Predictors of rapidly progressive interstitial lung disease and mortality in patients with autoantibodies against melanoma differentiation-associated protein 5 dermatomyositis
Jacqueline So, Ho So, Victor Wong, Roy Ho, Tsz Yuen Wu, Priscilla Ching-Han Wong, Lydia H.P. Tam, Chi Ho, Tommy Lam, Yuen Kwan Chung, Wai Ling Li, Chi Hung To, Chak Sing Lau, Chi Chiu Mok, Lai‐Shan Tam, Lai‐Shan Tam, Lai‐Shan Tam
Abstract
OBJECTIVE: Anti-melanoma differentiation-associated protein 5 (MDA5)-positive DM is associated with rapidly progressive interstitial lung disease (RP-ILD) and high mortality. This multicentre retrospective study aimed to identify predictors of mortality and RP-ILD. METHODS: Anti-MDA5-positive DM patients were identified from the Hong Kong Myositis Registry and the Clinical Data Analysis and Reporting System. Clinical characteristics were reviewed. Risk factors for mortality and RP-ILD were identified. RESULTS: Among the 116 recruited patients, 100 (86.2%) had ILD, 47 (40.5%) had RP-ILD and 44 (37.9%) patients died. Cox regression analysis revealed RP-ILD [hazard ratio (HR) 9.735 (95% CI 3.905, 24.272)], age >52 years [HR 4.750 (95% CI 1.692, 13.333)], ferritin level >2800 pmol/l [HR 3.042 (95% CI 1.323, 6.997)] and lactate dehydrogenase (LDH) >400 IU/l [HR 2.290 (95% CI 1.009, 5.198)] were independent predictors of mortality. With regard to RP-ILD, analyses showed that potential predictors at baseline included age >50 years [HR 2.640 (95% CI 1.277, 5.455)], LDH >300 IU/l [HR 3.189 (95% CI 1.469, 6.918)], fever [HR 1.903 (95% CI 0.956, 3.790)] and neutrophil:lymphocyte ratio >7.0 [HR 1.967 (95% CI 0.942, 4.107)]. We proposed a prediction model based on fever, LDH, age and white cell count (FLAW) to stratify the risk of development of RP-ILD. The probability of RP-ILD in a patient with a score of 4 was 100%. A small internal validation cohort showed the odds of RP-ILD with FLAW scores of 0, 1, 2 and 3 were 0%, 0%, 42.9% and 75%, respectively. CONCLUSIONS: Anti-MDA5-associated RP-ILD is significantly associated with poor survival rates. The FLAW model maybe useful to predict the development of RP-ILD.