Medical errors may now be the third-leading cause of death in the United States - claiming 251,000 lives every year, more than respiratory disease, accidents, stroke and Alzheimer's, according to a study published Tuesday.

From incidents of nurses giving potent drugs to the wrong patient to surgeons removing the wrong body part, errors in hospitals and other facilities are incredibly common, the patient-safety researchers behind the analysis concluded.

The study, appearing in BMJ, calculates far higher numbers than a 1999 report that called such mistakes an "epidemic." The new totals equate to nearly 700 deaths a day, or about 9.5 percent of all deaths annually in the United States.

Martin Makary, a professor of surgery at the Johns Hopkins University School of Medicine who led the research, said in an interview that "medical errors" include everything from bad doctors to more systemic issues such as communication breakdowns when patients are handed off from one hospital department to another.

"It boils down to people dying from the care that they receive rather than the disease for which they are seeing care," he said.

The issue of patient safety has been a hot topic ever since the Institute of Medicine issued a landmark report on preventable medical errors 17 years ago, shocking the medical establishment and leading to significant debate about potential remedies.

Based on one study, the institute estimated deaths due to medical errors to be as high as 98,000 a year. Makary's research involves a more comprehensive analysis of four large studies, including ones by the Health and Human Services Department's Office of the Inspector General and the Agency for Healthcare Research and Quality that took place between 2000 to 2008.

Makary said he and co-author Michael Daniel, also from Johns Hopkins, conducted the analysis to shed more light on a problem that many hospitals and health-care facilities try to avoid discussing.

Although all providers extol patient safety and highlight the various safety committees and protocols they have in place, few offer the public specifics on actual cases of harm. Moreover, the Centers for Disease Control and Prevention doesn't require the reporting of errors in the data it collects about deaths through billing codes, making it hard to see what is going on at the national level.

The CDC should update its vital-statistics-reporting requirements so that physicians must report whether there was any error that led to a preventable death, Makary said.

"We all know how common it is," he said. "We also know how infrequently it's openly discussed."

Kenneth Sands, who directs health-care quality at Beth Israel Deaconess Medical Center, a patient care and research affiliate of Harvard Medical School, said that the surprising thing about medical errors is the limited change that has taken place. Only hospital-acquired infections have shown improvement. "The overall numbers haven't changed, and that's discouraging and alarming," he said.

Sands, who was not involved in the BMJ study, said that one of the main barriers is the tremendous diversity and complexity in the way health care is delivered.

"There has just been a higher degree of tolerance for variability in practice than you would see in other industries," he said.

Frederick van Pelt, a doctor who works for the Chartis Group, a health-care consultancy, said another element of harm that is often overlooked is the number of severe patient injuries resulting from medical error.

"Some estimates would put this number at 40 times the death rate," he said. "Again, this gets buried in the daily exposure that care providers have around patients who are suffering or in pain that is to be expected following procedures."