Evaluating Novel Approaches for Estimating Awake and Sleep Blood Pressure: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluating Novel Approaches for Estimating Awake and Sleep Blood Pressure (NCT04307004), a randomized na study. The primary outcome is Absolute Difference Between Unattended and Attended Blood Pressure.

2. Clinical Question

3. Trial Design

The registry record describes a completed randomized crossover study of blood pressure measurement approaches. It records enrollment of 654, no masking, and University of Alabama at Birmingham as sponsor. The recorded start date is 2019-07-15 and the primary completion date is 2022-12-12. The record classifies the study phase as not applicable.

The clinic measurement comparison involved attended and unattended readings. The arm description states that participants’ blood pressure was measured three times attended and three times unattended using a Microlife WatchBP Office AFIB device. The order of attended and unattended measurement was assigned using a random number method, although the arm description cuts off before completing its explanation of the assignment process.

A separate study component compared ambulatory blood pressure monitoring (ABPM) with home blood pressure monitoring (HBPM). The record describes use of the Microlife WatchBP O3 for ambulatory monitoring and instructions for use of the Microlife WatchBP Home N for home monitoring. It indicates that the order of these approaches was assigned, but the complete sequence description is not reported in the registry record.

The crossover structure means the study compares measurement approaches within an ordered sequence rather than describing only parallel groups receiving a single approach. In a crossover, order and within-person pairing matter to analysis. The posted primary analyses use paired t tests for attended versus unattended readings. The record does not report the original sample-size justification, details of sequence balancing, an interim-analysis plan, or the statistical plan in enough detail to establish how all analyses were prespecified.

4. Participant Flow and Accounting

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

Before assignment: Of the 1,095 participants screened, 654 met the inclusion criteria and were randomized to either attended (technician present) before unattended (technician absent) blood pressure measurements or unattended before attended blood pressure measurements. The 654 participants were also randomized to undergo either Ambulatory Blood Pressure Monitoring before Home Blood Pressure Monitoring or Home Blood Pressure Monitoring before Ambulatory Blood Pressure Monitoring.

Randomization 1

Reasons for not completing this period:

Randomization 2

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Participants with complete attended and unattended blood pressure data.

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 Absolute Difference Between Unattended and Attended Blood Pressure, measured over 2 days.

The primary endpoint is the absolute difference between unattended and attended blood pressure measurements, in mm Hg, assessed over 2 days. It covers both systolic and diastolic readings. The endpoint description defines the comparison as measurements taken when a technician is present versus when the technician is not in the room, and the stated analysis population is participants with complete data for both approaches.

Comparing the two measurement conditions addresses whether the presence of staff is associated with a different clinic reading. The paired design is relevant because measurements from the same participant are related; the comparison can account for that pairing rather than treating each reading as independent. The posted sponsor analyses report separate paired comparisons for systolic and diastolic blood pressure.

This endpoint is useful for examining the measurement setting, but it is not itself a measure of the accuracy of home monitoring or of how well a clinic measurement represents blood pressure during sleep. Those broader aims are part of the study rationale, while the primary endpoint directly concerns attended versus unattended clinic readings. The registry record does not report an endpoint threshold defining an acceptable difference or a clinical interpretation boundary.

7. Results Posted in the Registry

• Attended Clinic Diastolic Blood Pressure: mean 72.70 versus 119.50 on control; difference -46.80 (95% CI -47.95 to -45.65), standardized effect d = -4.60; z-test p = <0.001.
• Unattended Clinic Systolic Blood Pressure: mean 118.70 versus 119.50 on control; difference -0.80 (95% CI -2.15 to 0.55), standardized effect d = -0.07; z-test p = 0.245.
• Unattended Clinic Diastolic Blood Pressure: mean 72.20 versus 119.50 on control; difference -47.30 (95% CI -48.44 to -46.16), standardized effect d = -4.66; 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.

Left Ventricular Mass Index

• 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:
  • Unattended Before Attended BP: mean 67.10 versus 67.60 on control; difference -0.50 (95% CI -3.30 to 2.30), standardized effect d = -0.03; z-test p = 0.726.
  • ABPM Before HBPM: mean 66.90 versus 67.60 on control; difference -0.70 (95% CI -3.53 to 2.13), standardized effect d = -0.04; z-test p = 0.628.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Unattended Before Attended BP and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between ABPM Before HBPM and the control. The interval gives the range of effects that remain compatible with the data.

