Mortality and prognostic factors in idiopathic inflammatory myositis: a retrospective analysis of a large multicenter cohort of Spain.

The present study was undertaken to assess mortality, causes of death, and associated prognostic factors in a large cohort of patients diagnosed with idiopathic inflammatory myositis (IIM) from Spain. A retrospective longitudinal study was carried out in 467 consecutive patients with IIM, identified from 12 medical centers. Patients were classified as primary polymyositis, primary dermatomyositis (DM), overlap myositis, cancer-associated myositis (CAM), and juvenile idiopathic inflammatory myopathies. A total of 113 deaths occurred (24%) after a median follow-up time of 9.7 years. In the overall cohort, the 2-, 5-, and 10-year survival probabilities were 91.9, 86.7, and 77%, respectively. Main causes of death were infections and cancer (24% each). Multivariate model revealed that CAM (HR = 24.06), OM (HR = 12.00), DM (HR = 7.26), higher age at diagnosis (HR = 1.02), severe infections (HR = 3.66), interstitial lung disease (HR = 1.61), and baseline elevation of acute phase reactants (HR = 3.03) were associated with a worse prognosis, while edema of the hands (HR = 0.39), female gender (HR = 0.39), and longer disease duration (HR = 0.73) were associated with a better prognosis. The standardized mortality ratio was 1.56 (95% CI 1.28-1.87) compared to the Spanish general population. Our findings indicate that IIM has a high long-term mortality, with an excess of mortality compared to the Spanish population. A more aggressive therapy may be required in IIM patients presenting with poor predictive factors.

Long-term pulmonary outcomes and mortality in idiopathic inflammatory myopathies associated with interstitial lung disease.

OBJECTIVE: To study prognostic factors in different types of idiopathic inflammatory myopathies (IIM) associated with interstitial lung disease (ILD). PATIENTS AND METHODS: Multicenter retrospective study of a Spanish cohort of patients diagnosed with IIM. Patients were classified into four categories: polymyositis (PM), dermatomyositis (DM), antisynthetase syndrome (ASS), and overlap myositis (OM). Sociodemographic data, clinical characteristics, antibodies, and treatments were collected. Cox regression models were calculated to identify factors associated with mortality, the necessity for long-term oxygen therapy (LTOT), and deterioration in respiratory function tests (RFT). RESULTS: The number of patients included was 478, of whom 112 (23.4%) suffered from ILD: 17% PM, 16% DM, 45% ASS, and 22% OM. Factors associated with mortality in the multivariate analysis were clinically meaningful progression of ILD after 3 months (CMP 3m) (hazard ratio (HR) 9.48, p = 0.005), severe infections (HR 6.41, p = 0.016), heliotrope erythema (HR 31.1, p = 0.002), delay in diagnosis (HR 1.29; p = 0.011), and Raynaud's phenomenon (HR 11.9, p = 0.007). However, being female (HR 0.19, p = 0.044) and positivity solely for ANAs (HR 0.08, p = 0.008) presented a protective effect. CMP 3m (HR 22.7, p = 0.027) was associated with the need for LTOT, while basal aldolase (HR 0.90; p = 0.049) had a protective effect. Likewise, joint manifestations (HR 0.04, p = 0.034) were shown to reduce risk of deterioration in RFT. CONCLUSIONS: CMP 3m, severe infections, delay in diagnosis, heliotrope erythema, and Raynaud's phenomenon were identified as factors of poor prognosis in different IIM associated with ILD.