Background/Purpose: Anti-melanoma differentiation-associated protein 5 (MDA-5) antibody positivity in dermatomyositis (DM) is often associated with development of interstitial lung disease (ILD), with factors such as advanced age, male sex, lymphopenia, elevated ferritin and elevated lactate dehydrogenase (LDH) increasing mortality risk. Limited studies exist evaluating these risk factors in Hispanic patients. This retrospective study aims to evaluate these risk factors in a predominantly Hispanic population.

Methods: A retrospective cohort analysis was performed using electronic medical record data from 2021 to 2024 including all adult patients with a diagnosis code of either ILD and an abnormal myositis panel or DM. A total of 184 medical record numbers (MRNs) met these criteria. After confirming clinical diagnosis and filtering for positive anti-MDA5-antibodies, 17 MRNs were included. Lymphopenia was defined as an absolute lymphocyte count (ALC) less than 1000 cells/microliter. Advanced age was defined as 50 years or older. Data was analyzed using fisher exact testing.

Results: 29.4% (n=5) of patients were male and 70.6% (n=12) were female with a median age of 58 years. 76.0% (n=13) were Hispanic, including all males and 8 females. 7 patients (41.2%) had amyopathic DM, 4 (23.5%) had DM, and 6 (35.3%) had ILD without inflammatory myositis. 76.5% (n=13) of patients had ILD, including all of the males and 8 females. 23.5% (n=4) of patients were deceased, all of whom were males with ILD. Of 12 patients with advanced age, 25% (n=3) were deceased and 83.3% (n=10) had ILD. 9 patients had available LDH levels. Of these, five patients had elevated LDH and 4 were deceased. 8 patients had available ferritin levels, all of which were elevated. Of those patients, 88.5% (n=7; 3 males and 4 females) had ILD, and 37.5 % (n=3) were deceased. Lymphopenia was found in 35.3% (n=6; 4 males and 2 females). Mean ALC was 564 cells/microliter. Of these patients, 83.0% (n=5; 4 males and 1 female) had ILD and 66.7% (n=4) were deceased. A Fisher-exact-test showed significant associations between deceased and lymphopenia (p=0.006), males and lymphopenia (p=0.028), and males and deceased (p=0.002). There was no significant association of advanced age, elevated LDH level, and ILD with increased mortality. Elevated ferritin was not included in this analysis as all those tested had elevated levels.

Conclusion: Our cohort suggests a possible increased risk of mortality in anti-MDA5 antibody positive ILD patients who are male and have lymphopenia. We looked at a largely Hispanic population, which is underrepresented in anti-MDA5 antibody literature. Due to the limited sample size, larger cohorts should be examined to see if this association remains.

Table 1: Comparison between males and females based on various classification groups.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/increased-mortality-in-hispanic-males-with-lymphopenia-a-descriptive-and-statistical-analysis-of-anti-melanoma-differentiation-associated-protein-5-mda-5-antibody-positive-patients/