Step-up versus primary intensive approach to the treatment of interstitial pneumonia associated with dermatomyositis/polymyositis: a retrospective study

Corticosteroids (CS) are the standard initial treatment for interstitial pneumonia (IP) associated with dermatomyositis (DM)/polymyositis (PM). However, many patients fail to respond and have significantly high mortality even if immunosuppressive drugs (ISDs) are subsequently added, while a more intensive initial approach using ISDs is suggested to improve their survival. We conducted a retrospective study to examine the association between initial therapeutic approaches and clinical outcomes of active IP in DM/PM patients. We reviewed medical records of 34 consecutive DM/PM patients who had active IP defined by the presence of pulmonary function abnormality or active symptoms, and compared clinical outcome between those patients to whom ISDs were added if CS alone did not result in a favorable response (a step-up approach) and those who were started on ISDs simultaneously with CS (a primary intensive approach). Clinical endpoints were death, pulmonary death, and progression or improvement of pulmonary function. The step-up approach was used in 20 patients, to 11 of whom ISDs were eventually added after a median of 2.0 weeks, while the primary intensive approach was used in 14 patients. The primary intensive approach group had significantly better survival than the step-up approach group (P = 0.030 by the log-rank test). These two groups did not differ significantly in demographic characteristics and baseline clinical and laboratory features. Intensive approach by starting ISDs simultaneously with CS in the initial treatment for active IP in DM/PM patients was associated with better survival, emphasizing the impact of initial treatment on their survival. Prospective clinical investigation of this approach is now needed, but the limited clinical utility of CS as an initial treatment might ethically challenge clinical-trial designing.