Excerpt: "Evidence indicates that these physician staffing firms charge significantly higher in-network rates than their counterparts, thereby driving reimbursement upwards as they enter into staffing arrangements with hospitals. We are concerned about the increasing role that private equity firms appear to be playing in physician staffing in our nation’s hospitals, and the potential impact these firms are having on our rising health care costs," said Pallone and Walden.

Click here to read the letter to KKR & Co. Inc.

Click here to read the letter to Blackstone Group.

Click here to read the letter to Welsh, Carson, Anderson, & Stowe.