Study of Pitavastatin in Elderly Patients With Primary Hypercholesterolemia or Combined Dyslipidemia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study of Pitavastatin in Elderly Patients With Primary Hypercholesterolemia or Combined Dyslipidemia (NCT00330876), a non-randomized phase 3 study. The primary outcome is Change From Baseline in LDL-C.

2. Clinical Question

3. Trial Design

This was a phase 3, open-label, non-randomized, parallel-group extension study sponsored by Kowa Research Europe. Its official title describes it as a long-term extension study of pitavastatin in elderly patients with primary hypercholesterolemia or combined dyslipidemia. The brief description identifies it as an extension of NK-104-306 (NCT00257686). The registry lists an enrollment of 545 and marks the study completed.

The registry lists two pitavastatin arms: 2 mg once daily and 4 mg once daily. Although those arms make a dose-based comparison possible as a description, non-randomized allocation means the groups cannot be assumed comparable at baseline. The record does not report how participants were assigned to doses, whether dose changes occurred, or whether analyses adjusted for baseline differences. No masking was used, and the study was open-label.

The listed study start was 2006-06 and primary completion was 2007-12. The primary outcome timeframe was baseline to 60 weeks, and the outcome population was subjects with a measurement at Week 60. This definition identifies a measurement-based analysis population, not necessarily every enrolled participant. The number with an endpoint measurement is not reported in the registry record.

The design and outcome descriptions do not establish how participants entered the extension, what treatments they received before it, or how the two doses were chosen. Those details are not reported in the registry record. As an extension study without randomized allocation, it is best interpreted as a description of outcomes among the enrolled participants rather than as a controlled estimate of a treatment effect.

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

Analysis population for the primary outcome, as defined in the registry: Subjects with measurement at Week 60

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 Change From Baseline in LDL-C, measured over Baseline to 60 weeks.

The primary endpoint is percent change from baseline in low density lipoprotein-cholesterol (LDL-C), assessed from baseline to 60 weeks. It is a continuous measure: each participant’s follow-up value is expressed relative to that participant’s baseline value, and the registry identifies the group summary as a mean with standard deviation. The analysis population is described as subjects with a measurement at Week 60.

LDL-C is the laboratory measure named in the registry outcome. A change-from-baseline endpoint can describe how a measured value shifts over follow-up while accounting for its starting value. Reporting a mean summarizes the average change in the analyzed group; the standard deviation describes the spread of individual changes around that mean. These are different quantities: the standard deviation reflects participant-to-participant variation, not uncertainty in the mean.

The endpoint is useful as a quantitative description of the measured laboratory outcome over the stated follow-up period. It does not by itself describe clinical events or establish why a change occurred. Because the outcome population includes subjects with a Week 60 measurement, the result would pertain to that measured subset unless additional missing-data methods were used; such methods are not reported in the registry record. No numerical endpoint result or uncertainty estimate is reported in the registry record, so the magnitude and precision of the change cannot be assessed from its posted results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous and is summarized in the registry as a mean with standard deviation. General statistical interpretation of these quantities can clarify what a complete report would convey, but it cannot substitute for the numerical outcome, which is not reported in the registry record.

What does a mean change describe?

A mean is the arithmetic average of the participant-level changes included in an analysis. For a change-from-baseline measure, each participant’s follow-up value is compared with their own baseline value before the group average is summarized. The mean therefore describes the central average change in the analyzed population. It does not show whether every participant changed in the same direction, nor does it describe the full distribution of individual responses.

The outcome is expressed as percent change from baseline in LDL-C. This scale relates a change to each participant’s starting measurement rather than reporting only an absolute change in the laboratory value. Interpretation still depends on the actual estimate, the analysis population, and the method used to handle incomplete observations. The estimate itself is absent from the posted results, so its direction and magnitude cannot be discussed.

What does the standard deviation convey?

The standard deviation describes the spread of observed participant-level values around the group mean. A larger spread indicates more variation among the measured changes; a smaller spread indicates that the changes are more clustered around the mean. It is not the standard error and is not, by itself, a measure of how precisely the group mean has been estimated. Since the registry record does not report the standard deviation for the primary outcome, the amount of variation in LDL-C change cannot be assessed.

How would a confidence interval be read?

General explanation: a confidence interval gives a range of values compatible with the data and the stated interval procedure. Its width conveys precision: a narrower interval indicates more precision, while a wider interval indicates less. A confidence interval would also show which directions and magnitudes of change remain compatible with the estimate. No interval for the primary outcome is reported in the registry record. Without an estimate and an interval, neither the size of the mean change nor its precision can be evaluated.

Why does allocation matter?

