The number of acute kidney injuries is increasing, a study finds.(Photo: Robert Hanashiro, USA TODAY)
Acute kidney injuries have more than doubled since 2000, causing nearly 39,000 deaths in 2009 alone, according to a new study.
Severe infections, heart failure, trauma, bad reactions to medication
or surgical complications can all cause sudden declines in kidney
function, but it's not yet clear which - or which combinations - of
these is driving the 10% annual rise.
It's possible, researchers
say, that some newer medications are damaging kidneys, or that pneumonia
strains are getting more dangerous. Or maybe it's simply that
treatments for other diseases, such as sepsis infections and respiratory
failure, are getting better, while treatment for acute kidney disease
"That would be my guess," says Ramon Bonegio, who studies
acute renal failure at the Boston University School of Medicine and is
an attending physician at Boston Medical Center.
There are no
drugs to reduce the incidence or severity of acute kidney injuries,
though several are under development, says Bruce Molitoris, president of
the American Society of Nephrology.
In the new study, published
Thursday in the society's journal, researchers reviewed 1.9 million U.S.
hospitalizations due to acute kidney injuries. Only the most serious
injuries, which required patients to go on dialysis, were counted.
Although acute kidney disease is far more common among African
Americans than whites, the study found that increases were consistent
across races, genders and from middle age up, says Raymond Hsu, a study
author and research fellow in the division of nephrology at the
University of California-San Francisco.
Molitoris, also a
professor of medicine at Indiana University, says he was surprised by
the high rate of increase Hsu found but does not doubt his conclusions.
"I think awareness is a big issue," Molitoris says. "It's an under-recognized major complication in the hospital."
Hsu and Molitoris drew a distinction between the acute kidney injuries
that were the subject of this study and the chronic kidney disease that
can come with diabetes, hypertension or immune conditions - although
chronic kidney disease can lead to acute injuries.
kidney disease, which affects a quarter of those over 60, once a patient
needs dialysis, the kidneys have been damaged beyond repair. In acute
kidney injury, dialysis is meant to be temporary, until the kidneys can
recover their ability to filter the blood. Nearly one-quarter of those
with acute kidney injury die before they can be taken off dialysis.
Hsu says the high death rate suggests that dialysis may be overused in
some of the sickest patients, who should be given a choice - before
they're acutely ill - about whether to pursue a painful procedure that
may do little to extend their lives.
"Would they want those
invasive measures?" asks Hsu. "By the time they reach us, they are
already too sick to express those wishes."
Hsu says he next hopes
to study patients who do well after an acute kidney infection and
dialysis, to better understand their recovery process and translate it
to those with worse outcomes.