Patients suffering from high blood pressure - the single most important risk for death worldwide - could be helped by a UK-wide clinical trial aimed at improving treatments.
Clinicians have recruited the 500th patient to the trial, which is evaluating the most effective drug combinations for newly diagnosed patients.
Researchers want to know whether prescribing two drugs at the start of treatment is better than the more common approach of starting patients on one drug and only introducing a second if the first is not effective enough.
Patients will be initially given both tablets or one tablet and a placebo. All patients will be given both tablets four months after they were first treated.
The two drugs in the trial - losartan and hydrochlorothiazide - work to lower blood pressure in different ways.
Losartan, an angiotensin receptor blocker, blocks a hormone that narrows blood vessels leading to high blood pressure. Hydrochlorothiazide is a diuretic, which works by increasing the loss of salt in urine - linked to high blood pressure.
People with high blood pressure are three times more likely to develop heart disease and stroke. They are also twice as likely to die from these conditions compared with people who have normal blood pressure.
The study, designed by the British Hypertension Society, is being run with a £2.6 million grant from the British Heart Foundation (BHF). University centres involved include Cambridge, Dundee, Edinburgh, Glasgow, Imperial College, Leicester and Queen Mary University of London.
Professor David Webb, of the BHF Centre for Cardiovascular Science at the University of Edinburgh, where the 500th patient was recruited, said: "We believe that patients' blood pressure will be controlled much better if they take two drugs from the outset as patients who first take one, and then a second drug, never appear to catch up to patients who were given both drugs in the first instance. If this is indeed the case, it could make a significant difference for many thousands of patients."
Professor Morris Brown, of the University of Cambridge, who is leading the study, said: "Around 16 million people in the UK are affected by high blood pressure. This study aims to look at how we can improve treatments to control blood pressure, and consequently reduce associated risks of stroke and heart attacks."
The trial is part of the PATHWAY (Prevention and Treatment of Hypertension With Algorithm-based therapy) initiative. The project also includes two further studies, which include best options for patients with treatment-resistant hypertension and ways to use diuretics while reducing the incidence of diabetes.
