(HealthScoutNews) -- More than 270,000 Americans have advanced kidney disease.

However, doctors warn that up to 13 million more are at risk for developing the deadly illness and they don't even know it.

In its early stages, kidney disease has almost no symptoms, explains Dr. William Keane, president of the National Kidney Foundation.

"There are usually very few symptoms that would cause a patient to bring it to the attention of their physician," Keane says. "No pain, headache, upset stomach or chest pain. Kidney disease is a silent disease."

Not surprisingly, many people have advanced kidney disease, called "end-stage renal disease," before they even discover it. At this point, the kidneys are so damaged patients often require dialysis -- where they are hooked up to a machine that purifies the blood because the kidneys can no longer do the job -- or a kidney transplant.

"Kidney disease is an under-recognized, under-diagnosed and under-treated," says Dr. Ellie Kelepouris, associate chief of nephrology at Temple University in Philadelphia. "And the incidence is rising tremendously. Several hundred thousand people out there already have mild kidney disease, and don't know it."

However, there is some good news. When caught early, the progression of the disease can be halted with medications, Kelepouris says.

"We need to get the message out to primary care physicians that they need to refer patients early to a nephrologist [kidney specialist]," Kelepouris says.

About 270,000 people in the United States are being treated for end-stage renal disease, according to recent Health Care Financing Administration statistics. The National Kidney Foundation projects this number will jump to 600,000 by 2010.

Two primary reasons for the growing number of people with kidney disease is the increase in Type II diabetes and hypertension, Keane says. Almost 33 percent of those being treated for end-stage kidney disease are diabetic. High blood pressure is the culprit in about 25 percent of cases.

Because diabetes and hypertension disproportionately affect minorities, blacks, Hispanics and Native Americans are at greater risk for kidney failure.

Other risk factors include a family history of diabetes or hypertension, as well as obesity and smoking.

Controlling diabetes, hypertension and the related protein in the urine is key to preventing kidney disease, Keane says.

Recently, doctors have also discovered that early in the course of kidney disease, many people become anemic. While the precise mechanism is not understood, anemia is believed to cause an enlargement of the left ventricle of the heart, which can lead to heart failure, Kelepouris says.

In other words, the cause of death in some people with kidney disease isn't kidney failure, but cardiovascular disease. By treating the anemia with medications, the swelling in the left ventricle subsides, she says.

Treatments for this type of anemia include folic acid and a drug called erythropoietin.

"This treatment can alter the course of the disease and save people's lives," Kelepouris says.

Keane recommends patients who are at risk of kidney disease ask their doctors three questions: "What's my blood pressure? What's my kidney function? Is there protein in my urine?"

"These three simple questions are the most important in assessing kidney disease risk," Keane says.

What to Do: For more information about kidney disease, visit the National Kidney Foundation, the American Association of Kidney Patients or the American Diabetes Association.

Reference Source 101

For more information on how to prevent other diseases, use
PreventDisease.com's "Quick Prevention Resources".