New guidelines for blood pressure matter

It is of concern that the Health Ministry (MOH) is disregarding key tenets of the American Heart Association's new guidelines on hypertension (Singapore won't take up new US cut-off for hypertension; Nov 18).

Since 2002, studies have shown that an increase in blood pressure (BP) from 120 to 140mm Hg doubles the risk of cardiovascular events, including strokes.

The incremental risk with blood pressure greater than 130 had been recognised and previously categorised as "pre hypertension".

In the 2015 Systolic Blood Pressure Intervention Trial, it was found that fewer high-risk patients (28 per cent were over 75 years old) with a blood pressure of less than 120mm systolic had heart attacks, strokes, heart failures or cardiac deaths, compared to those with a higher blood pressure. The risk of dying was also reduced by 27 per cent.

Recent meta-analysis have also supported lower BP targets.

Significant benefits to a BP lower than 140/90 are clear.

However, treatment must be individualised, as not all patients can tolerate a lower blood pressure.

The guidelines will change the way we manage hypertension.

The most important message is to relate the decision for treatment not only to blood pressure readings but also to a holistic cardiovascular risk assessment of the patient.

Hence, unlike previous guidelines, both non-pharmacological and pharmacological treatment can be indicated in a patient with a BP of 130/80 with an assessed 10-year calculated cardiovascular risk greater than 10 per cent.

Blood pressure, cholesterol and glucose are continuous biological variables. Targets are man-made for risk stratification.

There is no suggestion that you will have a cardiovascular event immediately if you are above the threshold.

But by elevating "pre hypertension" to hypertension Stage 1, more individuals will be alerted to a potentially life-threatening problem which requires active lifestyle changes for risk reduction.

The question "is the patient above the blood pressure goal?" should be replaced by "will the patient benefit by a reduction in blood pressure?".

This paradigm shift initially occurred in the 2013 United States lipid guidelines but, unfortunately, was not reflected in the 2016 MOH lipid guidelines.

Experts and professional bodies have taken several years to reach the new hypertension guidelines.

Further discussion with the local medical fraternity on the merits of these guidelines are needed.

Singaporeans will be done a disservice if the guidelines and targets are dismissed after only a few days' review.

Arthur Tan (Dr)

A version of this article appeared in the print edition of The Straits Times on November 28, 2017, with the headline 'New guidelines for blood pressure matter'. Print Edition | Subscribe