August 17th, 2014

Lower Treated BP Tied to Elevated Death Rates

Lower Treated BP Tied to Elevated Death Rates

August 11, 2014

NEW YORK - Death rates are higher with treated systolic blood pressures both above 139 mm Hg and below 130 mm Hg, with similar increases in individuals with diastolic blood pressures outside of the 60-79 mm Hg range, according to results of a retrospective study.

"Our study supports the current guidelines in terms of the upper limits of blood pressure, namely systolic blood pressure (SBP), but we feel that a lower limit needs to be established where clinicians should become wary of the dangers of aggressive treatment and consider down-titration or withdrawal of medicines," he told Reuters Health by email.

Particularly in patients with diabetes and chronic kidney disease, aggressive blood pressure lowering has not brought significant benefits and may actually cause harm, Dr. Sim and colleagues write in the Journal of the American College of Cardiology August 12.

Nonlinear associations have been demonstrated for other cardiovascular disease risk factors, so the researchers evaluated discrete ranges of achieved blood pressure and the subsequent risk for mortality and end-stage renal disease (ESRD) in a retrospective cohort study of nearly 400,000 hypertensive patients.

On multivariable analysis, the risk of mortality/ESRD was lowest at a systolic blood pressure of 137 mm Hg, whereas diastolic blood pressures (DBP) lower and higher than 71 mm Hg were associated with worse outcomes.

The mortality-only analyses revealed a U-shaped relationship with blood pressure, while there was a more linear relationship in the ESRD-only analyses, the researchers found.

The lowest-risk, or nadir, blood pressures were slightly lower (131 mm Hg for SBP and 69 mm Hg for DBP) for patients with diabetes than for patients without diabetes (142 mm Hg and 73 mm Hg, respectively).

The nadir blood pressure also differed by age, with higher SBP and DBP values for individuals age 70 years and older (140 and 70 mm Hg, respectively) than for individuals under age 70 (133 and 76 mm Hg, respectively).

"We need to shift our thinking away from the old mantra of 'the lower, the better' and consider 'optimal' or 'appropriate' ranges of blood pressure," Dr. Sim said. "It really comes down to individualizing care, which is what we always strive to do as clinicians."

Dr. Charlotte Andersson, who co-wrote an editorial on the new findings, told Reuters Health by email, "In my perspective, the data by Sim et al. should be regarded as hypothesis generating, and it will be very interesting to see if there are any differences in outcomes of ongoing clinical trials comparing intensive to standard blood pressure lowering therapy (such as the SPRINT trial). Until then, it makes sense to be concerned about poorly controlled hypertension (perhaps especially among younger individuals) and also perhaps too tightly regulated blood pressures among the elderly."

"For now, clinical management should follow the guidelines," concluded Dr. Andersson from Gentofte Hospital in Hellerup, Denmark. "These recommend a treatment target to <140/90 mm Hg for people

SOURCE: http://bit.ly/VcBZHv and http://bit.ly/1r5i246

J Am Coll Cardiol 2014;64:588-597,598-600.