HIGH blood pressure is a major problem in Jamaica, affecting about 20-30 per cent of the adult population. It is also a major promoter of stroke, cardiovascular and kidney disease, and a significant drain on public purse. Public enlightenment campaigns promote routine blood pressure (BP) measurements and control to achieve optimal blood pressure levels and reduce the risk of stroke, heart disease, kidney failure, death, and disability. Many health conscious individuals have incorporated BP measurements into their routine. What is not acknowledged is that all blood pressure values may not be created equal.

We tend to pay a lot of premium on the BP recordings obtained at the doctor’s office, but are there better options? Multiple cross-sectional and cohort studies have consistently shown that BP measured regularly at rest by the patient at home (Home BP) and BP measured automatically over a 24-hour period regardless of activity or time of day (Ambulatory BP or ABPM) are far superior and consistently more reliable than BP values obtained at the doctor’s office in predicting end-organ damage and incident cardiovascular disease.

What is not fully resolved are the relative benefits and disadvantages of home BP versus Ambulatory BP. An important advantage of ABPM over Home BP is the overnight readings, which accurately predict the risk of likelihood of cardiovascular disease events. A recent study from Finland involving more than 500 adults monitored over a median of 16 years evaluated the performance of office, home, and ABPM measurements in predicting the risk for cardiovascular disease. While both Home BP measurements and ABPM were superior to doctor’s office readings, ABPM proved most useful and reliable in predicting subsequent cardiovascular events like strokes and heart attacks. The study findings were presented at HYPERTENSION 2014 in Athens, Greece, a joint conference of the International Society of Hypertension and European Society of Hypertension and also published in the journal Hypertension.

In the study, Dr Teemu Niiranen and colleagues looked at 502 patients classified into two groups — 264 patients drawn from the general population and another 238 patients newly diagnosed with hypertension. Cardiovascular-event data, including heart attacks, stroke, hospitalisation for heart failure, coronary interventions, and death from cardiovascular disease were collected from national death and hospital discharge registers in Finland.

After rigorous statistical analysis looking at all factors including gender, age, weight and medical history, 24-hour ambulatory blood pressure measurements emerged as the most useful and reliable tool in predicting seriousness and risk of high blood pressure. Office BP measurements were found to be very weak in predicting outcomes in patients with hypertension. Interestingly, blood pressure measurements taken by patients at home were more reliable in predicting risk of cardiovascular event compared to blood pressure measurements taken at the doctor’s office.

When the general population and newly diagnosed hypertensive patients were analysed separately, similar results were observed.

Equally significant is that even with office BP so rigorously measured, home and ambulatory were still better. With this study, hypertension guidelines should begin to move away from office measurements to out-of-office measurements, as some like the UK have already done. The newest UK guidelines on hypertension, for example, no longer allow for diagnosis of hypertension solely on the reading of BP at the doctor’s office.

The take-home message is that Home BP and 24-hour ABPM are superior to traditional office BP values in predicting organ damage and risk of cardiovascular disease. However, home BP is limited by its current inability to provide overnight values, a major risk predictor. ABPM is superior to both office-based and home BP monitoring in predicting cardiovascular outcomes.

We now have strong objective evidence that the gold standard for BP measurement is a 24-hour ambulatory blood pressure measurement and should be obtained before initiation of treatment for any patient and should be monitored routinely in individuals concerned about hypertension or in established hypertensive patients to properly guide treatment for best outcomes. Have you checked your 24-hour ambulatory blood pressure? If not, please ask your doctor to do so. That will help protect you from stroke, heart failure or kidney disease.

Professor Ernest Madu, founder of the Heart Institute of the Caribbean, is an internationally acclaimed cardiologist and expert on innovative health solutions. HIC is a centre of excellence for cardiovascular care in the English-speaking Caribbean. Please send questions and comments to emadu@caribbeanheart.com.