NEW YORK (Reuters) - New York's attorney general on Thursday expanded his investigation into doctor-ranking programs run by health insurers, warning the programs may steer patients toward low-cost physicians at the expense of quality.

NEW YORK (Reuters) - New York's attorney general on Thursday expanded his investigation into doctor-ranking programs run by health insurers, warning the programs may steer patients toward low-cost physicians at the expense of quality.

Attorney General Andrew Cuomo sent separate letters to Empire Blue Cross Blue Shield, which is a state health plan under the umbrella of WellPoint Inc, as well as Preferred Care and HIP Health Plan/GHI, requesting information on their programs.

Cuomo requested Empire Blue Cross justify its current ranking system. He told Preferred Care to halt the launch of its planned program and warned HIP not to begin its program without his prior consent.

Thursday's letters follow similar ones sent to Aetna Inc, Cigna Corp and UnitedHealth Group Inc earlier this year.

"Consumers need to be aware that doctor ranking programs as currently designed may steer patients to the cheapest, but not necessarily the best doctors, letting profits trump quality," Cuomo said in a statement.

Health insurers nationally have been seeking to distribute more information to patients about health-care costs and quality as part of a push to arm them with more data to make health-care decisions.

Empire spokeswoman Lisa Grenier said the ranking system, Blue Precision, has not yet been launched in New York.

"While we strongly believe consumers, government, and labor paying for health care have every right to both quality and cost information, health care is local and therefore we will not initiate release of such data until we are comfortable that we have appropriately addressed questions raised by stakeholders," Grenier said in an e-mailed statement.

Ilene Margolin, spokeswoman for GHI and HIP, said the company would comply with the attorney general's request.

"HIP and GHI are committed to working collaboratively with providers and payors to develop effective programs that promote quality and protect consumers," Margolin said. She said the insurer would explore these issues with affected groups as well as other state officials.