Blood Pressure Checks for Diagnosing Hypertension (BP-CHECK)

Hypertension is usually diagnosed at a clinic or doctor's office when a patient has blood pressure (BP) that is high for several measurements. However, about 30 percent of patients with high BP in clinics have normal BP outside of clinics. This is called white-coat hypertension. Correct diagnosis of hyper-tension is important to prevent strokes, heart attacks, and heart failure but also to avoid making people worry or take medicines when they don't need to. To avoid misdiagnosis of hypertension, the US Preventive Services Task Force (USPSTF), which makes national recommendations about disease screening, recommends people should have 24-hour BP ambulatory monitoring (i.e., an arm cuff and BP monitor worn for 24 hours, with measurements taken every 30 minutes during the day and every 60 minutes at night), with home BP monitoring over several days as an alternative. However, most patients have never heard of 24-hour BP monitoring, and physicians rarely order it. Physicians sometimes use home BP monitoring, but not according to recommended guidelines. BP kiosks, for example at drug stores, offer another option. Newer models are accurate and easy to use. BP-CHECK will identify participants, ages 18 to 85, with high BP at their last clinic visit and invite them to a screening visit. Participants with high BP at the screening visit (510 patients) will be randomized and assigned to 1) clinic BP, 2) home BP, or 3) kiosk BP diagnostic groups for confirming a new diagnosis of hypertension. The clinic BP group will have BP measured at one clinic visit. The home BP group will measure BP two times, twice a day, for five days. The kiosk BP group will measure BP three times on three separate days at a kiosk at their clinic or nearby drugstore. Participants will complete their diagnostic tests over approximately three weeks. They will then be asked to complete 24-hour BP monitoring. Participants will complete surveys at baseline prior to randomization, after diagnostic tests, and at six months. Hypothesis 1: Compared to the reference standard (24-hour BP), home BP and kiosk BP will be more accurate than clinic BP. Hypothesis 2: Participants with clinic, home, or kiosk BP results concordant with reference standard results will prefer home or kiosk to clinic and 24-hour BP. Hypothesis 2: Participants with clinic, home, or kiosk BP results concordant with reference standard results will prefer home or kiosk to clinic and 24-hour BP.

The investigators will compare the accuracy and acceptability (i.e., comfort, convenience) of clinic, home, and kiosk BP testing to 24-hour BP ambulatory monitoring. The investigators will look at the impact of the study on outcomes that matter to participants: their BP and whether participants feel better or worse overall, worry about BP, and change health behaviors (e.g., lowering salt intake). Our study team includes patients. The study team also has patient and stakeholder advisors to ensure our study is conducted properly and is not a burden to patients and providers. The investigators will share study results with patient participants and publish papers in scientific journals.

Participants will be asked to check their blood pressure at their clinic once within the subsequent three weeks.

Participants will receive a validated upper-arm home blood pressure monitor and asked to take two measurements in the morning and two in the evening for at least 5 days over three weeks.

Participants will be asked to use a validated blood pressure kiosk in their clinic or local pharmacy to measure their blood pressure three times on three separate days over three weeks.

Participants will receive a validated upper-arm home blood pressure monitor and asked to two measurements in the morning and two in the evening for at least 5 days over three weeks.

Participants will be asked to use a validated blood pressure kiosk in their clinic or local pharmacy to measure their blood pressure three times on three separate days over three weeks.

Participants will be asked to wear an arm cuff and ambulatory blood pressure monitor for 24 hours, with measurements taken every 30 minutes during the day and every 60 minutes at night.

To compare the performance of clinic, home, and kiosk blood pressure to 24-hour blood pressure (reference standard) for new hypertension diagnoses. Our primary outcome is differences in mean systolic and diastolic blood pressure comparing clinic, home, and kiosk to 24-hour BP.

Inclusion Criteria: enrolled in the health plan for two years, no diagnosis of hypertension in the prior 2 years or more, not on anti-hypertensive medications, a high blood pressure at their last clinic visit (systolic blood pressure > or equal to 140 mm Hg or diastolic blood pressure > or equal to 90, planning to remain a Kaiser Permanente patient for the next six months, able to converse and read in English, required to have elevated blood pressure at the screening visit (BP taken 2 times, high each time). Exclusion Criteria: children and pregnant women, patients with end-stage renal disease, dementia, atrial fibrillation and other significant arrhythmias.

A final de-identified data set will be made available to the Patient-Centered Outcome Research Institute (PCORI). This data set will include de-identified, individual-level data and meet specifications set by our Institutional Review Board for sharing such data. The analytic data set will include data dictionaries and descriptions of the data such as cohort identification, study participant characteristics, and data captured electronically and via patient surveys. Parties may request data from Dr. Beverly Green and will need to indicate their plans for data use, acknowledge the source of the data in publications, and, if possible, collaborate with BP-CHECK research group.

Green BB, Anderson ML, Cook AJ, Ehrlich K, Hall YN, Hsu C, Joseph D, Klasnja P, Margolis KL, McClure JB, Munson SA, Thompson MJ. Clinic, Home, and Kiosk Blood Pressure Measurements for Diagnosing Hypertension: a Randomized Diagnostic Study. J Gen Intern Med. 2022 Sep;37(12):2948-2956. doi: 10.1007/s11606-022-07400-z. Epub 2022 Mar 3.

Green BB, Anderson ML, Campbell J, Cook AJ, Ehrlich K, Evers S, Hall YN, Hsu C, Joseph D, Klasnja P, Margolis KL, McClure JB, Munson SA, Thompson MJ. Blood pressure checks and diagnosing hypertension (BP-CHECK): Design and methods of a randomized controlled diagnostic study comparing clinic, home, kiosk, and 24-hour ambulatory BP monitoring. Contemp Clin Trials. 2019 Apr;79:1-13. doi: 10.1016/j.cct.2019.01.003. Epub 2019 Jan 8.