How do you measure up? The British Hypertension Society thresholds for drug treatment.

Many of us have no idea why or how doctor’s make a decision to put us on medication.  Well, as you may have guessed, it is not finger in the air stuff.  There are recommendations for treatment and the one used in the UK has been published by the British Hypertension Society (bhsoc.org.uk).  In brief, the thresholds are as follows with my explanations:

Drug treatment should be started in all patients with sustained systolic blood pressures ≥ 160 mm Hg or sustained diastolic blood pressures ≥ 100 mmHg despite non-pharmacological measures.

When you have your blood pressure measured ask about the numbers.  Blood pressure is often recorded as a number over a number – for instance “120 over 80”.  The top number is the systolic blood pressure and the bottom number is the diastolic blood pressure.  Sustained means over a period of time so your doctor may invite you back on a number of occasions over a few months to check your blood pressure.  Non-pharmacological measures are basically lifestyle changes such as increasing exercise, cutting out salt and losing weight.

Drug treatment is also indicated in patients with sustained systolic blood pressures 140-159 mm Hg or diastolic blood pressures 90-99 mm Hg if target organ damage is present, or there is evidence of established cardiovascular disease or diabetes, or if there is a 10 year cardiovascular disease risk of ≥ 20%.

If you have additional problems that may have been exacerbated or caused by your high blood pressure, doctor’s may give you medication when your blood pressure is at a lower level than previously managed.  End organ damage may be defined as things such as thickening in the heart muscle or problems with you kidneys which mean they are leaking protein into your urine.  Your cardiovascular risk is defined by more than your blood pressure.  Doctor’s will take into account things such as your cholesterol levels, your body mass index and your family history.  If all of these factors mean that your chance of having an event – a stroke or heart attack – in the next ten years is over 20% then they will also look at medication.

For most patients a target of ≤ 140 mm Hg systolic blood pressure and ≤ 85 mm Hg diastolic blood pressure is recommended. For patients with diabetes, renal impairment or established cardiovascular disease a lower target of ≤ 130/80 mm Hg is recommended.

This is the target which you and your doctor will be aiming for when you have been put on medication.  You can see that this is lightly lower for people who have diabetes or some other problems than for those who just have high blood pressure.

When using ambulatory blood pressure readings, mean daytime pressures are preferred and this value would be expected to be approximately 10/5 mm Hg

lower than the office blood pressure equivalent for both thresholds and targets. Similar adjustments are recommended for averages of home blood pressure readings.

Some of you may have been asked to wear an ambulatory blood pressure monitor for 24 hours which takes your blood pressure on a regular basis throughout the day and night.  Some of you may have been asked to take your blood pressure at home for a period of time.  In both these cases, the doctor’s expect those readings to be lower than the ones that are taken at the surgery and they make adjustments for this.

Full guideline