NEW YORK (Reuters Health) - Patients who suffer a heart attack often develop a kidney injury and this complication significantly increases the risk of death, new research shows.
In acute kidney injury (also called acute renal failure) the kidney cannot perform its function of filtering waste from the body. As a result, harmful substances can accumulate in the blood and cause harm. In heart attack patients and other high-risk groups, the incidence of acute kidney injury is high, ranging from 10 to 25 percent.
In a study of roughly 147,000 heart attack patients, researchers found that about 19 percent overall developed acute kidney injury, including 7 percent with mild kidney injury, 7 percent with moderate kidney injury, and 5 percent with severe acute kidney injury.
Dr. Chirag R. Parikh from Yale University School of Medicine, New Haven, Connecticut and colleagues found a "strong independent graded relationship" between the severity acute kidney injury and long-term mortality at all time points up to 10 years following heart attack.
At 10 years, mild acute kidney injury was associated with a 15 percent increased risk of death, moderate kidney injury with a 23 percent increased risk and severe kidney injury with a 33 percent increased risk of death, according to the study, published in the Archives of Internal Medicine.
Less than 10 percent of patients who had severe acute kidney injury post-heart attack were alive at 10 years. By comparison 12 percent, 21 percent and 32 percent of patients with moderate, mild and no acute kidney injury, respectively, were alive at the 10-year mark.
This study shows that acute kidney injury signifies a long-term risk of premature death, Parikh and colleagues say.
"Even patients with mild and moderate acute kidney injury, which in most cases is short lived and clinically reversible renal failure, had an elevated risk of death after hospitalization that did not dissipate over time," they point out.
"These findings are novel and do not support the conventional teaching that acute kidney injury in its mild form is inconsequential," the doctors add.
They recommended, based on their study, that heart attack patients who develop acute kidney injury "be closely monitored in the months to years" after discharge.
The researchers say studies are needed to gain a better understanding of the predictors of acute kidney injury, specifically, the current procedures and drug therapies for heart attack "that may be helpful to the heart but harm the kidney."
SOURCE: Archives of Internal Medicine, May 12, 2008.
