New BP figures spark debate

High blood pressure or hypertension is a major public health challenge. It is common among Malaysians with at least one in three above 18 classified as having hypertension based on periodic nationwide surveys by the Health Ministry since 1996.

It is the main cause of heart attack, stroke, heart failure and the second most important cause of end stage kidney disease in Malaysia. Heart attack and stroke are the top two killers in the country for both men and women.

Although the number of adult Malaysians with hypertension has shown signs of stabilising, only one in four patients with hypertension receiving treatment from their doctors have their BP (blood pressure) adequately controlled.

Patients whose BP remained uncontrolled despite treatment are at risk of developing and dying from heart attack, stroke, heart failure and developing end stage kidney disease requiring dialysis or kidney transplant.

This has been the criteria doctors used to diagnose and decide whether a patient needs to be treated. If the BP is equal to or more than 140/90 mmHg, doctors will start recommending the appropriate treatment such as practising a healthy lifestyle and if that fails, medications will be prescribed.

Two weeks ago, the medical world was abuzz with a guideline published by the American Heart Association and the American College of Cardiology (AHA/ACC) which now reclassifies hypertension as a BP of equal to or higher than 130/80 mmHg. Doctors all over the country have been inundated by questions by the public and patients alike on this new definition.

The medical and nursing communities are also bewildered by this, which is more aggressive. The implication of this new definition (if adopted) is that more individuals will be diagnosed and labelled as having hypertension and more will be receiving drug treatment.

The Health Ministry, the Academy of Medicine and the Malaysian Society of Hypertension have since 1998 published updated guidelines on hypertension every five years.

The 5th edition called “Clinical Practice Guideline on the Management of Hypertension” is in its final phase and will be released early next year.

The Guideline Committee at its last meeting on Nov 18 discussed the latest American Guideline and made the following recommendations:

> Any change in the definition of hypertension must be based on good scientific evidence based not only on research observing BP trends in the population (epidemiology) but more importantly research which attempts to reverse the trend using treatment (clinical trials). Ironically this was also stated by the American Guideline which states “categories (of BP) were based on a pragmatic interpretation of BP related CVD (cardiovascular disease) risk and benefit of BP reduction in clinical trials”.

> Malaysia took part in a global research project published in a major medical journal last year which investigated whether patients with a BP of 130/80 mmHg and low risk of developing CVD should be given drugs to lower BP. The research showed that there is no benefit achieved when these patients were treated with BP lowering drugs.

In that research, the group which benefited were those whose BP were more than 140/90 mmHg. There is therefore no need to redefine hypertension to a lower category especially in individuals with low risk of developing CVD. The American Guideline did mention this research in its reference but did not see it as strong enough evidence as compared to epidemiological studies.

In medicine there are many examples of epidemiological stu­dies which were subsequently disproved by clinical trials.

Decision to define a disease entity and more importantly on when to treat patients must not be based solely on epidemiological studies but must be backed up by a major outcome clinical trial. If the two produced conflicting results, then clinical trials takes precedence.

> As for patients with more than low risk (ie medium or high risk), since 2008 the Malaysia Hypertension Guideline recommended that any BP more than 130/80 mmHg in these patients needs to be treated. This was also the recommendation which the American Guideline stated two weeks ago albeit almost 10 years later. Examples of such patients who need to be treated even if their BP was 130/80 mmHg are those who have already developed heart attack, stroke, heart failure or kidney disease.

The Malaysian Hypertension Guideline Committee reiterates that we will not propose a lowering of the definition for hypertension to equal to or above 130/80 mmHg and it remains at equal to or above 140/90 mmHg. The main question is will a new definition change the way we treat our patients?

The answer is NO and thus there is no need for a new definition. We also wish to remind that once a patient develop cardiovascular complications, any BP equal to or more than 130/80 mmHg needs treatment to lower BP, which is not the same as redefining and lowering the definition of hypertension.

These patients in reality will be started on treatment to prevent further CVD complications. Many of these treatment given to them will also act to lower their BP.

Abdul Rashid Abdul Rahman
Chairman, Malaysian Clinical Practice Guidelines on Hypertension

Datin Chia Yock Chin
President, Malaysian Society of Hypertension

Feisul Idzwan Mustapha
Head of Non-Communicable Disease Sector
Disease Control Division, Ministry of Health Malaysia

Source