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Accuracy of Home Use Electronic Blood Pressure Monitors underScrutiny -  CHOICE # 439 (May 15, 2013) 

  • 2013.05.15

Does the electronic blood pressure monitor you use in the comfort of home give consistently accurate readings time after time?

As the prevalence of diagnosed hypertension in Hong Kong is on the rise so is the home use of electronic blood pressure monitors in the prevention and control of the chronic disease.

When it comes to one's health, it is vital the monitor offers accuracy every time. To help ease growing consumers' concern over the accuracy, the Consumer Council has put to test 27 models of home use electronic blood pressure monitors comprising 21 of the upper arm type and 6 of the wrist type.

A total of 1,002 patients, 540 men and 462 women aged 30 to 94, took part in the study at Queen Mary Hospital and Tung Wah Hospital. Co-ordinated by the Department of Cardiology of the University of Hong Kong, a large volume of test data was collected and analysed.

For the 21 upper arm models, each sample was tested with at least 33 patients to obtain a minimum of 99 sets of readings. Similarly, each of the 6 wrist models was tested with at least 15 patients to produce a minimum of 45 sets of readings.

The readings taken from the samples were compared against those of the mercury sphygmomanometer, a device generally considered accurate by medical professionals, with reference to the protocol of the European Society of Hypertension.

In general, according to the analysis, the upper arm models were judged to perform better in accuracy.

In 99 measurements, the arm models were able to obtain, on average, 55 and 59 "very accurate" readings - readings differ less than 5 mmHg compared to mercury sphygmomanometer - in systolic blood pressure and diastolic blood pressure respectively.

In the case of the wrist models, they obtained, on average, 21 "very accurate" readings in 45 measurements in both systolic blood pressure and diastolic blood pressure.

The monitors were rated for their overall performance on the basis of accuracy (55%) and stability (45%). (Stability of the readings is assessed by the standard deviation of the difference of readings between the samples and the mercury sphygmomanometer. The smaller the standard deviation the better the stability).

The results showed that on the whole, upper arm models fared better in the rating. 11 of the models were awarded with 4 points, 8 with 3.5 points, and 2 with 3 points.

Among the 6 wrist monitors, only 1 scored 3.5 points, 4 received 2.5 points and 1 only 2 points.

Consumers are advised to pay heed to maintenance: by storing the monitor in a cool and dry place, taking out the batteries when not in use for a prolonged period of time, making sure the cuff and tubings are in good conditions. If in doubt about the conditions of any parts or the accuracy of the device, bring it to the agents for servicing.

The World Health Organisation (WHO) has chosen the theme of "High Blood Pressure (Hypertension)" for World Health Day 2013, highlighting hypertension as a priority area of public health concern in the world.

If blood pressure rises and stays elevated over time, a number of serious health problems may ensue, including stroke, coronary heart disease, heart failure and chronic kidney disease.

To prevent or control hypertension, it is essential that healthy lifestyles be maintained, such as having a balanced diet that is low in salt, keeping physically active, avoiding obesity, quitting smoking avoiding alcohol consumption and managing stress properly, etc.

Adults should also regularly monitor their blood pressure. An accurate home use electronic blood pressure monitor is therefore important.

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