The Chronic Effects of Beetroot Juice in Hypertensive Subjects: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The Chronic Effects of Beetroot Juice in Hypertensive Subjects (NCT01405898), a randomized na study. The primary outcome is Difference in Change in Clinic Systolic Blood Pressure From Baseline.

2. Clinical Question

The trial asks whether change in clinic systolic blood pressure differs between people with hypertension assigned to beetroot juice and those assigned to nitrate-free beetroot juice. The registry summary describes interest in whether beetroot juice has an effect on blood pressure in people with high blood pressure, and suggests nitrate as a possible part of the explanation. That rationale is background, not proof of a mechanism.

The primary comparison is therefore not simply a comparison of final blood pressure values. It concerns the groups’ reported changes from baseline. The posted group means are both negative, while the between-group estimate is positive because the comparison is expressed as nitrate-free beetroot juice minus beetroot juice. The registry record does not report a broader clinical question or a prespecified threshold for an important difference.

3. Trial Design

The registry record describes a randomized, triple-masked, parallel-group trial. Participants were assigned to beetroot juice or nitrate-free beetroot juice. Random allocation is intended, in general, to make treatment groups comparable on average at the time of assignment, including for characteristics that were not measured. It does not guarantee that every characteristic will be balanced in a particular trial. The record does not provide details of the randomization sequence or allocation concealment.

Triple masking indicates that the registry records three parties as masked, but it does not identify those parties or describe how masking was maintained. The record also does not describe whether the two juices were matched in taste, appearance, or other features. The trial is listed as completed, with a start date of 2010-01 and primary completion in 2013-04. The registry lists an enrollment of 68.

The posted primary outcome summaries include 32 participants in each group. The registry record does not explain the relationship between the enrollment figure and the numbers included in these outcome summaries. It does not report whether there were withdrawals, excluded observations, or missing outcome measurements, so those group counts should not be treated as an explanation of participant flow.

The primary outcome was difference in change in clinic systolic blood pressure from baseline, measured over 4 weeks. Other posted outcomes concern plasma nitrite concentration, endothelial function, and arterial stiffness, each measured as a change from baseline over the same timeframe. The registry record lists seven outcome measures, but only three secondary outcome results are posted in this record. The trial phase is listed as NA. The registry record does not report the original sample-size justification, a detailed analysis plan, or definitions of the analysis populations.

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:

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 Difference in Change in Clinic Systolic Blood Pressure From Baseline, measured over 4 weeks.

The primary endpoint is the difference between groups in change in clinic systolic blood pressure from baseline over 4 weeks, expressed in mmHg. Each group’s change is reported as a mean with a standard deviation. The comparison then expresses how far apart those mean changes are, with the nitrate-free beetroot juice group subtracted from the beetroot juice group in the posted comparison’s sign convention.

In general, change from baseline summarizes how an outcome moves during a study relative to its starting measurement. Comparing those changes between randomized groups focuses on the contrast associated with assignment, rather than describing change in one group alone. Clinic systolic blood pressure is the specific blood-pressure measure chosen for this outcome. The registry record does not explain why it was selected as the primary endpoint or whether other blood-pressure measures were also collected.

The group means are -8.7 mmHg for beetroot juice and -1.0 mmHg for nitrate-free beetroot juice. The reported mean difference is 7.7 mmHg, with a 95% confidence interval from 3.633 to 11.77 and an unadjusted p-value of <0.001. In the posted comparison’s direction, a positive difference reflects a more negative mean change in the beetroot juice group. These statistics describe the posted endpoint; they do not by themselves establish the cause of the difference or its importance to individual participants.

7. Results Posted in the Registry

• Nitrate-free Beetroot Juice: mean -1.00 versus -8.70 on control; difference 7.70 (95% CI 3.63 to 11.77), standardized effect d = 0.93; 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.

