Efficacy and Safety of Azilsartan Medoxomil, Once Daily (QD), Co-Administered With Amlodipine in Participants With Essential Hypertension: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy and Safety of Azilsartan Medoxomil, Once Daily (QD), Co-Administered With Amlodipine in Participants With Essential Hypertension (NCT00591266), a randomized phase 3 study. The primary outcome is Change From Baseline in the 24-hour Mean Systolic Blood Pressure Measured by Ambulatory Blood Pressure Monitoring..

2. Clinical Question

The clinical question is about the change in a continuous blood-pressure measure over the stated follow-up, rather than a yes-or-no event. The two combination regimens allow comparison of each listed azilsartan dose with amlodipine alone. The registry record also includes a recalculated comparison between the combination-dose groups, but that is not one of the sponsor analyses listed for the primary outcome.

The study was randomized, quadruple-masked, and parallel-group. Those design features describe how the trial was organized; the record does not report further details about the randomization procedure or masking implementation. The primary endpoint is measured using ambulatory monitoring over a 24-hour period, and the listed timeframe is baseline and Week 6. The trial record addresses measured blood-pressure changes and recorded adverse events; it does not, by itself, establish how those findings apply to people or circumstances outside the trial.

3. Trial Design

This was a phase 3, randomized, quadruple-masked, parallel-group study sponsored by Takeda. It enrolled 566 participants with hypertension. The record gives a start of 2007-10, primary completion of 2009-03, and status of completed. It describes a double-blind, randomized, placebo-controlled study in its official title, while the listed treatment groups show two azilsartan medoxomil-plus-amlodipine regimens and an amlodipine-only group.

The combination groups received azilsartan medoxomil 40 mg once daily with amlodipine 5 mg once daily, or azilsartan medoxomil 80 mg once daily with amlodipine 5 mg once daily. The comparator group received amlodipine 5 mg once daily. The brief description frames the central comparison as combination treatment versus amlodipine alone. Although the official title uses the term placebo-controlled, the intervention and arm descriptions in the record identify amlodipine as the comparator; details of any additional placebo procedures are not reported in the registry record.

The primary outcome was measured at baseline and Week 6 in the Full Analysis Set. The posted arm summaries for the primary outcome include 165 participants in the 40 mg combination group, 166 in the 80 mg combination group, and 166 in the amlodipine group. These are outcome-specific analysis counts and should not be treated as a replacement for the overall enrollment figure.

The registry record does not report the planned sample-size justification, detailed randomization methods, adherence procedures, or the handling of protocol deviations. The original statistical analysis plan and further details about the masking procedures are not reported in the registry record. The design labels alone do not establish what specific safeguards or analysis choices were used.

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: Participants with uncontrolled hypertension were enrolled in one of three, once-daily (QD) treatment groups.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Full Analysis Set.

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 the 24-hour Mean Systolic Blood Pressure Measured by Ambulatory Blood Pressure Monitoring., measured over Baseline and Week 6..

The primary endpoint is change from baseline in 24-hour mean systolic blood pressure, measured by ambulatory blood pressure monitoring. The listed timeframe is baseline and Week 6, and the measurement unit is mmHg. The record describes ambulatory monitoring as taking measurements at regular intervals throughout the day and night; the 24-hour mean is the average of measurements recorded over the 24 hours after dosing.

A change score expresses how the measured value at follow-up differs from the baseline value. The posted arm results are least-squares means, with standard errors as their reported dispersion measure. Negative changes in this setting indicate a lower measured systolic blood pressure at follow-up than at baseline. The arm estimates therefore describe average within-group changes, while comparisons address differences between groups.

In general, ambulatory measurements can characterize blood pressure across both daytime and nighttime periods, rather than relying only on a clinic reading at a single visit. That makes a 24-hour average a way to summarize the monitoring period specified in the trial. The endpoint does not represent every blood-pressure measure collected: the registry record also lists clinic and other ambulatory pressure outcomes as secondary outcomes.

The record identifies the Full Analysis Set as the primary population. It does not provide further detail about the exact analysis-population rules or missing-measurement handling, so those aspects cannot be inferred from the endpoint description alone.

