NICE rewrites rules on hypertension diagnosis
By Lilian Anekwe
GPs are set for a huge shake-up of their management of millions of patients with hypertension after draft NICE guidance recommended use of 24-hour ambulatory blood pressure monitoring to make all new diagnoses and guide treatment.
NICE has also dramatically ripped up its 2006 treatment algorithm – installing calcium-channel blockers as preferred first-line drugs in over-55s and ethnic minorities, and advising diuretics should only be prescribed first if there are ‘compelling reasons' to do so.
And it has proposed a new target of 135/85mmHg for patients whose blood pressure varies when measured in the clinic and at home.
Cardiovascular experts admitted introduction of ambulatory blood pressure monitoring would be a ‘challenge' for practices, but claimed the move would save GPs time and the NHS millions in the long run by preventing inaccurate diagnoses. The draft advice recommends if GPs have taken two sequential office blood pressure measurements and both are above 140/90mmHg, ‘patients should be offered 24-hour ambulatory blood pressure monitoring to confirm the diagnosis of hypertension'.
Most GPs will need to refer to cardiology departments for access to ambulatory blood pressure monitors. Practices wishing to purchase their own face a bill of around £1,000.
GPs will be asked to combine use of blood pressure readings taken in clinics with the results of either 24-hour ambulatory or home measurements to guide treatment, depending on the average readings.
Professor Bryan Williams, chair of the guideline development group and professor of medicine at the University of Leicester, told Pulse the group had looked to make ‘progressive changes' to practice after they had seen evidence that a quarter of patients aged 18 to 40 were misdiagnosed.
‘This will be a challenge, but not one we should shy away from. Fewer people will be diagnosed, we will be using drugs in the right people and it will be cost negative to the NHS,' he said. ‘The first reaction from GPs will be: "How can we deliver this?" But nobody expects it to happen overnight. It's a big change, but I'm sure GPs will respond.'
The draft guideline also proposes new thresholds for diagnosis and grades of hypertension ‘which better reflect the values obtained using ambulatory blood pressure monitoring'.
In people with a discrepancy of more than 20/10mmHg between clinic blood pressure measurements and the ambulatory or home average, GPs should consider using daytime average ambulatory or average home readings for monitoring treatment, and aim for a target for either of 135/85mmHg or lower.
But the guidance stops short of radical plans for initial combination treatment being considered by the Joint British Societies for their guidance on management of cardiovascular diseases, due out later this year.
Professor Williams said: ‘Previously we recommended calcium-channel blockers or diuretics first line in over-55s and ethnic minorities. But the evidence favours calcium-channel blockers, unless there's a compelling reason for a diuretic. The evidence on use of initial combinations was not published in time to be included.'
Dr Chris Arden, a GP in Eastleigh, Hampshire, and chair-elect of the Primary Care Cardiovascular Society, said: ‘We need to make sure we get the diagnosis right in the first place because it commits patients to life-long treatment.
‘We have shied away from using ambulatory blood pressure monitoring in the past because of the logistics of organising it, but in the long run there will be fewer people diagnosed.' The draft will be out to consultation until 22 March.
The guidance recommends GPs should move away from clinic BP readings What the guidance recommends
- Offer 24-hour ambulatory blood pressure monitoring to all patients in whom two clinic blood pressure reading are both higher than 140/90 mmHg
- Treat all patients with a clinic blood pressure ?160/100 and subsequent ambulatory or home average readings >150/95 mmHg, and those with a blood pressure >140/90 mmHg in clinic and subsequent ambulatory or home average readings >135/85 mmHg who also have:
o target organ damage,
o established cardiovascular disease,
o renal disease,
o diabetes, or
o a 10-year cardiovascular risk equivalent to 20% or greater.
- Offer an ACE inhibitor to people aged under 55 years or an ARB if not tolerated
- Offer a CCB to over 55s older and ethnic minority patients
- Aim for a target blood pressure <140/90 mmHg in patients under 80, <150/90 mmHg in over 80s and 135/85 mm Hg in patients with a discrepancy of more than 20/10 mmHg between clinic and subsequent measurements
- Use clinic readings for ongoing monitoring
Source: NICE draft guideline on hypertension, February 2011