Cough predicts prognosis in idiopathic pulmonary fibrosis

BACKGROUND AND OBJECTIVE: The clinical associations and prognostic value of cough in IPF have not been adequately described. The objective of this study was to describe the characteristics and prognostic value of cough in IPF. METHODS: Subjects with IPF were identified from an ongoing longitudinal database. Cough and other clinical variables were recorded prospectively. Logistic regression was used to determine predictors of cough and predictors of disease progression, defined as 10% decline in FVC, 15% decline in DL(CO) , lung transplantation or death within 6 months of clinic visit. The relationship of cough with time to death or lung transplantation was analysed using Cox proportional hazards analysis. RESULTS: Two hundred and forty-two subjects were included. Cough was reported in 84% of subjects. On multivariate analysis, cough was less likely in previous smokers (OR 0.07, 95% CI: 0.01-0.55, P = 0.01), and more likely in subjects with exertional desaturation (OR 2.56, 95% CI: 1.15-5.72, P = 0.02) and lower FVC (OR 0.76, 95% CI: 0.60-0.96, P = 0.02). Cough predicted disease progression (OR 4.97, 95% CI: 1.25-19.80, P = 0.02) independent of disease severity, and may predict time to death or lung transplantation (HR 1.78, 95% CI: 0.94-3.35, P = 0.08). CONCLUSIONS: Cough in IPF is more prevalent in never-smokers and patients with more advanced disease. Cough is an independent predictor of disease progression and may predict time to death or lung transplantation.