Blood pressure targets shaped by outcome considerations
By Eleanor McDermid, Senior medwireNews Reporter
12 April 2013
Am J Med 2013; Advance online publication

medwireNews: The risk for different vascular outcomes in patients with hypertension may vary according to the systolic blood pressure (SBP) target they achieve, research suggests.

Overall, the prespecified analysis of 10,705 patients in the Avoiding Cardiovascular Events through Combination Therapy in Patients Living with Systolic Hypertension (ACCOMPLISH) trial validates the usual SBP target of less than 140 mmHg.

Patients had significantly fewer major cardiovascular events if they achieved this target, at a rate of 5.0% across 35.7 months of follow up, compared with 7.6% among those whose SBP remained at or above 140 mmHg. This amounted to a significant 38% risk reduction. Moreover, reducing patients' SBP to within the 10 mmHg range below 130 mmHg or below 120 mmHg did not add further benefits, with rates at 4.6% and 5.0%, respectively.

Major cardiovascular events were defined as cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke. But looking at individual outcomes gave a slightly different picture, report Michael Weber (SUNY Downstate College of Medicine, New York, USA) and team.

For example, patients tended to achieve larger reductions in stroke rates if their SBP was reduced to within the 10 mmHg range below 120 mmHg, at a rate of 1.3% compared with 2.1% for the 10 mmHg range below 130 mmHg and 3.1% for SBPs of 140 mmHg or above.

Conversely, the composite rate of clinical coronary events was higher if patients' SBP was reduced to within the 10 mmHg range below 120 mmHg, at a rate of 4.5% compared with 2.8% for the 10 mmHg range below 130 mmHg.

"It is tempting to argue that the offsetting outcomes we observed at levels <120 mmHg - higher coronary rates but lower stroke rates - could provide clinicians and patients with a context for deciding how aggressively to treat hypertension," say Weber et al. "Unfortunately, our data show that cardiac risk versus stroke risk does not seem to be an even trade."

They say that reducing SBP to below 120 mmHg would cause about two coronary events for every one stroke averted, according to their data. However, this may not be generalizable beyond the ACCOMPLISH trial population, which comprised high-risk patients with previous events or comorbidities such as diabetes.

Patients' achieved SBP also strongly affected renal outcomes, with significantly increased rates of elevated serum creatinine seen at SBPs of 140 mmHg and above, but also at levels below 130 mmHg.

"This sharp J-shaped relationship defines a narrow range between 130 and 140 mm Hg as optimal for preserving kidney function," writes the team in the American Journal of Medicine.

medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013

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