FimasaRtan-basEd BP Targets After Drug SwitcHing: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for FimasaRtan-basEd BP Targets After Drug SwitcHing (NCT03649646), a registered phase not stated study. The primary outcome is Percentage of Patients With Controlled Blood Pressure (<140/90 mmHg).

2. Clinical Question

The study was designed to describe treatment trends and blood-pressure target attainment after a switch to ARB-based therapy. Its summary also names treatment effect and cardiovascular disease risk as areas of interest. Those aims do not establish that the study can isolate the effect of the regimen change: the record describes an open, longitudinal, observational study, not a randomized comparison.

The target in the primary endpoint is specifically <140/90 mmHg. The registry record separately lists secondary outcomes based on the 2018 KSH Guideline, the 2017 ACC/AHA Guideline, and an investigator's target. These are distinct definitions of blood-pressure control, and results under one definition cannot be assumed to apply to the others. The posted record does not report the outcome estimates for any of these targets.

3. Trial Design

The registry describes a multicenter, open, longitudinal, observational study of patients whose antihypertensive regimens were changed to ARB-based therapy. Its status is COMPLETED. The listed enrollment is 4542, the study start date is 2018-07-03, and the primary completion date is 2020-10-29. These registry entries describe the study's conduct and registration; they do not, by themselves, establish when individual participants were followed or how complete their follow-up was.

The group description is “Patients with hypertension uncontrolled by antihypertensive drug.” The study summary says the changed regimens could be ARB monotherapy or ARB-containing combination therapy. The record does not report how clinicians selected a regimen, whether treatment changes followed a common protocol, or how use of additional medicines was handled. It also does not report the number of participants in each regimen type.

The primary endpoint is assessed at Week 12 after the treatment regimen change. The record lists one primary outcome and three secondary blood-pressure control outcomes, for four outcome measures in total. It does not report outcome estimates or analysis records. The primary endpoint is described as a percentage, while its listed parameter is COUNT OF PARTICIPANTS; the record does not clarify the relationship between that count and the percentage denominator.

Because allocation is not stated and the study is observational, the listed patient group is not a randomized control comparison. Changes in blood pressure after a treatment change may be described over time, but a before-and-after pattern alone cannot separate the treatment change from other influences, such as concurrent care or changes in participant circumstances. The registry record does not report a protocol, a detailed statistical analysis plan, or information that would resolve these questions.

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 Percentage of Patients With Controlled Blood Pressure (<140/90 mmHg), measured over Week 12 after the treatment regimen change.

The primary endpoint is the percentage of patients who attain blood pressure below 140/90 mmHg at Week 12 after the treatment regimen change. It uses a defined threshold to classify whether a participant's measured blood pressure meets the target. The registry description identifies the systolic and diastolic components as below 140 and 90 mmHg, respectively.

A threshold endpoint can make a clinical target easy to communicate: it describes the share of participants classified as controlled according to that particular definition. It does not show how far each participant's measurement lies from the threshold, how measurements changed from baseline, or whether control was sustained beyond the stated assessment time. Those are different questions and require their own reported outcomes.

The endpoint is useful for describing target attainment in the study's treatment setting, but its interpretation depends on how blood pressure was measured, how the analysis population was defined, and how missing Week 12 measurements were handled. These details are not reported in the registry record. Nor does the record report the number meeting the target, the denominator used to calculate the percentage, or a confidence interval. As a result, the magnitude and precision of target attainment cannot be assessed from the registry entry.

The registry also lists control outcomes using other guideline targets and an investigator's target. Different thresholds classify participants differently, so those outcomes should be interpreted according to their own definitions rather than treated as interchangeable with the primary endpoint. Their numerical results are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry labels the study observational, open, longitudinal, and multicenter. These design terms describe how evidence is gathered, not the result. Observational studies record care as it occurs rather than assigning treatment through a randomized allocation. Longitudinal follow-up permits outcomes to be recorded after a treatment change. An open study does not conceal treatment assignment from participants or study personnel, although the registry record does not describe measurement procedures or any masking of outcome assessment.

What does the primary endpoint measure?

The primary outcome is a threshold-based binary classification: whether a participant attained the stated blood-pressure target at the Week 12 assessment. The registry describes it as a percentage and also lists COUNT OF PARTICIPANTS as its parameter. A count can be part of calculating a percentage, but the record does not identify the denominator or explain how the count and percentage were reported. The number meeting the target and the percentage are not reported in the registry record.

For a binary outcome, an estimate of the proportion would describe how common the target classification was in the analyzed group. A confidence interval would express the uncertainty around that estimate under the statistical model. General statistical explanation: an interval is not a guarantee that the true value lies within its limits; it summarizes uncertainty associated with the estimate and its assumptions. No confidence interval is reported for this endpoint.

Why does the observational design matter?

Random assignment, when used, is intended to make treatment groups comparable on average with respect to factors that could affect outcomes. This registry record does not describe random assignment or a comparator group. As a result, it cannot support the same interpretation as a randomized treatment contrast. If outcomes changed after a regimen change, the change could be related to the regimen, but it could also reflect other differences or events during follow-up. Statistical adjustment can address measured factors under suitable assumptions, but the record does not report an adjusted analysis or enough detail to assess one.

