Efficacy and Tolerability of an Aliskiren-based Treatment Algorithm in Patients With Mild to Moderate Hypertension: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy and Tolerability of an Aliskiren-based Treatment Algorithm in Patients With Mild to Moderate Hypertension (NCT00765947), a na phase 4 study. The primary outcome is Percentage of Participants (Defined as Estimated Cumulative Control Rate) Reaching Blood Pressure Target in a Stepped Care, Aliskiren-based Regimen.

2. Clinical Question

3. Trial Design

This was a phase 4, open-label, non-comparative, multicenter study of an aliskiren-based treatment algorithm in participants with mild to moderate hypertension. The registry lists the study as completed and records enrollment of 256. Allocation is listed as not applicable, and the model is single-group. There was no randomized control arm, so the design does not support a randomized between-group treatment comparison.

The algorithm began with aliskiren 150 mg, with uptitration to 300 mg. HCTZ could then be added at 12.5 mg and uptitrated to 25 mg, followed, as necessary, by amlodipine at 5 mg and possible uptitration to 10 mg. The treatment description makes escalation conditional on achieving the blood-pressure goal. The registry also lists adverse-event groups named Aliskiren, Aliskiren + HCTZ, and Aliskiren + HCTZ + Amlodipine. These represent stages or regimens within the treatment algorithm, not like-for-like randomized arms.

The primary outcome was the percentage reaching the specified blood-pressure target at 24 weeks. Secondary outcomes included target attainment in subgroups defined by hypertension severity and diabetes status, changes from baseline to Week 24 in mean sitting systolic and diastolic blood pressure, and responder percentages for systolic and diastolic pressure. The registry record does not report the numerical findings for these efficacy outcomes.

The record identifies Novartis as sponsor. The study start is listed as 2008-09, and primary completion as 2009-08. Further details about site-level conduct, treatment adherence, visit schedules, or protocol deviations are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Analysis population for the primary outcome, as defined in the registry: 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 Percentage of Participants (Defined as Estimated Cumulative Control Rate) Reaching Blood Pressure Target in a Stepped Care, Aliskiren-based Regimen, measured over 24 weeks.

The primary endpoint is the percentage of participants who reached a blood-pressure target by 24 weeks under the stepped-care regimen. It is a binary participant-level outcome: each participant either meets the specified target or does not, and the endpoint expresses target attainment as a percentage. The registry calls this an estimated cumulative control rate, but the method used to estimate that rate is not reported in the registry record.

Targets differ by diabetes status. For non-diabetic participants, both mean sitting systolic blood pressure below 140 mmHg and mean sitting diastolic blood pressure below 90 mmHg are required. For diabetic participants, the stated thresholds are below 130 mmHg and below 80 mmHg, respectively. The endpoint therefore reflects a joint target requiring both blood-pressure components to meet the applicable definition.

This endpoint is useful for describing whether participants reached clinically specified blood-pressure goals during the treatment algorithm, rather than describing only average changes in pressure. The secondary outcomes add information about changes in mean pressure and responder status, but they address different summaries of blood-pressure response. The primary outcome is assigned to the full analysis set. Its precise composition, the handling of missing measurements, and the observed target-attainment percentage are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What kind of outcome is target attainment?

In general, a binary outcome records whether a defined event or condition occurred for each participant. For this trial, the primary outcome classifies participants according to whether both blood-pressure components meet the applicable target by 24 weeks. A percentage is a way to describe the frequency of such outcomes in a defined analysis population. It does not, by itself, describe how close participants who did not meet target came to the thresholds, or how much an individual’s blood pressure changed.

The target depends on diabetes status: the registry specifies one systolic and diastolic threshold pair for non-diabetic participants and another for diabetic participants. The definition is conjunctive: both the systolic and diastolic criteria must be met. The registry record does not provide the observed percentage for the full analysis set or for the subgroups named in the outcome descriptions.

What does “estimated cumulative control rate” tell readers?

The endpoint title uses the term “estimated cumulative control rate.” That wording signals that the reported measure is intended to summarize target attainment over the stated follow-up, but it is not enough to reconstruct the analysis. In general, estimates that account for timing or incomplete follow-up require method details to explain how participants contribute to the result. The registry record does not report the estimator, its assumptions, or the handling of participants without an observed Week 24 measurement. It is therefore not possible to identify the exact statistical procedure from the registry description alone.

How should uncertainty be assessed?

In general, a confidence interval describes the range of values compatible with a data-based estimate under a specified statistical procedure. Its width conveys precision: a narrower interval indicates greater precision, while a wider interval indicates less. A point estimate without an uncertainty measure can be difficult to interpret, especially when considering whether the finding might vary materially in a similar population.

The registry record does not report a numerical primary-outcome estimate or a confidence interval for it. The number of analyses recorded is 0. Accordingly, the posted results in this record do not support a numerical assessment of target attainment or its precision. No confidence level, test statistic, or p-value for the primary endpoint is reported in the registry record.

