More than half of all non-referred visits to specialists are for routine or preventive care that likely could have been managed by the patient's primary care physician, according to a study in the Annals of Family Medicine.

The authors studied nearly 1.3 billion visits between 2002 and 2004 to office-based medical and surgical specialists, as well as ob-gyns and psychiatrists. They found that more than 46 percent of the time, established patients visited specialists for routine or preventive care for a known condition. In more than half of those visits (53.4 percent), another doctor did not refer them. These 434 million visits, the authors contend, may not have required more expensive specialist care.