Wellness & Fitness

Why home-based tests are ideal for blood pressure screening


Young African woman checking blood pressure at home. PHOTO | SHUTTERSTOCK

Hypertension or high blood pressure still ranks high among the most prevalent Non-Communicable Diseases (NCDs) in Kenya.

Government statistics from the Ministry of Health show that a quarter of the Kenyan population aged between 18 and 69 years is estimated to have hypertension. These are individuals with a blood pressure reading of 140/90 mmHg or higher, compared to the normal rate of less than 120/80 mmHg.

In addition, 50 percent of people within the same age group are considered pre-hypertensive. They have blood pressure readings that are above the normal range but below the threshold for hypertension (between 120/80 mmHg and 139/80).

These individuals are at risk of the adverse effects of the disease which include heart attacks, strokes, heart disease and kidney failure.

Even though there is no cure for hypertension, people can effectively manage the disease and avert its complications through a combination of recommended medications, healthy diets and physical activity.

This, therefore, underscores the significance of people undergoing blood pressure screening tests as prompt diagnosis and treatment is important to forestall the adverse effects of the disease.

Before a diagnosis is made, people are usually required to do two tests at different intervals. If both turn positive for high blood pressure, then they can be confirmed to be suffering from hypertension and thus eligible for treatment.

As is the common practice in most parts of the country, both tests are usually conducted in health facilities or clinics before doctors and other health practitioners can confirm the diagnosis.

Despite its widespread use, health experts are casting doubt on this approach, indicating that it may not always yield accurate results.

A new study published in the Journal of General Internal Medicine indicates that blood pressure measurements routinely taken at home, are more likely to provide the basis for accurate diagnoses of hypertension than those taken in a clinic setting.

The study, which was led by researchers from Kaiser Permanente – one of the leading health providers in the US – indicates that routine home measurements offer a true picture of blood pressure levels in individuals and allows them to track their status continuously over a period of time.

People usually experience fluctuations in their blood pressure which is influenced by factors such as sleep patterns, physical activity or stress levels. Therefore, health experts note that relying on just two screening tests may be misleading.

“Blood pressure varies a lot over the day and one or two measurements in the clinic may not reflect your average blood pressure. Home blood pressure monitoring allows you to collect many more readings and average these,” said Dr Beverly Green, the study’s first author who is a senior investigator at Kaiser Permanente Washington Health Research Institute and a physician at Washington Permanente Medical Group.

The findings of this new study come from a research trial involving 510 adults who visited one of 12 Kaiser Permanente primary care centres in Western Washington over a period of two years (between 2017 and 2019).

During the study, the researchers used electronic health records to identify potential participants who were at high risk of having hypertension based on a recent clinic visit.

These people were divided into three groups based on the method they used for obtaining follow-up blood pressure measurements tests (in clinics, at home, or at kiosks in medical clinics or pharmacies).

In addition to these screening tests, every participant received a 24-hour Ambulatory Blood Pressure Monitoring (ABPM) assessment, which is the gold standard test for making a new diagnosis of hypertension. It is considered to yield the most accurate results.

The ABPM uses a full upper-arm cuff that is connected to a waist-carried device which is worn continuously for 24 hours. Even though it provides the most precise diagnostic information, it is not available for widespread use.

The researchers were able to determine the accuracy of the other three screening methods by comparing their results with the ABPM results.

At the end of the study, the researchers found that blood pressure readings taken at home were consistent with those of the gold standard ABPM test.

On the contrary, results based on follow-up clinic visits were found to be significantly lower for the systolic measure (upper number). This led to over half of the people with hypertension being missed.

Worse still, blood pressure readings taken from kiosks were found to be significantly higher than those of the ABPM test, resulting in a higher likelihood of hypertension overdiagnosis.

This refers to an irrelevant diagnosis that often leads to unnecessary tests and treatments which cause more harm than good to the patient.

“Home blood pressure monitoring was a better option because it was more accurate than clinic blood pressure readings. Furthermore, previous research has shown that people prefer taking their blood pressure at home,” said Dr Green.

The researchers noted that while previous studies have found similar benefits to home blood pressure reading, this new study may offer the most powerful evidence to date due to its large number of participants, involvement of primary care clinics and use of real-world practitioners to take blood pressure measures instead of research personnel.

“Also, this study is the first to compare kiosk and ABPM results,” they said.

In Kenya, it is estimated that more than half (56 percent) of the population aged between 18 and 69 have never undergone screening for hypertension. This means that many of them could be suffering from the disease unknowingly, and therefore not taking medication.

Yet, prompt diagnosis can save patients by enabling physicians to prescribe medication to lower blood pressure early enough, which averts heart attacks, strokes, kidney damage, among other problems linked to hypertension.

Encouraging the use of home-based tests is therefore expected to go a long way in boosting blood pressure screening, diagnosis and management in the country.

But for this goal to be attained, health experts note that the government needs to put in place mechanisms that will enable people to easily access blood pressure machines for home use, and learn how to use them effectively under the guidance of health practitioner in their nearest health facilities.

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