michael s
(Michael S)
#1
4 What blood pressure should I treat, and what
should I aim for when treating a 45 year old, a 60
year old, a 75 year old or an 85 year old?
Aroon Hingorani
Who to treat
The primary aim of blood pressure (BP) treatment is to reduce the
risk of stroke and CHD. Assuming secondary causes of hyper-
tension have been excluded, the decision to treat a particular level
of BP is based on an assessment of the risk of stroke, coronary
heart disease (CHD) and hypertensive renal disease in the
individual patient.
Allpatients with evidence of target organ damage (left ventricular
hypertrophy, retinopathy, or hypertensive nephropathy) are
considered to be at high risk and should receive treatment whatever
the level of BP. Similarly, all patients who have previously suffered
a stroke or CHD should have their BP lowered if it is above
140/90mmHg.
Difficulties arise in those without end-organ damage or a
previous cardiovascular event. Guidelines in the UK have
advocated antihypertensive treatment for sustained BP levels
above 160/100mmHg since in these individuals the risks of stroke
and renal disease are unacceptably high. Absolute risk of stroke
or CHD depends, however, not only on BP but also on the combi-
nation of other risk factors (age, gender, total cholesterol, HDL-
cholesterol, smoking, diabetes, and left ventricular hypertrophy).
Their synergistic interaction in any individual makes universal
application of BP thresholds perhaps inappropriate and some
individuals with BP >140/90mmHg will benefit from treatment.
Recent guidelines on treatment have also advocated a global
assessment of risk rather than focusing on individual risk factors.
The risk of stroke or CHD in an individual can be calculated using
tables^1 or computer programmes^2 based on a validated risk
function (for example Framingham Risk Equation). Having
calculated absolute risk (based on the variables above), one has to
decide what level of risk is worth treating. A low threshold for
treatment will result in a larger number of individuals exposed to
antihypertensive drugs and a higher cost, but a greater number of
cardiovascular events saved. Meta-analysis has shown that (for a
