As Congress begins to grapple with health reform, an influential senator is looking hard at one of the medical insurance industry’s most controversial practices and raising questions about how well insurers are regulated. Senator John D. Rockefeller IV, the West Virginia Democrat who is chairman of the committee on commerce, is holding hearings on whether health insurers have systematically short-changed patients when they use doctors outside of their health plan’s network. As a result of understating the fees charged by out-of-network doctors, the companies are accused of underpaying consumers by hundreds of millions of dollars over the last decade. ‘This is about outright fraud, Senator Rockefeller said in an interview. The practice came to light in January after an investigation by the New York attorney general, Andrew M. Cuomo, of the databases insurers use to determine the out-of-network payments. The databases are owned by the UnitedHealth Group, one of the nation’s biggest insurers. Mr. Cuomo reached a settlement in which UnitedHealth agreed to stop operating the databases, run by the company’s Ingenix unit, and replace them with a new, independent source of rate information. ‘Insurance companies are part of everybody’s frustration in terms of health […]