Aliskiren Plus HCTZ Compared to Aliskiren in Metabolic Syndrome Patients With Stage 2 Systolic Hypertension: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Aliskiren Plus HCTZ Compared to Aliskiren in Metabolic Syndrome Patients With Stage 2 Systolic Hypertension (NCT00797316), a randomized phase 4 study. The primary outcome is Change From Baseline to Week 8 in Mean Sitting Systolic Blood Pressure (msSBP).

2. Clinical Question

The trial addresses a comparative question about two assigned regimens in a defined hypertension population. It does not compare either regimen with no treatment or with a different class of therapy. The registry describes efficacy and safety as aims, but the main comparative endpoint is a continuous blood-pressure measure. A more negative change represents a larger reduction from baseline; interpretation of the difference therefore depends on the order in which the groups are compared. The posted comparison is expressed as aliskiren alone relative to the combination group.

3. Trial Design

The registry identifies this as a Phase 4, randomized, double-blind, parallel-group, multicenter study. It was completed. The recorded start is 2008-11, and the primary completion is 2009-12. The registry lists enrollment of 532. The primary endpoint analysis includes a full analysis set, with 264 participants in the combination group and 261 in the aliskiren group for that endpoint.

The study lasted 8 weeks and used forced titration. Both regimens began at a lower listed dose for one week and then increased to the higher listed dose. The combination arm received hydrochlorothiazide along with aliskiren; the comparator arm received aliskiren alone. Both were taken once daily by mouth. The registry identifies masking as double, but further operational details about how masking was maintained are not reported in the registry record.

Random allocation and parallel assignment support a direct comparison of the groups over the same follow-up period. The registry does not report the allocation ratio or details of the randomization procedure. It also does not report how the multicenter design was handled in the analysis, such as whether center was included as a model term. Those points should not be inferred from the design labels alone.

The stated population was patients with metabolic syndrome and stage 2 hypertension, with the summary specifying a mean sitting systolic blood pressure threshold of at least 160 mm Hg and below 200 mm Hg. Other eligibility criteria, recruitment procedures, adherence measures, and details of concomitant care are not reported in the registry record. The design description establishes the broad comparison and duration, but does not provide enough detail to reconstruct every protocol or analysis decision.

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

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 to Week 8 in Mean Sitting Systolic Blood Pressure (msSBP), measured over Baseline and Week 8.

The primary endpoint is change from baseline to Week 8 in mean sitting systolic blood pressure, measured in mm Hg. It is a continuous outcome: each participant's blood-pressure measurement contributes information about the magnitude of change, rather than only whether a threshold was crossed. The registry reports least-squares mean changes for the full analysis set, with standard errors for the group estimates.

Systolic blood pressure is the higher pressure recorded during a heartbeat. Repeated measurement at baseline and follow-up makes change a way to describe how the measured level shifted during the study. Comparing changes between randomized groups focuses the question on the difference in change under the assigned regimens, rather than on change in either group considered alone.

The endpoint is useful for assessing the study's stated blood-pressure-lowering objective because it preserves information about the size and direction of the measured change. A group mean, however, does not describe every participant's response or the full distribution of individual changes. It also does not by itself establish whether the observed difference is clinically important. That judgment would require clinical context and thresholds that are not reported in the registry record. The primary endpoint should therefore be read as a statistical comparison of average measured change over the specified follow-up period.

7. Results Posted in the Registry

• Aliskiren: mean -20.15 versus -30.38 on control; difference 10.23 (95% CI 7.43 to 13.03), standardized effect d = 0.63; 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 to Week 8 in Mean Sitting Diastolic Blood Pressure (msDBP)

• 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:
  • Aliskiren: mean -6.90 versus -11.26 on control; difference 4.36 (95% CI 2.71 to 6.01), standardized effect d = 0.45; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Aliskiren than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Percentage of Participants With Blood Pressure Response at Week 8

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Aliskiren: 55.2% (144/261) versus 78.4% (207/264) on control; risk difference -23.2 percentage points (95% CI -31.0 to -15.4), risk ratio 0.70 (0.62–0.80); unadjusted two-proportion z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically lower for Aliskiren than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Percentage of Patients Achieving Blood Pressure Control at Week 8

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Aliskiren: 34.5% (90/261) versus 58.7% (155/264) on control; risk difference -24.2 percentage points (95% CI -32.5 to -16.0), risk ratio 0.59 (0.48–0.71); unadjusted two-proportion z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically lower for Aliskiren than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The posted secondary outcomes broadly point in the same direction as the primary systolic-pressure comparison. The continuous diastolic-pressure result shows a more negative average change in the combination group, while the response and control outcomes show higher posted percentages in that group. Thus, the secondary findings are directionally consistent with the primary result across different ways of describing blood pressure.

