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.