By Pat Anson, Editor

Depressed patients with low back pain were twice as likely to be prescribed an opioid medication and to receive higher doses, according to the results of a new study that looked at data from a decade ago.

Lower back pain is the world’s leading cause of disability and the most common condition for which opioids are prescribed. Nearly a quarter of the opioid prescriptions written in the U.S. are for low back pain.

"Our findings show that these drugs are more often prescribed to low back pain patients who also have symptoms of depression and there is strong evidence that depressed patients are at greater risk for misuse and overdose of opioids," said John Markman, MD, director of the Department of Neurosurgery's Translational Pain Research Program at the University of Rochester Medical Center and senior author of the study published in the journal PAIN Reports.

The researchers found that patients who screened positive for depression were more than twice as likely to be prescribed an opioid, and they received twice the cumulative dose of opioids per year.

This not only suggests that doctors were more likely to prescribe opioids to a patient suffering both physically and psychologically, but it also implies that analgesics are less effective in pain patients who are depressed.

One obvious weakness of the study is that it relied on prescription data from 2004 to 2009 that was compiled by the Medical Expenditure Panel Survey, a federal survey of patients, their families, healthcare providers and employers. That time frame coincides with a steep rise in opioidprescribing, but does not represent the current environment in which opioid medication is harder to obtain.

The researchers believe, however, that understanding prescribing patterns from a decade ago may help improve the effectiveness of clinical trials. Low back pain is the condition most often studied to approve new pain medications, and depressed patients are often excluded from trials because of incentives to get positive findings about a new analgesic.

“Because several pivotal clinical trials for opioid treatment of LBP (low back pain) have systematically excluded the most depressed patients, it is probable that clinicians and patients alike are drawing conclusions from a study group that may differ in important ways from likely opioid recipients. These clinical trial populations may underrepresent the patients most likely to receive opioids, especially those who are mostly likely to receive higher dosages for longer durations,” Markman said.

Lower back pain may be the world’s leading cause of disability, but there is surprisingly little evidence about the best ways to treat it.

A recent review of 20 clinical studies involving nearly 7,300 patients found that opioids provide only “modest” short-term relief from lower back pain. Opioids were also no more effective than non-steroidal anti-inflammatory drugs (NSAIDs). About half of the patients involved in the studies dropped out because they didn’t like the side-effects of opioids or because they found them to be ineffective.