These outcomes are related but not interchangeable. A continuous change measure retains information about the amount of change, whereas response and control percentages classify participants according to outcome criteria. The registry does not include the criteria defining response or control in the information available for these results. The binary outcomes therefore should be interpreted as the posted classifications rather than as evidence about unreported thresholds or participant-level patterns.

The registry lists four secondary outcomes, including change in pulse pressure. Results for pulse pressure are not reported in the registry record. The posted secondary results include estimates and unadjusted comparisons for diastolic change, response, and control. This means the overall secondary pattern can be described, but it is not a complete numerical account of every listed secondary endpoint.

Unadjusted secondary p-values carry less confirmatory weight when several outcomes are assessed and no multiplicity procedure is reported. The chance of at least one apparently notable result can increase when many comparisons are considered. The registry does not report whether the secondary endpoints were ranked, designated as confirmatory, or adjusted for multiplicity. Their consistency with the primary finding is relevant context, but it does not establish independent confirmation or resolve uncertainty about the analysis plan.

The secondary outcomes should therefore be viewed as supportive descriptive evidence rather than as a replacement for the primary endpoint. Their shared direction offers a coherent picture across blood-pressure measures, while missing results and unreported multiplicity handling limit how strongly they can be used to make broader statistical claims.

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

• Change From Baseline to Week 8 in Mean Sitting Diastolic Blood Pressure (msDBP)
• Percentage of Participants With Blood Pressure Response at Week 8
• Percentage of Patients Achieving Blood Pressure Control at Week 8
• Change From Baseline to Week 8 in Pulse Pressure

9. Statistical Interpretation

10. Statistical Methods Explained

The primary endpoint is continuous, and the registry reports least-squares means rather than only raw group averages. A least-squares mean is a model-based estimate of a group mean. It can account for terms included in the fitted model, but the model specification and covariates used for this endpoint are not reported in the registry record. The term should therefore be read as the registry's stated analysis measure, without assuming which adjustments were made.

What does the mean change describe?

Change from baseline is the follow-up measurement expressed relative to the participant's baseline measurement. A negative group estimate indicates that the measured mean was lower at follow-up than at baseline. The reported primary estimates are -30.38 mm Hg for the combination group and -20.15 mm Hg for aliskiren alone. These are group-level least-squares mean changes, not individual response values. They provide a compact description of the average direction and magnitude of change, but do not show variation in individual trajectories or the distribution of outcomes.

How should the between-group estimate be read?

The posted mean difference is 10.23 mm Hg, defined by comparing aliskiren alone with the combination group. Since the group changes are negative, the positive contrast reflects the less negative change in the aliskiren-alone group relative to the combination group. The confidence interval, 7.43 to 13.03 mm Hg, gives a range of values compatible with the data and the analysis assumptions at the stated confidence level. The unadjusted p-value is p < 0.001. This is evidence against a zero contrast under the test used; it is not evidence that a null hypothesis has a particular probability of being true.

The comparison also reports a pooled standard deviation of 16.36 and a standardized effect estimate of 0.625. The record marks the pooled standard deviation as approximate. Standardizing expresses a mean contrast relative to a measure of variability, which can help describe effect size on a scale less tied to the original measurement units. It does not replace the estimate in mm Hg, and the approximation means it should not be mistaken for a directly reported participant-level standard deviation.

What do the standard errors contribute?

The standard error describes the sampling uncertainty in an estimated mean: it reflects how much the estimate would tend to vary across repeated samples under a statistical model. The primary group estimates each have a reported standard error of 1.01. A standard error is not the spread of individual participant outcomes. It is also not itself a confidence interval. The interval for a contrast incorporates uncertainty in the comparison and is the more direct summary for the group difference.

