The Department of Health and Human Services’ Centers for Medicare and Medicaid Services (CMS) launched an investigation into whether Humana improperly communicated with its senior citizen enrollees about health care reform legislation pending in Congress. In a warning letter to Humana, CMS expressed concern that some of the company’s mailers were misleading and confusing partly because the company’s lobbying campaign could be mistaken for an official communication about Medicare benefits. CMS ordered the company to immediately halt all such mailings and remove any related materials from its Web site. Humana, which is cooperating with the investigation, could be fined or suspended from marketing its plans and enrolling new beneficiaries if it is found to have violated regulations governing how health plans may communicate with beneficiaries.