 |
| Paricalcitol 4 µg ± 1 µg | 23 of 23 |
| Paricalcitol 4 µg ± 2 µg | 26 of 26 |
Most frequent serious adverse event terms
| Event term | Organ system | Paricalcitol 2 µg ± 1 µg | Paricalcitol 2 µg ± 2 µg | Paricalcitol 4 µg ± 1 µg | Paricalcitol 4 µg ± 2 µg |
|---|---|---|---|---|---|
| Shunt stenosis | Injury, poisoning and procedural complications | 1 of 27 | 0 of 30 | 1 of 23 | 1 of 26 |
| Myocardial infarction | Cardiac disorders | 1 of 27 | 0 of 30 | 1 of 23 | 0 of 26 |
| Pneumonia | Infections and infestations | 1 of 27 | 0 of 30 | 0 of 23 | 1 of 26 |
| Shunt occlusion | Injury, poisoning and procedural complications | 1 of 27 | 0 of 30 | 0 of 23 | 1 of 26 |
| Arteriosclerosis obliterans | Vascular disorders | 0 of 27 | 1 of 30 | 0 of 23 | 1 of 26 |
| Angina pectoris | Cardiac disorders | 0 of 27 | 0 of 30 | 1 of 23 | 0 of 26 |
| Cardiac failure | Cardiac disorders | 0 of 27 | 0 of 30 | 0 of 23 | 1 of 26 |
| Cardiac failure acute | Cardiac disorders | 0 of 27 | 0 of 30 | 1 of 23 | 0 of 26 |
| Supraventricular tachycardia | Cardiac disorders | 1 of 27 | 0 of 30 | 0 of 23 | 0 of 26 |
| Vertigo | Ear and labyrinth disorders | 1 of 27 | 0 of 30 | 0 of 23 | 0 of 26 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Paricalcitol 2 µg ± 1 µg | Paricalcitol 2 µg ± 2 µg | Paricalcitol 4 µg ± 1 µg | Paricalcitol 4 µg ± 2 µg |
|---|---|---|---|---|---|
| Hypercalcaemia | Metabolism and nutrition disorders | 15 of 27 | 23 of 30 | 17 of 23 | 22 of 26 |
| Nasopharyngitis | Infections and infestations | 20 of 27 | 20 of 30 | 15 of 23 | 15 of 26 |
| Hyperphosphataemia | Metabolism and nutrition disorders | 15 of 27 | 22 of 30 | 12 of 23 | 16 of 26 |
| Diarrhoea | Gastrointestinal disorders | 6 of 27 | 6 of 30 | 6 of 23 | 5 of 26 |
| Constipation | Gastrointestinal disorders | 3 of 27 | 5 of 30 | 8 of 23 | 4 of 26 |
| Contusion | Injury, poisoning and procedural complications | 4 of 27 | 4 of 30 | 4 of 23 | 8 of 26 |
| Hypertension | Vascular disorders | 3 of 27 | 11 of 30 | 0 of 23 | 5 of 26 |
| Pruritus | Skin and subcutaneous tissue disorders | 6 of 27 | 3 of 30 | 4 of 23 | 5 of 26 |
| Headache | Nervous system disorders | 5 of 27 | 4 of 30 | 4 of 23 | 4 of 26 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 7 of 27 | 3 of 30 | 2 of 23 | 4 of 26 |
Serious events with the highest arm-level rate: shunt stenosis (4.3%), myocardial infarction (4.3%), angina pectoris (4.3%), cardiac failure acute (4.3%), sudden death (4.3%).
The registry lists serious and other adverse-event counts for each paricalcitol regimen. For serious adverse events, the recorded numbers at risk and affected are 27 and 8 for 2 µg ± 1 µg; 30 and 6 for 2 µg ± 2 µg; 23 and 6 for 4 µg ± 1 µg; and 26 and 4 for 4 µg ± 2 µg. For other adverse events, the numbers at risk and affected are 27 and 27, 30 and 30, 23 and 23, and 26 and 26, respectively. These are descriptive counts as posted in the registry.
The serious-event terms listed include shunt stenosis, myocardial infarction, angina pectoris, acute cardiac failure, sudden death, and tendon rupture; each is accompanied by 4.3%. The registry record does not assign these terms to a particular group in the information. The meaning of the percentage denominator is not further explained, so those values should be read as posted rather than used to reconstruct group-specific rates.
These safety summaries do not establish that paricalcitol caused an event, nor do they permit a reliable comparison between the dose groups. Allocation was non-randomized, and the registry warns against treating the arms as like-for-like controls. Death counts are not reported in the registry record. The adverse-event counts are also distinct from the primary hypercalcemia endpoint, whose observed result is not reported.
13. What the Result Does, and Does Not, Mean
The registry record describes a completed, non-randomized Phase II safety extension of paricalcitol injection in people receiving hemodialysis. It identifies four dose-regimen groups, a binary primary safety endpoint based on adjusted calcium measurements, and several additional outcomes related to iPTH and alkaline phosphatase. It also supplies selected adverse-event counts and serious-event terms.