Random allocation is a design method intended to make comparison groups similar, on average, with respect to measured and unmeasured characteristics. This study is listed as non-randomized, so participants in the 2 mg and 4 mg groups cannot be presumed exchangeable. Dose assignment may be associated with clinical or participant characteristics that also relate to outcomes. A raw difference between the groups, if reported, would therefore be descriptive unless a credible analysis addressed confounding. The registry record does not report such an adjusted analysis.

Open-label means participants and study personnel were not masked to the assigned treatment. This matters particularly for outcomes that involve judgment or reporting; the primary endpoint is a laboratory measure, but open-label status remains part of the study context. The record does not describe procedures for laboratory measurement or outcome assessment beyond the stated endpoint definition.

What do planning calculations mean?

General explanation: sample-size planning asks how many participants per arm would be needed under specified assumptions to detect a particular effect with a chosen power and significance level. The planning assumptions described for illustrations use a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation; the effect to detect is expressed as a fraction of the observed effect. Those are planning assumptions, not evidence that the original study was designed or powered in that way. The sample-size justification for this study is not reported in the registry record.

Any planning illustration based on an observed effect is conditional on that effect and on the stated assumptions. Such a calculation is not observed power, does not change the evidence from the trial, and does not repair limitations of non-randomized allocation. The registry record does not report the primary observed effect needed to assess such an illustration or provide trial-specific sample-size estimates. It is therefore not possible to interpret a numerical planning result from the registry record alone.

Why can over-dispersion matter?

General explanation: over-dispersion describes variability greater than a statistical model expects. When a model assumes less variability than is actually present, uncertainty can be understated and inferential conclusions can be too confident. The primary endpoint is continuous and summarized with a standard deviation, but no model or estimate is reported. There is no basis in the registry record to claim that over-dispersion occurred or to identify a correction that was used.

Finally, the registry lists two outcome measures and zero posted analyses. A named outcome is not the same as a reported statistical analysis: without estimates, uncertainty measures, and methods, readers cannot determine how the outcomes were analyzed or whether any comparisons were adjusted. The registry record does not report a statistical analysis plan, interim analyses, multiplicity procedure, or model specification.

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("Pitavastatin 2 mg QD", "Pitavastatin 4 mg QD")
n   <- c(376, 77)
m   <- c(-43.18, -44.26)
sp  <- c(10.065, 10.764)
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  Pitavastatin 2 mg QD  376  -43.180  10.065  -44.201  -42.159
CARM  Pitavastatin 4 mg QD  77  -44.260  10.764  -46.703  -41.817

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures: change from baseline in LDL-C as the primary outcome and change from baseline in total cholesterol as a secondary outcome. It does not report numerical estimates or inferential results for either measure. The registry record also does not report a multiplicity procedure, such as an adjustment or a prespecified hierarchy for interpreting multiple tests. Without posted analyses, it is not possible to determine whether or how the outcomes were tested together or how any nominal significance levels should be interpreted.

The primary outcome population is defined as subjects with a measurement at Week 60. This indicates that the endpoint description concerns participants with an observed measurement at that time. The number of such participants and the number missing that measurement are not reported in the registry record. No missing-data method, imputation procedure, sensitivity analysis, or account of reasons for missing measurements is reported. The effect of missing measurements on the estimated outcome therefore cannot be evaluated.

The record does not specify analysis populations beyond the endpoint’s measurement-based description. It does not state whether all enrolled participants, all treated participants, or another defined group was included in any analysis. The analysis methods for the secondary outcome are also not reported. These omissions limit assessment of whether the results, if available, would represent all enrolled participants or a selected subset.

Because allocation was non-randomized, missingness and analysis-population selection could further complicate comparisons between the dose groups. The registry record does not provide enough information to establish whether those issues were assessed or addressed.

12. 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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: prostate cancer (1.3%), aortic valve incompetence (1.1%), cporonary artery occlusion (1.1%), retinal detachment (1.1%), urinary tract infection (1.1%).

The registry lists serious adverse events by dose group. In the 2 mg once-daily group, 51 of 449 participants at risk were affected by serious adverse events. In the 4 mg once-daily group, 7 of 90 participants at risk were affected. These are counts within the registry’s stated at-risk groups, not estimates from a randomized comparison. The record does not report death counts.

Serious-event terms listed include Prostate cancer (1.3%), Aortic valve incompetence (1.1%), Cporonary artery occlusion (1.1%), Retinal detachment (1.1%), Urinary tract infection (1.1%), and Femoral neck fracture (1.1%). The percentages are recorded as listed; the registry information does not specify a denominator or further explain how these term-level percentages were derived. The spelling “Cporonary” is retained as it appears in the registry record.

The record also lists 286 participants in the 2 mg group and 24 participants in the 4 mg group as affected by other adverse events. It does not define those events further in the information available. Counts and term frequencies describe events recorded during the study; they do not establish causation. Non-randomized allocation and the absence of a like-for-like control group limit comparative safety interpretation. The registry record does not provide additional context about event timing, exposure duration, or individual participant histories.

