The health system in the U.S. is failing, a startling new report finds.

The U.S. ranks as the worst performer among 10 developed nations in critical areas of health care, including preventing deaths, access (mainly because of high cost) and guaranteeing quality treatment for everyone, regardless of gender, income or geographic location, according to the report, published Thursday by The Commonwealth Fund, an independent research group.  

Based on the new findings, people in the U.S. die the…