7. Results Posted in the Registry

• Azilsartan Medoxomil 80 mg QD and Amlodipine 5 mg QD: mean -24.51 versus -24.79 on control; difference 0.28 (95% CI -1.81 to 2.37), standardized effect d = 0.03; z-test p = 0.793.
• Amlodipine 5 mg QD: mean -13.60 versus -24.79 on control; difference 11.19 (95% CI 9.10 to 13.28), standardized effect d = 1.15; z-test p = <0.001.

8. Secondary Efficacy Endpoints

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

Change From Baseline in Mean Trough Clinic Sitting Systolic Blood Pressure.

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Azilsartan Medoxomil 80 mg QD and Amlodipine 5 mg QD: mean -25.50 versus -26.96 on control; difference 1.46 (95% CI -1.43 to 4.35), standardized effect d = 0.10; z-test p = 0.322.
  • Amlodipine 5 mg QD: mean -15.94 versus -26.96 on control; difference 11.02 (95% CI 8.11 to 13.93), standardized effect d = 0.78; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Azilsartan Medoxomil 80 mg QD and Amlodipine 5 mg QD and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Amlodipine 5 mg QD than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Change From Baseline in the 24-hour Mean Diastolic Blood Pressure Measured by Ambulatory Blood Pressure Monitoring.

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Azilsartan Medoxomil 80 mg QD and Amlodipine 5 mg QD: mean -15.43 versus -15.26 on control; difference -0.17 (95% CI -1.53 to 1.19), standardized effect d = -0.03; z-test p = 0.807.
  • Amlodipine 5 mg QD: mean -7.79 versus -15.26 on control; difference 7.47 (95% CI 6.11 to 8.83), standardized effect d = 1.18; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Azilsartan Medoxomil 80 mg QD and Amlodipine 5 mg QD and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Amlodipine 5 mg QD than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Change From Baseline in Mean Trough Clinic Sitting Diastolic Blood Pressure

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Azilsartan Medoxomil 80 mg QD and Amlodipine 5 mg QD: mean -12.65 versus -12.00 on control; difference -0.65 (95% CI -2.33 to 1.03), standardized effect d = -0.08; z-test p = 0.448.
  • Amlodipine 5 mg QD: mean -7.07 versus -12.00 on control; difference 4.93 (95% CI 3.24 to 6.62), standardized effect d = 0.60; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Azilsartan Medoxomil 80 mg QD and Amlodipine 5 mg QD and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Amlodipine 5 mg QD than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The numerical secondary-outcome results in the record cover clinic and ambulatory blood-pressure measures. Across these posted results, both combination regimens generally show larger mean decreases than amlodipine alone. The sponsor's listed ANCOVA comparisons for the available secondary results report p < 0.001 for comparisons against amlodipine. This broad pattern is directionally consistent with the primary comparison against amlodipine, which also reports larger decreases in the combination groups.

The comparison between the two combination doses is less clearly separated in the unadjusted recalculations. For the secondary outcomes with numerical results, the relevant confidence intervals include zero and the corresponding recalculated p-values are not small. This pattern parallels the primary recalculation between doses. It does not prove the dose groups are equivalent, and the sponsor's record does not list an ANCOVA comparison of the two combination doses for these outcomes.

The registry record lists 14 posted secondary outcomes, while detailed numerical values are not present in the record for every listed outcome in the available result summaries. The stated pattern should therefore be understood as applying to the numerical secondary results available, not as a claim about every listed secondary endpoint.

In general, secondary outcomes can add context by examining related measures, but multiple outcomes create more opportunities for chance findings. The registry record does not report a multiplicity adjustment or a hierarchy for interpreting secondary tests. Unadjusted secondary p-values consequently carry less weight than a prespecified primary analysis, especially when many outcomes and comparisons are considered together. The secondary findings are supportive context, not independent confirmation that resolves the limitations of the primary analysis or the unreported multiplicity plan.

