PURPOSE: We used data from the IPF-PRO Registry of patients with idiopathic pulmonary fibrosis (IPF) to identify characteristics that predicted survival for a further >
5 years. METHODS: Participants had IPF that was diagnosed or confirmed at the enrolling center in the previous 6 months. Patients were followed prospectively. A Classification And Regression Tree (CART) was used to identify predictors of survival >
5 versus ≤ 5 years following enrollment. The following variables, assessed at enrollment, were considered: age
body mass index (BMI)
former smoker
current smoker
time from first imaging evidence, symptoms, or diagnosis of IPF to enrollment
forced vital capacity (FVC) % predicted
diffusing capacity of the lungs for carbon monoxide (DLco) % predicted
antifibrotic drug use
supplemental oxygen use
history of cardiac disease
pulmonary hypertension
COPD/emphysema
and rural location. RESULTS: The analysis cohort comprised 819 patients, of whom 278 (33.9%) survived >
5 years. DLco % predicted, supplemental oxygen use and FVC % predicted were the most important variables for predicting survival >
5 versus ≤ 5 years after enrollment. The importance of these variables (scaled such that the most important had an importance of 100%) was 100%, 78.2% and 74.2%, respectively. The optimism-corrected area under the curve (AUC) of the CART was 0.72, with an accuracy of 0.72. CONCLUSION: Among patients enrolled in the IPF-PRO Registry, a decision tree that included DLco % predicted, oxygen use and FVC % predicted facilitated the prediction of survival >
5 years. Understanding predictors of longer-term survival may facilitate conversations with patients about their prognosis and treatment.