The study summary describes ARB monotherapy and ARB-containing combination therapy. These are broad treatment categories, not a single specified regimen. The record does not describe how treatments were selected, whether categories were compared, or how changes in concomitant treatment were handled. These omissions make it impossible to assess treatment-specific contrasts from the registry entry.

What can be inferred from outcome definitions?

The primary threshold is <140/90 mmHg at Week 12. A threshold outcome compresses a continuous measurement into a controlled/not-controlled classification. General statistical explanation: this can simplify communication, but participants with measurements close to opposite sides of a cutoff may be classified differently even when their measurements are similar. The classification also does not convey the size of any change from baseline. The registry record does not report continuous blood-pressure results or baseline-to-follow-up changes.

The secondary outcomes use three other target definitions. When multiple thresholds are considered, the proportion classified as controlled may vary because the definition varies. This is not a contradiction; it reflects different criteria. The registry record lists the outcomes but does not report their estimates or explain whether they were analyzed in a prespecified order.

What does the record say about statistical analysis?

The registry lists zero analysis records. It does not report a statistical analysis plan, model specification, adjustment set, confidence intervals, or hypothesis tests. It also does not report interim analyses, a sample-size justification, or a planned power calculation. These items are not reported in the registry record, so no analysis method should be attributed to the investigators based on this entry alone.

The registry's sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. They are not evidence of the trial's original design or a report of observed power. The record describes the study as observational and does not provide a randomized two-arm comparison to which those planning assumptions could be directly attributed. Any planning illustration should be read as a hypothetical calculation, not as a measured study result or a justification documented by the registry.

General statistical explanation: over-dispersion occurs when variation in observed data exceeds what a chosen statistical model expects. If present, it can make standard errors and confidence intervals based on that model too optimistic unless the analysis accounts for the extra variation. The registry record does not report a model or data structure that would establish whether over-dispersion was relevant in this study.

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.

R code and output

arm    <- c("Patients")
n      <- c(4075)
events <- c(3083)
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  Patients  4075  3083  75.7  74.3  77.0  74.3  76.9  74.3  76.9

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint and three secondary blood-pressure outcomes. Considering multiple outcomes can raise a multiplicity question: when several results are examined, the chance of finding at least one apparently notable result may differ from the chance associated with a single planned test. General statistical explanation: investigators may address this by prespecifying a hierarchy, adjusting inference, or treating secondary analyses as descriptive. The registry record does not report a multiplicity strategy, an outcome hierarchy beyond identifying the primary endpoint, or hypothesis-test results. Since numerical analyses are not reported, the effect of multiplicity on conclusions cannot be evaluated.

The endpoint is assessed at Week 12, but the record does not state how many participants had an assessment at that time or how missing measurements were handled. It does not report reasons for missing data, whether participants who stopped or changed treatment remained in the analysis, or whether any sensitivity analyses were conducted. These details matter because an observed percentage among participants with available measurements may not represent all enrolled participants if missingness is related to blood pressure or treatment course.

The analysis population is also not specified. The record does not say whether the primary outcome included every enrolled participant, only participants who started a changed regimen, or a narrower set with an observed Week 12 measurement. The listed enrollment of 4542 should not be taken as the endpoint denominator absent that information. There is no reported participant flow or accounting of exclusions in the registry record.

These gaps do not demonstrate that data were missing or that analyses were biased. They mean the registry entry does not provide enough information to evaluate missingness, population definitions, or multiplicity. The outcome estimates and the methods used to obtain them are not reported in the registry record.

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 0.05% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: hyperkalaemia (0.0%), angina pectoris (0.0%), cardiac arrest (0.0%), cardiac failure (0.0%), coronary artery disease (0.0%).

The registry lists 4386 participants at risk in the safety group. It records 18 participants with serious adverse events, 37 with other adverse events, and 2 deaths. These are safety counts in the registry entry; they do not, on their own, establish why an event occurred or whether it was caused by the treatment change. The record does not provide a comparative safety analysis against a control group.

Several serious adverse event terms are listed with a frequency of 0.0%: Hyperkalaemia, Angina pectoris, Cardiac arrest, Cardiac failure, Coronary artery disease, and Rhegmatogenous retinal detachment. The registry entry does not give counts for these terms or explain how the listed percentages relate to the total serious adverse event count. The displayed 0.0% values should therefore be read as recorded, not used to infer that no serious adverse events occurred overall; the group-level count is 18.

The safety group denominator is not necessarily the denominator for every efficacy outcome. The primary endpoint denominator and the handling of missing safety information are not reported in the registry record. Nor does the entry provide event timing, severity detail beyond the serious-event category, exposure duration, or a causal assessment. These figures describe what the registry records, but they cannot establish comparative risk or attribute events to a particular regimen.

