Objectives: To evaluate the efficacy and safety of intravenous immunoglobulin (IVIG) in the treatment of dermatomyositis (DM) and polymyositis (PM).
Methods: We searched PubMed, Embase, and the China National Knowledge Infrastructure for relevant studies from July 1919 to May 2021.
Results: 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.
Conclusion: 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.
Keywords: Dermatomyositis; idiopathic inflammatory myopathy; intravenous immunoglobulin; meta-analysis; polymyositis.
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