By Lilian Anekwe
Exclusive: Hypertension guidance is set to encourage GPs to use renin testing to guide treatment for patients with resistant hypertension, prompting warnings that the test is only available in around a dozen centres across the UK.
Pulse has learned new draft guidance by the British Hypertension Society, due to be published in March, will recommend renin measurement in patients whose blood pressure remains uncontrolled even though they are on three different treatments.
Professor Morris Brown, former president of the BHS and professor of clinical pharmacology at the University of Cambridge, said he believed ‘the time has arrived for more routine measurement of plasma renin' by GPs.
‘It's the BHS' view people who are not at target despite being on three drugs should be tested. People with hypertension on lots of drugs who still have low renin need bigger doses of diuretic.'
Professor Brown is leading the PATHWAY trial to try to establish if use of treatment directed by plasma renin testing helps patients reach target more quickly.
Testing measures the renin-aldosterone ratio and can identify possible primary hyperaldosteronism in hypertensives. But it is not available in most pathology labs and GPs are unfamiliar with it.
Dr Terry McCormack, a GP in Whitby, Yorkshire, and a hypertension researcher, said: ‘If you recognise renin deficiency you should use diuretics differently. But I don't think it's available to the average GP. We need evidence about whether it's value for money.'
Dr Stuart Smellie, director of clinical practice at the Association of Clinical Biochemists, said: ‘Few local labs do this, it's pretty well the exclusive reserve of specialist labs, but local labs can organise testing through regional centres. GPs should check with labs as samples may need prompt separating.'
Dr Mark Davis, a GP in Garforth, Leeds said: 'It depends on where this research leads. When you get to that stage you could use renin testing - depending on renin levels you could go for a drug that works on the renin system or if renin is low use a diuretic. Theoretically it sounds like a good idea but it would have to be proven in a trial before we could use it in a widespread way.'
The BHS view is that patients with resistant hypertension should have their renin levels checked Managing the blood pressure of challenging patientsAn afternoon seminar for GPs focusing on practical treatment strategies for tackling hypertension that is difficult to manage in practice.
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