HRCT composite fibrosis score correlates with clinical and physiological parameters in IPF

Introduction: Few studies describe whether the extent of radiologic fibrosis correlates with other measures of disease severity in patients with idiopathic pulmonary fibrosis (IPF). A direct correlation could confirm that the clinical and physiological limitations in these patients are attributed to the extent of fibrosis, rather than co-morbidities, such as emphysema, or subjective factors. Objectives: To assess the correlation between a visual fibrosis score and lung function, quality of life and symptoms. Methods: Patients with IPF were recruited from the Danish PFBIO cohort. The HRCT scans were scored by two experienced thoracic radiologists using a standardized form and blinded to patient data, each-others scores and the time of scan. The extents of reticulation, traction bronchiectasis and honeycombing were combined in a composite quantitative fibrosis score. Dyspnoea was assessed in a questionnaire on a scale from 0 to 5. Results: In the 66 included patients, fibrosis score was correlated with FVC (r=-0.35, p=0.005), DLCO (r=-0.53, p<0.001), St. George’s Respiratory Questionnaire (r=0.46, p=0.002) and dyspnoea (r=0.51, p<0.001). There was no significant difference between patients with or without concomitant emphysema. Conclusions: A visual fibrosis score in IPF correlates with lung function tests, quality of life and dyspnoea, further validating these measurements as directly related to the extent of lung fibrosis.