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

• Change From Baseline in Mean Trough Clinic Sitting Systolic Blood Pressure.
• Change From Baseline in the 24-hour Mean Diastolic Blood Pressure Measured by Ambulatory Blood Pressure Monitoring.
• Change From Baseline in Mean Trough Clinic Sitting Diastolic Blood Pressure
• Change From Baseline in Daytime (6am to 10 pm) Mean Systolic Blood Pressure Measured by Ambulatory Blood Pressure Monitoring.
• Change From Baseline in Daytime (6am to 10 pm) Mean Diastolic Blood Pressure Measured by Ambulatory Blood Pressure Monitoring.
• Change From Baseline in the Nighttime (12 am to 6 am) Mean Systolic Blood Pressure Measured by Ambulatory Blood Pressure Monitoring.
• Change From Baseline in the Nighttime (12 am to 6 am) Mean Diastolic Blood Pressure Measured by Ambulatory Blood Pressure Monitoring.
• Change From Baseline in the 12-hour Mean Systolic Blood Pressure Measured by Ambulatory Blood Pressure Monitoring

9. Statistical Interpretation

10. Statistical Methods Explained

What do the arm estimates describe?

The primary outcome is continuous: each participant's measurement is expressed on a numerical scale, and the arm summaries describe means. The posted least-squares mean changes are -24.79 mmHg, -24.51 mmHg, and -13.6 mmHg for the 40 mg combination, 80 mg combination, and amlodipine groups, respectively. A least-squares mean is an estimate from a statistical model rather than necessarily a simple arithmetic average. The record does not explain the model details used to generate these arm estimates, so the adjustment variables and other model specifications are not reported in the registry record.

The dispersion measure attached to the arm estimates is the standard error. In general, a standard error describes the precision of an estimated mean, not the spread of individual participant values. The standard errors for the primary arm estimates are 0.757, 0.754, and 0.754. They should not be interpreted as standard deviations. The individual-level distributions are not reported in the registry record.

What is a mean difference?

A mean difference compares two group estimates by subtracting one from the other. The direction depends on the order of subtraction. For the recalculated primary comparison between the 80 mg and 40 mg combination groups, the estimate is 0.28 mmHg. For the recalculated comparison of amlodipine against the 40 mg combination group, the estimate is 11.19 mmHg. The sponsor's reported ANCOVA analysis expresses the latter comparison in the opposite direction, as -11.19 mmHg. Direction matters when interpreting whether the estimate corresponds to a larger or smaller decrease.

The recalculated comparisons are simple, unadjusted calculations based on posted summary statistics. They are not the sponsor's ANCOVA model. The recalculation uses an approximate pooled standard deviation inferred from the reported standard errors, as indicated in the posted calculation details. Since it reconstructs a comparison from summarized data, it cannot reproduce all possible features of the original participant-level analysis. The discrepancy flag is a further reason to prioritize the sponsor's own reported analysis.

How should p-values be read?

In general, a p-value describes how compatible the observed data are with a specified null model, assuming the model's conditions hold. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of an effect. The recalculated comparison between the combination-dose groups has p = 0.793; the comparison of the 40 mg combination group with amlodipine has p < 0.001. The sponsor reports p < 0.001 for each of its listed primary ANCOVA comparisons against amlodipine. The record does not report a prespecified multiplicity procedure for interpreting these tests together.

What does ANCOVA add?

The sponsor identifies ANCOVA as the method for the reported primary comparisons and reports mean differences in final values. In general, analysis of covariance models an outcome while accounting for one or more covariates. It can therefore produce an adjusted comparison that differs from a subtraction of the posted arm-level changes. The registry record does not state which covariates were included, how they were entered, or how missing observations were handled. Those details are not reported in the registry record and should not be assumed.

Why can results from two methods differ?

The arm summaries are change-from-baseline least-squares means with standard errors; sponsor comparisons are ANCOVA mean differences in final values. The recalculated estimates are unadjusted and use approximate dispersion reconstructed from summary information. These are not identical estimands or analytical procedures. Small differences in estimates or interval limits can arise from the change in comparison direction, adjustment, endpoint formulation, and reconstruction from rounded summaries. The registry record flags a discrepancy, so the sponsor's own analysis takes precedence for interpreting the trial's reported inferential result.

In general, randomization supports comparisons between assigned groups by reducing systematic baseline differences in expectation, while masking can limit some forms of knowledge-related influence. These design features do not eliminate uncertainty, missing-data concerns, measurement issues, or the need to assess the analysis methods. The record confirms randomized allocation and quadruple masking but does not give enough detail to evaluate each implementation feature.

