No benefit to excessive BP lowering, study says

Medical Tribune September 2009 P14
David Brill

Lower is not necessarily better when it comes to blood pressure (BP), a recent systematic review has found.

The analysis of seven randomized trials concluded that there was no clinical benefit to lowering BP beyond a currently recommended target of 140/90 to 160/100 mmHg.

Patients treated to lower targets did achieve significantly lower BPs (-4/-3 mmHg), but there were no differences in total mortality, major cardiovascular events, myocardial infarction or stroke rates compared to those treated to standard targets.

The review included data from a total of 22,089 patients, who had taken part in trials targeting various different diastolic BPs below 85 mmHg. No suitable trials of low systolic BP targets were identified. [Cochrane Database Syst Rev 2009;(3):CD004349]

“At present there is no evidence from randomized trials to support aiming for a BP target lower than 140/90 in the general population of patients with elevated blood pressure,” said lead author Dr. Jose Arguedas, of the University of Costa Rica, Costa Rica.

“Our research included patients with diabetes or chronic renal disease, and the evidence was slightly less robust for those subgroups of patients. We intend to carry out separate systematic reviews for those subgroups, especially because guidelines recommend even lower blood pressure targets for them,” he added.

There were also no significant differences in the incidence of congestive heart failure (relative risk [RR] 0.88, 95% CI 0.59 – 1.32) and end-stage renal disease (RR 1.01, 95% CI 0.81 – 1.27) between patients treated to low, as compared to standard, targets.

The full picture remains unclear with regard to safety, the authors note, since six of the seven trials did not provide complete information on serious adverse events and withdrawals.

Excessive BP lowering could cause unnecessary cost and inconvenience to patients, as well exposing them to a potential increased risk of adverse events if the number of antihypertensive medications is increased, they add.