MINNEAPOLIS (AP) — Minnesota Attorney General Lori Swanson sued a debt collection agency on Thursday, saying it failed to protect the confidentiality of health care records for thousands of state residents and did not reveal the extent of its involvement in their health care.

The lawsuit says Accretive Health Inc., a Chicago-based company that works with hospitals to maximize revenue, gained access to patient data through contracts with two Minnesota hospitals, then scored patients' risk of becoming hospitalized. Swanson said the agency then shared its activities with investors on Wall Street "without the knowledge or consent of patients who have the right to know how their information is being used and to have it kept confidential."

A spokeswoman for Accretive, part of a New York private equity fund, did not immediately return messages seeking comment.