In this July 12, 2012 photo, a woman stands at the registration window at Nuestra Clinica Del Valle in San Juan, Texas. The state has one of the nation's most restrictive Medicaid programs. Eric Gay/AP

The health care that doctors provide to Medicaid patients and the uninsured through the so-called safety-net system is no different from the care delivered to privately insured patients in terms of appointment length and treatments offered, both of which are key measures of health care quality, according to a new study published Monday in the journal Health Affairs.

One of the thorniest debates surrounding the Obama administration's Affordable Care Act is whether individual states should accept federal funding to expand Medicaid programs, in order to cover a greater swath of uninsured people who weren't previously considered poor enough to qualify for Medicaid but who still couldn't afford to buy insurance on their own.

And those who oppose Medicaid expansion, such as Louisiana Gov. Bobby Jindal, argue that costs will eventually be shifted to state taxpayers, or claim that patients on Medicaid receive substandard medical care, citing a 2010 University of Virginia study which found that Medicaid patients were more likely to die in surgeries than those who were uninsured or insured privately.

But the new study conducted by George Washington University's School of Public Health and Health Services could potentially lend credence to the states that have opted to expand Medicaid coverage.

That's because the researchers found "no meaningful difference" between the quality of care doctors gave patients who were privately insured and the quality of care received by the uninsured, Medicaid patients and those who were treated at community health centers, which primarily cater to the poor and uninsured.

"The findings refute the belief that primary care doctors deliver less care to the nation's poor," said lead author Brian K. Bruen, a research scientist at GWU's School of Public Health and lead author of the study.

Bruen and his team examined data gathered by the National Center for Health Statistics from more than 31,000 visits to primary care doctors by patients under the age of 65 between the years 2006 and 2010. They looked at how long doctors spent with each patient, the types of treatments provided and whether doctors offered patients preventive health counseling about topics like smoking or obesity. They statistically accounted for age, gender, race and reason for visit.

What they found surprised them. Studies have shown that patients are more satisfied with their health care and are more likely to adhere to treatment plans when their doctors spend more time on visits. And in this study, doctors spent the same amount of time — an average of 18.5 minutes — treating patients who were uninsured or on Medicaid as they did with patients who had private health insurance.

Whether or not the care took place at a community health center or a private doctor's office didn't affect visit length, either.

The researchers found that doctors did spend an average of four minutes longer on new patients or those with more severe health problems.