This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Safety/Efficacy of Valsartan/Hydrochlorothiazide Combination Compared to Hydrochlorothiazide in Obese Hypertensive Adults (NCT00439738), a randomized phase 4 study. The primary outcome is Change in Mean Sitting Systolic Blood Pressure (MSSBP).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00439738 |
| Phase | Phase 4 |
| Condition | Hypertension |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 412 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Novartis Pharmaceuticals |
| Results posted | Yes |
2. Clinical Question
Population
Obese adults with hypertension. The brief summary describes patients with mean sitting systolic blood pressure >150 mmHg. The registry record lists the condition as hypertension and does not give further participant characteristics.
Intervention
Valsartan/HCTZ is one of the two listed drug interventions. The arm description is blank, so treatment details beyond the intervention name are not reported in the registry record.
Comparator
The other listed intervention is HCTZ + Amlodipine. The study summary describes a comparison with hydrochlorothiazide or HCTZ-based therapy, while the listed intervention includes amlodipine. The registry record does not resolve this difference in wording or give further arm details.
Primary question
How did mean sitting systolic blood pressure change from baseline to Week 8 in the intent-to-treat population, using last observation carried forward? The record names this endpoint but does not report a single extractable comparison of the two groups.
The clinical question is framed around antihypertensive efficacy in an obese hypertensive population. Systolic blood pressure is the pressure measured during the heart’s contraction; the trial’s named measure is the mean sitting systolic blood pressure, abbreviated MSSBP. The registry summary identifies participants with MSSBP >150 mmHg, but does not give a fuller description of eligibility or the range of baseline measurements.
The comparison should be understood from the intervention labels with care. The official title and brief summary frame the study as a comparison of valsartan/HCTZ therapy with HCTZ-based therapy. The intervention list names HCTZ + Amlodipine as the other treatment. Since the arm descriptions are blank, the registry record does not explain the exact regimens or reconcile this difference in wording. The record also does not report a treatment-effect estimate, so the clinical question can be described, but not answered from the posted results.
3. Trial Design
The study is identified as Phase 4 and is described in its official title as a 16-week, double-blind, randomized, multicenter, force-titration study. The registry lists a randomized allocation, double masking, and a parallel-group model. These features describe the broad design: participants were allocated to treatment groups, masking was used, and the groups were followed in parallel. The registry record does not give further detail about who was masked or how the force-titration process was carried out.
The registry lists enrollment as 412. This is the registered enrollment figure; the record does not state how many participants were assigned to each arm, contributed data to the primary endpoint, or were included in each analysis. The study is marked completed. Its recorded start is 2006-12, and its primary completion is 2007-11.
The official title describes a 16-week study, while the primary endpoint timeframe is baseline to Week 8. These refer to different aspects of the record: the former describes the study duration in the title, and the latter specifies the time window for the named primary outcome. The record does not explain the timing of all other assessments or identify which visit was considered the end of treatment for every outcome.
The two drug interventions listed are valsartan/HCTZ and HCTZ + Amlodipine. The arm descriptions contain no details. The summary’s wording instead refers to valsartan/HCTZ compared with hydrochlorothiazide or HCTZ-based therapy. Without further arm information, the precise treatment schedules and the relationship between the comparator wording and the intervention list are not reported in the registry record.
The accompanying tables, plots, and sample-size section are intended to present calculated material without repeating it. The registry record itself does not state a statistical analysis plan or a sample-size justification. It also does not report details of randomization procedures, allocation concealment, treatment adherence, or protocol deviations.
