Long-term effects of early pulse methylprednisolone and intravenous immunoglobulin in patients with dermatomyositis and polymyositis.

Objective: To evaluate the long-term effects of pulse i.v. methylprednisolone (IVMP) or IVIG administered during the first year of diagnosis in DM and PM patients.
Methods: This is a retrospective single-centre cohort study of patients with PM/DM followed for up to 4 years from 2001 to 2017. We used Cox regression models to estimate hazard ratios (HRs) and assess the effects of early pulse IVMP or IVIG on three outcomes: complete clinical response, CS discontinuation, and survival. Analysis was adjusted for clinical, laboratory and treatment covariates.
Results: A total of 204 patients were included and categorized into four initial treatment groups: pulse IVMP (n = 46), pulse IVMP + IVIG (n = 55), IVIG (n = 10), and without IVMP or IVIG (n = 93). The groups of early pulse IVMP and pulse IVMP + IVIG had a higher HR for complete clinical response in the multivariate models (HR = 1.56, 95% CI: 1.05, 2.33, P = 0.029; and HR = 1.58, 95% CI: 1.02, 2.45, P = 0.041, respectively). Only the group of pulse IVMP + IVIG had a significant association with CS discontinuation in the multivariate analysis (HR = 1.65, 95% CI: 1.02, 2.68, P = 0.043). Early pulse IVMP or IVIG had no impact on mortality.
Conclusion: Despite having a more severe disease profile, patients with PM/DM submitted to pulse IVMP or pulse IVMP + IVIG during the first year of diagnosis had a higher HR for complete clinical response, whereas the combination of pulse IVMP + IVIG had an association with CS discontinuation. Prospective long-term studies are warranted to confirm these benefits of early pulse IVMP and IVIG on patients with PM/DM.
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