Aspirin Reduces Cardiac Risk in Hypertensive Kidney Disease

Aspirin Reduces Cardiac Risk in Hypertensive Kidney Disease

By David Douglas

NEW YORK (Reuters Health) Sep 14 - The benefits of antiplatelet therapy appear to outweigh the risks in hypertensive patients with chronic kidney disease (CKD), say Australian and Italian researchers.

"There's been no clear evidence that aspirin therapy benefits people at high risk of heart disease and stroke, including those with CKD. This has led to uncertainty about whether to recommend aspirin therapy," said lead author Dr. Meg J. Jardine in a statement.

But based on a post-hoc analysis of data from the randomized HOT study, she told Reuters Health by e-mail, "Aspirin appears to be an effective way to improve the health of people with kidney disease, many of whom do not realize they have it. And, the good news is that aspirin is cheap and available."

In the September 14th issue of the Journal of the American College of Cardiology, Dr. Jardine of The George Institute for Global Health in Sydney and colleagues report on 18,597 patients with diastolic hypertension who took either aspirin (75 mg) or placebo every day for an average of nearly four years.

At baseline, the median estimated glomerular filtration rate (eGFR, given in ml/min/1.73 m2) was 73, but 3619 patients had eGFRs less than 60.

According to the report, 671 people had at least one major cardiovascular event (a stroke, myocardial infarction, or cardiovascular-related death).

Aspirin reduced the risk of these events by 9% in patients with a baseline eGFR of 60 or more, by 15% with an eGFR of 45 to 59 and by 66% in patients with an eGFR below 45.

Aspirin also reduced total mortality in patients with the worst renal function -- by 11% when eGFR was 45 to 59 and by 49% when it was below 45.

Major bleeding events were more prevalent with lower eGFR, but not significantly. The researchers estimate that for every thousand people with eGFR below 45 treated for 3.8 years, 76 major cardiovascular events and 54 all-cause deaths would be prevented at the cost of 27 excess major bleeds.

The author of an accompanying editorial, Dr. Ravinder Wali of the Inova Transplant Center in Fairfax, Virginia told Reuters Health by e-mail that "If a single daily dose of aspirin can be proven to prevent these events in people with chronic kidney disease, that will be of tremendous benefit since people with CKD more often than not die from cardiovascular disease."

In a separate study reported online August 23rd in the American Journal of Kidney Disease, researchers present another approach to reducing mortality in CKD patients.

Dr. Csaba P. Kovesdy of Salem VA Medical Center, Virginia and colleagues observe that men with non-dialysis dependent CKD appear to benefit from phosphorus binders -- a therapy that has been employed in patients on dialysis.

Dr. Kovesdy and colleagues studied 1188 men with moderate to severe CKD, 344 of whom received phosphorus binder therapy. Over a median follow-up of three years, 658 patients died.

"Administration of phosphorus binders was associated with a significantly lower mortality," Dr. Kovesdy told Reuters Health by e-mail. The hazard ratio for death was 0.61 in treated patients.

Treatment was not associated with progression of CKD, he said. "Our findings apply mostly to calcium-based binders, since most of the patients in our study received such agents; but based on the postulated mechanisms of action responsible for the observed associations similar effects could be present for other types of binders too," he noted.

The findings were observational, Dr. Kovesdy concluded, and "the main implication of our study is that it should encourage clinical trials to examine the effect of phosphorus binders on mortality in CKD."

J Am Coll Cardiol. Posted online September 14, 2010. Abstract

Am J Kidney Dis. Posted 2010. Abstract

http://www.medscape.com/viewarticle/728533