Difference in Change in Plasma Nitrite Concentration From Baseline

• 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 deviations.
• Result:
  • Nitrate-free Beetroot Juice: mean 0.01 versus 0.53 on control; difference -0.52 (95% CI -0.66 to -0.38), standardized effect d = -1.82; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Nitrate-free Beetroot Juice than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Difference in Change in Endothelial Function From Baseline

• 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 deviations.
• Result:
  • Nitrate-free Beetroot Juice: mean 0.10 versus 0.90 on control; difference -0.80 (95% CI -1.30 to -0.30), standardized effect d = -0.79; z-test p = 0.002.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Nitrate-free Beetroot Juice than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Difference in Change in Arterial Stiffness From Baseline

• 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 deviations.
• Result:
  • Nitrate-free Beetroot Juice: mean 0.01 versus -0.59 on control; difference 0.60 (95% CI 0.10 to 1.10), standardized effect d = 0.59; z-test p = 0.019.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Nitrate-free Beetroot Juice than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The secondary outcomes cover plasma nitrite concentration, endothelial function, and arterial stiffness, all reported as changes from baseline over 4 weeks. Taken together, their posted group summaries show a pattern in which changes in the beetroot juice group differ from those in the nitrate-free beetroot juice group across several physiologic measures. This broad pattern accompanies the primary blood-pressure comparison, but the secondary endpoints are distinct outcomes and do not independently establish why the primary difference occurred.

The outcome descriptions align with the registry summary’s interest in nitrate and blood pressure: plasma nitrite relates to the stated nitrate rationale, while endothelial function and arterial stiffness provide additional vascular measurements. Alignment with that rationale is not the same as evidence that one outcome caused another. The record does not report a mediation analysis, an analysis of relationships among outcomes, or a protocol explaining how these outcomes were prioritized relative to one another.

The posted secondary comparisons include unadjusted p-values. Because several outcomes are considered, the chance of at least one result appearing unusual under a null scenario can be greater than for a single planned comparison. Without a reported multiplicity procedure or a clearly documented hierarchy of endpoints, secondary p-values deserve more caution than a result from a single prespecified primary test. This does not make the secondary findings irrelevant; it means they are best regarded as supportive or hypothesis-generating rather than definitive evidence on their own.

The registry lists seven outcome measures, while three secondary outcome results are posted. The remaining outcome results and their analysis details are not reported in the registry record. Selective availability of results can complicate an overall reading, especially when the full outcome set and analysis plan are unavailable. The secondary pattern is therefore informative context for the primary result, but it cannot substitute for a complete account of all planned outcomes and analyses.

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

• Difference in Change in Plasma Nitrite Concentration From Baseline
• Difference in Change in Endothelial Function From Baseline
• Difference in Change in Arterial Stiffness From Baseline

9. Statistical Interpretation

10. Statistical Methods Explained

The posted results use continuous-outcome summaries: a mean change and standard deviation for each group, followed by a mean difference, confidence interval, and unadjusted p-value. The registry record identifies the outcome summary as a mean with standard deviation. The information below explains these statistical concepts generally and how they relate to this trial.

What does a mean change represent?

General: a mean is the arithmetic average across the observations included in a group summary. A mean change describes the average difference between each participant’s follow-up measurement and baseline, according to the outcome definition. The registry title specifies change from baseline, but it does not report the exact calculation procedure for individual participants or the handling of repeated measurements.

The primary means are -8.7 mmHg for beetroot juice and -1.0 mmHg for nitrate-free beetroot juice. A negative value indicates a decrease in the measured outcome as represented by the posted change score. The group summaries alone do not indicate how consistently individual participants changed. For that, the standard deviations provide information about spread around each group’s mean, although they do not show the full distribution.

Why report a standard deviation?

General: a standard deviation describes how dispersed observations are around their mean. Larger values indicate more variability in the observations, while smaller values indicate less. It is not the same as the uncertainty in the mean: uncertainty also depends on how many observations contribute to the estimate. The primary group standard deviations are 8.2 and 8.4 mmHg, with 32 participants in each group’s posted summary.

How should the mean difference be read?

A between-group mean difference subtracts one group’s mean from the other according to a defined ordering. In this comparison, the reported estimate of 7.7 mmHg corresponds to the nitrate-free beetroot juice mean change minus the beetroot juice mean change. Because the beetroot juice group’s mean change is more negative, the estimate is positive under this ordering. Changing the order of subtraction would reverse the sign but would not change the underlying distance between the group means.

The comparison is an average contrast between groups, not a measure of the difference experienced by each individual. In a randomized study, comparing assigned groups is generally the central way to estimate the contrast associated with assignment. The registry record does not state whether the reported analysis followed an intention-to-treat principle or another analysis population, so the precise population represented by the comparison is not reported in the registry record.

