Hypertension and cardiovascular risk in primary care (WHO HEARTS)

Raised blood pressure damages arteries quietly for years before it causes a stroke, heart attack, heart failure or kidney failure. Most people with it feel completely well, which is why so many are never diagnosed.

WHO estimates that about 1.4 billion adults aged 30 to 79 had hypertension in 2024, around one in three in that age group, and two thirds of them live in low- and middle-income countries. Roughly 44% do not know they have it, and only about 23% have it controlled.

Source: WHO hypertension fact sheet

The good news is that treatment is safe, cheap and effective. The problem is rarely a lack of medicines in the world; it is that health systems do not find people, start treatment, or keep them on it.

The HEARTS technical package

WHO launched the Global Hearts Initiative in 2016. Its HEARTS technical package gives primary care teams six practical modules:

The rest of this course follows the same logic: measure well (lesson 2), treat by protocol (lesson 3), think about total risk (lesson 4), keep people on treatment as a team and track the results (lesson 5), and take extra care in pregnancy and other special situations (lesson 6).

Every treatment decision rests on the reading, so a careless measurement leads to wrong treatment. Small habits make a big difference.

Technique

• Seat the person with the back supported, legs uncrossed and bladder empty.
• Let them rest quietly for 5 minutes, and do not talk during the measurement.
• Choose the right cuff: use a large cuff if the upper arm is more than 32 cm round. A cuff that is too small reads falsely high.
• At a first assessment, measure at least twice a few minutes apart and use the second reading.
• Measuring both arms once and using the higher arm is ideal, but may not be practical in a busy clinic.

Equipment

Where the clinic has electricity or batteries, use a validated automated device with a digital display: it gives more consistent readings and does not depend on the operator's technique. Without power, use a manual cuff with a gauge and a stethoscope.

Who to measure

Measure blood pressure in every adult at their first visit to the facility and, if normal, at regular intervals afterwards (for example every 1 to 5 years). It matters most in people with previous heart attack or stroke, diabetes, chronic kidney disease, obesity, tobacco use, or a family history of heart attack or stroke.

Making the diagnosis

Pitfalls that lead to a wrong diagnosis

Most measurement errors push the reading up, so people are labelled and treated when they do not need it. A few push it down, so people at risk are missed. Look for these at every clinic you work in.

WHO now recommends validated automated devices for clinical use. Mercury devices are no longer recommended because mercury is toxic and is being phased out, and dial devices need frequent recalibration and retraining of staff. Automated devices also remove observer bias and rounding.

Second case: the dropped device

Mr E, 70, comes for a repeat prescription. The clinic's dial device fell off the table last week and since then most readings have been 150 to 160 systolic. Today it reads 168/96. His radial pulse is irregular.

When to start

• Confirmed hypertension with systolic 140 or more, or diastolic 90 or more: start medicines (WHO strong recommendation).
• Existing cardiovascular disease and systolic 130 to 139: start medicines (strong).
• No cardiovascular disease but high cardiovascular risk, diabetes or chronic kidney disease, and systolic 130 to 139: WHO suggests starting medicines (conditional).
• Start no later than 4 weeks after diagnosis; start without delay if BP is very high (for example 160/100 or more) or there is organ damage.

Tests

If available, check electrolytes and creatinine, lipids, HbA1c or fasting glucose, a urine dipstick and an ECG. But never let tests delay treatment: in places without a laboratory, start treatment and test later. A long-acting calcium channel blocker such as amlodipine is the easiest medicine to start without tests.

Which medicines

WHO recommends any of three classes as first line: a thiazide or thiazide-like diuretic, an ACE inhibitor or ARB, or a long-acting dihydropyridine calcium channel blocker. Long-acting, once-daily medicines are preferred. WHO suggests starting with two medicines from different classes, ideally as a single-pill combination, because it improves adherence and control, especially when BP is 20/10 mmHg or more above target.

