FRIDAY, Dec. 7 (HealthDay News) -- The incidence of the most severe form of acute kidney injury increased dramatically in the United States over the past decade, and deaths associated with the condition doubled over that time, a new study says.

Acute kidney injury refers to the abrupt or rapid decline in kidney function that can occur after serious infections, major surgery or taking certain medications. Acute kidney injury is one of the most common and serious complications of hospitalized patients. The most severe form of acute kidney injury requires dialysis.

Researchers analyzed national data for the years 2000 to 2009 and found that the incidence of acute kidney injury requiring dialysis rose about 10 percent on average a year. Older people, men and blacks were most likely to develop dialysis-requiring acute kidney injury.

The number of deaths associated with dialysis-requiring acute kidney injury increased from 18,000 in 2000 to nearly 39,000 in 2009, according to the study released Dec. 6 in advance of publication in an upcoming issue of the Journal of the American Society of Nephrology.

The incidence of dialysis-requiring acute kidney injury is now greater than the incidence of kidney failure requiring dialysis or transplant, the researchers said.

"Most of the discussion regarding the 'epidemic of kidney disease' in the past decade or more has been focused on chronic kidney disease and end-stage [kidney] disease. We want to point out that acute kidney injury is equally important," study author Dr. Chi-yuan Hsu, of the University of California, San Francisco, said in a news release from the American Society of Nephrology.

Because the number of acute kidney injury cases that don't require dialysis is about 10 times higher than the number of dialysis-requiring acute kidney injury cases, and because even small changes in kidney function are associated with increased illness and death, the data in the study likely represent only the "tip of the iceberg" in terms of the public health burden of acute kidney injury, the researchers pointed out in the news release.

Further research is needed to pinpoint the causes behind the sharp rise in the incidence of dialysis-requiring acute kidney injury, they added.

The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more about the kidneys.