Urinary Albumin-to-creatine Ratio

• 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:
  • Unattended Before Attended BP: mean 17.00 versus 21.70 on control; difference -4.70 (95% CI -11.01 to 1.61), standardized effect d = -0.12; z-test p = 0.144.
  • ABPM Before HBPM: mean 19.70 versus 21.70 on control; difference -2.00 (95% CI -9.09 to 5.09), standardized effect d = -0.05; z-test p = 0.580.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Unattended Before Attended BP and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between ABPM Before HBPM and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover left ventricular mass index and urinary albumin-to-creatinine ratio. Across the simple unadjusted comparisons, the estimates are uncertain: their confidence intervals include zero. The general pattern therefore does not provide clear evidence of a difference between the posted comparison groups on these secondary measures.

The registry also reports linear regression results. For left ventricular mass index, the posted regression estimates have confidence intervals that do not include zero and p-values below 0.001, whereas the simple recalculations are less conclusive. For urinary albumin-to-creatinine ratio, the posted regression confidence intervals include zero and the p-values are 0.17 and 0.20. The record does not specify enough about the regression models to explain the divergence between the left ventricular mass index regression results and the simple comparisons. The discrepancy should be kept in view when interpreting the secondary findings.

These secondary measures do not replace the primary clinic blood pressure comparison. They address different outcomes and should be read as supporting or exploratory evidence rather than as confirmation of the primary result. The registry record does not report a hierarchy that would establish how these outcomes were intended to support a primary conclusion.

Unadjusted secondary results carry less inferential weight when many outcomes and analyses are examined. General explanation: testing multiple hypotheses increases the chance that at least one result appears statistically significant by chance, even if no underlying effect exists. Adjustments or a prespecified testing hierarchy can address this issue, but whether either was planned or applied is not reported in the registry record. The secondary results should therefore be interpreted cautiously, especially where the simple and regression analyses differ.

The registry states that the secondary measurements were assessed over 3 days. It does not report the clinical importance thresholds for these measures or provide enough model detail to interpret the regression coefficients as fully adjusted effects. These limitations make the overall direction and consistency of evidence more informative than treating any single secondary p-value as decisive.

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

• Left Ventricular Mass Index
• Urinary Albumin-to-creatine Ratio

9. Statistical Interpretation

10. Statistical Methods Explained

For the primary endpoint, the registry reports paired, two-sided t tests. General explanation: a paired analysis compares two measurements linked to the same participant, such as attended and unattended readings, and focuses on the within-person difference. This accounts for the fact that the two measurements from one person are likely to be related. A two-sided test evaluates evidence of a difference in either direction rather than only a prespecified increase or decrease.

The reported paired analyses give a mean difference, a 95% confidence interval, and a p-value for each blood pressure measure. General explanation: the mean difference describes the average direction and size of the paired contrast. A confidence interval gives a range of values compatible with the data and analysis, subject to the assumptions of the method. A p-value describes how unusual the observed result, or a more extreme one, would be under a model with no average difference. It does not measure the probability that the no-difference model is true, and it does not describe the size or importance of an effect.

The registry also includes recalculated mean-difference comparisons based on posted group means and standard deviations. These are simple unadjusted calculations, not the sponsor’s paired analyses. In this record, the comparison inputs for the primary endpoint pair an attended systolic mean with attended or unattended diastolic means. That mismatch means these recalculations do not represent valid systolic or diastolic comparisons. The record flags a discrepancy, so the sponsor’s own analysis takes precedence.

The registry reports continuous measures as means with standard deviations. General explanation: a standard deviation describes the spread of individual observations around a mean, whereas a confidence interval describes uncertainty in an estimated quantity such as a mean or mean difference. They answer different questions. A broad standard deviation can coexist with a fairly precise estimate of a mean when the analysis includes many observations.

The registry record also posts regression analyses for the secondary outcomes. It identifies them as linear regression and gives beta coefficients with 95% confidence intervals and p-values. The registry does not report sufficient model detail to establish which covariates were included, how the repeated measurement structure was handled, or how the two posted regression results for each secondary endpoint differ. Those details are not reported in the registry record, so the coefficients should be interpreted as the posted model estimates rather than as fully specified adjusted effects.

