1. 2021;24;73-82Efficacy and Safety of Opioid Analgesics for the Management of Chronic Low Back Pain: An Evidence from Bayesian Network Meta-Analysis
   Systematic Review
   Babita Ghai, MD, Shailaja Kanakagiri, MPharm, Chandrasekhar Boya, PhD, and Dipika Bansal, MD.

BACKGROUND: Chronic low back pain (CLBP) incurs huge costs owing to increased healthcare expenditure, disability, insurance, and work absenteeism. Opioid analgesics are commonly used for the management of CLBP.

OBJECTIVE: To compare and rank the opioids used in the management of CLBP, in terms of efficacy and safety.

STUDY DESIGN: Systematic review and network meta-analyses (NMA).

METHOD: The search was conducted in Embase, PubMed, Cochrane databases for randomized controlled trials (RCTs) that had evaluated the efficacy and safety of opioids in CLBP. Two authors independently performed data extraction and quality assessment. The proportion of patients reporting either 30% or 50% reduction in pain from baseline to follow-up on the numeric rating scale, was measured as efficacy outcome. Pairwise meta-analyses and Bayesian NMA, within the random-effects model, were used to synthesize data. Effect estimates from Bayesian NMA were presented as odds ratio (OR) with 95% credible intervals (CrI). Heterogeneity and convergence were assessed by using I 2 and deviation information criteria.

RESULTS: Twenty-three RCTs with a total of 8,420 patients, evaluating 13 different opioids were included in this NMA. For 30% pain reduction, oxymorphone (OR: 5.36; 95% CrI: 1.02-30.3), tramadol with acetaminophen (OR: 2.37; 95% CrI: 1.08-5.17), and buprenorphine (OR: 2.29; 95% CrI: 1.05-5.07) shown statistically significant more effective than placebo. For 50% pain reduction, the statistically significant difference is observed with buprenorphine (OR: 2.38 95% CrI: 1.08-5.24), oxymorphone (OR: 5.10; 95% CrI: 1.31-20.41), and tramadol with acetaminophen (OR: 2.11; 95% CrI: 1.07-4.21). Hydrocodone (OR: 0.33; 95% CrI: 0.14-0.77) was found statistically safer compared to the other opioids.

LIMITATIONS: Only 5 trials had more than a 12-week study duration. We need clinical trials with longer follow-up as CLBP management requires a longer duration, and long-term prescribing of opioids associated with severe adverse event profile, development of tolerance, and dependence.

CONCLUSIONS: Oxymorphone has an advantage over other opioids to reduce pain by 30% and 50% in patients with CLBP.

KEY WORDS: Chronic low back pain, opioids, Bayesian analyses, network meta-analyses, systematic review