Connected Health Blood Pressure Monitoring In Stroke and TIA Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Connected Health Blood Pressure Monitoring In Stroke and TIA Patients (NCT02450760), a randomized na study. The primary outcome is Adherence With Home Blood Pressure Monitoring, Defined by the Proportion of Home Blood Pressure Recordings Successfully Completed.

2. Clinical Question

This was a pilot question about adherence to monitoring, not a direct test of whether blood pressure control or clinical outcomes improved. Blood pressure change and health-care use were among the secondary outcomes, but the principal comparison concerned completion of requested home readings. The randomized allocation makes the arm comparison relevant to the effect of assignment in this trial, while the pilot size and the way outcomes are reported limit how precisely the results characterize that comparison.

3. Trial Design

The registry record describes a randomized, parallel-group study with no masking. It lists an enrollment of 33 and a completed status. The recorded start was 2015-11 and primary completion was 2018-07. The sponsor was the University of Pennsylvania. The phase is listed as NA.

Participants received a home blood pressure cuff and instructions to measure blood pressure twice daily for 90 days. The control description includes automated alerts when a reading was missed and weekly emails with blood pressure data. In the social incentive arm, participants identified a social supporter who could help them adhere to daily readings; the brief study description says the supporter received updates about adherence and average blood pressure by email and/or text message. The exact wording in the arm descriptions is incomplete in the registry record, so details beyond those stated are not reported in the registry record.

The primary outcome was assessed among all enrolled subjects. Although the outcome timeframe is listed as 90 days, the registry explanation says participants were enrolled for 90 +/- 7 days and the percentage calculation was made at day 83 rather than day 90. This timing detail matters when interpreting the endpoint: it is a measure of completed recordings at the specified assessment point, not a report of every reading over an identical calendar interval for every participant.

The record lists secondary outcomes involving systolic blood pressure change, physician and emergency department visits, medication changes, and participants’ perceptions of the device and monitoring. A full statistical analysis plan, details of allocation concealment, and a sample-size justification for the trial are not reported in the registry record. The sample-size illustrations associated with posted results are based on observed effects and are not the trial’s design justification.

4. Participant Flow and Accounting

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

Overall Study

Analysis population for the primary outcome, as defined in the registry: All enrolled subjects

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 Adherence With Home Blood Pressure Monitoring, Defined by the Proportion of Home Blood Pressure Recordings Successfully Completed, measured over 90 Days.

The primary endpoint is the percentage of requested home blood pressure measurements successfully completed. It describes adherence to the monitoring schedule rather than the blood pressure level itself. The registry reports the outcome as a median with an inter-quartile range, using all enrolled subjects, over a 90-day timeframe. The description clarifies that the calculation was completed at day 83 because enrollment lasted 90 +/- 7 days.

Recording completion is a practical endpoint for a pilot study whose stated goal was to assess adherence to home monitoring and whether a social incentive might improve that adherence. It captures whether participants returned the requested measurements through the monitoring process. It does not by itself establish whether recorded readings were accurate, whether blood pressure was controlled, or whether care decisions or health outcomes changed.

The posted medians were 40.0% in control and 60.0% in the social incentive arm. The inter-quartile ranges were 16.0 to 73.0 and 31.0 to 91.0, respectively. These ranges indicate substantial spread in the observed completion percentages within each arm. The reported arm comparison used a Wilcoxon (Mann-Whitney) test and had p = 0.29. The registry record does not report a confidence interval for the difference between arms, so the precision of a direct treatment contrast cannot be read from a reported interval.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Why report a median and inter-quartile range?

General statistical explanation: A median describes the middle observation after values are ordered. It is less influenced than a mean by a small number of unusually high or low values. The inter-quartile range describes the interval from the lower to the upper quartile, covering the middle half of the observations. It gives information about variability without assuming that the outcome follows a symmetric distribution.

That summary is pertinent to an adherence percentage, where participants may have very different completion patterns. In this trial, each arm’s reported inter-quartile range is wide, so the arm median alone does not convey all of the variation among participants. The registry gives no standard deviation for the primary outcome; that is not needed to interpret the reported median and inter-quartile range.

