Prime Healthcare Services acquired 11 California hospitals from 2005 to 2009. After Prime acquired each facility, the percentage of seniors with Medicare who were sent from the emergency room to the main hospital increased. Meanwhile, the statewide Medicare admission rate fell from 44 percent to 41 percent from 2005 through 2009.

California Watch's analysis of 7.4 million patient records shows seniors with Medicare were far more likely to be admitted to the hospital at facilities run by Prime Healthcare Services than in other California hospitals.