Botulinum Toxin Type B vs Type A in Cervical Dystonia: A Meta - analysis of high quality trials

Introduction: cervical dystonia (CD) is a frequent disabling condition. Botulinum Toxin (BT) type A is effective for CD. BT type B is an alternative, but its use for patients who develop neutralizing antibodies against BT type A is debatable. Objetive: the aim of this study was to compare the efficacy of BT type B (>5000 U) versus type A and placebo patients with CD. Materials and methods: we identified RCTs comparing interventions. Quality assessment was made according to Cochrane Collaboration. A pooled analysis was conducted for continuous and dichotomous data using a random effect model identifying OR [CI95%, p < 0.05]. Primary outcomes were improvement in TWSTRS until week sixteen. Secondary outcomes were adverse effects and costs. Results: five RCTs fulfilled inclusion criteria (217 patients treated with BT type B; 224 patients in placebo group or type A). Two trials compared BT type B versus type A and three versus placebo. Quality assessment showed high quality of trials. BT type B improved TWSTRS scores at 4 weeks versus placebo [OR: 6.54 (CI 95%: 2.68 - 10.39; p