Home blood pressure (BP) monitors are as accurate as those used in professional settings, with some provisos, suggest the findings of the ACCU-RATE trial published in the British Journal of General Practice today (2 June 2020).
The cross-sectional, observational study included 6891 patients on the hypertension register at seven practices in the West Midlands, England. They were surveyed to ascertain whether they owned a BP monitor and wanted it tested.
Monitor accuracy was compared with a calibrated reference device at 50 mmHg intervals between 0 mmHg and 280/300 mmHg (static pressure test). A difference from the reference monitor of +/−3 mmHg at any interval was considered a failure. Cuff performance was also assessed.
In total, 76 per cent (95% CI, 71%-80%) of 331 tested devices passed all tests of monitors and cuffs, and 86 per cent (95% CI, 82%-90%) passed the static pressure test. Deficiencies were primarily because of monitors overestimating BP.
Forty per cent of monitors were not validated. The pass rate on the static pressure test was greater in validated monitors (96%; 95% CI, 94%-98%) versus unvalidated monitors (64%; 95% CI, 58%-69%), those retailing for >£10 (90%; 95% CI, 86%-94%), those retailing for ≤£10 (66%; 95% CI, 51%-80%), those in use for ≤4 years (95%; 95% CI, 91%-98%) and those in use for >4 years (74%; 95% CI, 67%-82%). Twelve per cent of cuffs failed.
The authors say the findings show that clinicians can be confident of the accuracy of patients’ own BP monitors if the devices are validated and are ≤4 years old.