What does the confidence interval add?

General: a confidence interval gives a range of values compatible with the observed data under the statistical model and its assumptions. It conveys uncertainty about the estimated group difference, not the range of individual participant outcomes. The primary interval extends from 3.633 to 11.77 mmHg around the estimate of 7.7 mmHg. Its endpoints are not guarantees about where the true effect lies, and the interval does not address bias from missing data, measurement procedures, or analysis choices.

What does the p-value address?

General: a p-value measures how unusual data at least as incompatible with a specified null hypothesis would be if that hypothesis and the statistical assumptions were correct. It is not the probability that the null hypothesis is true, nor does it quantify clinical importance. The posted primary p-value is <0.001 and is explicitly unadjusted. The registry record does not give the test procedure, model details, or any adjustment for multiple comparisons.

Why can variability affect the estimate’s precision?

General: when observations vary more, a group mean or between-group difference is often estimated less precisely, unless additional information or a larger amount of data offsets that variability. This is why the standard deviations and group counts matter alongside the means. In this trial the primary summaries report 32 participants per group and similar standard deviations. The confidence interval incorporates uncertainty under its calculation method, but the record does not report enough methodological detail to verify all assumptions or determine how departures from them would affect the result.

Other statistical details—including the original sample-size calculation, missing-data procedures, covariate adjustment, interim analyses, and analysis-population definitions—are not reported in the registry record. They should not be inferred from the outcome summaries or from the trial’s posted p-values.

11. Confidence Intervals and Precision

The primary mean difference is 7.7 mmHg, with a 95% confidence interval from 3.633 to 11.77. The interval describes uncertainty around the estimated difference in mean change, under the assumptions used to obtain it. It is not an interval containing 95% of individual participants’ changes, and it should not be read as a guarantee that the true difference falls within those limits.

The interval’s lower and upper limits are both positive in the stated comparison direction. Thus, the interval does not include zero. The estimate is also not exact: values across the interval represent differing magnitudes of between-group difference compatible with the calculation. The interval is more informative about precision than the p-value alone, because it conveys both direction and a range of magnitudes.

Precision is distinct from validity and clinical importance. A narrow interval can still be affected by bias if measurements, follow-up, or analysis are problematic; a statistically clear difference does not establish that its magnitude matters to participants. The registry record does not report a threshold for clinical importance, so the interval cannot be classified against such a threshold from this record.

The posted summaries list 32 participants in each group for the primary outcome. The enrollment is 68, and the registry record does not explain the difference between enrollment and the outcome-summary counts. Without participant-flow and missing-data information, it is difficult to assess whether the precision calculation reflects all randomized participants or only those with usable outcome data. The registry record also does not describe the interval calculation method. These omissions limit independent evaluation of how robustly the interval represents uncertainty.

In general, confidence intervals are most useful when considered together with the endpoint definition, group summaries, study design, and analysis choices. Here, they quantify uncertainty around the posted primary mean difference but do not resolve questions about missing observations, multiplicity, generalizability, or the trial’s unreported analysis plan.

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 sample-size figures are planning illustrations based on the observed effect, not the trial’s original design justification. For this continuous-outcome comparison, each figure is a number of participants per arm, not a total across both arms and not a total number of events. The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set to the stated fraction of the observed effect. The original design assumptions are not reported in the registry record.

The 80% power column describes the planned number per arm under those assumptions for a design with an 80% chance of detecting the specified effect if that effect were the true one and the assumptions held. The 90% power column uses the same idea with a higher target probability of detection. These values are prospective planning quantities; they do not describe the probability that this completed trial found a real effect, and this is not observed power.

The rows express planning for 100%, 75%, and 50% of the observed effect. As the effect to detect is made smaller, more participants per arm are required in the illustration. For the primary endpoint, the figures range from 19 and 25 participants per arm for planning at 100% of the observed effect, to 73 and 98 for planning at 50%, for the 80% and 90% targets respectively.

These are conditional illustrations, not proof that the trial was adequately or inadequately planned. The registry record does not report the trial’s own sample-size justification, and the observed effect used as a planning reference may not be a stable estimate for future studies. The values should be read as demonstrations of how assumed effect size and target power influence a planning calculation.

