What can ambulatory blood pressure tell you about your future health?

This study investigated whether ambulatory blood pressure accurately helps predict risks of high blood pressure. 

Hypertension (high blood pressure) occurs when pressure inside blood vessels is too high. Over time, hypertension can lead to heart-related problems such as a heart attack or stroke.

A way of measuring high blood pressure is called ambulatory blood pressure (ABP). This involves measuring blood pressure at regular intervals over a 24-hour period. Blood pressure can vary throughout the day so ABP can be more accurate than reading blood pressure at one sitting at a clinician’s office, called “office” blood pressure. It can also help diagnose “masked” hypertension which is when a person has hypertension but has normal office blood pressure.

For blood pressure readings two numbers are shown – the top number which measures the pressure inside blood vessels when the heart is beating (systolic blood pressure: SBP) and the bottom number which measures the pressure when the heart is relaxing or filling (diastolic blood pressure: DBP).

Blood pressure is considered normal at around 120/80 mmHg. Prehypertension is considered to be around 120-139 / 80-89 mmHg, and hypertension is >140/>90 mmHg.

This study investigated whether measuring ambulatory blood pressure in individuals with normal office blood pressure can help diagnose masked hypertension and predict the risk of developing hypertensive complications.

A total of 7,826 participants were included in the study. Participants had their blood pressure measured for 24 hours and were followed-up around 11 years after to see if they had experienced health problems or passed away due to hypertension.

The study found that participants who were prehypertensive had a 41% increased risk of having a heart related event such as a heart attack, and a 92% increased risk of having a stroke, compared with participants who had normal blood pressure. Compared to participants with hypertension, those who had prehypertension had a 34% reduced risk of having a hypertensive-related event and a 29% reduced risk of dying from a hypertensive-related event. 

It was also found that 8% of participants with “normal office blood pressure” actually had masked hypertension, and 29% of participants with “office prehypertension” also had masked hypertension. 

The study concluded that ambulatory blood pressure is important in diagnosing patients with masked hypertension, and helps measure the risk of hypertensive complications based on normal, prehypertensive and hypertensive ambulatory blood pressure. 

Ambulatory blood pressure was measured from peoples’ homes, at different intervals, and at different seated or lying positions and therefore the results may not be as precise and reliable than wished for. 

If you or someone you know have prehypertension or are worried about developing hypertension, talk to a doctor about measuring ambulatory blood pressure so you can take appropriate steps to keep blood pressure under control.