Statistical significance and precision should be considered separately. General explanation: a p-value can be small even when an estimated difference is modest, particularly when estimates are precise; conversely, an estimate can be uncertain even if its point estimate appears substantial. Confidence intervals help assess both the range of plausible values and the degree of precision. Neither statistic determines clinical importance without a context-specific benchmark.

The record does not report the original sample-size justification, the trial’s planned statistical analysis in full, or whether any interim analyses were conducted. The posted planning illustrations are based on observed effects and stated assumptions; they are not evidence of the original design rationale. The record also does not report whether multiplicity adjustments were planned for the several endpoints and analyses. These missing details limit assessment of the full inferential framework.

Why pairing matters

General explanation: when two approaches are measured on the same person, the within-person contrast can remove some variability attributable to stable differences between people. A paired test uses the variability of those within-person contrasts. If the observations were incorrectly treated as independent, the estimated uncertainty could differ. The registry’s stated paired test is therefore consistent with the crossover nature of the clinic comparison.

Why over-dispersion matters

General explanation: over-dispersion means that observed variability is greater than a statistical model expects. When that occurs, a model that assumes less variability can understate uncertainty and make results appear more precise than they are. The registry record does not identify an over-dispersion assessment or report an over-dispersion issue for these continuous endpoints. The concept is relevant to statistical interpretation generally, but no such conclusion can be drawn for this study from the posted information.

11. Confidence Intervals and Precision

The sponsor-reported systolic estimate is a mean difference of 0.8 mm Hg, with a 95% confidence interval from 0.5 to 1.1. The diastolic estimate is 0.5 mm Hg, with a 95% confidence interval from 0.3 to 0.7. Both intervals are relatively narrow around their respective estimates, indicating precision for the average differences under the reported paired analyses. Both intervals lie above zero, consistent with the reported p-values of < 0.001.

General explanation: a 95% confidence interval is a range produced by a method designed to cover the true parameter in 95% of repeated samples when the assumptions hold. It is not a statement that 95% of individual measurements fall within the interval, nor does it guarantee that the true value is inside this particular interval. The interval is most useful when read alongside the point estimate and the outcome’s units.

The group standard deviations describe variation among measurements, not uncertainty about the average paired difference. The registry does not post a confidence interval for each group mean in the arm results. It does post intervals for the sponsor’s paired differences, which are the relevant estimates for the primary comparison.

Precision of an average difference does not establish that the approaches produce similar readings for every participant. Individual paired differences may vary, and the registry record does not report limits of agreement or another analysis of person-level agreement. It also does not report an acceptable-difference margin. Consequently, the intervals characterize uncertainty in the average contrast, not interchangeability for individual measurements or suitability for a particular decision.

The simple recalculated intervals in the comparison fields should not be used to judge primary-endpoint precision: their inputs mix systolic and diastolic measures. The record flags a discrepancy, and the sponsor’s own paired estimates are the appropriate posted primary results to interpret.

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 illustrations give participants per arm for 80% power and participants per arm for 90% power. They do not give total event counts; the registry’s stated convention is that time-to-event calculations, if present, would report total events, while these non-time-to-event illustrations report participants per arm.

The illustrations use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is expressed as a stated fraction of the observed effect. The planning figures are computed from the observed effect, not from the trial’s original design assumptions; those original assumptions are not reported in the registry record.

In plain terms, the 80% power column gives a planning estimate of participants per arm for a design with an 80% chance of detecting the stated effect under the listed assumptions, if that effect is real and the assumptions hold. The 90% power column applies the same idea with a higher target chance of detection. These are design illustrations, not guarantees about a future study’s performance.

The rows for smaller fractions of the observed effect generally require more participants per arm. This reflects a general statistical principle: smaller differences are harder to distinguish from random variation and usually require more information to detect. The figures are not observed power, and they should not be read as a retrospective measure of how likely this completed study was to detect its results.

These illustrations use simple two-arm planning assumptions, while the primary clinic comparison was analyzed as paired measurements within a crossover study. The registry record does not report the trial’s own sample-size calculation or design assumptions, so the illustrations should not be treated as a reconstruction of the study’s planned enrollment target.

