Study design: Systematic review and meta-analysis.
Objective: To assess the efficacy of opioids in adults with chronic low back pain (CLBP).
Summary of background data: Opioids for CLBP has increased dramatically. However, the benefits and risks remain unclear.
Methods: We updated a 2007 Cochrane Review through October 2012 of randomized controlled trials from multiple databases. Use of noninjectable opioids in CLBP for at least 4 weeks was compared with placebo or other treatments; comparisons with different opioids were excluded. Outcomes included pain and function using standardized mean difference (SMD) or risk ratios with 95% confidence intervals (CIs), and absolute risk difference with 95% CI for adverse effects. Study quality was evaluated using Grading of Recommendations Assessment, Development, and Evaluation criteria.
Results: Fifteen trials (5540 participants), including twelve new, met the criteria. Tramadol was better than placebo for pain (SMD, -0.55; 95% CI, -0.66 to -0.44) and function (SMD, -0.18; 95% CI, -0.29 to -0.07). Compared with placebo, transdermal buprenorphine decreased pain (SMD, -2.47; 95% CI, -2.69 to -2.25), but not function (SMD, -0.14; 95% CI, -0.53 to 0.25). Strong opioids (morphine, hydromorphone, oxycodone, oxymorphone, and tapentadol), were better than placebo for pain (SMD, -0.43; 95% CI, -0.52 to -0.33) and function (SMD, -0.26; 95% CI, -0.37 to -0.15). One trial demonstrated little difference with tramadol compared with celecoxib for pain relief. Two trials (272 participants) found no difference between opioids and antidepressants for pain or function. Reviewed trials had low to moderate quality, high drop-out rates, short duration, and limited interpretability of functional improvement. No serious adverse effects, risks (addiction or overdose), or complications (sleep apnea, opioid-induced hyperalgesia, hypogonadism) were reported.
Conclusion: There is evidence of short-term efficacy (moderate for pain and small for function) of opioids to treat CLBP compared with placebo. The effectiveness and safety of long-term opioid therapy for treatment of CLBP remains unproven.