Stage 2 hypertension: what the readings mean and how it is treated

High blood pressure, also called hypertension, puts extra strain on the blood vessels, heart and other organs such as the brain, kidneys and eyes. The NHS says that if it is not treated it can increase the risk of heart disease, heart attacks, strokes, heart failure, kidney disease and vascular dementia, and that lowering it even a small amount helps reduce these risks.

NICE guideline NG136 divides hypertension into stages. Stage 1 is a clinic blood pressure from 140/90 to 159/99 mmHg, confirmed by an ambulatory or home average from 135/85 to 149/94 mmHg. Stage 2 is a clinic reading of 160/100 mmHg or higher but under 180/120 mmHg, confirmed by an ambulatory or home average of 150/95 mmHg or higher. Stage 3, or severe hypertension, is a clinic systolic of 180 mmHg or higher or a diastolic of 120 mmHg or higher.

The NHS says high blood pressure does not usually cause symptoms and many people have it without realising. Rarely it can cause headaches, blurred vision and chest pain. The only way to find out is to have blood pressure measured.

The NHS lists increasing age, close relatives with high blood pressure, Black African, Black Caribbean or South Asian ethnic background, a diet high in salt, being overweight, smoking, drinking too much alcohol and long-term stress as things that increase the chance. It advises a blood pressure check at a pharmacy or GP surgery if you are aged 40 or over and have not had one for more than 5 years, or if you think you might be at risk.

NICE says that when considering a diagnosis of hypertension, blood pressure should be measured in both arms. If clinic blood pressure is 140/90 mmHg or higher, a second reading is taken during the consultation, and the lower of the last two is recorded as the clinic reading.

If clinic blood pressure is between 140/90 mmHg and 180/120 mmHg, NICE says ambulatory blood pressure monitoring (ABPM) should be offered to confirm the diagnosis, or home monitoring if ABPM is unsuitable or not tolerated. ABPM takes at least 2 measurements an hour during usual waking hours, using the average of at least 14. Home monitoring records two consecutive readings at least a minute apart, twice daily, for at least 4 days and ideally 7, discarding day one. The diagnosis is confirmed when a clinic reading of 140/90 mmHg or higher is matched by an ABPM daytime average or home average of 135/85 mmHg or higher.

While the diagnosis is being confirmed NICE advises tests for target organ damage: a urine albumin to creatinine ratio and a check for blood in the urine, blood tests including HbA1c, electrolytes, creatinine, eGFR and cholesterol, an examination of the back of the eyes, and a 12-lead ECG. A formal cardiovascular risk assessment follows.

NICE says lifestyle advice should be offered to everyone with suspected or diagnosed hypertension and continued periodically. This includes reducing excessive alcohol and caffeine, keeping dietary sodium low, and stopping smoking. It specifically does not recommend calcium, magnesium or potassium supplements to lower blood pressure, and warns that salt substitutes containing potassium chloride should not be used by older people, people with diabetes, pregnant women, people with kidney disease and people taking some blood pressure medicines such as ACE inhibitors and ARBs.

For persistent stage 2 hypertension NICE recommends offering antihypertensive drug treatment in addition to lifestyle advice to adults of any age, using clinical judgement for people with frailty or multiple long-term conditions. The NHS says there are many different medicines, that the one recommended depends on factors such as how high the blood pressure is, your age and ethnicity, that most are taken as once-a-day tablets, and that you may need more than one.

At the first step NICE says to offer an ACE inhibitor or an angiotensin receptor blocker (ARB) to adults with type 2 diabetes of any age or family origin and to those under 55 who are not of Black African or African-Caribbean origin. It says to offer a calcium-channel blocker to adults aged 55 or over without type 2 diabetes, and to people of Black African or African-Caribbean origin without type 2 diabetes. For adults of Black African or African-Caribbean origin an ARB is preferred over an ACE inhibitor if one of those is chosen. An ACE inhibitor should never be combined with an ARB, and neither should be used in pregnancy unless absolutely necessary.

NICE says the aim is to reduce clinic blood pressure to below 140/90 mmHg and keep it there for adults with hypertension under 80, and below 150/90 mmHg for adults aged 80 and over. Lower targets apply in some cases of kidney disease or type 1 diabetes with higher levels of protein in the urine.

People who choose to monitor at home are advised to use home blood pressure monitoring, and readings at home are 5 mmHg lower than clinic readings for the diagnostic thresholds. NICE says to check for postural hypotension in people with type 2 diabetes, symptoms of it, or aged 80 and over. For adults under 40 with hypertension, NICE says clinicians should consider specialist evaluation for secondary causes.

NICE also says to discuss personal cardiovascular risk and treatment preferences, including the option of no treatment, before starting medicines, and to continue lifestyle support whether or not medicine is started.

NICE says people with a clinic blood pressure of 180/120 mmHg or higher together with signs of retinal haemorrhage or swelling of the optic nerve, or life-threatening symptoms such as new confusion, chest pain, signs of heart failure or acute kidney injury, should be referred for same-day specialist assessment.

The NHS says to call 999 if you have sudden chest pain or discomfort that does not go away, pain spreading to the arms, neck, jaw, stomach or back, or chest pain with sweating, sickness, light-headedness or breathlessness, because you could be having a heart attack. It says to call NHS 111 if you often have headaches or blurred vision, have chest pain that comes and goes, or have other symptoms you are worried about.

Blood pressure can be checked at a GP surgery or pharmacy. Many pharmacies offer free blood pressure checks for people aged 40 or over, and NICE mentions the NHS blood pressure@home scheme for supporting home monitoring.

Private health checks and private cardiology review are available, but they do not change the diagnostic thresholds or recommended treatment steps, whichever route you use.