What does the Wilcoxon (Mann-Whitney) test assess?

General statistical explanation: The Wilcoxon (Mann-Whitney) test compares the ordering of observations in two independent groups. It is often used when a continuous outcome is summarized with medians or when a normal-distribution model for the raw values is not suitable. Its direct test concerns the distributions or ranks; interpreting it strictly as a test of medians requires additional assumptions about the shapes of the group distributions.

The registry names this method for the primary comparison and reports p = 0.29. No test statistic, confidence interval, or more detailed specification of the test is reported in the registry record. The p-value is therefore interpreted as the result of the reported comparison, not as a measure of the size of the difference or its practical importance.

How should a p-value be understood?

General statistical explanation: A p-value is calculated under a null hypothesis and a statistical model. It indicates how unusual data at least as incompatible with that null would be under those assumptions. It does not give the probability that the null is true, and a value that does not cross a chosen threshold does not demonstrate equality. Nor does a small p-value alone establish that an effect is large or consequential.

The registry does not state a primary significance threshold or provide a full statistical plan. Consequently, the reported p-value can be described, but claims about prespecified thresholds, multiplicity handling, or other testing choices are not reported in the registry record.

What do the secondary-outcome calculations add?

General statistical explanation: The posted secondary comparisons include means and standard deviations for systolic blood pressure change, and counts for participant perceptions. A mean difference expresses the difference between two group averages. A confidence interval expresses a range of values compatible with the data and model at the stated confidence level; a wide interval indicates limited precision. For binary outcomes, a risk difference expresses a difference in the proportions with the event. These estimates are unadjusted recalculations from posted summary statistics, rather than replacements for the sponsor’s reported tests.

For systolic blood pressure change, the posted means were 3.1 mm Hg in control and 2.7 mm Hg in the social incentive arm, with standard deviations of 14.0 and 14.6. The recalculated mean difference was -0.4 mm Hg, with a 95% confidence interval from -10.18 to 9.382 and an unadjusted p-value of 0.936. The sponsor-reported test was a two-sided t-test with p = 0.95. The values describe an imprecise comparison in this small study; the interval spans effects in either direction.

For the perception outcomes, the recalculated risk differences and confidence intervals are based on the posted event counts and group sizes. The small denominators make these comparisons imprecise. The sponsor reported chi-squared tests. Because the recalculated estimates and reported tests need not use identical procedures, they should be kept distinct when interpreting the record.

What are planning sample sizes?

General statistical explanation: Sample-size calculations estimate how many participants might be required to detect a specified effect under stated assumptions. The posted planning illustrations use the observed effect or stated fractions of it, a two-sided significance level of 0.05, equal allocation, and a normal approximation. They are planning illustrations, not observed power and not evidence about what the trial was designed to detect. The trial’s own sample-size justification is not reported in the registry record. Observed power should not be inferred from the trial’s outcome or p-values.

Planning calculations based on effects observed in a small pilot can be unstable: the observed effect may be unusually large or small, and a near-zero estimate can produce very large planning requirements. Such figures are conditional on their assumptions and should not be treated as a forecast of a definitive study’s result. They do not change the interpretation of the data actually observed in this randomized pilot.

10. Analyses Reported by the Sponsor

The registry reports the sponsor’s primary comparison as a Wilcoxon (Mann-Whitney) test with p = 0.29. It also posts the arm medians and inter-quartile ranges, but no sponsor-reported confidence interval or numerical estimate of the between-arm contrast. The descriptive summaries and the reported test are therefore the direct basis for interpreting the primary result.

For systolic blood pressure change, the sponsor-reported two-sided t-test had p = 0.95, while the simple unadjusted recalculation from the posted group summaries gives p = 0.936 and a mean difference of -0.4 mm Hg. These are not identical values. The recalculation is based on posted summary statistics and is not a substitute for the sponsor’s own analysis; the sponsor’s result should be treated as the reported trial analysis.