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
| Stage | Valsartan/HCTZ (Hydrochlorothiazide) | HCTZ +Amlodipine |
|---|---|---|
| STARTED | 206 | 206 |
| COMPLETED | 170 | 178 |
| NOT COMPLETED | 36 | 28 |
Reasons for not completing this period:
| Reason | Valsartan/HCTZ (Hydrochlorothiazide) | HCTZ +Amlodipine |
|---|---|---|
| Withdrawal by Subject | 16 | 13 |
| Adverse Event | 6 | 4 |
| Lost to Follow-up | 5 | 6 |
| Protocol Violation | 6 | 3 |
| Lack of Efficacy | 2 | 2 |
| Abnormal Lab Values | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: Intent to Treat (ITT), Last Observation Carried Forward (LOCF)
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.
| Characteristic | Unit | Valsartan/HCTZ (Hydrochlorothiazide) | HCTZ +Amlodipine | Total |
|---|---|---|---|---|
| Participants analysed | 206 | 206 | 412 | |
| Age, Customized: < 65 years | participants | 172 | 180 | 352 |
| Age, Customized: >=65 years | participants | 34 | 26 | 60 |
| Sex: Female, Male: Female | Participants | 124 | 148 | 272 |
| Sex: Female, Male: Male | Participants | 82 | 58 | 140 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Mean Sitting Systolic Blood Pressure (MSSBP), measured over Baseline to Week 8.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | mm Hg |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change in mean sitting systolic blood pressure (MSSBP), measured in mm Hg, from baseline to Week 8. The registry identifies the analysis population as intent to treat (ITT) and specifies last observation carried forward (LOCF) for missing endpoint measurements. The endpoint is continuous: it represents a measured quantity rather than a count of participants meeting a threshold.
In general, change from baseline expresses how a measurement differs between an initial assessment and a later assessment. Comparing changes between randomized groups can describe whether their average blood-pressure trajectories differed over the specified period. The mean summarizes the group’s measurements, while the standard deviation describes how spread out individual measurements are around that mean. The record identifies standard deviation as the dispersion measure but does not report the group means, changes, or standard deviations in the material.
Blood pressure is used as an outcome because it directly represents the physiological measurement targeted by an antihypertensive study. The sitting systolic measure focuses on the upper of the two commonly recorded blood-pressure values. The registry also lists mean sitting diastolic blood pressure and blood-pressure control thresholds among secondary outcomes, but those are distinct from the named primary endpoint.
The endpoint definition alone does not establish the size or precision of any treatment difference. Numerical results, an uncertainty interval, and a single extractable comparison are not reported in the registry record. Thus, the measure and its planned timeframe are clear, while the result cannot be interpreted quantitatively from the record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a focused primary outcome: change in mean sitting systolic blood pressure from baseline to Week 8 in an ITT population, with LOCF used for missing measurements. It also gives the measurement unit and names standard deviation as the dispersion measure. These details define what the primary outcome concerns, but they are not themselves evidence about the direction or magnitude of a difference between treatment groups.
A single primary comparison is not reported in the registry record. The record does not give group-specific baseline or Week 8 means, average changes, a between-group estimate, a confidence interval, or a p-value. It therefore does not allow a reader to determine how the groups’ recorded values differed, or how precisely any difference was estimated. A completed study status and a defined endpoint do not substitute for outcome estimates.
The trial’s population and treatment labels also set boundaries on interpretation. The summary concerns obese hypertensive adults and describes a baseline MSSBP criterion of >150 mmHg. That framing should not be generalized to populations not described in the record. The intervention list names valsartan/HCTZ and HCTZ + Amlodipine, while the title and summary use HCTZ or HCTZ-based comparator language. Because the arm descriptions are blank, the exact regimens cannot be established from this record alone.
Other outcomes listed include change in mean sitting diastolic blood pressure, blood-pressure control at < 140/90 mm Hg and < 130/80 mm Hg, and changes in postprandial glucose, insulin, and non-esterified fatty acids. The registry record lists these outcomes but does not report their numerical findings in the material. Their presence indicates that the trial considered outcomes beyond the primary systolic measure, but does not establish whether any threshold was reached or whether any outcome differed between groups.
