Efficacy of duloxetine versus alternative oral therapies: an indirect comparison of randomised clinical trials in chronic low back pain

The objective of this study was to obtain parameter estimates for the efficacy of duloxetine versus alternative oral therapies for the treatment of chronic low back pain. Electronic databases were searched to identify randomised, double-blind placebo-controlled trials. Studies reporting pain intensity, with parallel-group design of oral treatments with length of treatment of more than 8 weeks were included. A Bayesian approach to indirect comparisons was applied, using standardised mean difference as a measure of relative treatment effect. Fifteen studies were identified comparing duloxetine with the following oral drug classes: non-scheduled opioids, cyclooxygenase-2 inhibitors, scheduled opioids, selective serotonin reuptake inhibitors, and 'other' (i.e. glucosamine). The primary analysis found scheduled opioids to be more effective than duloxetine for the fixed effects model. However, the estimate of the treatment difference reflected a less than small magnitude of effect (|standardised mean difference| < 0.2), and there was no difference for the random effects model. No differences were found in sensitivity analyses involving the subset of patients not receiving concomitant non-steroidal anti-inflammatory medication. The available evidence shows that there does not seem to be any difference in efficacy between duloxetine and other oral pharmacological therapies, providing a valuable alternative for this disabling condition.