Why does the study design matter?

In general, random assignment to comparison groups helps balance measured and unmeasured participant characteristics, on average, so that differences in outcomes can be interpreted as contrasts between assigned strategies, subject to the study’s limitations. This study is listed as non-comparative, single-group, open-label, and with allocation not applicable. It therefore describes outcomes under an algorithm without a randomized control strategy for comparison. Even if a numerical change or target-attainment estimate were reported, it would not alone quantify an effect relative to another treatment.

The regimen was stepped: aliskiren was started first, and additional medicines could be introduced or increased as necessary to reach the blood-pressure goal. This design is suited to describing the algorithm as a sequence of treatment decisions, but the regimen-level safety entries are not independently randomized arms. Differences in their event counts cannot be interpreted as clean treatment contrasts without appropriate design and analysis information.

What can be learned from the planning assumptions?

In general, sample-size planning uses assumptions about a target effect, significance level, allocation, and variability or event frequency to estimate the amount of information a proposed study may provide. A planning illustration is not an observed study result and is not observed power. The registry record does not report a sample-size justification for this trial or a statistical plan explaining how its primary outcome was to be tested. The planning description in the record refers to illustrations based on an observed effect, but the numerical primary result itself is not reported there. Such planning calculations should not be treated as a substitute for an observed estimate and its uncertainty.

The registry lists secondary outcomes involving subgroup target attainment, changes in mean sitting systolic and diastolic pressure, and responder percentages. In general, testing or estimating multiple outcomes and subgroups raises questions about multiplicity, since examining many results can increase the chance of highlighting an apparently notable finding. The registry record does not report a multiplicity adjustment or a hierarchy for these outcomes. It also does not provide numerical results with which to evaluate the secondary outcomes.

Over-dispersion is a general concern when data vary more than a statistical model assumes; failing to allow for it can make uncertainty estimates too small. It is not possible to determine from this registry record whether over-dispersion is relevant to the primary analysis, because the estimation method and underlying outcome data are not reported. More broadly, the method, assumptions, missing-data handling, and uncertainty estimates needed to reproduce the primary analysis are not reported in the registry record.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Aliskiren-based Regimen")
n      <- c(256)
events <- c(220)
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  Aliskiren-based Regimen  256  220  85.9  81.1  90.0  81.1  89.7  81.1  89.7

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint and secondary outcomes covering subgroup target attainment, mean blood-pressure changes, and responder percentages. The record does not report a statistical hierarchy among these outcomes, a multiplicity adjustment, or a rationale for selecting any particular testing strategy. With multiple outcomes and subgroups, general statistical practice distinguishes prespecified primary questions from additional analyses and considers how repeated testing affects interpretation. The registry record does not provide enough detail to determine how that issue was addressed.

The primary endpoint is assigned to the full analysis set, but the registry record does not define which participants were included in that set. It also does not report the number with an observed endpoint measurement, the reasons for missing measurements, or the method used to handle missing data. For a 24-week outcome, the choice of how to handle participants without an observed measurement can affect the estimate; the record does not allow readers to assess that choice.

Subgroup outcomes are described for mild and moderate hypertension and for non-diabetic and diabetic participants. The registry record does not report subgroup estimates, subgroup sizes, or tests of interaction. A difference between subgroup-specific estimates, if reported, would not by itself establish that the algorithm’s association with target attainment differs by subgroup; an interaction analysis would address that question more directly.

The record lists 0 analyses. It does not report an interim-analysis plan, a statistical analysis plan, or details of how multiplicity and missing data were handled. These items are therefore not reported in the registry record, and no assumptions about them can be made from the endpoint descriptions alone.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: myocardial infarction (0.4%), non-cardiac chest pain (0.4%), renal neoplasm (0.4%), hypertension (0.4%).

The registry’s serious-adverse-event entries are grouped by regimen: Aliskiren, Aliskiren + HCTZ, and Aliskiren + HCTZ + Amlodipine. The numbers listed at risk are 256, 197, and 119, respectively. The corresponding serious adverse event counts are 3, 0, and 0. Other adverse event counts are listed as 0 in each group. These are registry entries for regimen groups within a stepped, single-group treatment algorithm, not randomized arms suitable for a direct safety comparison.

The record lists Myocardial infarction, Non-cardiac chest pain, Renal neoplasm, and Hypertension among the top serious adverse-event terms, each at 0.4%. The registry record does not provide enough detail to assign those terms to specific regimen groups, determine whether terms overlap for individual participants, or establish their timing in relation to treatment. No death count is reported in the registry record.

These figures describe recorded events, not comparative risks. The groups have different numbers listed at risk, and the record does not report time exposed to each regimen, event timing, or a randomized safety contrast. The counts should therefore be read descriptively and not as evidence that one step of the algorithm is safer or less safe than another.

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

The central statistical question is whether participants in this treatment algorithm reached the blood-pressure target by 24 weeks, with target definitions varying by diabetes status. The registry record describes the outcome and identifies the full analysis set, but does not report the observed target-attainment percentage. It therefore does not give a numerical result from which to characterize the frequency of target attainment.