The registry reports a full analysis set for the primary endpoint, but does not report the detailed membership rules or missing-data approach. The outcome-specific arm counts are 264 and 261. The registry enrollment figure is 532; these values refer to different record summaries and should not be combined to infer participant flow or exclusions. Reasons for any difference between enrollment and endpoint analysis counts are not reported in the registry record.

Why does randomization matter statistically?

Randomization is intended to make assigned groups comparable on average before treatment, including with respect to factors that may affect the outcome. This supports interpreting a between-group contrast as an estimate of the effect of assignment within the trial, subject to adherence, missingness, measurement, and analysis limitations. It does not guarantee that every characteristic is balanced, nor does the design label alone establish that the analysis preserved all benefits of randomization. The registry record does not give baseline comparison details or the handling of departures from assigned treatment.

Double masking is intended to reduce the risk that knowledge of assignment influences behavior, measurement, or outcome assessment. The registry identifies the study as double-blind but does not state which roles were masked or describe the masking procedures. The parallel-group design means assigned groups were followed concurrently rather than participants crossing between regimens. These labels clarify the general design, while the full operational details are not reported in the registry record.

What does an unadjusted result mean?

An unadjusted p-value is reported without a stated multiplicity correction for the set of outcomes or comparisons. It should be read as the result for that individual comparison under its test, not as a family-wise error-controlled conclusion across all endpoints. The registry does not report the model details, test specification, or multiplicity plan. Accordingly, the posted p-value and confidence interval can be described as the reported comparison, while the degree to which other analysis decisions affect inference cannot be independently assessed from the record.

The calculations labelled recalculated are simple unadjusted re-calculations from posted summary statistics. They are not a substitute for the sponsor's full analysis. No discrepancy is flagged in this record. No further assumptions about interim analyses, sample-size justification, or a detailed statistical analysis plan can be made because those details are not reported in the registry record.

11. Confidence Intervals and Precision

The primary between-group estimate is 10.23 mm Hg, with a 95% confidence interval from 7.43 to 13.03 mm Hg. A confidence interval expresses the statistical uncertainty around an estimate under the analysis assumptions. In repeated use of the same procedure, intervals constructed this way would cover the underlying parameter at the stated rate if the model and sampling assumptions hold. It is not a range containing a specified proportion of individual participant outcomes, and it does not mean there is a 95% probability that the fixed effect lies in this particular interval.

The interval is entirely above zero, matching the positive direction of the contrast as defined in the registry. This supports a difference between the group mean changes under the unadjusted analysis. The interval's width also conveys that the estimate is not known exactly. Precision does not answer whether the size of the difference is important in clinical practice; a threshold for meaningful change is not reported in the registry record.

Each primary group estimate has a standard error of 1.01 mm Hg. Those standard errors characterize uncertainty in the estimated group means, whereas the confidence interval for the mean difference characterizes uncertainty in the contrast. The group means and their standard errors alone should not be treated as a direct substitute for the comparison interval.

Confidence intervals for the secondary continuous and binary comparisons are also reported. They quantify uncertainty for their own estimands and should be interpreted in light of their unadjusted status. The registry does not report whether confidence intervals were adjusted to account for multiple endpoints. Consequently, their nominal coverage should not be read as simultaneous coverage across all the secondary outcomes.

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 for 80% power and participants per arm for 90% power. They are not total event counts: the primary outcome and other listed outcomes are not time-to-event outcomes. The illustrations use the observed effect as a reference and show planning for 100%, 75%, and 50% of that effect. As the effect assumed for planning becomes smaller, more participants per arm are needed to achieve the same target power.

The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is the stated fraction of the observed effect. These are planning illustrations based on the observed result, not a description of the trial's original sample-size calculation. The trial's own design assumptions and sample-size justification are not reported in the registry record.

In plain terms, 80% power means that a study designed under the stated assumptions would have an 80% chance of meeting its specified statistical criterion if the assumed effect were the true effect. The 90% column describes the corresponding chance under that planning scenario at the higher target. Neither column guarantees that a future study will achieve its target, because the actual effect, variability, and conduct can differ from the assumptions. This is not observed power.

These values are prospective planning illustrations, not an assessment of the probability that the completed trial detected an effect. They should be read as conditional on the assumed effect fraction and the listed calculation approach. A smaller assumed effect requires a larger planned sample to retain the same power target, all else being equal.