General statistical interpretation depends on both an estimate and its uncertainty. An estimate describes the observed group contrast; a confidence interval describes a range of values compatible with the data under the method used. Neither is reported for a primary comparison. Without those quantities, the result cannot be judged for magnitude or precision. The posted material also does not establish whether analyses adjusted for baseline values or other covariates, or how any departures from the planned analysis were handled.
The accompanying sample-size material is a planning illustration based on the observed effect, with assumptions including a two-sided significance level of 0.05, equal allocation, and a normal approximation. Such illustrations address how many participants per arm might be needed under stated assumptions to detect an effect set as a fraction of the observed effect. They do not describe power attained by the completed trial. The assumptions do not replace a reported treatment estimate, confidence interval, or trial analysis.
Accordingly, the appropriate reading is descriptive: the registry records a randomized, double-blind parallel-group trial and specifies an endpoint and analysis population. It does not report the primary comparison needed to characterize the observed treatment difference. No conclusion about treatment benefit, lack of benefit, or equivalence can be drawn from the endpoint description alone.
9. Statistical Methods Explained
The registry describes a randomized, double-blind, parallel-group study. In general, randomization is intended to create groups whose differences at entry are not systematically determined by treatment choice. Masking can reduce the influence of treatment knowledge on care, outcome assessment, or participant reporting, depending on who is masked. A parallel-group design follows the assigned groups alongside one another rather than switching participants between treatments. These are general explanations; the registry record does not report the detailed procedures used to implement randomization or masking in this trial.
What does a change-from-baseline endpoint represent?
The primary endpoint is change in mean sitting systolic blood pressure from baseline to Week 8. In general, a change score relates a later measurement to the participant’s starting measurement, and a group mean summarizes those individual changes. A comparison between groups can then describe the contrast in average change. The registry names the measure, time window, and unit, but does not report the group values or a single between-group estimate. It therefore does not support a numerical interpretation of the primary contrast.
The record identifies standard deviation as the dispersion measure. In general, a standard deviation describes variation in measurements within a group; it is not the same as the uncertainty around a group mean or around a treatment contrast. A confidence interval is a way to express uncertainty around an estimate, conditional on the analysis and its assumptions. No primary confidence interval is reported in the registry record. The distinction matters because a group’s variability and the precision of a comparison answer different questions.
What do ITT and LOCF indicate?
The stated population is intent to treat (ITT). In general, an ITT analysis aims to retain participants in the groups to which they were randomized, regardless of treatment adherence or changes after assignment. This can preserve the comparison created by randomization, although the precise operational definition depends on the protocol and analysis rules. Those rules, including how participants with no post-baseline data were handled, are not reported in the registry record.
The endpoint specifies last observation carried forward (LOCF). In general, LOCF fills a missing later measurement with the participant’s last recorded value. This creates a value for an analysis time point, but it relies on an assumption that the carried-forward measurement is an appropriate representation of the missing measurement. The assumption may be unsuitable when the outcome is changing over time or when missingness is related to health or treatment. These are general considerations, not findings about this trial. The registry does not report how many measurements were missing, why they were missing, whether other missing-data approaches were used, or whether sensitivity analyses were conducted.
What can be inferred from the design labels?
Randomized allocation and double masking are meaningful design features, but they do not by themselves show that the groups were comparable in the analyzed data or that all sources of bias were avoided. General evaluation also considers allocation concealment, protocol adherence, the completeness of outcome collection, and how outcomes were assessed. Those details are not reported in the registry record. The record labels the study multicenter in its official title, but does not state the number or locations of centers.
The official title describes force titration. In general, titration means changing a treatment according to a specified approach, but the precise rules, timing, and criteria for changes are not reported in the registry record. The blank arm descriptions also limit understanding of what participants received. The intervention list names valsartan/HCTZ and HCTZ + Amlodipine, while the title and summary describe the comparison using HCTZ or HCTZ-based wording. This wording difference should not be resolved by assuming details that are absent from the record.
