Pragmatic Method Using Blood Pressure Diaries to Assess Blood Pressure Control

Twenty-four-hour ambulatory blood pressure (ABP) is the reference standard of blood pressure control. Home blood pressure (HBP) is superior to clinic blood pressure for assessing control, but a barrier to its use is the need for physicians to calculate average blood pressure from patient diaries. We sought to develop a quick and pragmatic method to assess blood pressure control from patients' HBP diaries.

Seven-day HBP and 24-hour ABP were measured in 286 patients with uncomplicated treated hypertension (aged 64 ± 8 years; 53% female). We determined the optimal ratio of home systolic blood pressure readings above threshold (≥135 mm Hg) for the last 10 recorded that would best predict elevated 24-hour ABP. Uncontrolled blood pressure was defined as 24-hour ABP systolic blood pressure ≥130 mm Hg or 24-hour ABP daytime systolic blood pressure ≥135 mm Hg. Validation by corroborative evidence was tested by association with markers of end-organ disease.

The best predictor of 24-hour ABP systolic blood pressure above treatment/target threshold was having 3 or more (≥30%) of the last 10 home systolic blood pressure readings ≥135 mm Hg (area under the receiver operating characteristic curve = 0.71). Importantly, patients meeting this criterion had evidence of target organ disease, with significantly higher aortic stiffness, left ventricular relative wall thickness, and left atrial area, and lower left ventricular ejection fraction, compared with those who did not meet this criterion.

To facilitate uptake of HBP monitoring, we propose that physicians can determine the percentage of the last 10 home systolic blood pressure values ≥135 mm Hg for a patient and tailor management accordingly.