Prognostic determinants among clinical, thin-section CT, and histopathologic findings for fibrotic idiopathic interstitial pneumonias: Tertiary hospital study

Purpose: To evaluate the utility of clinical, thin-section computed tomography (CT), and histopathologic findings in predicting the prognosis of patients with usual interstitial pneumonia (UIP) or fibrotic nonspecific interstitial pneumonia (NSIP). Materials and Methods: The institutional review board approved this retrospective study, with waiver of informed consent. Included were 108 patients (71 men, 37 women; mean age, 61 years +/- 8 [standard deviation]) with UIP (n = 79; 60 men, 19 women; mean age, 63 years +/- 7.4) and fibrotic NSIP (n = 29; 11 men, 18 women; mean age, 57 years +/- 12.9). Patients underwent pulmonary function tests (PFTs), bronchoalveolar lavage (BAL) fluid analysis, and thin-section CT. Two chest radiologists independently assigned scores for the extent of lung abnormalities detected at CT twice at 3-month intervals. The effect of histopathologic diagnoses and clinical and thin-section CT features on survival was evaluated by using Cox regression analyses. Results: The 5-year survival rate (mean follow-up, 45 months) of patients with fibrotic NSIP was 76% in contrast to 46% for patients with UIP (P = .006). With multivariate analysis, a high fibrotic score (the extent of reticulation plus honeycombing) (hazard ratio = 1.200, P = .043) and an initial low diffusing capacity of lung for carbon monoxide (DLCO) level (hazard ratio = 0.973, P = .025) were identified as associated with increased death risk. Conclusion: Patients with UIP or fibrotic NSIP who have a high fibrotic score determined at thin-section CT and a low DLCO level appear to have a high death risk. (c) RSNA, 2008.