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 = 10.230; pooled standard deviation σ = 16.364.
2. n = 2 × (1.96 + 0.842)² × 16.364² / 10.230² = 40.2, rounded up to 41 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 <- 10.23                      # observed difference in means
sigma <- 16.3641384481754                     # 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(797316)
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 = 41 (80% power), 54 (90% power)
 75% of observed effect: n per arm = 72 (80% power), 96 (90% power)
 50% of observed effect: n per arm = 161 (80% power), 216 (90% power)
power.t.test: 41.2 
Simulated power at n = 41 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. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when several outcomes or comparisons are examined. Even if each individual test uses a conventional significance threshold, the chance of observing at least one apparently strong result across a collection of tests can increase. This matters when interpreting the secondary results, because the registry reports unadjusted p-values and does not report a multiplicity adjustment or a hierarchy of endpoints. The primary outcome is clearly identified, but the registry record does not state how the secondary outcomes were intended to support or qualify the primary analysis.

The posted secondary p-values should therefore be understood as results for their individual comparisons, not as evidence that error rates were controlled across the entire set of outcomes. The confidence intervals are likewise reported without a stated simultaneous or multiplicity-adjusted interpretation. The registry record does not report whether any other planned endpoints were analyzed but not posted, or whether any interim analyses were conducted.

Missing-data handling is important because endpoint estimates can be affected if participants without follow-up measurements differ from those with measurements. The primary population is described as the full analysis set, but the rules defining that set are not reported in the registry record. The registry does not report the method used for missing endpoint values, the amount or pattern of missingness, or sensitivity analyses addressing missing data. The analysis counts identify the participants included in the posted endpoint results, but they do not explain participant flow or the reasons for any absent outcome data.

The registry also does not report whether the primary analysis followed intention-to-treat principles, how treatment discontinuation or nonadherence was handled, or whether additional per-protocol analyses were conducted. Those details affect the interpretation of an estimate based on assigned treatment and cannot be reconstructed from the group summaries alone. No assumption should be made about the original statistical analysis plan, sample-size justification, or interim monitoring; these are not reported in the registry record.

These omissions do not negate the posted estimates, but they limit independent assessment of the analysis choices and the robustness of inference. A reader can describe the recorded primary and secondary comparisons accurately while recognizing that multiplicity, missing data, and analysis-population definitions remain unresolved in the registry record.

15. 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: acute myocardial infarction (0.4%), gastroenteritis viral (0.4%), basal cell carcinoma (0.4%), alcohol abuse (0.4%), cellulitis (0.4%).

The registry reports serious adverse events for 3 of 267 participants at risk in the aliskiren/HCTZ group and 4 of 265 at risk in the aliskiren group. These are counts of participants affected, not counts of all event episodes. The registry lists acute myocardial infarction, viral gastroenteritis, basal cell carcinoma, alcohol abuse, cellulitis, and pneumonia among the serious adverse-event terms, each reported as 0.4%. The record does not assign these listed terms to a particular group in the information presented.

Other adverse events are reported for 13 of 267 participants at risk in the combination group and 18 of 265 at risk in the aliskiren group. These counts should be read separately from serious adverse events. The registry does not provide event-level details or additional context about severity, timing, or causal assessment in these summaries. Death counts are not reported in the registry record.

These safety summaries are descriptive. They do not establish whether an event was caused by a study regimen, and group counts alone cannot characterize the full clinical context or the range of possible harms. The short, 8-week follow-up also defines the period covered by this trial record; longer-term safety is not established by these figures.

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

The results describe an 8-week randomized comparison of aliskiren plus hydrochlorothiazide with aliskiren alone among patients with metabolic syndrome and stage 2 systolic hypertension. For the primary endpoint, the combination group had a more negative posted mean change in sitting systolic blood pressure. The estimated contrast was 10.23 mm Hg, with a 95% confidence interval from 7.43 to 13.03 mm Hg and an unadjusted p < 0.001. These statistics describe the observed group comparison and its sampling uncertainty.

They do not establish what will happen to a particular person, because a group mean does not capture individual responses. Nor does statistical evidence against a zero difference determine whether the size of the observed contrast is clinically important. The registry does not report a threshold for clinical importance, and the endpoint is a measurement over the stated follow-up rather than a direct measure of every aspect of health.

The trial compared two assigned regimens, not the combination with no treatment or with other antihypertensive strategies. Its findings therefore apply most directly to the comparison, population, and duration recorded. The registry does not provide enough information to infer effects in people outside the stated population, under different dosing or follow-up conditions, or on outcomes not reported in the record.

