About 1 in 10 patients experience some kind of harm while receiving medical care and in about half of those cases -1 in 20 -the harm is preventable, according to a study published this week in the BMJ.

The study, a large systematic review of existing scientific literature on the topic, examined data from 66 previously published studies involving 70 different groups of mostly adult patients -337,025 patients in total -from countries around the world.

Thirty-three of the patient groups in the studies were in the United States, and all of the studies were conducted within the past 19 years.

The studies identified 28,150 patients who had been harmed during the course of their medical care. Of those, 15,419 had experienced harm that was preventable.

In 12 percent of the cases, the preventable harm was severe enough to result in permanent disability or death.

“Our findings affirm that preventable patient harm is a serious problem across medical care settings,” the authors of the study conclude. The authors also say their findings are applicable across all countries.

As the authors point out, the disability and death caused by preventable medical harm is equal to that caused by multiple sclerosis or cervical cancer in developed countries or by tuberculosis or malaria in developing countries.