Stepping up

HEARTS protocols are drug- and dose-specific so that every member of the team does the same thing. A typical one: start an ACE inhibitor or ARB with amlodipine at starting doses; if BP is still 140/90 or more at the monthly visit, move to full doses; then add a thiazide-like diuretic; if still not controlled, check the tablets are being taken correctly and, if they are, refer.

Targets

• Below 140/90 for people with hypertension and no other conditions (strong).
• Systolic below 130 for people with known cardiovascular disease (strong).
• Systolic below 130 suggested for people at high cardiovascular risk, or with diabetes or chronic kidney disease (conditional).

• ACE inhibitors cause a dry cough in about 1 in 10 people: switch to an ARB.
• Check creatinine and potassium before and a few weeks after starting an ACE inhibitor, ARB or diuretic, where possible. Low potassium is more common at full diuretic doses.
• Beta-blockers are not first line, but add one after a recent heart attack, or for atrial fibrillation or heart failure.
• If someone is already controlled on an affordable regimen, there is no need to change it.

Blood pressure is one risk factor among several. A 45-year-old non-smoker with BP 145/92 and a 68-year-old smoker with diabetes and the same BP have very different chances of a heart attack or stroke. Treating according to total risk puts effort where it saves most lives.

The WHO risk charts

WHO's 2019 cardiovascular risk charts estimate the 10-year risk of a fatal or non-fatal heart attack or stroke. There are charts for 21 world regions, so choose the one for your country. The laboratory version uses age, sex, smoking, systolic BP, diabetes and total cholesterol. The non-laboratory version uses body mass index instead of blood tests, so it can be used anywhere.

Treat without a chart

Some people are high risk whatever the chart says, so do not waste time scoring them: anyone with established cardiovascular disease (heart attack, angina, stroke or TIA, peripheral vascular disease) or kidney disease, people with diabetes and cardiovascular disease, people with albuminuria, retinopathy or left ventricular hypertrophy, anyone with BP persistently 160/100 or more, and anyone with total cholesterol of 8 mmol/L or more.

Statins and aspirin

• Give a statin to people at 20% or higher risk and after a heart attack or stroke; HEARTS-D also recommends a statin for everyone with type 2 diabetes aged 40 and over. Use the statin and dose in your national formulary. No statins in pregnancy.
• Low-dose aspirin is for people who have already had a heart attack or ischaemic stroke, not for prevention in people without cardiovascular disease.
• WHO counts medicines plus counselling for people with a previous heart attack or stroke, or a 10-year risk of 20% or more, among its "best buys" for noncommunicable diseases.

How often to see people

• Monthly after starting or changing treatment, until BP is at target (WHO suggestion).
• Every 3 to 6 months once BP is controlled.
• Each visit: BP, side effects, tablets taken, supply at home, and one lifestyle message.

Helping people stay on treatment

• Explain what hypertension is, that it causes no symptoms, and what it can lead to: stroke, heart attack, kidney failure.
• Explain the difference between long-term medicines and quick-relief tablets such as painkillers.
• Show the dose, label the tablets, and use once-daily medicines taken at the same time each day.
• Ask the person to keep a supply at home and to come back before it runs out.
• Check understanding before they leave.

These tablets do not cure high blood pressure; they control it, like a roof keeps out the rain. If you stop them, the pressure goes back up even though you feel well.

Lifestyle messages

• Less than 5 g of salt a day (under 2 g of sodium, just under one teaspoon), counting salt already in food.
• At least 5 portions of fruit and vegetables a day; healthy oils; less added sugar.
• About 150 minutes of brisk walking or similar a week.
• Stop tobacco (smoked and smokeless) and avoid others' smoke; avoid harmful alcohol.

Team-based care

WHO suggests that hypertension treatment can be given by non-physician professionals such as nurses and pharmacists, as long as four conditions are met: proper training, prescribing authority, a specific management protocol, and physician oversight (which can be remote). Community health workers can help with education, delivering medicines and measuring and monitoring BP, within local rules.

