Statistical analysis. The descriptive analysis of the data included median, minimum, and maximum values. The probabilities (odds ratios) that patients with underlying diseases and comorbidities would develop specific pulmonary histopathological patterns and die of ARF-related pulmonary alterations were determined by logistic regressions. The independent variables included the following major diseases and/or comorbidities: BBP, cancer, liver cirrhosis, HIV/AIDS, acute myocardial infarction, systemic arterial hypertension, dilated cardiomyopathy, pulmonary embolism, chronic obstructive pulmonary disease, diabetes mellitus, sepsis and septic shock, chronic kidney failure, and tuberculosis. All the statistical procedures were performed using the SPSS v10.0 statistical software. Statistical significance was set at a p-value of 5%.