For the posted binary perception outcomes, sponsor-reported chi-squared p-values and unadjusted recalculations are also presented through different statistical summaries. In particular, a recalculation from aggregate counts does not establish that the sponsor used the same model or assumptions. The registry record does not provide enough methodological detail to explain any difference between those results. The recalculations are useful as transparent, simple checks, but they do not supersede the sponsor-reported analyses.

The registry record does not report a full statistical analysis plan that would clarify all model specifications, missing-data rules, or planned contrasts. No discrepancy flag is recorded for these recalculations. Regardless, they remain unadjusted analyses of posted summaries and should be interpreted as supplementary rather than as the trial’s official inferential results.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists multiple secondary outcomes, including blood pressure change, physician visits, emergency department visits, medication changes, and participant perceptions. It also reports multiple analyses. Testing several outcomes raises a multiplicity issue: even if no true differences exist, a larger collection of tests can produce apparently notable results by chance. General statistical explanation: A prespecified hierarchy or adjustment can help control interpretation across multiple tests, but the registry record does not report whether such a plan was used. It is therefore not possible to determine whether the secondary analyses were intended as confirmatory, exploratory, or both.

The primary endpoint is described as applying to all enrolled subjects, but the registry record does not report a detailed missing-data method, the amount of missing primary outcome data, or whether all enrolled participants contributed to the posted arm summaries. The endpoint is defined by completed readings, so missed monitoring is part of the measured adherence outcome; that is distinct from missing or unavailable outcome data in the analysis itself. The record does not clarify how those situations were distinguished or handled.

Analysis populations are also not described in detail beyond “all enrolled subjects” for the primary outcome. The secondary summaries have different participant counts, but the registry does not explain the reasons for those analysis-set sizes. No imputation strategy, sensitivity analysis, or rule for excluding participants is reported in the registry record. These omissions make it difficult to assess whether the posted results could be affected by incomplete observations or differences in outcome availability between arms.

The registry describes randomized allocation but does not report the allocation-generation method, concealment procedures, or whether the analyses followed assigned groups regardless of monitoring behavior. These details should not be inferred. The registry record also does not report interim analyses or a complete statistical analysis plan. As a result, the timing and prespecification of all analyses cannot be assessed from the registry information alone.

12. 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.

The registry’s adverse-event summary lists 15 control participants and 18 social incentive participants at risk for serious adverse events. It records zero affected participants in each group and zero deaths in each group. It also records zero affected participants for the other adverse-event category in both groups. No serious adverse-event terms are listed.

These entries mean that no events in the listed categories were recorded in the posted summary during the recorded study period. They do not establish that the risk of an event is zero, or that the arms have equivalent safety. With a small number of participants, a count of zero provides limited information about uncommon events. The registry record does not provide additional detail about event definitions, collection procedures, severity gradings, or the period over which every event was monitored.

Safety counts should be read alongside the study’s scale and purpose. This was a pilot monitoring study, and the adverse-event figures are descriptive rather than a precise comparison of risks. They do not establish a broader safety profile for the intervention or device.

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

The result shows that participants assigned to the social incentive arm had a higher observed median percentage of requested home blood pressure recordings completed than participants assigned to control. The reported test did not provide strong statistical evidence of a between-arm difference, and the broad inter-quartile ranges indicate substantial variation among participants. With no reported confidence interval for the primary contrast, the registry does not quantify the uncertainty around a direct difference estimate.

This result does not show that the two approaches are equivalent. A non-significant test cannot establish that any difference is absent, particularly in a pilot with 33 enrolled participants and varied adherence. Conversely, the higher observed median in the social incentive arm is not, by itself, proof that the social incentive caused higher adherence. Randomization supports a comparative design, but precision, implementation, missing-data handling, and the full analysis plan affect what can be concluded.

The endpoint is adherence to home monitoring, not blood pressure control. The primary comparison therefore does not establish whether either group achieved controlled blood pressure, whether clinical care changed, or whether health outcomes improved. The listed secondary outcomes address some related questions, but their results are exploratory and do not make the primary endpoint a clinical outcome.

