Pharmacological treatment in adult patients with CRPS-I: A systematic review and meta-analysis of randomised controlled trials

Objective. Several pharmacological treatments have been proposed for the treatment of complex regional pain syndrome type-I (CRPS-I) in adults, but data regarding the efficacy of various agents for this disease is scarce. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) to analyse the efficacy of the various pharmacological approaches in adults with CRPS-I.Methods. We systematically searched PubMed, Scopus, and Web of Science databases from the inception date to 30 June 2021 to identify placebo-controlled or active-controlled RCTs using bisphosphonates, ketamine, CSs, anti-epileptics, NSAIDs/COXIBs, opiates, antidepressants, scavengers/magnesium sulphate or IVIGs for the treatment of CRPS-I. The primary outcomes included changes in the visual analogue scale (VAS) or numeric rating scale (NRS) for pain before and after treatment.Results. We included 20 placebo-controlled or active-controlled RCTs (including a total of 818 adults with CRPS-I) that used bisphosphonates (n = 7), ketamine (n = 2), CSs (n = 2), anti-epileptics (n = 1), NSAIDs/selective inhibitors of cyclooxygenase-2 (COXIBs) (n = 2), scavengers/magnesium sulphate (n = 5), or IVIGs (n = 1) to treat CRPS-I during a median follow-up of 26 weeks. Treatment with bisphosphonates showed a significant reduction in the values of the VAS/NRS pain scale compared with placebo or reference therapy (random effects weighted mean difference [WMD]: -23.8, 95% CI: -28.0 to -19.6; I-2 = 36.4%). Treatment with ketamine also documented a reduction in the values of the VAS/NRS for pain (random effects WMD: -8.27, 95% CI: -12.9 to -3.70; I-2 = 0%). Treatment with other agents did not reduce the values of the VAS/NRS assessments of pain.Conclusion. This systematic review and meta-analysis supports the recommendation of parenteral bisphosphonates as the first-line agent in the treatment of CRPS-I.