Insured patients rejected by doctors.

• Position: Patient Protection Act

As required under the Patient Protection and Affordable Care Act of 2010, millions of people soon will be added to the ranks of the insured. However, this rapid expansion of coverage is colliding with a different, potentially problematic trend that could end up hampering access to health care. Since 2005, doctors have been accepting fewer and fewer patients with health insurance, according to a study by Tara Bishop, assistant professor of public health at Weill Cornell Medical College, New York.

Insured patients could face new obstacles to receiving the medical attention they need, and overall access to health care actually could contract.

Bishop looked at data from a national survey run by the Centers for Disease Control's National Center for Health Statistics and found an overall decline in physician acceptance of several types of insurance. First, she noted a modest drop in acceptance of Medicare patients, from 95.5% in 2005 to 92.9% in 2008. Physicians also turned more and more Medicaid patients away over the four-year period--a phenomenon the authors attribute to Medicaid's historically low reimbursement rates.

The most surprising decline of all, though, was seen in doctors' acceptance of new patients with private...