Karolinska ranked fourth best hospital in the world by Newsweek, remains best in Europe

This is the seventh year in a row that Karolinska has been placed on the annual top ten list, the hospital said in a press release.

"It is above all a recognition of the world-leading healthcare, research and education that all our employees conduct," hospital director Christophe Pedroletti said in the press release.

The list - which includes hospitals in 32 countries - is based on, among other things, treatment outcomes, patient safety, and how patients experience treatment and quality.

This year, the Mayo Clinic in the US retains its first place.