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 = -46.800; pooled standard deviation σ = 10.180.
2. n = 2 × (1.96 + 0.842)² × 10.180² / -46.800² = 0.7, rounded up to 1 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 <- -46.8                      # observed difference in means
sigma <- 10.1796365357512                     # 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(4307004)
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 = 1 (80% power), 1 (90% power)
 75% of observed effect: n per arm = 2 (80% power), 2 (90% power)
 50% of observed effect: n per arm = 3 (80% power), 4 (90% power)
power.t.test: 2.2 
Simulated power at n = 1 per arm: NA (20000 replicates)

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

14. Analyses Reported by the Sponsor

The sponsor-reported primary results are paired, two-sided t tests. They report an attended-versus-unattended mean difference of 0.8 mm Hg for systolic blood pressure, with a 95% confidence interval from 0.5 to 1.1, and 0.5 mm Hg for diastolic blood pressure, with a 95% confidence interval from 0.3 to 0.7. Both reported p-values are < 0.001.

The registry also contains simple unadjusted recalculations from posted summary values. Those comparison fields pair the attended systolic mean of 119.5 with diastolic means of 72.7 and 72.2. Since systolic and diastolic blood pressure are different measures, these calculations do not provide valid estimates of either primary paired contrast. This is the discrepancy flagged in the registry record.

The sponsor’s analysis takes precedence for the primary result. It uses paired tests, consistent with comparing attended and unattended readings from the same participants, and its reported contrasts align with the displayed group means. The recalculated values should not be substituted for the sponsor’s endpoint-specific paired estimates.

The registry record does not provide enough detail to independently reproduce the sponsor’s paired tests from individual-level data, nor does it report all analysis specifications. The posted sponsor results can therefore be described, but the record does not support a full audit of the analysis.

15. Multiplicity, Missing Data and Analysis Populations

The registry record lists multiple outcome measures and analyses, including two primary blood pressure measures and secondary outcomes. It does not report whether a multiplicity adjustment, a hierarchical testing strategy, or another method for controlling the overall false-positive risk was prespecified or used. Without that information, individual p-values should not be interpreted as if they arose from a single isolated test.

General explanation: when many statistical tests are conducted, the chance of at least one nominally significant result can increase. Multiplicity procedures can adjust the evidence threshold or order testing according to a prespecified hierarchy. Whether such procedures are appropriate depends on the study’s aims and analysis plan. The registry record does not provide enough information to determine the intended approach.

The primary endpoint population is described as participants with complete attended and unattended blood pressure data. The posted group results show 603 observations for each of the four clinic measurement groups. The record does not explain why other enrolled participants are not represented in those endpoint results, whether the same participants contribute to every group, or how any missing readings were handled.

The secondary endpoint results include group counts that differ by outcome and comparison. The registry record does not report reasons for missing secondary measurements, whether missingness was assessed, or whether any imputation or sensitivity analyses were performed. It also does not provide a complete analysis-population definition for each secondary analysis.

These omissions matter because missing data and analysis-population choices can affect both estimates and uncertainty. The registry record does not report a full statistical analysis plan, the original sample-size justification, or details of interim analyses. Those aspects should be treated as not reported in the registry record rather than inferred from the posted outcome results.

16. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports zero serious adverse events and zero deaths in each of the four listed sequence groups. The numbers at risk are 326 for attended before unattended blood pressure, 328 for unattended before attended blood pressure, 330 for ABPM before HBPM, and 324 for HBPM before ABPM.

For other adverse events, the clinic measurement sequence groups each have zero affected participants in the posted figures. In the monitoring sequence groups, 228 participants are reported as affected in the ABPM-before-HBPM group and 244 in the HBPM-before-ABPM group. These are registry counts; the record does not identify the specific types, severity, timing, or attribution of those other events in the information posted.

Zero reported serious events in these groups means none were recorded in the registry’s serious-event counts. It does not establish that no event could occur, and it does not provide a comparison of risks adjusted for exposure or follow-up. The record does not report event definitions, follow-up duration for safety, or a detailed account of how adverse events were collected.

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

The primary result describes a small average difference between attended and unattended clinic blood pressure readings in this study. The sponsor-reported paired comparisons show estimates above zero for both systolic and diastolic measurements, with confidence intervals that are relatively narrow and p-values below < 0.001. The result is evidence about the average paired readings in the posted analysis population.

It does not mean that every participant had the same difference, or that the readings were interchangeable for each person. The registry record does not report limits of agreement, the distribution of individual paired differences, or a threshold for an acceptable difference. Average differences alone cannot answer those questions.

