— Photo by Dan Saelinger

En español | American hospitals are capable of great medical feats, but they also are plagued by daily errors that cost lives. No one knows that better than Ilene Corina. In the 1990s, she saw a medical team rescue her fragile premature newborn, but she also endured the death of another son — a healthy 3-year-old — when, she says, doctors failed to attend to complications from a routine tonsillectomy.

Sign up for the AARP Health Newsletter.

When a family member dies because of a hospital's mistake, "what do we care about the excellence in the system?" says Corina, 51, of Long Island, N.Y., founder and president of a patient safety advocacy group. "We have to voice our anger about the problems we see in the health care system."

Corina had already joined the patient safety movement when, in 1999, the Institute of Medicine's now-famous report, To Err Is Human, burst into public consciousness with its startling announcement: Each year as many as 100,000 Americans die in hospitals from preventable medical mistakes.

Today, more than a decade into the fight against medical errors, there's little reason to believe the risks have declined substantially for the 37 million people hospitalized each year. In fact, recent studies suggest a problem that's bigger and more complex than many had imagined. A report released in January on Medicare patients found that hospital staff did not report a whopping 86 percent of harms done to patients. If most errors that harm patients aren't even reported, they can never be tracked or corrected, the Health and Human Services Department report pointed out.

This latest study built on an earlier HHS study of Medicare patients that found one in seven suffered serious or long-term injuries, or died, as a result of hospital care. Researchers said about 44 percent of the problems were preventable.

In another key study published last spring in the journal Health Affairs, researchers examined patient charts at three of America's leading hospitals and found that an astounding one in three admissions included some type of harm to the patient.

Next: Safety innovators introduce new way to minimize slipups. »