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NICE proposes lower threshold for treating high blood pressure

BMJ 2019; 364 doi: https://doi.org/10.1136/bmj.l1105 (Published 08 March 2019) Cite this as: BMJ 2019;364:l1105
  1. Harriet Pike
  1. Cambridge

Thousands more people could be eligible for drugs to lower blood pressure under draft clinical guidelines published by the UK National Institute for Health and Care Excellence on 8 March 2019.1

The new recommendations reduce the threshold for risk of cardiovascular disease (CVD) at which blood pressure lowering treatment should be considered. The draft guideline suggests that treatment be offered to patients under the age of 80 years with a diagnosis of stage 1 hypertension if they have a 10 year CVD risk of 10% or more. This is in contrast to the 20% risk threshold used in previous NICE guidelines.2

The change could result in as many as 450 000 more men and 270 000 more women in England with high blood pressure being eligible for treatment. But NICE said that many of these patients were likely to be already being treated because of variation in how earlier recommendations were implemented.

Anthony Wierzbicki, consultant in metabolic medicine and chemical pathology and chair of the guideline committee, said that the guidelines shifted the focus to earlier intervention. “It unifies and simplifies the advice given to GPs in implementing the NHS Health Check, and it supports the NHS long term plan’s aim to improve chronic disease prevention,” he said. “The guideline also places a greater emphasis on achieving and maintaining blood pressure targets, as many people with high blood pressure are undertreated.”

Helen Stokes-Lampard, chair of the Royal College of General Practitioners, acknowledged the value of taking steps to prevent CVD. But she said that many GPs had concerns about overdiagnosis and the unintended harms of prescribing drugs whose benefit was limited. She said, “Lowering the threshold for treatment or diagnosis of hypertension . . . is likely to affect thousands if not millions of patients, so this decision must not be taken lightly and must be evidence based.”

Stokes-Lampard added that though clinical guidelines were useful for GPs when developing treatment plans, they were not “tramlines forcing us to practise in certain ways.” She said, “GPs are highly trained to prescribe taking into account the guidelines but also the circumstances of the individual patient sitting in front of them, including physical, physiological, and social factors that might be affecting their health.”

Some experts said that the new recommendations did not go far enough. Stephen MacMahon, professor of medicine and principal director of the George Institute for Global Health at the University of Oxford, described the draft guidelines as “surprisingly conservative.”

He said, “There is strong evidence that greater reductions in blood pressure produce greater reductions in stroke and heart attack. Yet the draft guidance recommends blood pressure targets that are only slightly lower than the starting level for treatment. This will almost certainly result in large numbers of patients not achieving the full potential benefits of treatment as a consequence of inadequate reduction in blood pressure.”

He also criticised NICE’s recommendation for a stepped approach to treatment. “Much lower blood pressure targets are required, and multiple drugs need to be used right from the start if patients are to achieve the largest reduction in the risks of stroke and heart attack.”

Liam Smeeth, head of the department of non-communicable disease at the London School of Hygiene and Tropical Medicine, criticised NICE’s reliance on “arbitrary thresholds” for diagnosis of hypertension. The guideline specifies that treatment should be considered for patients with a diagnosis of stage 1 hypertension (a clinic blood pressure of 140/90 mm Hg or higher).

“There is higher risk at higher blood pressure levels, but no evidence to support a distinct threshold above which people need treatment and below which they don’t need treatment,” he said. “We should be moving towards a more unified approach to cardiovascular disease prevention, identifying people at high risk and targeting all their major risk factors rather than seeing blood pressure in isolation.”

NICE said that its guideline committee had considered new studies indicating that people with blood pressure below 140/90 mm Hg might also benefit from drug treatment. But it said that some of the studies were difficult to interpret and could not be used directly to inform its recommendations.

In November 2017 the American Heart Association and American College of Cardiology published new US guidelines for the management of hypertension.3 In the US hypertension is now defined as pressure over 130/80 mm Hg.

NICE’s draft guideline is open for public consultation until 23 April. Final guidance is expected to be published in August.

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