Inflammatory myopathies are treated with glucocorticoids and other immunosuppressive medications. Intravenous immunoglobulin (IVIG) is increasingly used for refractory or severe cases; however, the evidence for their effectiveness is limited. We assessed effectiveness and safety of IVIG when used with other immunomodulatory agents in the treatment of inflammatory myopathies.

This study reviewed records of patients diagnosed with dermatomyositis or polymyositis and treated with IVIG, from 2009 through 2016 in 1 tertiary medical center. Mixed-effects general linear regression models were applied to determine effectiveness of treatment on muscle strength, creatinine phosphokinase levels, and steroid dosage.

Twenty-three patients with dermatomyositis/polymyositis treated with IVIG were followed up for a mean of 31 (SD, ±25) months. During this period, a significant improvement in muscle strength was demonstrated, with a mean increase of 0.92 Medical Research Council scale points (β = 0.14; confidence interval [CI], 0.136-0.149; p < 0.0001), a significant reduction of creatinine phosphokinase levels and steroid dosage with a mean decrease of 1140 IU/L (β = -0.274; CI, -0.354 to -0.195; p < 0.0001), and 36 mg/d (β = -0.008; CI, -0.011 to -0.006; p < 0.0001), respectively. Overall, remission was observed in 10 patients (43.5%), and partial remission in 6 patients (26%), whereas 1 patient (17%) remained refractory to treatment, and 6 patients (27%) were lost to follow-up.

The majority of patients with inflammatory myopathies experienced a clinical and laboratory improvement during IVIG treatment. In addition, a steroid-sparing effect was noticed in most patients. These results encourage the use of IVIG as an alternative treatment option for patients with limited responsiveness to conventional methods.