A draft NICE guideline says patients with stage 1 hypertension who have an estimated 10-year CVD risk of 10% should be offered BP-lowering drugs.
NICE says this is the 'biggest change' to its existing guideline on diagnosis and treatment of hypertension, which recommends a 20% risk threshold.
The move could mean that as many as 450,000 more men and 270,000 more women should be prescribed BP-lowering medication.
However, according to UK research quoted in the draft NICE guideline, 'potentially around 50% of people with stage 1 hypertension and risk below 20% are already being treated with antihypertensive drugs'.
The final updated guideline is expected to be published in August. The RCGP urged caution, and warned that GPs 'have concerns about overdiagnosis and the unintended harms of prescribing medication to groups of patients when the benefits may be limited'.
High BP affects around 13.5m people in England and contributes to around 75,000 deaths a year. Clinical management of hypertension accounts for 12% of visits to primary care and up to £2.1bn of healthcare expenditure, NICE said.
Anthony Wierzbicki, consultant in metabolic medicine/chemical pathology and chair of the guideline committee, said high BP was 'by far the biggest preventable cause of death and disability in the UK through strokes, heart attacks and heart failure'.
Explaining the overhaul proposed to the NICE guideline, he said: 'The guideline effectively shifts the focus to earlier intervention with lifestyle or drug treatment because this may slow the age-related deterioration of blood pressure. This would keep people well for longer and reduce the long-term need for multiple medications.
'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. The guideline also places a greater emphasis on achieving and maintaining blood pressure targets as many people with high blood pressure are undertreated.'
RCGP chair Professor Helen Stokes-Lampard said: 'Taking steps to prevent cardiovascular disease in patients is vital to help safeguard their long-term health and wellbeing, and it is a key pledge in the NHS long-term plan. But many GPs do also have concerns about overdiagnosis and the unintended harms of prescribing medication to groups of patients when the benefits may be limited.
'Lowering the threshold for making a diagnosis of hypertension, or high blood pressure – a condition that already affects a very large number of patients in the UK - is likely to affect thousands, if not millions of patients, so this decision must not be taken lightly and must be evidence-based.
'We know that weight control, careful diet, and better exercise habits all remain key ways to prevent or reduce hypertension. GPs already advocate healthy lifestyle changes and discuss these with their patients where possible within the constraints of a standard 10-minute appointment.'
Stage 1 hypertension is defined as a clinic blood pressure reading of 140/90 mmHg or higher, or an ambulatory blood pressure daytime average or home blood pressure monitoring average of 135/85 mmHg or higher.