New NICE guideline will radically change how high blood pressure is diagnosed

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The UK National Institute for Health and Clinical Excellence (NICE) has published on 24 August 2011 an updated guideline on the diagnosis and treatment of hypertension. Developed in conjunction with the British Hypertension Society (BHS), it makes a number of new recommendations that are set to significantly improve the way health professionals diagnose and treat high blood pressure in the NHS in England and Wales.

In one of the biggest changes to NICE’s previous guidance, published in 2006, the guideline recommends that a diagnosis of primary hypertension should be confirmed using 24-hour ambulatory blood pressure monitoring (ABPM), or home blood pressure monitoring (HBPM), rather than be based solely on measurements of blood pressure taken in the clinic. The recommendation draws on substantial new evidence, including that published online in The Lancet on 24 August 2011, suggesting that ABPM is more accurate than both clinic and home monitoring in defining the presence of hypertension, and that implementation of a diagnostic strategy for hypertension using ambulatory monitoring following an initial raised clinic reading would reduce misdiagnosis and be cost saving for the NHS.

High blood pressure is one of the most important preventable causes of premature ill health and death in the UK. It is a major risk factor for stroke, heart attack, heart failure, chronic kidney disease and cognitive decline. Primary hypertension is diagnosed when there is no simple identifiable cause of the raised blood pressure: the hypertension may be related, in part, to obesity, dietary factors such as salt intake, physical inactivity or genetic inheritance. There are currently about 12 million people in the UK who have hypertension (blood pressure ≥140/90mmHg) and more than half of those are over the age of 60 years. Around 5.7 million people have hypertension which is undiagnosed. The risk associated with increasing blood pressure is continuous, with each 2mmHg rise in systolic blood pressure associated with a 7% increased risk of mortality from ischaemic heart disease and a 10% increased risk of mortality from stroke. As a consequence of commonplace routine periodic screening for high blood pressure in the UK as part of National Service Frameworks for cardiovascular disease prevention, the diagnosis, treatment and follow-up of patients with hypertension is one of the most common interventions in primary care, accounting for approximately 12% of Primary Care consultation episodes and approximately £1 billion in drug costs in 2006.

 

Other recommendations that have been reviewed in this partial update of the guideline for the clinical management of primary hypertension in adults include: blood pressure targets for people receiving treatment; the pharmacological treatment of hypertension; the treatment of hypertension in the very elderly (people aged over 80); treatment of hypertension in younger adults (younger than 40); and the treatment of drug resistant hypertension.

Key priorities for implementation include:

  • If the clinic blood pressure is 140/90mmHg or higher, offer ambulatory blood pressure monitoring (ABPM) to confirm the diagnosis of hypertension.
  • When using ABPM to confirm a diagnosis of hypertension, ensure that at least two measurements per hour are taken during the person’s usual waking hours (for example, between 08:00 and 22:00). Use the average value of these measurements to confirm a diagnosis of hypertension.
  • Offer antihypertensive drug treatment to people aged under 80 years with stage 1 hypertension (that is, initial clinic systolic blood pressure of 140/90mmHg or higher and subsequent ABPM daytime average or HBPM average of 135/85mmHg or higher) who have one or more of the following: target organ damage; established cardiovascular disease; renal disease; diabetes; a 10-year cardiovascular risk equivalent to 20% or greater.
  • Offer antihypertensive treatment to people of any age with stage 2 hypertension, (that is, initial clinic systolic blood pressure exceeds ≥160mmHg and/or diastolic blood pressure ≥100mmHg and subsequent ABPM daytime average or HBPM average of 150/95mmHg or higher).
  • For people aged under 40 years with stage 1 hypertension and no evidence of target organ damage, cardiovascular disease, renal disease or diabetes, consider seeking specialist evaluation of secondary causes of hypertension and a more detailed assessment of potential target organ damage. This is because 10-year cardiovascular risk assessments can underestimate the lifetime risk of cardiovascular events in these people.

 

The guideline, The clinical management of primary hypertension in adults, is available on the NICE website at www.nice.org.uk/guidance/CG127