Results of a study in this week's issue of THE LANCET provide further evidence that a class of drugs that lower blood pressure are a treatment option for older people at high cardiovascular risk. The study also emphasises the importance of early blood-pressure lowering after the start of treatment to reduce the risk of cardiovascular events such as heart attack and stroke.
The VALUE (Valsartan Antihypertensive Long-term Use Evaluation) trial investigated whether the angiotensin-receptor blocker valsartan would reduce cardiac illness and death more than the calcium antagonist amlodipine among patients with high blood pressure at high cardiovascular risk.
Around 15000 patients from 31 countries (aged 50 years or older with treated or untreated high blood pressure) were randomly allocated either valsartan or amlodipine until 1450 patients had reached the primary endpoint-a composite outcome of cardiac illness or death.
Patients were followed up for over 4 years. There was no difference in the occurrence of cardiac disease between the two groups, although initial blood-pressure lowering was more pronounced for patients assigned amlodipine. Fewer patients in the valsartan group (13%) developed type 2 diabetes compared with those allocated amlodipine (16%).
The effects of either valsartan or amlodipine among patients who achieved adequate blood-pressure control in VALUE is outlined by the same investigators in a research letter in this week's issue (p 2049). Although major subsequent cardiac events were similar between patients given either drug, admission to hospital for heart failure was significantly lower with valsartan. The investigators comment: 'Reaching blood pressure control (systolic <140 mm Hg) by 6 months, independent of drug type, was associated with significant benefits for subsequent major outcomes; the blood pressure response after just 1 month of treatment predicted events and survival.'
Commenting on the VALUE study and two previously published trials investigating the efficacy of angiotensin-receptor blockers for lowering blood pressure in patients at high cardiovascular risk (p 2010), Lars Lindholm from Umea University, Sweden, states: "So what can we learn from these three trials of angiotensin-receptor blockers? First, this group of drugs seems to be at least as effective as other types of antihypertensives in preventing cardiovascular events, provided blood pressure is equally well lowered. Second, the degree of lowering of blood pressure-and especially early control of blood pressure-is very important for the cardiovascular outcome. Third, the incidence of new-onset diabetes is lower in the patients treated with an angiotensin-receptor blocker than in the control groups of these trials." He concludes: "What we do not know for sure, however, is whether there are any differences between the preventive effects of losartan, candesartan, and valsartan. To answer that question, we need a new randomised trial that compares them. I suspect, however, that we will have to wait a very long time for the results of such a trial, if it is ever carried out".