Tuesday, August 7, 2007

Reduced mortality in treatment group halts BP trial in elderly

Reduced mortality in treatment group halts BP trial in elderly

August 7, 2007

London, UK - The largest ever study to look at the effects of lowering BP in those aged 80 and over—the Hypertension in the Very Elderly Trial (HYVET)—has been halted prematurely due to significant reductions in both stroke and overall mortality in the treatment arm [1].

One of the investigators, Dr Ruth Peters (Imperial College, London), told heartwire that the reductions in stroke and mortality observed "were statistically significant and not trivial." She declined, however, to give specific figures. "We are being really cautious about this." She said the plan is to simultaneously publish the results in a peer-reviewed journal and present them at a major medical meeting, "probably sometime next spring."

The decision to halt the study was taken by the steering committee following a recommendation to that effect from the data safety monitoring board last month. All patients in the study are being brought back to have their treatment reviewed and will have the option of switching to the active-therapy arm. The trial had been slated to end in 2009.

Great news for the over-80s

HYVET was being conducted in a number of countries in Eastern and Western Europe as well as in Tunisia and China and included 3845 patients aged 80 or older. HYVET was undertaken because previous smaller studies had produced inconclusive results with regard to whether blood-pressure lowering was beneficial or not in the very elderly. In some studies, although antihypertensive therapy reduced the risk of stroke, it did not reduce—and in some cases increased—mortality.

The entry criteria for HYVET were a sitting systolic blood pressure of 160 to 199 mm Hg and a diastolic BP of 90 to 109 mm Hg. Peters said that later on in the trial, patients with isolated systolic hypertension were also allowed to participate. Patients were randomized to either placebo or a low-dose diuretic (indapamide 1.5 mg sustained release) and an additional ACE inhibitor (perindopril 2 mg or 4 mg a day) if required.

The primary end point is stroke events (fatal and nonfatal), and secondary outcome measures include total mortality, cardiovascular mortality, cardiac mortality, stroke mortality, and skeletal fracture.

"It was not clear prior to our study whether the over-80s would benefit from blood-pressure-lowering medication in the same way as younger people," says lead investigator Dr Chris Bulpitt (Imperial College, London) in a press release.

"Our results are great news for people in this age group because they suggest that where they have high blood pressure, such treatment can cut their chances of dying as well as [suffering a] stroke," he added.

Imperial College, London. Trial stops after stroke and mortality significantly reduced by blood-pressure-lowering treatment for those aged 80 and over [press release]. August 7, 2007. Available here.

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