Characteristics of idiopathic pulmonary fibrosis -associated cough. A case-control study

<b>Introduction:</b> Most patients with idiopathic pulmonary fibrosis (IPF) complain of cough. IPF-associated cough is widely characterized as dry or non-productive by an expert opinion or general assumption. <b>Aims and objectives:</b> The aim of this study was to compare chronic cough in IPF patients to cough in subjects with chronic cough from a community-based sample, and to investigate whether cough in IPF is less productive than chronic cough in a community. <b>Methods:</b> The IPF cough population consisted of 46 biopsy-confirmed patients. The control population consisted of subjects with chronic cough, gathered by a community-based email survey sent to public service employees and the Finnish Pensioners’ Federation. A case-control setting was applied by having four age, gender, and smoking-status matched subjects from the community sample for each IPF cough patient. A cough specific quality of life questionnaire (Leicester Cough Questionnaire (LCQ)) was filled in by all subjects. The LCQ questionnaire contains 19 questions, each question is scored from 1 to 7 and the total score from 3 to 21 with a smaller value indicating more severe impairment. <b>Results</b>: The sputum production frequency was 5.0 (3.0-6.0) in the IPF chronic cough population and 5.0 (3.0–6.0) in the community-based chronic cough population (median and interquartile range p=0.72). The LCQ total score was 14.8 (11.5-18.1) in the IPF chronic cough population and 15.4 (13.0–17.5) in the community-based chronic cough population (p=0.76). <b>Conclusion:</b> Cough in IPF patients was not distinguishable from chronic cough in the community-based population. There were no differences in sputum production or the LCQ total scores between the two populations.