The primary result also does not establish the accuracy of home blood pressure monitoring for awake or asleep blood pressure. Nor does it establish that home monitoring can replace ambulatory monitoring. Those questions appear in the study rationale, but the primary endpoint is the attended-versus-unattended clinic comparison. The posted record includes separate monitoring arms and secondary outcomes, but it does not provide a primary result in the information presented that directly resolves those broader questions.

Statistical significance is not the same as clinical importance. The reported p-values indicate evidence against a zero average difference under the paired-test assumptions; they do not determine whether the observed mean differences matter for a particular clinical purpose. The registry record does not report a clinical threshold or decision rule for interpreting the size of the difference.

The results should also be read with the record’s data limitations in mind. The simple recalculated primary contrasts mix systolic and diastolic group means, and the record flags a discrepancy. The sponsor’s paired analyses take precedence. Details of missing data, multiplicity handling, and the full statistical plan are not reported in the registry record.

18. Why This Trial Matters Statistically

This study is statistically interesting because it compares measurement procedures, not only clinical treatments. The attended and unattended readings are paired within a crossover framework, so the analysis needs to respect the relationship between measurements from the same participant. The sponsor’s paired t tests reflect that feature of the primary comparison.

It also illustrates why the match between an endpoint and its calculation matters. The primary endpoint distinguishes systolic from diastolic pressure, but the registry’s simple recalculated contrasts combine a systolic reference mean with diastolic comparison means. Those figures cannot answer the endpoint-specific questions. Recognizing that mismatch prevents an invalid arithmetic contrast from being mistaken for a clinical finding.

The posted confidence intervals add information beyond the p-values. They show the range of uncertainty around average paired differences and help readers distinguish precision from importance. At the same time, average differences do not describe the agreement of measurements for individual participants, a separate statistical question that the registry record does not report.

Finally, the study’s broad motivation concerns ways to assess awake and asleep blood pressure with less burden, while its primary endpoint is narrower: attended versus unattended clinic measurement. Keeping that distinction clear prevents a result about clinic measurement conditions from being extended to claims about home monitoring or ambulatory monitoring that the primary analysis does not directly test.

19. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry’s arm description for the clinic order ends before fully explaining the randomization procedure. The description of the ABPM and HBPM order is also incomplete. The record identifies the study as randomized and crossover, but does not report enough detail to assess sequence generation, concealment, or handling of possible order effects.

The primary endpoint population is defined as participants with complete data for both clinic measurement conditions, but the registry does not explain missing readings or the relationship between enrollment and endpoint analysis. Reasons for missing data and methods for handling them are not reported in the registry record.

The posted primary sponsor analyses are paired, but detailed model assumptions and diagnostic checks are not reported. The record also does not provide a clinical threshold for an acceptable attended-unattended difference or an individual-level agreement analysis. Thus, the average contrasts do not establish participant-level interchangeability.

The registry flags a discrepancy because its simple recalculated comparisons combine systolic and diastolic summary means. The sponsor’s own paired analyses take precedence, but the record does not include participant-level data that would allow independent reproduction. For secondary outcomes, model details are limited and some posted regression findings differ from simple unadjusted comparisons.

Finally, the registry does not report the original sample-size justification, a full statistical analysis plan, multiplicity procedures, or whether interim analyses occurred. These omissions constrain evaluation of prespecification and the strength of secondary inferences. They should not be filled in by assuming a conventional protocol.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Evaluating Novel Approaches for Estimating Awake and Sleep Blood Pressure — NCT04307004.
• Registry record last updated 2024-12-13; status last verified 2024-12.
• Results first posted 2024-12-12.
• 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.

23. Record Summary

The Better BP Study is a completed randomized crossover study sponsored by University of Alabama at Birmingham, with enrollment of 654 and no masking recorded. It examined attended and unattended clinic blood pressure measurement and compared approaches involving ambulatory and home monitoring.

The primary endpoint was the absolute difference between attended and unattended systolic and diastolic readings among participants with complete data. Sponsor-reported paired analyses show mean differences of 0.8 mm Hg systolic and 0.5 mm Hg diastolic, with 95% confidence intervals above zero and p-values < 0.001.

The registry flags a discrepancy in simple recalculated comparisons because the listed inputs mix systolic and diastolic means; the sponsor’s paired analyses take precedence. Secondary findings, safety counts, missing-data details, and statistical-plan information should be interpreted in light of the limits described in the registry record.