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How Accurate Are Home Blood Pressure Devices in Use? A Cross-Sectional Study
Marcel Ruzicka1,2,3, Ayub Akbari1,3,4, Eva Bruketa5
1Division of Nephrology, Faculty of Medicine, University of Ottawa, Ottawa, Canada.
Insights
Many home blood pressure monitors are inaccurate, with a significant percentage differing by 5 mm Hg or more. Re-validating these devices is crucial for reliable hypertension management.
Area of Science:
- Cardiology
- Nephrology
- Medical Device Technology
Background:
- Home blood pressure monitoring is recommended for hypertension management.
- Validation protocols exist for manufacturers, but clinical practice accuracy data is limited.
- This study reviewed charts from a tertiary care center's blood pressure assessment clinic.
Purpose of the Study:
- To assess the accuracy of home blood pressure monitors used by patients in a nephrology clinic.
- To compare home monitor readings with mercury sphygmomanometer measurements.
Main Methods:
- Chart review of 210 patients (2011-2014) in an Ottawa nephrology clinic.
- Recorded patient demographics, blood pressure (BP) measurements, arm circumference, and monitor manufacturer.
- Compared average home BP monitor readings to mercury sphygmomanometer using Bland-Altman plots and t-tests; accuracy defined as a difference of ≤5 mm Hg.
Main Results:
- 30% of home BP monitors showed a mean systolic BP difference of ≥5 mm Hg compared to mercury.
- 32% of home BP monitors showed a mean diastolic BP difference of ≥5 mm Hg.
- No significant differences in accuracy were found based on patient characteristics, cuff size, or monitor brand.
Conclusions:
- A substantial proportion of home blood pressure monitors used in clinical practice are inaccurate.
- Re-validation of in-use devices is necessary before relying on their measurements for clinical decisions.
- Ensuring the accuracy of home blood pressure monitors is vital for effective hypertension management.
Background:
Out of office blood pressure measurements, using either home monitors or 24 hour ambulatory monitoring, is widely recommended for management of hypertension. Though validation protocols, meant to be used by manufacturers, exist for blood pressure monitors, there is scant data in the literature about the accuracy of home blood pressure monitors in actual clinical practice. We performed a chart review in the blood pressure assessment clinic at a tertiary care centre.
Methods:
We assessed the accuracy of home blood pressure monitors used by patients seen in the nephrology clinic in Ottawa between the years 2011 to 2014. We recorded patient demographics and clinical data, including the blood pressure measurements, arm circumference and the manufacturer of the home blood pressure monitor. The average of BP measurements performed with the home blood pressure monitor, were compared to those with the mercury sphygmomanometer. We defined accuracy based on a difference of 5 mm Hg in the blood pressure values between the home monitor and mercury sphygmomanometer readings. The two methods were compared using a Bland-Altman plot and a student's t-test.
Results:
The study included 210 patients. The mean age of the study population was 67 years and 61% was men. The average mid-arm circumference was 32.2 cms. 30% and 32% of the home BP monitors reported a mean systolic and diastolic BP values, respectively, different from the mercury measurements by 5 mm Hg or more. There was no significant difference between the monitors that were accurate versus those that were not when grouped according to the patient characteristics, cuff size or the brand of the home monitor.
Conclusions:
An important proportion of home blood pressure monitors used by patients seen in our nephrology clinic were inaccurate. A re-validation of the accuracy and safety of the devices already in use is prudent before relying on these measurements for clinical decisions.
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