MPO and respiratory failure: Factors linked to a worse prognosis or mortality in AAV-ILD have included the presence of a radiological UIP pattern and a higher lobe fibrosis score, age over 65 years, history of smoking, anti-MPO positivity, progressive course, respiratory failure, ILD exacerbation, requirement of LTOT, and associated DAH and renal involvement [7,8,9,10,13,14,15,16,17,18,21,24,26,27,29,32,33,34].