The registry record supports a cautious description of a pilot comparison: observed completion percentages differed in their medians, while the reported test was inconclusive. It does not provide a definitive estimate of the effect of social incentives in a wider population, a basis for clinical recommendations, or evidence about long-term outcomes. Further interpretation would require details not reported in the registry record, including the full analysis plan and handling of missing data.

14. Why This Trial Matters Statistically

This trial is statistically useful because it makes adherence itself an outcome. In a home monitoring study, the number of readings actually completed is central to understanding whether a monitoring process is feasible. Measuring completion directly distinguishes the practical behavior of recording readings from the separate question of whether blood pressure changes.

The comparison also illustrates why a difference in sample medians should be interpreted alongside the spread of the observations and the inferential test. The two arms’ inter-quartile ranges are broad, and the reported p-value does not establish a clear difference. A pilot can reveal patterns worth examining, but its estimates may be imprecise and should not be treated as stable population effects.

The registry record is also a reminder that outcome timing needs careful reading. The primary outcome is labeled as a 90-day measure, while the description says the calculation was completed at day 83 because participants were enrolled for 90 +/- 7 days. That qualification helps define what the adherence summary represents.

Finally, the study shows the value of distinguishing sponsor-reported analyses from simple recalculations of posted summaries. Recalculations can make effect estimates and uncertainty more explicit, but they are not a substitute for a full analysis plan or the sponsor’s analysis. The record’s omissions about missing data, multiplicity, and design assumptions limit what can be concluded. Those limitations do not make the observed data uninformative; they define the appropriate degree of confidence in their interpretation.

15. Limitations

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

The enrolled sample was 33, making the study a small pilot comparison. The primary outcome has broad inter-quartile ranges, which indicate appreciable variation in monitoring completion within both arms. The registry does not report a confidence interval for the primary treatment contrast, so the precision of that contrast is not directly available.

The outcome timing requires qualification: the primary endpoint is described as a 90-day measure, but the calculation was made at day 83 because enrollment was 90 +/- 7 days. The registry does not give further detail about how differences in individual monitoring duration affected each participant’s percentage or how missing readings were handled beyond their inclusion in the adherence concept.

The arm descriptions are incomplete in the registry record. The control description ends after the text about weekly emails, and the social incentive description is also truncated. The brief description supplies some details about the social supporter, but a full account of intervention delivery, adherence support, or fidelity is not reported in the registry record. Masking is listed as none, and the record does not report allocation concealment procedures.

Several secondary outcomes have different participant counts from the primary analysis, and the reasons for those counts are not reported. Some outcome values are missing or not estimable for a two-arm comparison. The record also does not report a complete statistical analysis plan, a multiplicity strategy, or a sample-size justification for the trial itself. These limitations constrain interpretation of the secondary analyses and the generalizability of the pilot findings.

The results concern this study’s monitoring process and enrolled participants. The registry record does not establish long-term effects or report enough information to assess whether the findings would apply to settings with different participants, devices, or support arrangements.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Connected Health Blood Pressure Monitoring In Stroke and TIA Patients — NCT02450760.
• Registry record last updated 2022-02-17; status last verified 2021-12.
• Results first posted 2022-02-17.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT02450760 is a completed, randomized, parallel-group pilot study sponsored by the University of Pennsylvania, with 33 participants enrolled. The registry lists no masking and a phase of NA. Participants with a history of cerebral infarction and uncontrolled blood pressure were assigned to control monitoring or monitoring with a social incentive.

The primary outcome was the percentage of requested home blood pressure readings completed. The reported median was 40.0% in control and 60.0% in the social incentive arm; the Wilcoxon (Mann-Whitney) comparison had p = 0.29. The endpoint description states that the calculation was made at day 83, despite its 90-day timeframe.

Secondary outcomes covered blood pressure change, health-care use, medication changes, and participant perceptions. The registry record does not report a full analysis plan, detailed missing-data methods, or a sample-size justification for the trial.