Major guidelines recommend home blood pressure monitoring to guide diagnosis and treatment of patients with hypertension; however, little is known about the real-world accuracy of home blood pressure monitors that patients use. Researchers led by Swapnil Hiremath, (Ottawa Hospital and University of Ottawa, in Canada) compared measurements from home blood pressure monitors with validated mercury sphygmomanometers, which are used in doctors’ offices, in 210 patients.

The investigators found that 63/210 of the home monitor systolic blood pressure readings (30%) were > 5 mm Hg different and 16 (8%) were > 10 mm Hg different from the mercury systolic blood pressure measurement. For diastolic blood pressure, these proportions were 32% (67/210) and 9% (18/210) respectively.

“Home blood pressure monitors may be inaccurate in 5% to 15% of patients, depending on the threshold for accuracy used,” said Dr. Hiremath. “We recommend all patients with home monitors get them validated with their health care providers at least once.”