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

The registry record establishes the study's descriptive aim and its primary target: blood pressure below 140/90 mmHg at Week 12 after a regimen change to ARB-based therapy. It also identifies the observational design, the enrolled population, and secondary target definitions. This information explains what the investigators intended to study, but it does not supply the outcome estimate needed to describe how often participants met the primary target.

Without a reported numerator, denominator, percentage, or confidence interval, the magnitude and precision of primary target attainment cannot be assessed. The absence of those estimates is not evidence that the target was or was not attained. Likewise, the secondary outcomes are listed but their results are not reported in the registry record.

The design matters for interpretation. Because the record describes an observational study and does not state an allocation method or randomized comparator, outcomes after a regimen change cannot be treated as a randomized estimate of treatment effect. Even if a before-and-after result were available, other factors could contribute to the pattern. The registry does not report analyses that would establish a causal effect.

The safety counts are descriptive. The record lists 18 participants with serious adverse events, 37 with other adverse events, and 2 deaths among a safety group with 4386 at risk. Those counts do not identify cause, quantify comparative risk, or resolve how the adverse-event term percentages relate to the total. They should not be converted into a treatment conclusion.

Overall, the entry supports a careful account of study design, intended endpoints, enrollment, and listed safety figures. It does not support a claim about the size or certainty of a blood-pressure outcome, a comparison between treatments, or whether a treatment caused an outcome. Those conclusions require results and analysis details that are not reported in the registry record.

14. Why This Trial Matters Statistically

This study addresses a statistical question that depends on how “controlled blood pressure” is defined. Its primary endpoint uses <140/90 mmHg, while the registry also lists outcomes based on the 2018 KSH Guideline, the 2017 ACC/AHA Guideline, and an investigator's target. Distinguishing these definitions matters because they classify outcomes according to different criteria. A clear threshold helps make an endpoint interpretable, but it does not replace reporting the underlying estimate and its uncertainty.

The observational design also makes the distinction between description and causal comparison especially important. A longitudinal account can describe treatment patterns and outcomes after a regimen change. Without random assignment or a stated comparator, however, an observed pattern cannot automatically be attributed to the change itself. This is a general issue of confounding and selection in observational research, not evidence that a particular bias occurred in this study.

From a reporting perspective, the registry entry demonstrates why endpoint labels alone are not enough to assess a trial result. Interpreting target attainment requires the numerator, denominator, analysis population, missing-data handling, and a measure of precision. The record does not report these for the primary outcome. It also lists multiple target definitions without reporting their numerical results or a multiplicity strategy.

The entry therefore has value as a record of a study's aims, design, and outcome definitions, while leaving the main statistical findings unavailable. This distinction is important for readers: a registered endpoint is not an outcome result, and a completed study status does not supply an estimate. The study's statistical contribution cannot be judged from the registry entry alone.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

Several limitations specific to interpreting this study follow from the information recorded. First, the primary outcome result is not reported. The registry gives the Week 12 target definition but not the number of participants attaining it, the percentage, the denominator, or a confidence interval. The clinical question is therefore specified, but its answer cannot be assessed from the entry.

Second, the record describes an open, longitudinal, observational study and does not state an allocation method. It does not describe a randomized comparator. The registry itself cautions that this is not a randomized comparison and that the arms are not a like-for-like control comparison. Consequently, the record does not support interpreting an outcome pattern as a causal treatment contrast.

Third, details needed to evaluate the endpoint are absent. Blood-pressure measurement procedures, the analysis population, missing Week 12 data, exclusions, and the denominator for the reported percentage are not reported in the registry record. The entry also does not give baseline or follow-up continuous blood-pressure values, so the threshold outcome cannot be supplemented with information about the size of measurement changes.

Fourth, the treatment category includes ARB monotherapy or ARB-containing combination therapy in the study summary, but specific regimens, treatment selection, and regimen-specific outcome results are not reported. The record lists other guideline-based targets but provides no results or multiplicity strategy. Finally, it does not report a statistical analysis plan, interim analyses, or a sample-size justification. These omissions limit assessment of both analytic choices and precision; they do not establish that the study was conducted improperly.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: FimasaRtan-basEd BP Targets After Drug SwitcHing — NCT03649646.
• Registry record last updated 2021-01-12; status last verified 2018-08.
• Results first posted 2020-12-21.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT03649646 is a completed, multicenter, open, longitudinal, observational study of patients with hypertension uncontrolled by antihypertensive drug treatment. The registry lists 4542 enrolled participants, a start date of 2018-07-03, and a primary completion date of 2020-10-29. The study summary describes changes to ARB-based therapy, including ARB monotherapy or ARB-containing combination therapy.

The primary outcome is the percentage attaining blood pressure <140/90 mmHg at Week 12 after the regimen change. Three secondary outcomes use other guideline or investigator-defined targets. The registry record does not report outcome estimates, analysis details, or an analysis population. It lists a safety group of 4386 participants at risk, with 18 serious adverse event participants, 37 other adverse event participants, and 2 deaths. Because the study is observational and no randomized comparator is described, the entry does not establish a causal treatment effect.