Those design and definition details show what the study set out to observe, but they do not show how often the primary endpoint occurred. The percentage of participants meeting the hypercalcemia definition is not reported in the registry record. Nor are the primary event count, confidence interval, p-value, or a comparative analysis. Thus, the record does not support a conclusion about the observed frequency or statistical precision of hypercalcemia in the study population.
The listed safety counts are descriptive and should not be treated as causal estimates. Participants were not randomly allocated, and there was no listed untreated or placebo group. The registry explicitly warns that the regimen groups are not a like-for-like control comparison. Any apparent differences across groups would need careful interpretation and appropriate analysis; those analyses are not reported.
The absence of a posted result is not evidence that no events occurred or that groups were equivalent. It means the registry record does not report the outcome needed to judge those questions. Likewise, the listed serious-event terms do not establish causation, and their percentages cannot be confidently assigned to individual regimens from the available record.
The stated objective was long-term safety evaluation. The available information identifies the intended endpoint and describes treatment and follow-up, but the primary results, handling of missing data, multiplicity procedures, and statistical analysis plan are not reported in the registry record. The defensible interpretation is therefore limited to the study's design and the descriptive safety figures actually recorded, not a claim about treatment benefit or harm.
14. Why This Trial Matters Statistically
This study is statistically informative as an example of the distinction between a stated safety question and a reported safety result. A registry can define an endpoint, identify its population and follow-up, and describe treatment groups without reporting the event count or analysis. Here, the primary outcome is specified in detail, but its observed percentage and statistical precision are not reported.
The design also illustrates why study structure matters. The four groups received different paricalcitol regimens, but allocation was non-randomized and no control group is listed. The registry's caution that the arms are not like-for-like controls is central: group differences cannot automatically be attributed to the dose regimen. A percentage is a descriptive summary; a causal comparison requires a design and analysis that support that interpretation.
The endpoint definition combines a single higher adjusted calcium threshold with a consecutive-measurement rule at a lower threshold. That makes the relationship between measurement frequency, follow-up completeness, and event classification relevant. Yet the registry does not report missing-data methods or the handling of incomplete measurements. Statistical interpretation depends not only on a threshold, but also on how observations were collected and analyzed.
Finally, the record lists multiple outcomes but zero analyses. General statistical principle: when multiple outcomes are considered, prespecification and multiplicity handling help readers understand which results are confirmatory and how to interpret chance findings. Those details are not reported. The case underscores that a completed study record may still leave key questions about results, analysis, and uncertainty unresolved.
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 most important limitation for interpreting this record is that the primary endpoint result is not reported. No event count, percentage, confidence interval, or test is available, so the frequency and precision of hypercalcemia cannot be assessed. The registry lists zero analyses.
The study was non-randomized, unmasked, and had four paricalcitol regimen groups without a listed placebo or untreated comparator. The registry cautions that the arms are not a like-for-like control comparison. Assignment procedures and methods for addressing baseline differences are not reported in the registry record, limiting comparative interpretation.
The registry describes the primary timeframe as through Week 53, while the endpoint definition refers to 52 weeks. It does not explain this difference. The arm descriptions are also incomplete in the record, ending during the description of dosage adjustment. Additional details of titration and follow-up are not reported in the registry record.
Although 11 outcomes are listed, their results and the approach to multiplicity are not reported. Missing-data procedures, the handling of incomplete calcium measurement sequences, and the analysis populations for outcomes beyond the stated primary population are also not reported. The record does not provide a protocol-based sample-size justification or a statistical analysis plan.
Serious-event terms and percentages are listed, but the record does not specify their group assignment in the information available. Death counts are not reported in the registry record. These limits mean that the available safety data remain descriptive and do not support a causal comparison or a complete assessment of uncertainty.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Long-term Safety Study of Paricalcitol Injection in Chronic Kidney Disease Patients With Hemodialysis (HD) — NCT00701805.
- Registry record last updated 2011-04-19; status last verified 2011-03.
- Results first posted 2011-04-19.
- 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
This completed Phase II study evaluated long-term safety of paricalcitol injection in people with chronic kidney disease receiving hemodialysis and with secondary hyperparathyroidism. The registry records non-randomized allocation, no masking, a parallel-group model, and enrollment of 107. Four paricalcitol dose-regimen groups are listed.
The primary endpoint was the percentage of participants meeting a hypercalcemia definition based on adjusted calcium measurements. Its timeframe is described as through Week 53, while the definition refers to 52 weeks. The primary endpoint result, statistical analyses, and confidence intervals are not reported in the registry record. The record lists 11 outcome measures and zero analyses.
Group-specific serious and other adverse-event counts and several serious-event terms are recorded. The registry cautions that the regimen groups are not like-for-like controls. Missing-data procedures, multiplicity handling, and the statistical analysis plan are not reported in the registry record.