Physicians' prescriptions of opioid drugs for back pain are inconsistent, found a Duke University Medical Center study, the largest and most comprehensive of its kind.

The study found significant regional, social and economic disparities in the use of the powerful painkillers. Specifically, the researchers found that patients are more likely to take opioid drugs for their back pain if they live in the South, hold public insurance, are less educated and have low income. Moreover, the use of a powerful opioid drug, oxycodone, doubled from 1996 to 1999, found the researchers.

The study, published in the April 15, 2004, issue of the journal Spine, constitutes the largest and most comprehensive look at the use of opioids for the treatment of back pain, according to the researchers.

Because of the heated controversy in medical circles about whether the use of opioids is an effective and safe long-term treatment strategy for back pain, the researchers believe the patterns and trends in opioid use they have uncovered could provide a rational scientific basis for future investigation of safety and effectiveness of these drugs in the U.S.

"The wide variations in the use of opioids suggest that there is a definite need to improve prescribing patterns for patients with back pain," said Duke lead researcher Xuemei Luo, Ph.D. "A better understanding of the underlying reasons why the variations occurred and what constitute most optimal prescribing should help in setting effective national policy related to prescribing practice."

Back pain is a major health-care issue, Luo said, with an estimated 15 to 20 percent of all Americans suffering from back pain at least once during a one-year period. An earlier study (January 2004) by Luo showed that back pain patients consume more than $90 billion annually in health-care expenses, with approximately $26 billion of that amount directly attributable to treating the back pain.

"Despite its widespread use for back pain, no study has examined at the national level the patterns and trends of opioid use among individuals with back pain," Luo continued. "While opioids are the most potent analgesic available, many physicians are reluctant to prescribe them because of their serious side effects, the potential for addiction and the possibility of drug tolerance.

"Just as importantly, no well-designed large-scale clinical trial has proven the efficacy of opioids as a long-term treatment of back pain," said Luo, a member of Duke's Center for Excellence in Surgical Outcomes.

To better understand the use of opioids, the Duke team mined the 1996 to 1999 data from the Medical Expenditure Panel Survey (MEPS). The MEPS is a national survey conducted by the Agency of Healthcare Research and Quality (AHRQ) and the National Center for Health Statistics. Between 23 and 27 million people reported back pain during each year of the four-year period.