Illicit Drug Use Linked with Chronic Low Back Pain

Study results published online ahead of print in Spine indicate that community-based adults in the United States who have chronic low back pain are more likely to use illicit drugs—including marijuana, cocaine, heroin, and methamphetamine—when compared with those without chronic low back pain. The study also found that patients with chronic low back pain and a history of illicit drug use were more likely to have a current prescription for an opioid analgesic.

Lead researcher Anna Shmagel, MD, a core investigator at the Minneapolis VA Center for Chronic Disease Outcomes Research and an associate professor of Medicine at the University of Minnesota, and colleagues were unable to determine the direction of the relationship, but they feel the patterns of illicit drug use may have implications when making decisions regarding opioid prescribing in patients with back pain.

With addictive medications like opioids and benzodiazepines frequently prescribed to patients with chronic low back pain, but little known regarding illicit drug use among this population, Dr. Shmagel, et al. used data from the back pain survey, which was administered to a representative sample of U.S. adults aged 20 to 69 years during the 2009-2010 cycle of the National Health and Nutrition Examination Survey, or NHANES.

For the study, chronic low back pain was defined as pain in the area between the lower posterior margin of the ribcage and the horizontal gluteal fold for at least 3 months. The drug use questionnaire was self-administered in a private setting, covering lifetime and current use of marijuana or hashish, cocaine, heroin, and methamphetamine. Chi-square tests, one way ANOVA and logistic regression, adjusted for age, gender, race and level of education, were used for comparisons.

The study team found that approximately 49% of participants with chronic low back pain had ever used illicit drugs, compared with a rate of 43% observed among those without chronic low back pain. Illicit drug use within the past 30 days (classified as current for the study) was reported by 14% of participants with chronic low back pain versus 9% of those without such pain.

Respondents with chronic low back pain were more likely to use all four illicit drugs assessed in the study. Lifetime rates of each drug for those without and without chronic back pain, respectively, were as follows:

• Marijuana: 46.5% vs 42.0%.
• Cocaine: 22.0% vs 14.0%
• Methamphetamine: 9.0% vs 5.0%.
• Heroin: 5.0% vs 2.0%.

After adjustments, patients with chronic low back pain were more than two times as likely to report methamphetamine and heroin use. Active prescriptions for opioid analgesics were reported by 22.5% of subjects who had ever used illicit drugs, versus 15% of those who had not. Opioid prescriptions were also more likely in current illicit drug users, but the difference compared with other subjects was not statistically significant.

“As we face a prescription opioid addiction epidemic, careful assessment of illicit drug use history may aid prescribing decisions,” wrote the study team.