Background Interstitial lung diseases (ILD) complicated with polymyositis (PM) or dermatomyositis (DM) are frequently aggressive and refractory to immunosuppressive treatment. Recently, some anecdotal case reports suggested the potential benefit of tacrolimus for severe ILD complicated with PM/DM. However, little evidence has yet shown the efficacy of tacrolimus.
Objectives To evaluate the prognosis of patients diagnosed as ILD complicated with PM/DM and treated with tacrolimus.
Methods This retrospective study comprised 46 untreated patients with ILD complicated with PM/DM who were admitted to Hokkaido University Hospital from January 2000 to October 2011. These patients were treated with tacrolimus plus conventional therapy (n=25) or only with conventional therapy (prednisolone 1mg/kg/day, intravenous cyclophosphamide and/or cyclosporine; n=21) and were followed up for 35.3 (1.0-121.3) months. Because patients with severe ILD were more frequently treated with tacrolimus, matching was done based on the propensity for tacrolimus therapy to reduce confounding by indication. Propensity score was calculated using logistic regression model with age, sex, dermatomyositis, amyopathic manifestation, oxygen administration, acute progression within 60 days, serum KL-6 levels, ground glass opacity and extensive ILD (over 50% lesion of total lung assessed by high resolution CT). Primary endpoint was defined as death, relapse of underlying diseases or serious infections. The hazard ratio of tacrolimus use was evaluated in the Cox regression model stratified by matched pair.
Results Based on propensity scores, 12 patients from each group were well matched. In the matched pairs, tacrolimus group had significantly longer event-free-survival as compared with conventional therapy group (hazard ratio = 0.708, 95% confidence interval = 0.506-0.991; p=0.044).
Conclusions Addition of tacrolimus to conventional therapy significantly improved the prognosis of patients with PM/DM-related ILD.
Disclosure of Interest None Declared