Establishment and Application of the BRP Prognosis Model for Idiopathic Pulmonary Fibrosis

Abstract

Background Idiopathic pulmonary fibrosis (IPF) is the most common idiopathic interstitial lung disease, with varying disease progression and prognosis. Clinical models to accurately evaluate the prognosis of IPF are currently lacking. Objective To train and validate a prediction model for transplant-free survival (TFS) of IPF based on the clinical and radiological information. Methods A multicenter prognostic study was conducted, involving 166 IPF patients followed up for three years. The end point of follow-up was death or lung transplantation, and the outcome indicator was TFS. The clinical information, lung function tests, and chest computed tomography (CT) scans were collected. Body composition quantification on CT was performed using 3D Slicer software. Risk factors in Blood routine examination-Radiology-Pulmonary function (BRP) were identified by Cox regression, and were utilized to construct the “BRP Prognosis Model”. The performance of the BRP model and the gender-age-physiologic variables (GAP) was compared using time-ROC curve, calibration curve, and decision curve analysis (DCA). Kaplan-Meier and Log-rank tests were used for risk stratification based on individual BRP scores. Furthermore, the Spearman correlation analysis was utilized to explore the correlation between body composition, lung function and serum inflammatory cytokines. Results Our study identified neutrophil percentage༞68.3%, pericardial adipose tissue (PAT)༞94.91 cm3, pectoralis muscle radiodensity (PMD) ≤ 36.24 HU, diffusing capacity of the lung for carbon monoxide/alveolar ventilation (DLCO/VA) ≤ 56.03%, and maximum vital capacity (VCmax)༜90.5% as independent risk factors for poorer TFS among patients with IPF. We constructed BRP model, which showed superior accuracy, discrimination, and clinical practicability to GAP model. Median TFS differed significantly among patients at different risk levels identified by the BRP model (low-risk: TFS > 3 years; intermediate-risk: TFS = 2–3 years; high-risk: TFS ≈ 1 year). Additionally, serum proinflammatory markers were positively correlated with visceral fat volume and infiltration, and negatively correlated with lung function indicators. Conclusion In this study, the BRP prognostic model of IPF was successfully constructed, and internally and externally validated. Compared with the most commonly used GAP, the BRP model had better performance and generalization with easily obtainable indicators. The BRP model is suitable for clinical promotion.