How should the planning illustrations be read?
The sample-size assumptions describe an illustration based on the observed effect, using a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The illustration uses a stated fraction of the observed effect as the effect to detect. In general, such a calculation estimates participants per arm under a chosen effect size and analysis assumptions. It is a planning exercise, not a report of how many participants were analyzed and not a measure of power attained by the completed trial. The numerical outputs should be read as hypothetical planning quantities, not as observed clinical outcomes.
Any such illustration depends on its assumptions. A different target effect, allocation, significance level, or statistical model can lead to a different planning result. The normal approximation is a simplifying basis for the calculation, not a description of every aspect of the trial’s analysis. The registry record does not state that these illustration assumptions were used to design the original study, and it does not report the original sample-size justification. No trial-specific design rationale should be inferred from the planning section.
The record does not state a statistical model for the primary outcome, whether baseline adjustment was performed, whether standard errors were adjusted for center, or how multiplicity was managed. General statistical principles cannot identify which methods were actually used. The posted endpoint description therefore supports explanation of the measure and its named population, but not reconstruction of the full analysis.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary outcome and several secondary outcomes. The secondary list includes change in mean sitting diastolic blood pressure; blood-pressure control by visit at < 140/90 mm Hg and < 130/80 mm Hg; and changes from baseline in postprandial glucose, insulin, and non-esterified fatty acids. The record also identifies seven outcome measures overall. It does not report how testing across these outcomes or across visits was handled.
In general, multiplicity arises when several hypotheses or comparisons are examined. Without an appropriate plan, the chance of at least one apparently notable finding can increase as the number of tests grows. Methods for addressing multiplicity may define a testing hierarchy, adjust significance thresholds, or treat secondary outcomes as exploratory. The registry record does not report which approach, if any, was used. It is therefore not possible to infer the evidential status assigned to each secondary finding.
The primary endpoint specifies ITT and LOCF, but this does not fully describe missing-data handling. In general, missing observations can affect the analysis if their occurrence is related to the outcome or treatment. LOCF carries a previous measurement forward, yet the registry does not report the extent or pattern of missingness, reasons for missing data, the number included in the endpoint analysis, or sensitivity analyses. The record also does not state whether other imputation or modeling methods were used.
Analysis populations beyond the named ITT population are not reported in the registry record. The number randomized to each group and the numbers contributing to each outcome are also not reported. These omissions limit assessment of completeness and make it difficult to relate the registered enrollment to the analyzed population.
11. What the Result Does, and Does Not, Mean
The registry record establishes that a completed randomized, double-blind, parallel-group Phase 4 trial was registered to examine blood-pressure treatment in obese hypertensive adults. It names valsartan/HCTZ and HCTZ + Amlodipine as interventions and identifies change in mean sitting systolic blood pressure from baseline to Week 8 as the primary endpoint. It also specifies an ITT population and LOCF for the primary outcome.
Those design and endpoint details do not establish what the trial found. A treatment result requires a reported estimate of the group contrast, along with information about its uncertainty and the analysis used. A single extractable primary comparison, numerical effect estimate, confidence interval, and p-value are not reported in the registry record. The record therefore does not show the direction, size, or precision of a difference between the groups.
The absence of a reported comparison should not be read as evidence that the treatments had the same effect. Nor does it establish that one treatment was better or worse. Equivalence or non-inferiority would require a prespecified framework and reported results; those are not reported in the registry record. This page can describe the trial question and the statistical issues, but cannot answer the efficacy question from the available outcome information.
The listed secondary outcomes likewise do not establish findings. Their descriptions identify measurements and thresholds, not results. In general, a threshold outcome reports the number of participants meeting a stated criterion, while a continuous outcome reports measurements or changes on a scale. To interpret either type, readers need the observed group results and an appropriate comparison. Those numerical findings are not included in the record.
