Modern blood pressure trials combine seated office readings, a week of home readings and sometimes a 24-hour ambulatory recording. Capture holds all three, calculates mean arterial pressure and pulse pressure on the office form, and runs the home diary on participants’ phones. Free sandbox, no credit card.
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Seated, after 5 minutes rest
Reading 1 systolic
SYSBPReading 1 diastolic
DIABPReading 2 systolic
SYSBPReading 2 diastolic
DIABPMean arterial pressure (reading 2)
MAPPulse pressure (reading 2)
PULSEPRWhat a hypertension trial needs from its EDC
The study data
A hypertension protocol rarely depends on one kind of reading. Office blood pressure is the traditional efficacy measure and is taken by trained staff, seated after rest, often as the average of repeated readings. Home blood pressure is increasingly collected alongside it. The common design is a block of about 7 days before each decision point, with duplicate readings in the morning and evening taken with a validated upper-arm cuff, the first day often discarded and the rest averaged; reviewers call this the 722 schedule. Ambulatory blood pressure monitoring over 24 hours is widely treated as the reference method and gives daytime, night-time and 24-hour means that office readings cannot. Thresholds differ by guideline (for example, a home average of 135/85 mmHg is a widely used threshold), so the protocol fixes which one your endpoints use.
Each method has its own data-quality failure mode. Office readings suffer from terminal digit preference and from sites that skip the rest period. Home readings suffer from missed sessions, single readings and entries typed in the waiting room before the visit. Ambulatory recordings need enough valid readings to be usable, and the vendor report, not the raw device file, usually becomes the study record. A good EDC design addresses each: structured office form with a rest and position check, a phone diary with separate fields for each reading and completion windows, and a form for ambulatory summary values (valid reading count, percentage valid, 24-hour, daytime and night-time means) that the site transcribes from the vendor report.
Be precise about what Capture does not do. Home readings are typed in by the participant from their cuff, and ambulatory summaries are entered by site staff; Capture does not pull data from blood pressure cuffs or ambulatory recorders, and it does not use cuffless wearables for BP. The study team can enable the native Oura Ring sync for studies that want wearable context such as resting heart rate or sleep, but that is a separate, optional stream. Where a protocol wants both, the wearable device studies page describes how the sync works.
Mean arterial pressure and pulse pressure are two of the derived values Capture can calculate from systolic and diastolic fields and show read-only during entry, which removes site-by-site formula differences. They are useful as secondary or exploratory outcomes, in vasoactive-drug studies and as a sanity check, because an implausible pulse pressure often points to a transposed entry. The calculated fields and skip logic page describes how they are set up, and the vital signs eCRF template provides the form structure.
| Assessment | Screen | Run-in | BL | W4 | W8 | W12 |
|---|---|---|---|---|---|---|
| Office BP, duplicate seated readings | ||||||
| Home BP, 7-day block | D | D | D | D | D | |
| 24-hour ambulatory BP summary | ||||||
| Potassium, creatinine, eGFR | ||||||
| Adverse events and dose changes |
D = home diary block before the visit
Choosing methods
| Method | Who records it | Data to store | Main data-quality risk |
|---|---|---|---|
| Office BP | Site staff | Two or three readings, arm, position, rest, cuff size, MAP and pulse pressure | Skipped rest, digit preference |
| Home BP | Participant, on a phone | Each reading, time, rest, arm, dose timing, from the home BP diary | Missed sessions, entries made from memory |
| 24-hour ambulatory | Site staff, from the vendor report | Valid reading count, percentage valid, 24-hour, day and night means | Too few valid readings |
| Orthostatic | Site staff | Supine and standing readings with timing | Inconsistent timing between readings |
Build the form from the live home blood pressure diary template, set morning and evening windows and enter a week of practice readings. Free sandbox, no credit card.
Safety and visit pattern
Antihypertensive safety is mostly about too much effect and about kidney and electrolyte changes. Symptomatic hypotension, dizziness, syncope and falls are the obvious ones. Renin-angiotensin drugs and diuretics shift potassium and creatinine, so protocols schedule safety labs a few weeks after any start or dose increase. Build a lab form with reference ranges and range checks, so an out-of-range potassium raises a query as it is entered; the lab results eCRF template gives the layout, and the eGFR CKD-EPI calculator shows how kidney function is derived from creatinine. Where the protocol sets a dose-reduction rule on a creatinine rise, the audit trail shows who saw the value and when.
Titration designs add complexity. Participants start on a dose, and at set visits the dose steps up if BP is above target. Record the dose at each visit, the reason for any change and the BP values that triggered it, in the same form or a linked one. Visit windows keep the titration steps on schedule, and edit checks can query a dose increase when the recorded BP was below target. Adverse events use the adverse event form, with a separate SAE path; the adverse event reporting software page covers the workflow. For cardiovascular outcome studies with adjudicated events, plan the adjudication data separately in the data management plan.
The visit pattern follows the phase. Early-phase studies cluster measurements around dosing with intensive office and ambulatory readings. Phase 2 dose-finding studies use 4 to 12 weeks with office and ambulatory endpoints. Phase 3 registrational studies run longer, with many sites and often add outcomes. Capture runs all three, and multi-site work uses site-level participant numbering and a site coordinator portal; see EDC for cardiology clinical trials for the general cardiovascular build and multi-site clinical trial management for site operations.
Build sequence
Upload the protocol and let the AI study builder propose run-in, baseline and treatment visits. A person reviews before anything is saved.
Duplicate readings, rest and position checks, MAP and pulse pressure as calculated fields, and range rules on each reading.
Start from the home blood pressure diary template, with morning and evening tasks, reminders, and a completion window that closes before the dose.
A summary form for ambulatory values and a lab form with potassium, creatinine and eGFR.
Enter practice participants through titration, check queries and the export, then approve forms and go live.
Before first participant
Office, home or ambulatory, and which summary statistic is analysed.
Validated upper-arm cuffs, cuff sizes and who supplies them.
Days, sessions per day, readings per session, which readings count.
Minimum valid readings per recording and what happens if it is missed.
Potassium and creatinine thresholds that prompt a dose action.
Yes. Both can be set up as calculated fields from the systolic and diastolic entries, shown read-only during entry and included in exports with the data dictionary.
Yes. The home blood pressure diary template opens from a secure link in the phone browser, with reminders and completion windows. Participants type readings from their own cuff; Capture does not connect to cuffs.
As a summary form completed by site staff from the vendor report: valid reading count, percentage valid and the 24-hour, daytime and night-time means. Capture does not import files from ambulatory recorders.
No. The only native device sync is Oura, which supplies wearable context, not blood pressure measurement.
Yes. Record dose, reason and the triggering BP at each visit, use visit windows to keep steps on schedule and edit checks to query dose changes that do not match the rule.
Yes. Capture is used from Phase 1 through Phase 3, with site-level numbering, a site coordinator portal and by-site exports.
Capture provides Part 11-aligned controls: a field-level audit trail, electronic signatures and role-based access. Compliance is shared with the sponsor’s own validated use of the system. This is not legal advice.
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