Improving BP Control in Diverse Populations Using BP MAP: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Improving BP Control in Diverse Populations Using BP MAP (NCT03818659), a randomized na study. The primary outcome is Change in Blood Pressure Control, % of Patients.

2. Clinical Question

The study focused on a quality-improvement program intended to support accurate measurement, timely action, and partnership with patients. The registry describes the trial as comparing the effectiveness of BP lowering from Full Support with a Self-Guided version of the program. Its primary outcome was the change in the proportion of patients whose blood pressure met the registry’s definition of control.

Assignment was randomized at the cluster level, with clinics as the unit of measure. This matters to the question: the comparison is between clinic-level changes, not a simple comparison of independent individual patients. The record also describes a comparison with non-participating Usual Care institutions, but identifies those comparisons as non-randomized. The randomized Full Support versus Self-Guided comparison is therefore distinct from the Usual Care comparison.

The registry record does not report estimates of change, a between-arm effect, or uncertainty around that effect. It therefore does not establish how the observed changes compared across the two randomized approaches.

3. Trial Design

The registry describes BP-MAP as a cluster randomized controlled trial with parallel groups and no masking. The randomized intervention groups were Full Support and Self-Guided. The record also describes Usual Care institutions as a non-randomized comparison group; those institutions were not part of the randomized comparison as described in the registry.

In the Full Support group, clinics were to receive online access to M.A.P. materials, an orientation webinar, and a Practice Change Facilitator. The facilitator was to support clinic staff, site champions, and physician leads over 6 months. In the Self-Guided group, clinics were to receive access to a web platform containing M.A.P. materials and limited access to AMA staff who could answer questions. The record describes the American Medical Association as the developer of the intervention framework.

The stated enrollment is 1,238,835. Because the registry identifies the clinic as the unit of measure, this enrollment figure should not be read as the number of randomized clinics. The number of clinics assigned to each group is not reported in the registry record. The record names hypertension as the condition and indicates that all patients with hypertension at included clinics were used to evaluate the metrics.

The study is marked completed. Its recorded start date is 2019-07-01, and its primary completion date is 2021-02-28. The primary outcome was assessed at baseline and 6 months after the intervention began. The registry does not report the number of clinics retained through follow-up, the duration of follow-up beyond that primary time point, or details of intervention adherence.

The registry record does not report the randomization method, allocation concealment, cluster eligibility criteria, or the statistical plan. It also does not report whether other aspects of care differed between groups. These omissions limit what can be concluded about implementation and the conduct of the comparison from the record alone.

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: 24 clinic leaders agreed to participate in a BP control quality improvement program and 24 clinics were randomized and assigned to one of the intervention arms. We included 18 PCORnet clinics in our Blood Pressure Control Laboratory Surveillance Program (BP Track) for our control arms. No individuals were consented. This study was exempt from IRB review as a quality improvement program not human subjects research.

Overall Study

Analysis population for the primary outcome, as defined in the registry: The unit of measure in this study is a clinic. All patients with hypertension at each of the included clinics were analyzed and used to evaluate the numerator and denominator for each metric.

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.

Population: The unit of measure in this study is a clinic.

6. Primary Endpoint

The registry lists the primary outcome as Change in Blood Pressure Control, % of Patients, measured over baseline and 6 months.

The primary endpoint was clinic-level change in the percentage of patients with controlled blood pressure from baseline to 6 months after the intervention began. Control was defined as systolic blood pressure <140 mmHg and diastolic blood pressure <90 mmHg. The registry specifies measurements at the most recent ambulatory clinical encounter at each time point, using the lowest systolic and diastolic measures from that encounter.

This endpoint expresses control as a proportion rather than as a mean blood pressure. It is intended to describe how often patients at a clinic meet the stated threshold, making the measure relevant to a program aimed at changing clinic processes and patient management. General statistical context: a proportion can be easy to interpret as a frequency, but it does not show how far readings lie above or below the threshold, and a change in the proportion can reflect different patterns of readings.

The registry lists the primary measure as a mean with a 95% confidence interval. In general, a confidence interval describes statistical uncertainty around an estimate under the analysis assumptions; it is not a guarantee that the true value lies within the interval. The registry record does not report the estimated changes, confidence interval limits, or a treatment contrast. Thus, the endpoint definition is available, but its observed result and precision are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a randomized, parallel, cluster trial with no masking. General statistical context: in a parallel trial, groups are compared over the same study period, while cluster randomization assigns groups of participants—here, clinics—rather than individual patients. The clinic is also the stated unit of measure for the primary outcome. This alignment is important because the assignment and the outcome summary operate at the clinic level.

