Hypertension

Hypertension is today a major health problem in Singapore, as well

as in many other countries around the world. It is an important risk

factor for stroke, coronary artery disease, heart failure and chronic

renal disease.

Considerable controversies have arisen regarding the definition,

as wel l as the sub- c las s i f i cat ion of hyper tens ion

(1)

. Thi s i s largely

because it is widely believed that there is no level of blood pressure (BP)

that can be considered to be completely safe. Although this is true,

i t i s never theles s impor tant to note that the relat ionship between

the absolute risk of cardiovascular complications versus BP levels is

not a straight line but is curvilinear and that at lower BP levels, this

curve is relatively flat. Furthermore, at any given level of BP, the risk of

complications can differ by many folds depending on the presence

or absence of other risk factors such as diabetes mellitus and

hyperlipidaemia. Despite these difficulties, most of the current major

Hypertension Guidelines have defined hypertension as follows: systolic

BP ≥140 mmHg and/or diastolic BP ≥90 mmHg in individuals who

are 18 years and above (BP measured in a clinic setting)

(2)

. Using this

d e f i n i t i o n , a s we l l a s i n c l u d i n g k n own h y p e r t e n s i v e s wh o a r e o n

treatment, the 1998 Singapore National Health Survey found that 27%

of our adult population, aged 30-69 years, have hypertension

(3)

.

Both systolic and diastolic BP increase with age. In the case of

systolic BP, this increase continues throughout the individuals’s life.

On the other hand, the rise in diastolic BP reaches a plateau at about

60 years of age, after which it begins to slowly decline. Therefore in

the elderly, isolated systolic hypertension is the commonest form of

hypertension. Fig. 1, which is based on data from the 1998 Singapore

Na t i o n a l He a l t h S u r v e y

( 3 )

, h...