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

The registry record establishes that an open-label, non-randomized extension study of pitavastatin was conducted in elderly patients with primary hypercholesterolemia or combined dyslipidemia. It identifies two once-daily dose arms and defines the primary outcome as percent change from baseline in LDL-C from baseline to 60 weeks among subjects with a Week 60 measurement. It also records serious adverse-event counts and a short list of serious-event terms.

Those details do not reveal the primary endpoint result. The mean change, standard deviation, confidence interval, and inferential analysis are not reported in the registry record. Therefore, the posted results do not show how large the average change was, how much participants’ changes varied, or how precisely a group mean was estimated. The outcome definition should not be mistaken for evidence of a particular result.

The study design also limits what any dose comparison could establish. Participants were not randomly allocated, and no masking was used. The groups may have differed for reasons related to dose assignment, so a difference between them would not automatically represent an effect caused by dose. The registry record does not report an adjusted comparison that would address this concern.

The endpoint concerns a laboratory measure over the stated follow-up, not clinical events or outcomes beyond that period. Serious adverse-event counts are descriptive and do not demonstrate causation or provide a randomized safety comparison. The record does not report deaths or methods for handling missing Week 60 measurements.

Accordingly, the record supports a description of study design, endpoint definition, and selected safety information. It does not support a conclusion about the magnitude or precision of LDL-C change, a causal comparison between doses, or effects on unreported outcomes.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of why the design and the availability of results matter as much as an outcome name. It identifies a continuous primary endpoint, a defined follow-up window, and a measurement-based analysis population. Those features help readers understand what was intended to be measured. But without a numerical mean, standard deviation, or uncertainty interval, the endpoint cannot be quantitatively interpreted.

The non-randomized, open-label design is central to reading the dose groups. Listing two doses may invite a direct comparison, but non-random allocation does not guarantee that the groups are comparable. Any observed difference could reflect characteristics associated with dose assignment rather than dose itself. This is a useful distinction between describing group outcomes and estimating a causal effect.

The Week 60 measurement requirement also makes the analysis population important. An endpoint based on those with a measurement at that time may not represent all enrolled participants. The number assessed and the treatment of missing outcomes are not reported in the registry record, so readers cannot judge the extent or potential influence of incomplete follow-up.

Safety figures likewise need context. Participant counts and listed event terms can convey what was recorded, but they are not proof of causation, and the non-randomized design does not provide a like-for-like safety contrast. Taken together, the record illustrates why transparent outcome estimates, precision measures, analysis methods, and participant accounting are necessary for a complete statistical interpretation.

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 principal limitation for interpretation is that the registry record does not report numerical primary or secondary outcome results. Without the mean LDL-C change, its standard deviation, or an uncertainty estimate, the primary endpoint cannot be characterized quantitatively. The record lists two outcome measures and zero posted analyses.

Allocation was non-randomized, and the study was open-label. The two dose groups are therefore not guaranteed to be comparable, and a difference between them cannot be treated as a randomized dose effect. The registry record does not report an adjusted comparison, a statistical analysis plan, or details of the method used to assign doses.

The primary outcome applies to subjects with a Week 60 measurement, but the number meeting that definition is not reported. The record does not describe missing-data handling, participant flow by arm, or the analysis populations used. It is not possible to assess whether missing measurements or selection into the endpoint population affected the results.

The safety information is limited to group counts, a list of serious-event terms with percentages, and counts for other adverse events. Death counts are not reported. Further details about event timing, exposure, causal assessment, and the definition of other adverse events are not reported in the registry record. With non-randomized groups, these figures do not provide a controlled safety comparison.

The registry record also does not report the study’s sample-size justification, interim analyses, multiplicity handling, or detailed statistical model. The listed enrollment of 545 does not resolve these gaps or establish the number analyzed for any outcome.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Study of Pitavastatin in Elderly Patients With Primary Hypercholesterolemia or Combined Dyslipidemia — NCT00330876.
• Registry record last updated 2010-03-16; status last verified 2010-03.
• Results first posted 2010-01-18.
• 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

The registry describes a completed phase 3, open-label, non-randomized, parallel-group extension study sponsored by Kowa Research Europe. It enrolled 545 participants and evaluated pitavastatin 2 mg once daily and 4 mg once daily in elderly patients with primary hypercholesterolemia or combined dyslipidemia. The study is identified as an extension of NK-104-306 (NCT00257686).

The primary outcome was percent change from baseline in LDL-C from baseline to 60 weeks among subjects with a Week 60 measurement. Change from baseline in total cholesterol was listed as a secondary outcome. Numerical outcome estimates and inferential analyses are not reported in the registry record. Serious adverse-event counts and selected serious-event terms are listed, but deaths are not reported. The non-randomized design limits direct comparisons between dose groups.