A retrospective cohort study of prognostic factors for death in patients with idiopathic pulmonary fibrosis

Abstract

To investigate the prognostic implications of clinical, radiographic, and physiological variables in idiopathic pulmonary fibrosis (IPF). The clinical, pulmonary physiological, bronchoalveolar lavage fluid (BALF) cell differentials and lung high-resolution computed tomography (HRCT) at diagnosis in 126 patients with IPF were retrospectively analyzed. Univariate and multivariate Cox proportional-hazards regression analysis was used to evaluate various parameters associated with hazard ratio (HR). The survival rates of all groups were compared using the Kaplan-Meier method. In 29.6 months of average follow-up time, the survival rate of the IPF patients was 46.8% (59/126), and the median survival time was 30 months after diagnosis. Glucocorticoids and/or cytotoxic drugs for patients with IPF did not change the prognosis. The survival rates between groups by gender and smoking status showed no statistically significant difference (Ward: 0.11, 1.65, P>0.05). The patients were divided into 2 groups by the median (the cutoff point value) of significant variables in univariate Cox proportional-hazards regression analysis, and the survival rates showed statistically significant difference by dyspnea scale, FVC%, TLC%, DLCO%, neutrophil percentage and eosinophil percentage in BALF, and the reticular and honeycomb lung score (Logrank: 13.52-57.52, P<0.05). The results of multivariate Cox proportional-hazards regression analysis showed that TLC%, DLCO%, HRCT reticular score and honeycomb lung score were factors that affected the prognosis of patients with IPF (Wald=5.76-21.48, P<0.05). TLC%, DLCO%, cell differentials of BALF and the degree of pulmonary fibrosis were the main factors affecting the prognosis of patients with IPF. TLC% and DLCO% showed a negative correlation with the prognosis of patients with IPF. Glucocorticoids and/or cytotoxic drug therapy had no effect on the prognosis of patients with IPF.