Cluster designs require analysis methods that reflect the grouping of patients within clinics. General statistical context: outcomes within a clinic can be more alike than outcomes from different clinics. This within-clinic similarity is called intracluster correlation. If it is ignored, the apparent amount of independent information may be overstated and uncertainty may be understated. The registry record does not report the method used to account for clustering, the number of clinics, or the degree of within-clinic correlation.

The primary endpoint is a change in a percentage. At each time point, the registry defines the percentage from eligible patients whose systolic pressure is <140 mmHg and diastolic pressure is <90 mmHg, based on the most recent ambulatory encounter and the lowest measures at that encounter. General statistical context: a change score compares a measure at follow-up with its baseline value. A between-group comparison of change is different from asking whether either group changed on its own; both the change and its uncertainty matter when evaluating a comparative effect. The registry does not report those estimates.

The record describes a mean and a 95% confidence interval for the primary outcome. General statistical context: the mean is a summary of a measured quantity, while a confidence interval communicates uncertainty in an estimate under the assumptions of the analysis. A narrow interval generally indicates more precision than a wide one, but precision alone does not determine whether an effect is important. Neither the estimate nor the interval limits are reported in the registry record.

The trial’s clinic-level outcome and cluster assignment call for care when interpreting standard errors and tests. General statistical context: standard errors quantify sampling uncertainty; confidence intervals and hypothesis tests rely on those standard errors and on assumptions about the analysis. In cluster-randomized studies, appropriate methods may account for clustering through a model or a design-based approach. The particular approach, covariates, and test used are not reported in the registry record, so they cannot be evaluated from this information.

The record lists a range of secondary outcomes, including change in the proportion of patients with improved blood pressure control, repeat measurement at visits, medication intensification, systolic pressure reduction after intensification, follow-up within 4 weeks after elevated blood pressure, use of specified medication combinations or classes, and terminal-digit-zero measurements. These outcomes address different clinical processes and measurement patterns. General statistical context: each outcome has its own definition and scale, and estimates should be interpreted in relation to that definition. The registry lists ten outcome measures overall but reports zero analyses, so no secondary-outcome result is available to interpret.

When many outcomes are tested, the chance of at least one apparently unusual result can increase. General statistical context: multiplicity procedures can adjust inference across a family of comparisons, while a prespecified hierarchy can distinguish primary from secondary questions. The registry record does not report whether multiplicity was addressed, whether a testing hierarchy was specified, or whether the secondary outcomes were intended for confirmatory or exploratory interpretation.

Missing data also matter for a change outcome because measurement at both baseline and follow-up may be needed. General statistical context: missingness can reduce precision and can bias an estimate when availability of measurements is related to the outcome or intervention. Analyses may use different assumptions or methods to address missing values, and sensitivity analyses can assess how conclusions depend on those choices. The record does not report missing-data counts, handling methods, or sensitivity analyses.

The registry does not report analysis populations, such as whether clinics and patients were analyzed according to their randomized assignment. Nor does it describe protocol deviations, intervention uptake, or exclusions from the primary analysis. Those details would help readers assess whether the reported estimate—if available—reflects the intended randomized comparison.

The record includes a description of sample-size illustrations based on an observed effect, with stated planning assumptions. General statistical context: such illustrations are prospective planning scenarios, not observed power and not evidence that a trial detected an effect. No numerical illustration results or trial-specific sample-size justification are reported in the registry record. The illustrations therefore cannot establish the study’s original design rationale or the precision of its findings.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists ten outcome measures, including the primary blood pressure control endpoint and secondary measures spanning clinical processes and measurement practices. It does not report an analysis for any of them: the number of analyses is listed as zero. No outcome estimates, confidence intervals, or p-values are reported in the registry record.

General statistical context: when several outcomes or comparisons are tested, multiplicity can make chance findings more likely across the full set. Interpretation may depend on whether outcomes were prespecified as primary or secondary, whether a testing hierarchy was used, and whether any adjustment was made. The registry identifies a primary endpoint and secondary outcomes, but does not report a multiplicity strategy or the intended inferential status of the secondary outcomes.

The registry record does not report the amount or pattern of missing outcome data. It also does not describe how missing measurements or incomplete follow-up were handled, whether sensitivity analyses were conducted, or how the analysis population was defined. These are important details for a change endpoint assessed at baseline and 6 months. General statistical context: missingness can affect both precision and the interpretation of a change estimate, depending on why measurements are absent and what assumptions are used in the analysis.

The number of clinics assigned or included in each analysis, clinic-level attrition, patient-level exclusions, and adherence to assigned intervention are not reported in the registry record. Without these details, it is not possible to assess the completeness of follow-up or how closely any analysis—if reported elsewhere—would correspond to the randomized groups.

