Cough-specific quality of life may predict adverse outcomes in ILD

Worse cough-specific quality of life appears to be associated with risk for respiratory hospitalization, death and lung transplantation in patients with interstitial lung disease, researchers reported in Chest.

“To our knowledge, this is the first study demonstrating that independent of disease severity, poorer cough-specific quality of life ... is associated with increased risk of respiratory hospitalization, death and lung transplantation at 12 months among a large and diverse population of patients with ILD,” Janet Lee, MD, pulmonologist in the section of pulmonary and critical care medicine at the University of Utah, Salt Lake City, and colleagues wrote.

Researchers evaluated data from 1,447 patients with ILD (mean age, 67.6 years; 36.9% women) from the Pulmonary Fibrosis Foundation Registry and analyzed associations between patient factors and baseline scores on the Leicester Cough Questionnaire. Then, researchers evaluated associations between baseline cough-specific quality of life scores and patient-centered clinical outcomes along with pulmonary function parameters.

Severe impairment in cough-specific quality of life was defined as less than 10 points, mild impairment was defined as 14 or more points and moderate was defined as 10 to 14 points in the Leicester Cough Questionnaire.

The following patient factors were associated with worse cough-specific quality of life in the multivariable proportional odds model:

• younger age;
• diagnosis of other ILD;
• GERD; and
• lower FVC percent predicted.

After adjustment for several variables including baseline disease severity, researchers reported that a 1-point decrease in cough-specific quality of life 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 death (HR = 1.074; 95% CI, 1.02-1.13) and an 8.7% higher risk for lung transplantation (HR = 1.087; 95% CI, 1.022-1.156) compared with patients with mild or moderate impairment in cough-specific quality of life.

“Future studies are needed urgently to understand better the underlying mechanisms of cough in ILD, the means by which cough may lead to poorer outcomes in ILD, as well as its treatment,” the researchers wrote.