# Evaluating the value of lactic dehydrogenase in anti-MDA5-positive Dermatomyositis associated with interstitial lung disease

## TL;DR

This study shows that high lactic dehydrogenase levels are linked to worse outcomes and disease severity in a specific type of muscle disease with lung involvement.

## Contribution

The study identifies lactic dehydrogenase as a potential biomarker for disease severity and prognosis in anti-MDA5-positive dermatomyositis with ILD.

## Key findings

- LDH levels are significantly higher in anti-MDA5-positive DM patients with ILD compared to controls.
- Elevated LDH levels correlate with disease severity and are associated with poor prognosis in these patients.
- LDH levels change in response to ILD progression or improvement, suggesting its utility as a monitoring tool.

## Abstract

This retrospective cohort study aimed to investigate the relationship between lactic dehydrogenase (LDH) and anti-melanoma differentiation-associated gene 5 antibodies-positive dermatomyositis (anti-MDA5-positive DM) associated with interstitial lung disease (ILD).

A total of 168 anti-MDA5-positive DM patients with ILD underwent comprehensive evaluation, including LDH, anti-Ro-52 antibodies, serum ferritin determination, and lung high-resolution computed tomography (CT).

The levels of LDH were significantly elevated in anti-MDA5-positive DM patients compared with the control group (p < 0.01). Anti-Ro-52-positive patients exhibited significantly higher LDH levels than 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 levels 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).

(1) The LDH levels were affected by anti-Ro-52 antibodies and serum ferritin. (2) The severity of ILD in anti-MDA5-positive DM patients was 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.