Chronic cough associated with COPD exacerbation, pneumonia and death: A prospective study of the general population

Abstract

Chronic cough has previously been associated with more severe disease in individuals with COPD. We tested whether chronic cough is associated with future COPD exacerbation, acute pneumonia, COPD hospitalization, or all-cause mortality in the general population. We identified chronic cough and measured lung function in about 45.000 individuals from the Copenhagen General Population Study and recorded COPD exacerbation, acute pneumonia, COPD hospitalization, and all-cause mortality as outcomes. At 80 yrs of age individuals with chronic cough vs without chronic cough had cumulative incidences of 12% vs 3.2% for COPD exacerbation, 30% vs 15% for acute pneumonia, 30% vs 8.6% for COPD hospitalisation, and 25% vs 13% for all-cause mortality in the general population (all Ps<0.001). Age and sex adjusted hazard ratios in individuals with chronic cough vs without were increased at 5.9 (95% CI: 3.7-9.3) for COPD exacerbation, 2.4 (1.9-2.9) for acute pneumonia, 4.0 (3.2-5.0) for COPD hospitalization and 1.9 (1.6-2.3) for all-cause mortality. The highest absolute 5-yr risks for COPD exacerbation, acute pneumonia, COPD hospitalization and all-cause mortality were, respectively, 10%, 16%, 27%, and 19% in individuals with chronic cough and age above 60 yrs, who were current smokers and had airway obstruction. