Prognostic classification in acute exacerbation of idiopathic pulmonary fibrosis: a multicentre retrospective cohort study
Takahito Suzuki, Hironao Hozumi, Koichi Miyashita, Masato Kono, Yuzo Suzuki, Masato Karayama, Kazuki Furuhashi, Hirotsugu Hasegawa, Tomoyuki Fujisawa, Noriyuki Enomoto, Yutaro Nakamura, Naoki Inui, Koshi Yokomura, Hidenori Nakamura, Takafumi Suda
Abstract
Abstract Acute exacerbation (AE) in idiopathic pulmonary fibrosis (IPF) is a major prognostic determinant. However, evidence for its prognostic strength is mainly based on the results of small cohort studies with statistical limitations. This retrospective study, which included 108 patients with a first episode of AE-IPF, aimed to identify prognostic factors and to develop prognostic classification models. Multivariate Cox regression analysis revealed that a lower percent-predicted forced vital capacity within 12 months before AE onset (baseline %FVC) and a lower PaO 2 /FiO 2 ratio at AE onset were independent mortality predictors. If the value of each predictor was lower than the cutoff determined by receiver-operating characteristic analysis, 1 point was assigned. Classification of patients into mild, moderate, and severe groups based on total score showed post-AE 90-day cumulative survival rates of 83.3%, 66.2%, and 22.2%, respectively (model 1: C-index 0.702). Moreover, a decision tree-based model was created with the recursive partitioning method using baseline %FVC and PaO 2 /FiO 2 ratio at AE onset from among multivariable; accordingly, patients were classified into 3 groups with post-AE 90-day cumulative survival rates of 84.1%, 64.3%, and 24.0%, respectively (model 2: C-index 0.735). These models can guide clinicians in determining therapeutic strategies and help design future studies on AE-IPF.