The therapeutic efficacy and safety of intravenous immunoglobulin in dermatomyositis and polymyositis: A systematic review and meta-analysis

To evaluate the efficacy and safety of intravenous immunoglobulin (IVIG) in the treatment of dermatomyositis (DM) and polymyositis (PM).We searched PubMed, Embase, and the China National Knowledge Infrastructure for relevant studies from July 1919 to May 2021.Seventeen papers pertinent to our questions were found: In a meta-analysis, we found that IVIG significantly improved the level of CK (SMD (STD. Mean Difference) = -0.69; 95%CI -0.93, -0.46; P < 0.0001), Manual Muscle Test (SMD = 1.12; 95%CI 0.77, 1.47; P < 0.00001), Medical Research Council (SMD = 1.59; 95%CI 0.86, 2.33; P < 0.00001), Activities of Daily Living (SMD = 1.07; 95%CI 0.59, 1.56; P < 0.0001). The CK levels in DM and PM were also significantly improved after IVIG (SMD = -0.73; 95%CI -1.12, -0.34; P = 0.0002 and SMD = -3.29; 95%CI -5.82, -0.76; P < 0.0001, respectively). The meta-analysis of three RCTs showed that there was a statistically significant improvement after IVIG (SMD = 0.63; 95%CI 0.22, 1.03; P = 0.002). In a random effects model, pooled muscle power improvement rate was 77% (95% CI: 66.0-87.0%). Meta-analyses of IVIG as first-line therapy showed a significant improvement of the CK level (SMD = -0.71; 95%CI -1.12, -0.30; P = 0.0007). The polled improvement rate of oesophageal disorders was 88% (95% CI: 80.0-95.0%). There was no statistically significant difference in the rate of improvement between the number of courses <2 and ≥2 (0.80% vs. 0.80%, P = 0.9). The proportion of corticosteroid-sparing success reached 81.8%. Adverse reactions following IVIG administration are usually mild and transient. Seven patients developed serious adverse events.IVIG seems to be an effective drug for DM/PM, improving muscle strength, CK levels, and oesophageal involvement, and it is well tolerated by patients.