Secondary outcomes generally align in direction with the primary comparison, but they have unadjusted results and multiplicity handling is not reported. One listed secondary outcome, pulse-pressure change, has no posted result. Safety counts are also descriptive and do not by themselves establish causation or a complete safety profile. In short, the record supports a statistical description of the measured outcomes, while leaving clinical importance, longer-term effects, and several analysis details unresolved.

17. Why This Trial Matters Statistically

This trial illustrates how a randomized comparison can be summarized with several complementary statistics. The primary result includes arm-level estimates, standard errors, a between-group contrast, a confidence interval, and an unadjusted p-value. Each answers a different question: the means describe average change, the standard errors indicate uncertainty in those estimates, the contrast quantifies the comparison, and the interval shows a range of values compatible with the analysis.

It also shows why direction and contrast definition matter. Both group mean changes are negative, but the comparison is defined as aliskiren alone relative to the combination group. Reading the sign of the contrast alongside the arm estimates avoids mistaking a positive reported difference for an increase in blood pressure in either group.

The registry's secondary outcomes add different views of blood-pressure change, but their unadjusted status makes multiplicity an important part of interpretation. Likewise, planning illustrations based on observed effects can be useful for considering future study sizes, but they do not describe the original design calculation and are not observed power. Keeping those distinctions clear helps separate completed-trial evidence from planning scenarios.

Finally, the record highlights the value of transparent reporting. The primary population and outcome are identified, while model details, missing-data handling, multiplicity procedures, and several design assumptions are not reported. Recognizing both the information available and the information absent makes the statistical reading more precise without overstating what the trial can establish.

18. 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 registry record leaves several trial-specific details unavailable. The full analysis set is named for the primary outcome, but its inclusion rules, participant flow, and reasons for any missing endpoint measurements are not reported. The handling of missing data, treatment discontinuation, and adherence is also not reported, limiting assessment of how closely the analysis reflects assignment to the randomized groups.

The least-squares mean model is not described in detail. Covariates, center handling, assumptions, and the specific test used for the contrast are not reported in the registry record. The record provides an approximate pooled standard deviation for the primary comparison, but this does not supply the individual-level distribution of outcomes. Baseline balance information is also not reported in the registry record for this record.

Multiplicity procedures for the secondary endpoints are not reported. The pulse-pressure outcome is listed, but its result is not reported in the registry record. The definitions of blood-pressure response and control are not included with the posted outcome summaries. These omissions constrain interpretation of the secondary results and prevent a full assessment of how they relate to the original analysis plan.

The registry does not report the original sample-size justification, detailed statistical analysis plan, allocation procedure, masking procedures, or interim analyses. The study's 8-week duration limits the conclusions to the recorded follow-up period. The adverse-event summaries provide participant counts and selected serious-event terms, but death counts are not reported in the registry record, and the available summaries do not establish event causality or provide detailed clinical context.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Aliskiren Plus HCTZ Compared to Aliskiren in Metabolic Syndrome Patients With Stage 2 Systolic Hypertension — NCT00797316.
• Registry record last updated 2011-03-11; status last verified 2011-03.
• Results first posted 2011-01-12.
• 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.

22. Record Summary

NCT00797316 is a completed Phase 4 randomized, double-blind, parallel-group, multicenter study comparing aliskiren plus hydrochlorothiazide with aliskiren alone in patients with metabolic syndrome and stage 2 systolic hypertension. The recorded study period begins 2008-11, with primary completion in 2009-12, and the registry lists enrollment of 532.

The primary endpoint was change from baseline to Week 8 in mean sitting systolic blood pressure, measured in mm Hg, in the full analysis set. The combination group had a posted least-squares mean change of -30.38 mm Hg, compared with -20.15 mm Hg for aliskiren alone. The reported mean difference was 10.23 mm Hg, with a 95% confidence interval from 7.43 to 13.03 mm Hg and an unadjusted p < 0.001.

Secondary blood-pressure outcomes generally had results in the same direction, although multiplicity handling is not reported and pulse-pressure results are not reported in the registry record. Serious and other adverse events are summarized descriptively; death counts are not reported in the registry record. Details of missing-data handling and the original statistical plan are also not reported.