The sample-size section is a planning illustration based on the observed effect and stated assumptions. It should not be mistaken for a clinical outcome or for proof that the trial had sufficient or insufficient power. It shows how planning quantities depend on assumed effect size and analysis conditions; it does not reveal the actual precision of the trial’s primary estimate.
12. Why This Trial Matters Statistically
This trial is statistically notable for the way its registry record separates a clearly named endpoint from the missing information needed to interpret that endpoint. The record identifies the outcome, unit, timeframe, population, and missing-data convention. Those details are essential to define an analysis question. But without a reported comparison and uncertainty measure, they are not enough to assess the magnitude or precision of an observed treatment difference.
The study also illustrates why intervention descriptions matter to statistical interpretation. The intervention list names valsartan/HCTZ and HCTZ + Amlodipine, while the title and summary describe a comparator in HCTZ or HCTZ-based terms. Because the arm descriptions are blank, the precise contrast cannot be reconstructed from the record. A treatment effect is always an effect for a defined comparison, so uncertainty about the regimen limits the clarity of the estimand a reader can attach to any result.
Another important feature is the stated use of ITT and LOCF. These terms indicate choices relevant to preserving randomized groups and handling missing measurements, but they do not fully describe the analysis. General statistical interpretation requires attention to who was included, how many data were missing, and whether conclusions depended on assumptions about those missing values. The record does not report those details.
Finally, the accompanying planning illustrations are distinct from trial findings. Their assumptions make clear that sample-size calculations depend on a target effect and chosen analysis conditions. Treating those planning quantities as observed trial power would confuse a hypothetical calculation with the evidence actually collected. Keeping design, analysis, results, and planning separate is central to sound interpretation of clinical-trial statistics.
13. 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 does not report a single extractable primary comparison. Without group-specific endpoint values or a between-group estimate, readers cannot assess the direction, magnitude, or precision of the primary result. The record also does not report a confidence interval or p-value for that comparison.
Descriptions of the treatment groups are incomplete. The arm descriptions are blank, and the intervention list names HCTZ + Amlodipine while the title and summary describe a comparison with HCTZ or HCTZ-based therapy. The exact regimens, schedules, and titration rules are not reported in the registry record, which limits interpretation of the intended treatment contrast.
Participant-flow information is also limited in the record. Although enrollment is listed as 412, the numbers assigned to each group, analyzed for the primary outcome, or included in secondary analyses are not reported. Baseline characteristics, adherence, withdrawals, protocol deviations, and reasons for missing data are likewise not reported.
The primary endpoint uses LOCF, but the record does not describe the extent of missingness or sensitivity analyses. It does not report the statistical model, baseline adjustment, center handling, or multiplicity strategy. The record also does not state the original sample-size justification or give a detailed protocol for the force-titration process. These limitations concern what can be learned from the registry record; they do not establish that these procedures were absent from the full study documentation.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: Safety/Efficacy of Valsartan/Hydrochlorothiazide Combination Compared to Hydrochlorothiazide in Obese Hypertensive Adults — NCT00439738.
- Registry record last updated 2017-05-16; status last verified 2017-04.
- Results first posted 2009-02-10.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
17. Record Summary
NCT00439738 is a completed Phase 4 randomized, double-blind, parallel-group study in obese hypertensive adults. The official title describes a 16-week multicenter force-titration study. Enrollment is listed as 412; the recorded start is 2006-12 and primary completion is 2007-11.
The interventions listed are valsartan/HCTZ and HCTZ + Amlodipine. The primary outcome is change in mean sitting systolic blood pressure from baseline to Week 8, in mm Hg, for an ITT population using LOCF. Secondary outcomes include diastolic blood pressure, blood-pressure control thresholds, and postprandial metabolic measures.
The registry record does not report a single extractable primary comparison or numerical treatment-effect results. Arm descriptions and several analysis details are also not reported in the registry record. The tables, plots, and planning illustrations should be read separately from the trial’s registered design and endpoint definitions.