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

The registry record establishes that a cluster-randomized, parallel comparison of Full Support and Self-Guided BP-MAP was planned, and it defines the primary endpoint as clinic-level change in blood pressure control from baseline to 6 months. It also describes non-randomized comparisons with Usual Care institutions. These design and endpoint details explain the intended questions, but the record does not report results with which to answer them.

No estimate of change, between-group contrast, confidence interval, or test result is reported in the registry record. As a result, the direction, magnitude, and precision of any difference between the randomized groups cannot be determined from this record. The completed study status does not itself indicate whether the intervention groups differed or whether any change was large or small.

The listed secondary outcomes do not establish that the corresponding care processes changed. Likewise, the adverse-event entries of zero at risk and zero affected in each group do not demonstrate absence of events, because the record supplies no usable at-risk denominator for interpreting those entries.

General statistical context: an estimate describes the observed effect in the analyzed data, and its uncertainty helps show how compatible the data are with a range of effects under the analysis assumptions. Neither an estimate nor a confidence interval alone establishes causation beyond the design and analysis limitations. For the non-randomized Usual Care comparisons, differences between participating and non-participating institutions could also complicate interpretation.

The record therefore supports conclusions about the study’s stated design, interventions, population framing, and endpoint definition. It does not support a claim that either approach did or did not change blood pressure control, nor does it allow assessment of the size or reliability of an effect.

12. Why This Trial Matters Statistically

This trial is statistically notable for assigning clinics rather than individual patients. That design matches an intervention delivered through clinic systems and staff, but it also changes how evidence must be analyzed. General statistical context: clustered outcomes can share within-clinic patterns, so valid uncertainty estimates need to reflect the assignment unit and the dependence among patients treated at the same clinic.

The primary endpoint also connects a clinic-level intervention to patient measurements. It summarizes the proportion meeting a specified blood pressure threshold at baseline and at 6 months. This offers an interpretable measure of control, while leaving open other questions, such as how readings are distributed around the threshold. The registry’s focus on the clinic as the unit of measure makes it important to distinguish patient-level counts used to form a metric from the unit used for assignment and comparison.

The record further distinguishes randomized intervention groups from non-randomized Usual Care institutions. That distinction matters because the strength of causal interpretation differs across comparison types. General statistical context: random assignment supports a more direct comparison of assigned groups, whereas observational comparisons can reflect differences in who participates and how institutions operate.

These features make transparent reporting of cluster counts, analysis methods, uncertainty, missing data, and outcome estimates especially useful. Those details are not reported in the registry record. The statistical importance of the trial’s design can therefore be described, but its quantitative findings cannot be evaluated from this record.

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 principal limitation for interpreting results is that the registry record does not report primary or secondary outcome estimates, confidence intervals, or test results. It lists zero analyses, so the record cannot establish the size, direction, or precision of the randomized comparison.

Several design and analysis details are also not reported in the registry record: the number of clinics, the number assigned to each group, the randomization procedure, the method used to account for clustering, and the analysis population. These details are particularly relevant because the trial randomized clinics and used clinic-level measures. Without them, readers cannot assess the statistical handling of the design or the amount of independent information contributing to an estimate.

The record does not describe missing-data handling, clinic or patient attrition, intervention adherence, protocol deviations, or sensitivity analyses. It also does not report whether multiplicity was addressed across the listed secondary outcomes. Each omission limits assessment of how complete and robust any results might be.

The Usual Care comparison is described as non-randomized, so it should not be treated as equivalent to the randomized Full Support versus Self-Guided comparison. The registry does not provide details needed to assess comparability between participating clinics and non-participating institutions.

Finally, adverse-event entries list zero participants at risk in each group. These entries do not provide an interpretable basis for concluding that no events occurred. The registry record does not report further adverse-event information.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: Improving BP Control in Diverse Populations Using BP MAP — NCT03818659.
• Registry record last updated 2025-03-03; status last verified 2025-02.
• Results first posted 2025-03-03.
• 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.

17. Record Summary

The registry describes NCT03818659, “Improving BP Control in Diverse Populations Using BP MAP,” as a completed, parallel cluster-randomized trial with no masking. It lists hypertension as the condition, University of California, San Francisco as the sponsor, and enrollment of 1,238,835. The recorded start date is 2019-07-01 and the primary completion date is 2021-02-28.

The randomized intervention groups were Full Support and Self-Guided versions of the M.A.P. BP Improvement Program. The registry also describes non-randomized comparisons with non-participating Usual Care institutions. The primary endpoint was clinic-level change in the percentage of patients with controlled blood pressure from baseline to 6 months, using systolic blood pressure <140 mmHg and diastolic blood pressure <90 mmHg.

The record lists ten outcome measures and zero analyses. It does not report outcome estimates, confidence intervals, or test results. Consequently, the registry record describes the design and planned measures but does not provide quantitative findings for evaluating the intervention comparison.