In 44-page report released last week, the Government Accountability Office concluded that concierge care will not limit access to care for Medicare patients because so few of the nation's physicians are charging the membership fees associated with the so-called boutique practices. The report was mandated by the Medicare Modernization Act, but identified only 146 physicians nationwide charging membership, a tiny fraction of the 692,000 doctors in the U.S. and the 470,000 who submitted Medicare claims last year. The study did find that most of these concierge practices are in California and Florida and on average, physicians said they had 491 patients under their care, far fewer than the average of 2,716 for the year before they launched the specialized practices.