Prognostic Determinants among Clinical, Thin-Section CT, and Histopathologic Findings for Fibrotic Idiopathic Interstitial Pneumonias: Tertiary Hospital Study

Abstract

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). 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. 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. 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.