Evaluation of clinical prognostic factors for interstitial pneumonia in anti-MDA5 antibody-positive dermatomyositis patients

Objectives: We retrospectively investigated clinical prognostic factors for interstitial pneumonia (IP) in anti-melanoma differentiation-associated gene 5 (MDA5) antibody (Ab)-positive dermatomyositis (DM) patients. Methods: Subjects comprised 18 patients with anti-MDA5 Ab-positive DM-IP (9 survivors; 9 deaths). Results: Initial serum albumin levels, ferritin levels, and ground-glass opacity (GGO) scores in the right middle lobes were significantly higher in the death group than in the survivor group (p = .033, .013, and .005, respectively). Initial alveolar-arterial oxygen gradient (P[A-a]O-2) was also higher in the death group than in the survivor group (p = .064). Initial serum ferritin, P[A-a]O-2, and right middle lobe GGO score were found to significantly relate to death. Survival rates after 24 weeks were significantly lower among patients with an initial ferritin level of >= 450 ng/mL (25%), P[A-a]O-2 of >= 30 mmHg (31%), and a right middle lobe GGO score of >= 2 (11%) than each of the others (p = .006, .020, and .002, respectively). Conclusions: An initial serum ferritin level of >= 450 ng/mL, P[A-a]O-2 of >= 30 mmHg, and right middle lobe GGO score of >= 2 (GGO >= 5% of the lobe) were identified as poor prognostic factors for anti-MDA5 Ab-positive DM-IP patients.