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 = 7.700; pooled standard deviation σ = 8.301.
2. n = 2 × (1.96 + 0.842)² × 8.301² / 7.700² = 18.2, rounded up to 19 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 <- 7.7                      # observed difference in means
sigma <- 8.30060238777885                     # 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(1405898)
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 = 19 (80% power), 25 (90% power)
 75% of observed effect: n per arm = 33 (80% power), 44 (90% power)
 50% of observed effect: n per arm = 73 (80% power), 98 (90% power)
power.t.test: 19.3 
Simulated power at n = 19 per arm: 0.796 (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

The registry record lists a primary outcome and multiple secondary outcomes, but does not report a multiplicity plan. Multiplicity arises when statistical tests are carried out across several endpoints, time points, subgroups, or analytical choices. In general, the more comparisons considered, the greater the opportunity for an apparently strong result to arise by chance. Adjustment procedures or a prespecified hierarchy can address this issue, but no such approach is described in the registry record.

The primary p-value is reported as unadjusted. The secondary p-values are also unadjusted. They should not be interpreted as if each were the sole test conducted in the study. The registry record does not report whether additional analyses were performed but not posted, whether secondary outcomes were exploratory, or whether any outcomes were selected for emphasis after results were known. Those matters are not reported in the registry record.

Missing-data handling is also not described. The primary outcome summaries list 32 participants in each group, while enrollment is listed as 68. The record does not provide a participant-flow account, reasons for any difference in counts, or the number of missing measurements. It also does not say whether missing values were imputed, whether participants with incomplete data were excluded, or how such choices might affect estimates.

The analysis populations are not defined in the registry record. It is therefore not possible to determine from the posted record whether results include all randomized participants, only participants with outcome data, or a different population. The statistical model, any adjustment for baseline measurements or other covariates, and the handling of protocol deviations are also not reported.

These gaps do not demonstrate that the trial’s analyses were inappropriate; they limit what can be independently assessed from the registry record. A detailed protocol and statistical analysis plan, together with participant flow and missing-data reporting, would be needed to evaluate prespecification, multiplicity control, and the consequences of incomplete outcome data.

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 0% reporting threshold.

The registry reports zero serious adverse events among 32 participants at risk in the beetroot juice group and zero among 32 participants at risk in the nitrate-free beetroot juice group. It also reports zero other adverse events among 32 participants at risk in each group. These figures describe events recorded in the registry; they do not establish that no event of any kind occurred outside the reported categories or observation period.

Deaths are not reported in the registry record. The record does not provide descriptions of the adverse-event collection procedures, the period during which events were monitored, or how events were judged to be related to either intervention. It also does not give further detail on event types or severity beyond the serious and other categories.

Zero reported events in these group summaries should be read as a count in this trial’s posted safety record, not as proof that an intervention cannot be associated with an adverse event. The enrollment and outcome-summary counts are not reconciled, and the registry record does not explain whether the safety populations included all enrolled or randomized participants. These limits matter when interpreting the scope of the reported safety information.

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

The primary result is a difference in mean change in clinic systolic blood pressure between two randomized groups over 4 weeks. The mean change was more negative in the beetroot juice group than in the nitrate-free beetroot juice group, and the reported between-group estimate was 7.7 mmHg in the comparison’s stated direction. The confidence interval and unadjusted p-value describe statistical uncertainty and compatibility with a zero difference under the calculation’s assumptions.

The result does not show that every participant experienced the group-average change, nor does it indicate how an individual would respond. Group means do not describe the full distribution of outcomes. The standard deviations show that there was participant-level variation around the means, but the registry record does not provide individual data or subgroup summaries.

The comparison also does not establish a mechanism. The registry summary discusses nitrate as a possible explanation, and plasma nitrite is among the secondary measures, but the posted outcomes do not demonstrate that a change in nitrite caused the blood-pressure difference. The record does not report a mediation analysis or other test of that proposed pathway.

Statistical evidence and clinical importance are separate questions. The registry record does not state a threshold for a clinically important difference, so the posted estimate cannot be judged against such a threshold from this record alone. Nor do the 4-week results establish persistence beyond the measured timeframe. Longer-term outcomes are not reported in the registry record.

