Evaluating Value of Lactic Dehydrogenase in Anti-MDA5-positive Dermatomyositis Associated with Interstitial Lung Disease

Abstract Objective This study aimed to investigate the relationship between lactic dehydrogenase (LDH) and anti-melanoma differentiation-associated gene 5 antibodies-positive dermatomyositis (anti-MDA5-positive DM) complicated by interstitial lung disease (ILD). Method 168 anti-MDA5-positive DM patients with ILD underwent comprehensive evaluation, including LDH, anti-Ro-52 antibodies, serum ferritin determination, and lung high-resolution CT. Results The level of LDH were significantly elevated in anti-MDA5-positive DM patients compared with control group (p < 0.01). Anti-Ro-52-positive patients demonstrated significantly higher LDH levels compared to anti-Ro-52-negative patients (p < 0.01). Patients with elevated serum ferritin exhibited markedly increased LDH levels compared with those with lower serum ferritin (p < 0.01). After treatment, LDH levels significantly increased in patients with ILD deterioration (p < 0.01), whereas LDH decreased in patients with ILD amelioration or stabilization (p < 0.01). The LDH levels were significantly elevated in the death group compared to the survival group before treatment (p = 0.02). Conclusion 1. The LDH levels were affected by anti-Ro-52 antibodies and serum ferritin. 2. The ILD severity of anti-MDA5-positive DM patients positively correlated with LDH, suggesting that LDH might serve as an effective assessment indicator to evaluate the changes in ILD in these patients. 3. Elevated LDH levels were a crucial indicator of poor prognosis in anti-MDA5-positive DM patients, warranting close attention from rheumatologists.