Pain threshold 

Few medical conditions have as complicated and far-reaching of an impact on the economy and health care coverage as pain. The Mayo Clinic reports that the cost of pain on employee productivity is more than $47 billion annually.

But the treatment of pain is extremely controversial. Opioids — medications like Vicodin, OxyContin, and Percocet — can play an important role in reducing pain and promoting recuperation. But concerns about narcotic abuse in the US, also a serious health problem, cause many physicians to be reluctant to prescribe these drugs. And some people are more likely than others to be denied.

A new study by the University of Rochester Medical Center shows that socioeconomic status influences who gets powerful painkillers. Affluent whites are much more likely to be prescribed opioids than poor African Americans and Hispanics, the study shows.

While it's been known for some time that racial and ethnic disparities play a role in who receives opioids, the URMC team found that income and education also influence the prescription of the medications.

URMC researchers examined data collected from 2006 to 2009 of 50,000 visits to about 1,400 emergency departments. Patients from the most affluent neighborhoods were more likely to receive prescriptions for opioids, while patients from the poorest were least likely to receive the drugs.

The researchers don't say why the disparity occurs, but other research suggests that there are multiple factors, including language barriers, poor general health care and coverage, and political influence.

A Michigan study showed that pharmacies located in minority neighborhoods are less likely to adequately stock the drugs.