Development and Validation of a Comprehensive Multiparameter-based Scoring System to Assess Pulmonary Fibrosis Severity

Background Survival time varies greatly in patients with idiopathic pulmonary fibrosis (IPF). An assessment method that can accurately assess the severity and prognosis of idiopathic pulmonary fibrosis is currently lacking. This study aimed to develop a new method, which can be easily used to assess pulmonary fibrosis severity. Method 1. Development of a HRCT combined pulmonary function & physiological parameter (CTPF) assessment method: The method included two parts. 1) CT-based fibrosis staging: Four representative lung CT sections were selected and evenly divided into 100 small areas. The percentage of honeycomb lesion area in the four sections was determined fibrosis stage,2) PF-based severity grade: FVC%pred,DLco%pred,SpO2% age and gender were used to assess PF severity grade. 2. Validation of the new method: The method was used to assess 192 patients with IPF. Two radiologists used the CT-based fibrosis staging method to determine the fibrosis stage. Pulmonologist determined the PF severity grade. 3. Statistical analyses: Intra-group correlation coefficient to estimate the consistency between the CT scores from the two radiologists. Spearman correlation coefficient to evaluate the correlation between CT scores and lung function parameters. The competitive risk Fine–Gray model was used to analyze the relationship between CT-based stage/PF-based grade and prognosis. CT-based stage, PF-based grade, and GAP stage were used as predictors to predicted the death risk. Results 1. The intra-group correlation coefficient of the CT scores of the two radiologists was 0.95, P<0.05. 2. The CT scores negatively correlated with pulmonary function. 3. The CTPF comprehensive model, showed higher predictive accuracy. Conclusion Combined CT-based staging and PF-based grading methods CTPF can be adopted easily in clinical practice, and can assess IPF severity and predict death risk more accurately.