Risk factors for the recurrence of interstitial lung disease in patients with polymyositis and dermatomyositis: a retrospective cohort study.

To identify risk factors for the recurrence of interstitial lung disease (ILD) in patients with polymyositis (PM)/dermatomyositis (DM). Forty-four PM/DM-ILD patients who had been treated with glucocorticoid and/or immunosuppressive agents as a remission induction therapy were enrolled. The patients were first classified into two groups: the early recurrence group that recurred within 52 weeks, and the non-early recurrence group, which was further classified into the late recurrence group that recurred after 52 weeks, and the non-recurrence group. The characteristics and treatment regimen between the groups were compared. Recurrence was experienced by 15 of 44 patients. The pulmonary vital capacity of the early recurrence group was significantly lower than the non-early recurrence group (46 vs 76%, p = 0.0003), and 60% of the early recurrence group was treated with glucocorticoid alone as a maintenance therapy in contrast to 10% in the non-early recurrence group (p = 0.004). The late recurrence was only related with a positivity for autoantibodies against aminoacyl-tRNA synthetases (anti-ARS antibodies, odds ratio 8.4, p = 0.02), but calcineurin inhibitors tended to decrease the relapse incidence in patients with anti-ARS antibodies. Low pulmonary vital capacity at disease onset and anti-ARS antibodies positivity are the risk factors for the recurrence of ILD with PM/DM. Calcinuerin inhibitors are important in preventing relapse.