Outcomes and prognostic factors of patients with anti-melanoma differentiation-associated protein 5 and anti-aminoacyl-RNA synthetase antibodies positive idiopathic inflammatory myopathies in intensive care unit

Background: This study aims to identify prognostic factors for mortality of patients with anti-melanoma differentiation-associated protein 5 (anti-MDA5) or anti-aminoacyl-RNA synthetase (anti-ARS) antibodies positive and acute respiratory failure in the intensive care unit. Methods: : Clinical characteristics, laboratory test findings, imaging performance, and management were retrospectively collected in all cases with anti-MDA5 and anti-ARS antibodies positive, as well as follow-up survival data. Risk factors related to prognosis were identified by Cox regression analysis. Results: : The 28-day mortality of all patients was 68.8% (n=44/64). The patients who died were more likely to have anti-MDA5 antibody( p<0.001 ), presented more Gottron papules( p=0.021 ) or heliotrope rash( p=0.008 ), had a relatively lower level of WBC( p=0.038 ), CRP( p=0.004 ), and had a higher level of LDH( p=0.029 ), serum ferritin( p=0.002 ). The main risk factors associated with 28-day mortality were anti-MDA5 antibody positive [HR 10.827 (95% CI: 4.261-27.514), p<0.001 ], presence of Gottron papules [2.299 (1.203-4.394), p=0.012 ], heliotrope rash [3.423 (1.773-6.606), p<0.001 ], and arthritis/arthralgia [2.365 (1.130-4.948), p=0.022 ). At a median of 14 (IQR 6.33-35.0) months of follow-up, the overall mortality of all patients was 75.0% (n=48/64). The non-survivors were more likely to own anti-MDA5 antibody( p<0.001 ), had a higher rate of Gottron papules( p=0.020 ) or heliotrope rash( p=0.014 ), had lower PFR( p=0.032 ) while ICU admission, and existed a higher level of serum ferritin( p=0.005 ). Main risk factors associated with overall mortality were consistent with risk factors for 28-day mortality. Conclusions: : Anti-MDA5 antibody positive, presence of Gottron papules, heliotrope rash, or arthritis/arthralgia were the main independent risk factors of poor prognosis for IIM patients admitted to the ICU due to acute respiratory failure.