Ashish Jha, a professor of health policy at Harvard School of Public Health, calls American hospitals the most dangerous place on earth for human beings. 

"On a Friday afternoon, my dad become sick. He was confused and wasn't responding, as he headed to the hospital, he was heading to the most dangerous place on earth, an American hospital," Jha said. 

Jha's father spent two days in the hospital. During his visit, medical staff misdiagnosed his condition and he received the wrong medication as a result. 

"In the U.S., chances of being injured or killed from medical care that is intended to help, maybe as high as 15 to 20 percent," Jha said.  

According to research, more than 400,000 deaths and injuries occur each year from medical care.

What are the causes of patient injury from medical errors? 

A number of reasons contribute to patient harm from health care mistakes. 

The most common are patient falls (when a patient falls to the ground), infections from health care facilities and misdiagnoses. 

Patient falls are the number one cause of injuries in hospitals. More than 500,000 falls happen yearly in the U.S., resulting in 150,000 injuries. 

According to a study, one-third of adults over 65 fall each year, injuries include bone fractures, excessive bleeding and even death. 

"Poor performing health care systems represent a major problem for the world's population but the good news is there's room for improvement," Jha said.