Cough-specific quality of life was independently associated with respiratory hospitalization, mortality and lung transplantation among patients with interstitial lung disease, researchers reported in Chest.
“There is much to learn about the mechanism of cough in ILD. In idiopathic pulmonary fibrosis, postulated cough mechanisms include increased cough reflex sensitivity, architectural distortion of the airways from fibrosis, and overexpression of airway mediators such as mucin and neurotrophins,” Janet Lee, MD, pulmonologist in the section of pulmonary and critical care medicine at the University of Utah, Salt Lake City, and colleagues wrote. “Complicating this further is the fact that many patients with ILD have comorbidities such as COPD, GERD, obstructive sleep apnea and asthma, which can also influence cough.”
Researchers evaluated data from the Pulmonary Fibrosis Foundation Registry to identify 1,447 patients with ILD (mean age, 67.6 years; 36.9% women). Researchers then assessed associations between patient factors and baseline Leicester Cough Questionnaire and cough-specific quality of life scores and examined associations between baseline questionnaire scores and patient-centered clinical outcomes and pulmonary function parameters.
Younger age (OR = 1.292; 95% CI, 1.155-1.445; P < .0001), a diagnosis of other ILD (OR = 2.701; 95% CI, 1.511-4.829; P = .0008), GERD (OR = 1.351; 95% CI, 0.995-1.834; P = .0539) and lower FVC (OR = 1.283; 95% CI, 1.194-1.379; P < .0001) were factors associated with worse cough-specific quality of life in the univariable model, according to the results.
When adjusting for other variables, the researchers reported a 1-point decrease in Leicester Cough Questionnaire score was associated with a 6.5% higher risk for respiratory-related hospitalization (HR = 1.065; 95% CI, 1.025-1.107), a 7.4% higher risk for mortality (HR = 1.074; 95% CI, 1.02-1.13) and an 8.7% higher risk for lung transplant (HR = 1.087; 95% CI, 1.022-1.156), according to the results.
“This study adds evidence to the existing literature supporting the value of measuring and assessing cough not only in IPF but also in the broader ILD population,” the researchers wrote. “Future studies are urgently needed to better understand the underlying mechanisms of cough in ILD, the means by which cough may lead to poorer outcomes in ILD, as well as its treatment.”