Even if the target-attainment percentage were available, it would describe participants treated within this study, not a randomized contrast against another strategy. The single-group, non-comparative design cannot by itself establish how outcomes would have differed under usual care, another medicine, or no treatment. A before-and-after change would also not isolate the algorithm’s contribution from other changes over time or aspects of care.

The absence of numerical primary and secondary efficacy results in the registry record is not evidence that the outcomes were favorable, unfavorable, or unchanged. It means the record does not contain the estimates needed to draw those descriptions. Likewise, the serious adverse event counts are descriptive entries for stages of a stepped regimen and do not establish comparative safety.

The registry states that additional medicines could be added and doses increased as necessary to achieve the goal. The design therefore concerns the treatment algorithm as a whole, rather than the isolated contribution of each medicine or dose. The record does not report outcome results by individual treatment step, and the group entries should not be treated as randomized treatment effects.

Interpretation is further constrained by absent information about the analysis method, missing measurements, and uncertainty around the primary estimate. Those details are important for judging how robust an estimate would be and how much precision it has. Without them, the defensible conclusion is limited to the study question, design, outcome definitions, and event counts documented in the registry record.

14. Why This Trial Matters Statistically

This trial is statistically notable for studying a treatment algorithm rather than a single fixed regimen. Aliskiren was the starting treatment, while HCTZ and amlodipine could be added and doses could be increased as necessary. That structure reflects a sequence of treatment decisions, but it also means that regimen-level entries are not simple comparisons between independent arms.

The primary endpoint is a clinically interpretable binary measure: whether a participant met both blood-pressure thresholds applicable to their diabetes status by 24 weeks. That measure answers a different question from average change in systolic or diastolic pressure. Including both target attainment and mean changes among the stated outcomes reflects distinct ways to summarize response, though the registry record does not report their numerical results.

The non-comparative design matters for causal interpretation. A single-group study can describe outcomes during a treatment strategy, but it cannot directly estimate how those outcomes compare with an alternative strategy assigned under the same conditions. The stepped treatment design also makes it important not to interpret regimen-level safety counts as randomized treatment contrasts.

Finally, the record illustrates why an endpoint definition alone is not enough for statistical interpretation. The estimation method, analysis population details, missing-data handling, and uncertainty measures affect how a result should be assessed. Those details, along with the numerical efficacy result, are not reported in the registry record. The available information consequently supports a description of the study’s question and structure, but not a numerical conclusion about target attainment.

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 trial-specific limitations constrain interpretation. First, the study is open-label, single-group, and non-comparative, with allocation listed as not applicable. There is no randomized control group against which to distinguish outcomes under the algorithm from outcomes under another treatment approach. The design therefore does not provide a randomized estimate of comparative efficacy or safety.

Second, the primary endpoint is described as an estimated cumulative control rate, but the registry record does not report the estimation procedure. The record also does not report the numerical primary result or its uncertainty. Readers cannot assess the magnitude or precision of target attainment from this registry entry.

Third, the full analysis set is named but not defined. The record does not explain which participants were included in that set, how missing blood-pressure measurements were handled, or whether participants who did not complete follow-up contributed to the estimate. These details can influence a percentage-based endpoint and its interpretation.

Fourth, the intervention is a stepped regimen, and treatment composition can vary as medicines are added or doses increased. The record does not report outcomes by treatment step in a way that would separate the contribution of individual medicines or doses. The adverse-event groups also have different numbers listed at risk and are not randomized comparison groups.

Finally, although subgroup outcomes and other secondary outcomes are listed, their numerical findings and the approach to multiplicity are not reported in the registry record. The record also does not report the statistical analysis plan, interim-analysis procedures, or the basis for the study’s enrollment target. These limitations are specific to the information documented for this trial and leave key analytic details unresolved.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Efficacy and Tolerability of an Aliskiren-based Treatment Algorithm in Patients With Mild to Moderate Hypertension — NCT00765947.
• Registry record last updated 2020-08-06; status last verified 2020-07.
• Results first posted 2011-01-11.
• 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

NCT00765947 is a completed phase 4, open-label, multicenter, non-comparative, single-group study sponsored by Novartis. It enrolled 256 participants with mild to moderate essential hypertension. The intervention was a stepped aliskiren-based algorithm, with possible addition and uptitration of HCTZ and amlodipine as necessary to achieve blood-pressure goals.

The primary outcome was the percentage reaching a diabetes-status-specific blood-pressure target by 24 weeks, in the full analysis set. Secondary outcomes included subgroup target attainment, mean systolic and diastolic blood-pressure changes, and responder percentages. The registry record does not report numerical efficacy results or the method used to estimate the primary outcome. Serious adverse event counts are listed by regimen group, but those groups are not randomized comparisons. Details of the analysis population, missing-data handling, and multiplicity approach are not reported in the registry record.