Hospital-acquired infection rates worsened by about 20 percent from 2000 to 2003, accounted for 9,552 deaths, and cost $2.6 billion dollars, according to a recent study of Medicare patients by HealthGrades, Inc., a Colorado-based company that rates health-care quality. Although overall mortality declined, patients experienced more medical errors and infections.

HealthGrades examined 13 possible medical incidents, called "patient safety indicators" (PSIs), in the medical records of Medicare patients over 65 admitted to 5,000 hospitals between 2001 and 2003. PSIs included blood clots, complications of anesthesia, hip fractures, failure to rescue, bedsores, and postoperative infection. Using the data, HealthGrades identified general trends about patient safety and analyzed medical incident rates for most U.S. hospitals