11. Confidence Intervals and Precision

The sponsor's reported primary comparison of the 40 mg combination group with amlodipine is -11.19 mmHg, with a 95% confidence interval from -13.29 to -9.09. For the 80 mg combination group compared with amlodipine, the estimate is -10.91 mmHg, with a 95% confidence interval from -13.00 to -8.81. Both intervals lie on the negative side of zero under the sponsor's comparison direction, and both reported p-values are < 0.001.

In general, a confidence interval gives a range of values compatible with the data and the analysis procedure at the stated confidence level. It conveys uncertainty around an estimate; it is not a range containing a specified proportion of individual participant outcomes. The width of an interval reflects precision: narrower intervals indicate more precision under the same method and confidence level.

The recalculated 80 mg versus 40 mg comparison is 0.28 mmHg, with a 95% confidence interval from -1.814 to 2.374. That interval spans zero and includes differences in either direction. It indicates uncertainty about the difference between these combination-dose groups, not proof that the groups have identical effects. The recalculated 40 mg combination versus amlodipine estimate is 11.19 mmHg, with a 95% confidence interval from 9.096 to 13.28, expressed in the reverse direction from the sponsor's estimate.

Because the record flags a discrepancy and the recalculations use a different, unadjusted approach, the sponsor's ANCOVA estimates and intervals are the primary reported inferential results. Precision should also be distinguished from clinical importance: the registry record does not provide a threshold for judging whether a given difference is clinically important.

12. Planning a Similar Trial: Sample Size

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

The planning figures are participants per arm, because the outcome is continuous; they are not total event counts. The planning illustration assumes a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It uses the stated fraction of the observed effect as the effect to detect. These are planning assumptions for the illustration, not the original trial's design assumptions, which are not reported in the registry record.

The 80% power column gives an illustrative number of participants per arm for a design with an 80% chance of detecting the specified effect under those assumptions, if that effect and the model assumptions were correct. The 90% power column uses a higher target chance of detection and therefore generally requires more participants per arm. For example, planning for 75% of the observed primary comparison of the 40 mg combination group with amlodipine gives 22 participants per arm for 80% power and 29 participants per arm for 90% power. Those values are illustrations, not trial enrollment targets.

Rows for 100%, 75%, and 50% of the observed effect ask how planning changes when the target effect is set to a fraction of the estimate. Smaller effects are harder to distinguish from random variation, so they require more participants under the same assumptions. When the observed effect is very close to zero, calculations based on a fraction of it can produce very large planning figures, as in the comparison between the two combination-dose groups.

This is not observed power. It is a forward-looking planning illustration calculated from an observed estimate; it does not measure the probability that the completed trial found a result. The registry record does not report the trial's original sample-size justification or planning assumptions.

13. How the Sample Size Is Derived

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

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 0.280; pooled standard deviation σ = 9.719.
2. n = 2 × (1.96 + 0.842)² × 9.719² / 0.280² = 18,914.0, rounded up to 18,915 participants per arm for 80% power.

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

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 0.279999999999998                      # observed difference in means
sigma <- 9.71921281851314                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(591266)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 18,915 (80% power), 25,321 (90% power)
 75% of observed effect: n per arm = 33,625 (80% power), 45,015 (90% power)
 50% of observed effect: n per arm = 75,657 (80% power), 101,283 (90% power)
power.t.test: 18915 
Simulated power at n = 18,915 per arm: 0.797 (20000 replicates)

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

14. Analyses Reported by the Sponsor

The sponsor's primary analyses are ANCOVA comparisons of each combination group with amlodipine. For the 40 mg combination group, the reported mean difference in final values is -11.19 mmHg, with a 95% confidence interval from -13.29 to -9.09 and p < 0.001. For the 80 mg combination group, the reported estimate is -10.91 mmHg, with a 95% confidence interval from -13.00 to -8.81 and p < 0.001.

The recalculation compares posted summary statistics without adjustment. It gives 11.19 mmHg for amlodipine versus the 40 mg combination group, with a 95% confidence interval from 9.096 to 13.28 and p < 0.001; the reversed comparison direction accounts for the opposite sign of the sponsor's corresponding estimate. The sponsor's adjusted estimates and intervals do not match every recalculated value exactly. The record marks a discrepancy, and the sponsor's own analysis takes precedence.

