The American Medical Association, Connecticut State Medical Society, and others are suing WellPoint Inc., claiming that the company conspired with other insurers to underpay doctors for out-of-network care. The lawsuit, filed in federal court in Los Angeles, is proposed as a class action against Indianapolis-based WellPoint, the parent of Anthem Blue Cross and Blue Shield plans. The suit follows similar cases filed last month by the AMA and other medical societies against Aetna and CIGNA. The physician groups say insurers used manipulated data, provided through a database operated by UnitedHealth Group's Ingenix unit, to deliberately underpay doctors who don't belong to the health plans' networks and to maximize profits.