Background: Idiopathic pulmonary fibrosis was recently redefined as usual interstitial pneumonia of unknown etiology. Consequently, the prognostic value of histological findings needs to be reassessed. Objective: To correlate clinical, functional and histological findings with survival in patients with idiopathic pulmonary fibrosis. Method: Patients (n = 51; mean age: 66 ± 8 years; gender: 21 females/30 males) were evaluated. Of the 51, 26 were smokers or ex-smokers. Duration of symptoms, forced vital capacity and smoking habits were recorded. All patients presented usual interstitial pneumonia verified through histology. Degree of honeycombing, established fibrosis, desquamation, cellularity, myointimal thickening of blood vessels and number of fibroblastic foci were graded according to the semiquantitative method. Results: Median duration of symptoms was 12 months and initial forced vital capacity was 72 ± 21%. Cox multivariate analysis revealed that survival correlated inversely and significantly (p < 0.05) with duration of symptoms and fibroblastic foci score, as well as with myointimal thickening of blood vessels. Limited numbers of fibroblastic foci, as well as myointimal thickening involving less than 50% of blood vessels, were predictive of greater survival. No correlation with survival was found for gender, age, forced vital capacity, inflammation or degree of cellularity. Conclusion: Semiquantitative analysis of lung biopsies yields relevant prognostic information regarding patients with usual interstitial pneumonia.

Keywords: Pulmonary fibrosis. Lung diseases, interstitial. Survival analysis.