The recalculated comparison of the 80 mg and 40 mg combination groups is not one of the sponsor-reported primary ANCOVA comparisons listed in the record. It should be read as a separate unadjusted summary-statistic comparison, not as a replacement for the sponsor's prespecified analysis. The record does not explain the discrepancy or provide enough detail to reconstruct the sponsor's model.

15. Multiplicity, Missing Data and Analysis Populations

The record reports one primary endpoint and lists multiple secondary outcomes, with 30 analyses recorded. It also gives sponsor-reported ANCOVA results for two primary comparisons against amlodipine and several secondary comparisons. The multiplicity method, if any, is not reported in the registry record. The record does not state whether the sponsor adjusted p-values or confidence intervals for the number of outcomes, pairwise comparisons, or repeated analyses.

In general, testing multiple hypotheses increases the chance that at least one result will appear statistically notable by chance if each test is considered separately. A multiplicity plan can define which comparisons are confirmatory, control an error rate, or specify an order for testing. Without a reported plan, individual unadjusted p-values should be read as nominal evidence rather than as a complete accounting of uncertainty across all analyses. This is particularly relevant for secondary outcomes.

The registry record identifies the Full Analysis Set for the primary endpoint, but detailed inclusion rules for that population are not reported. The handling of missing endpoint measurements, withdrawals, deviations, and incomplete ambulatory monitoring is also not reported in the registry record. No imputation method, sensitivity analysis, or missing-data assumption is described. These gaps limit assessment of whether the reported estimates could be affected by missing outcomes or by analysis-population choices.

The record identifies ANCOVA as the sponsor's analysis method but does not give the model covariates or other specification details. It also does not report interim analyses, stopping rules, or the original sample-size justification. These are not evidence that such procedures were or were not used; their details are simply not reported in the registry record. The available descriptions support interpretation of the stated estimates, but not a full audit of the analysis plan.

16. 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: chest pain (0.5%), urinary tract infection (0.5%), ovarian cyst torsion (0.5%), syncope (0.5%).

The adverse-event record lists serious adverse events for each group using an at-risk count and an affected count. The 40 mg combination group has 1 affected participant among 190 at risk; the 80 mg combination group has 2 among 188; and the amlodipine group has 1 among 185. These are the recorded counts for serious adverse events, not measures of the primary blood-pressure outcome.

The record also gives counts for other adverse events: 11 among 190 at risk in the 40 mg combination group, 10 among 188 in the 80 mg combination group, and 10 among 185 in the amlodipine group. The registry record lists chest pain, urinary tract infection, ovarian cyst torsion, and syncope among serious adverse-event terms, each at 0.5%.

Deaths are not reported in the registry record. These counts are descriptive and do not establish whether an event was caused by treatment. Differences in counts should not be interpreted as reliable evidence of a safety difference without the full event definitions, exposure information, statistical analysis, and context. The record does not provide those details here, and adverse-event counts alone do not determine the overall safety profile.

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

The posted results show that mean 24-hour systolic blood pressure decreased from baseline in all three groups at Week 6. The decreases were more pronounced in the two combination groups than in the amlodipine-only group in the posted arm summaries. The sponsor's ANCOVA analyses report differences between each combination group and amlodipine, with confidence intervals that do not include zero and p-values < 0.001.

The recalculated comparison between the two combination doses is close to zero, and its confidence interval includes zero. That does not establish equivalence or show that the doses have identical effects. It means the posted summaries, under this unadjusted recalculation, do not clearly distinguish the two dose-group means. The record does not report an equivalence margin or a sponsor ANCOVA comparison for this dose contrast.

In general, statistical evidence about an average group difference does not imply that every participant had the same response. Nor does statistical significance by itself show that a difference is clinically important. The registry record does not provide a clinical-importance threshold, detailed individual outcome distributions, or longer-term results for this primary endpoint.