Finally, the findings are specific to the trial population, interventions, measurements, and analysis represented in the registry record. Participant characteristics, adherence, missing-data procedures, analysis populations, and the original statistical plan are not reported. These omissions make it difficult to assess how broadly the results apply or how sensitive they may be to study conduct and analysis choices. The posted data describe a group contrast; they do not by themselves settle those broader questions.

17. Why This Trial Matters Statistically

This trial offers a useful statistical example of separating within-group change from a between-group comparison. Both groups had negative mean changes in clinic systolic blood pressure, but the principal question is whether their changes differed. The estimated contrast and its confidence interval address that comparative question more directly than either group’s change considered alone.

The outcome is reported with means and standard deviations, making it possible to distinguish the average change from variation among participants. The confidence interval adds information about uncertainty in the estimated contrast, while the unadjusted p-value provides a test-based summary under a null hypothesis. These measures answer related but different questions and should not be treated as interchangeable.

The record also illustrates why a statistically notable primary result does not resolve every interpretive issue. The study includes several secondary outcomes, yet no multiplicity strategy is reported. Participant counts in the outcome summaries do not match the recorded enrollment, and the record does not explain the difference. Missing-data procedures, analysis populations, and the original sample-size rationale are also not reported. These details affect confidence in the completeness and interpretability of the evidence, even when the point estimate and interval are available.

Finally, the secondary endpoints show how biologically related measures can provide context without proving a causal pathway. A consistent pattern can motivate further inquiry, but it does not replace a prespecified analysis of mechanism or a complete account of all planned outcomes. Statistically, the trial is informative as a comparison of mean changes, while the registry’s reporting gaps place limits on conclusions about robustness, multiplicity, and generalizability.

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 provides limited detail about who participated beyond identifying the study population as hypertensive subjects. It does not report participant demographics, baseline blood-pressure distributions, eligibility criteria, or other characteristics that would help readers judge how closely the trial population resembles a broader clinical population. Generalizability therefore cannot be fully assessed from this record.

Intervention descriptions are brief. The arm descriptions are empty, and the registry record does not report the amount of juice, administration schedule, adherence, or how the nitrate-free comparator was prepared and matched. Although the study is recorded as triple-masked, the parties masked and the procedures used to preserve masking are not reported. These limitations affect assessment of intervention fidelity and potential differences in participant experience.

The registry lists enrollment of 68, while the primary outcome summaries include 32 participants per group. It does not explain this difference or report participant flow, withdrawals, exclusions, or missing measurements. No missing-data procedure or analysis-population definition is given. As a result, the extent to which the summaries represent all randomized participants is unclear.

Only three secondary results are posted despite seven outcome measures being listed. The record does not report a multiplicity procedure, a complete hierarchy of outcomes, or the original statistical analysis plan. It also does not give the primary analysis method in sufficient detail to assess modeling choices, baseline adjustment, or the calculation of uncertainty. The original sample-size justification is not reported, so the planning illustrations should not be mistaken for the trial’s design rationale.

The posted primary outcome covers 4 weeks. Longer-term outcome data are not reported in the registry record. The record also does not report a clinical-importance threshold or explain the intended interpretation of the endpoint. These reporting limitations do not negate the numerical results, but they constrain judgments about their robustness, relevance, and applicability.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: The Chronic Effects of Beetroot Juice in Hypertensive Subjects — NCT01405898.
• Registry record last updated 2016-01-08; status last verified 2015-12.
• Results first posted 2015-12-09.
• 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

NCT01405898, titled “The Chronic Effects of Beetroot Juice in Hypertensive Subjects,” is recorded as a completed randomized, triple-masked, parallel-group trial sponsored by Queen Mary University of London. It lists 68 participants enrolled and compares beetroot juice with nitrate-free beetroot juice.

The primary outcome is difference in change in clinic systolic blood pressure from baseline over 4 weeks. The posted mean changes are -8.7 mmHg and -1.0 mmHg, respectively, with a mean difference of 7.7 mmHg, a 95% confidence interval from 3.633 to 11.77, and an unadjusted p-value of <0.001.

Three secondary outcomes are posted: plasma nitrite concentration, endothelial function, and arterial stiffness. The registry record does not report the original sample-size justification, analysis populations, missing-data procedures, multiplicity approach, or a reconciliation of enrollment with the endpoint summary counts.