Is opioid analgesic treatment effective in patients with low back pain?
Effective pain control in patients with low back pain is still elusive. Approximately one-half of all patients with low back pain who take an opioid analgesic will stop treatment because of ineffectiveness or adverse effects. Patients staying the course will experience, on average, a small decrease in pain relative to patients who take placebo (similar to the benefit from nonsteroidal anti-inflammatory drugs) and will not have improved function. (Level of Evidence = 1a)
To identify randomized controlled trials that enrolled patients with nonspecific low back pain, published in any language, and evaluated an opioid analgesic, these researchers searched five databases including Cochrane Central, as well as reference lists of identified studies. Two reviewers independently selected studies for inclusion, and two reviewers independently extracted the data and evaluated study quality. They retrieved 20 studies with an enrollment of 7,295 patients; all but one study enrolled patients with chronic low back pain. The length of studies was 12 weeks or less. Most of the studies were of moderate to high quality.
Based on 13 studies with moderate-quality evidence, opioids reduced pain in the short term, although the mean difference in pain scores was minimal (mean difference = 10.1 on a scale of 0 to 100). This effect size is similar to that for nonsteroidal anti-inflammatory drugs vs. placebo for low back pain in a prior Cochrane review. Overall, opioid treatment did not produce clinically important pain relief compared with placebo (i.e., a mean difference in pain scores of at least 20), even with doses up to 240 mg of morphine per day. One-half of the studies had more than 50% of the enrolled patients drop out because of adverse effects or lack of effectiveness. The patients who dropped out were not considered in the estimates of treatment benefit, meaning that the actual overall likelihood of benefit is even smaller in clinical practice. Low-quality studies of disability did not show a reduction in disability using the Oswestry Disability Index or the Roland Morris Disability Questionnaire. Study results were homogeneous, but there was some evidence of publication bias.
Study design: Meta-analysis (randomized controlled trial)
Funding source: Government
Setting: Various (meta-analysis)
Reference: Abdel ShaheedCMaherCGWilliamsKADayRMcLachlanAJEfficacy, tolerability, and dose-dependent effects of opioid analgesics for low back pain: a systematic review and meta-analysis. JAMA Intern Med2016;176(7):958–968.