Monitoring

A simple register (paper or electronic) of everyone on treatment is the backbone of follow-up. HEARTS asks for four items for each person: date of registration, date of last visit, and the systolic and diastolic BP at that visit. With those four items the team can see who is overdue and how many people are controlled.

People who have died, moved or been lost stay in the denominator, so a low control rate often shows a retention problem, not a medicine problem. Review the figures with the whole team every quarter and agree one change to try.

We keep your name in our book so we notice if you miss a visit. If you move or cannot come, tell us and we will help you get your tablets.

Second case: a team-based clinic day

At a rural health centre, a community health worker measures BP in the village and brings people to the clinic; a nurse runs the hypertension clinic under the national protocol; the pharmacist dispenses; the doctor visits monthly. Mrs F, 60, takes amlodipine 5 mg and lisinopril 20 mg. Her BP today is 152/94 on two good readings. She says she takes her tablets every morning.

High blood pressure in pregnancy is common and dangerous. WHO estimates that hypertensive disorders complicate about one pregnancy in ten, and in Asia and Africa nearly one tenth of maternal deaths are associated with them. Pre-eclampsia can progress within hours, so every antenatal contact includes a BP measurement and a check for danger signs.

Classify

The full first-level steps, with doses, are in the protocol Pre-eclampsia and eclampsia. In short: give magnesium sulfate, the medicine of choice to prevent and treat eclamptic fits; if you cannot give the full regimen, give the loading dose and transfer at once. Start an antihypertensive when systolic BP is 160 or more or diastolic 110 or more. Do not lower BP into the normal range quickly.

Medicines in pregnancy

• Stop ACE inhibitors and ARBs as soon as pregnancy is known; they harm the baby. Thiazides and statins are also not used in pregnancy (HEARTS).
• For non-severe hypertension in pregnancy (140 to 159 / 90 to 109), WHO (2020) recommends offering treatment only where the woman has good antenatal follow-up. Methyldopa (fewest safety concerns, on the WHO essential medicines list) and beta-blockers are reasonable choices; the evidence suggests calcium channel blockers should be avoided for this indication. Choose with the antenatal provider.
• For severe hypertension, the acute medicines and doses are in your obstetric protocol and the pre-eclampsia protocol.
• Women who were on antihypertensives in pregnancy should continue them after birth, and severe hypertension after birth should be treated (WHO 2011).

Preventing pre-eclampsia

• Women at high risk (previous pre-eclampsia, chronic hypertension, diabetes, kidney or autoimmune disease, twins): low-dose aspirin 75 mg daily, started before 20 weeks.
• Where dietary calcium is low: calcium 1.5 to 2.0 g a day in pregnancy.
• These belong in routine antenatal care: see The antenatal contact.

A woman with known hypertension who wants a baby

Ask every woman of childbearing age on BP medicines about pregnancy plans and contraception at each review. If she may become pregnant, use a regimen without an ACE inhibitor, ARB or thiazide (lesson 3), and ask her to come as soon as she thinks she is pregnant so that care can be handed to the antenatal team early.

Very high BP outside pregnancy

A very high reading with symptoms (for example BP above 180/110 with headache, chest pain, breathlessness, confusion, weakness or visual loss) needs same-day referral. Without symptoms, 160/100 or more means starting or stepping up treatment the same day, not emergency lowering. Rapid lowering in a clinic can cause a stroke.

Second case: a severe reading at 34 weeks

Ms H, 24, is 34 weeks pregnant with her first baby. She has had a headache since last night and sees flashing lights. BP is 164/112 on two readings 15 minutes apart. Urine protein is 2+.

Answer all 15 questions, then press Mark. You need 12 or more to pass. You can look back at the lessons: the aim is learning. A pass gives a printable certificate of completion for 4 hours of self-directed learning; you need a free account, signed in, to issue it.