The results are limited to the recorded population, treatment regimens, outcome definitions, and follow-up. They do not establish effects for populations or circumstances not described in the record. The adverse-event counts provide descriptive safety information, but deaths are not reported and the record does not establish event causality. These findings should be read as evidence about the trial's measured outcomes and uncertainty, rather than as medical advice or a general conclusion about treatment.

18. Why This Trial Matters Statistically

This trial illustrates several important distinctions in clinical-trial statistics. First, a within-group change is not the same as a between-group treatment contrast. All three posted primary arm estimates are negative, but the comparative question is addressed by examining differences between groups rather than interpreting the changes in isolation.

Second, analysis method and comparison direction matter. The sponsor reports adjusted ANCOVA comparisons of each combination group with amlodipine, whereas the recalculations are unadjusted comparisons reconstructed from arm summaries. The sign of a mean difference depends on which group is subtracted from which. The record's discrepancy flag makes it especially important to keep the sponsor's own analysis distinct from the recalculation.

Third, precision is not the same as certainty about every scientific question. The sponsor intervals for the combination-versus-amlodipine comparisons are separated from zero, while the recalculated comparison between the two combination doses has an interval that spans zero. Neither pattern answers every question about clinical importance, equivalence, or individual outcomes.

Finally, the trial record demonstrates why an endpoint and its analysis population must be read together. The primary outcome is a 24-hour ambulatory measure in the Full Analysis Set, with results at Week 6. The record does not explain several analysis-plan details, including missing-data handling and multiplicity. Those omissions limit how completely readers can assess the analysis, even when reported estimates and confidence intervals are available. Statistical interpretation depends not only on the result itself, but also on what was measured, how groups were compared, and which uncertainties remain unaddressed.

19. 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 primary outcome summaries are least-squares mean changes with standard errors, but the registry record does not specify the model used to obtain those arm estimates. The sponsor's ANCOVA model is named, yet its covariates and other specifications are not reported. This makes it difficult to reproduce or fully evaluate the sponsor analysis from the registry record.

The recalculations are unadjusted and rely on an approximate pooled standard deviation derived from reported standard errors. They are based on rounded summary statistics rather than participant-level data. The record marks a discrepancy, so these reconstructed results should not be treated as substitutes for the sponsor's analysis.

The primary endpoint is observed at baseline and Week 6. Longer-term primary-outcome results are not reported in the registry record. The record also does not provide a clinical-importance threshold, an equivalence margin for comparing the combination doses, or detailed information about adherence and ambulatory-monitoring completeness.

The handling of missing values, exclusions, and deviations from the assigned regimen is not reported. Although the Full Analysis Set is identified, its operational definition is not included. Multiplicity adjustment for the numerous outcomes and analyses is also not reported, which limits interpretation of secondary p-values as confirmatory evidence.

The safety record provides event counts and several serious-event terms, but deaths are not reported. The available counts do not explain causality, duration of exposure, event severity beyond the serious classification, or the statistical approach to safety comparisons. The registry record's official title calls the study placebo-controlled, while the listed comparator arm is amlodipine alone; additional placebo details are not reported. These limitations qualify interpretation of both efficacy estimates and safety descriptions.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Efficacy and Safety of Azilsartan Medoxomil, Once Daily (QD), Co-Administered With Amlodipine in Participants With Essential Hypertension — NCT00591266.
• Registry record last updated 2011-07-22; status last verified 2011-07.
• 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.

23. Record Summary

The registry record describes a completed, phase 3 randomized, quadruple-masked, parallel-group trial sponsored by Takeda, enrolling 566 participants with essential hypertension. The groups received azilsartan medoxomil 40 mg or 80 mg once daily with amlodipine 5 mg once daily, or amlodipine 5 mg once daily.

The primary outcome was change from baseline in 24-hour mean systolic blood pressure by ambulatory monitoring at Week 6, in the Full Analysis Set. Sponsor ANCOVA comparisons against amlodipine were reported with 95% confidence intervals and p < 0.001. The record also flags a discrepancy with simple unadjusted recalculations; the sponsor's own analysis takes precedence.

Secondary blood-pressure outcomes generally show a similar direction in the numerical results posted. The record does not report multiplicity handling, detailed missing-data methods, or the original sample-size justification. Serious adverse-event counts are listed by group, while deaths are not reported in the registry record.