Interstitial lung disease in clinically amyopathic dermatomyositis (CADM) patients: a retrospective study of 41 Chinese Han patients.

To study the clinical features and associated risk factors of interstitial lung disease (ILD) in clinically amyopathic dermatomyositis (CADM) in Chinese patients. Forty-one Chinese Han patients with a diagnosis of CADM in West China Hospital from August 2008 to 2011 were retrospectively analyzed. The prevalence of ILD in CADM patients is 60.98 %, in which 26.83 % for acute/subacute interstitial pneumonia (A/SIP) and 34.15 % for chronic interstitial pneumonia (CIP). Mortality of A/SIP is 63.64 %, with a 6-month survival rate of 54.50 %. Levels of erythrocyte sedimentation rate, serum ferritin, alanine aminotransferase, aspartate aminotransferase, creatine kinase, lactate dehydrogenase, hydroxybutyric dehydrogenase, and immunoglobulin A (IgA) are higher in CADM-ILD patients than CADM patients without ILD. Levels of serum ALB and lymphocyte count in peripheral blood are significant lower in A/SIP than in CIP group. Sign of ground glass opacities in high-resolution computed tomography (HRCT) images is more common in A/SIP group, and diffusion function is worse in these patients compared with CIP group. The prevalence of ILD in Chinese CADM patients is strikingly high, and A/SIP is a major cause of death in CADM patients. Laboratory findings combined with HRCT examination and pulmonary function tests can provide valuable predictive information of ILD or A/SIP in CADM patients.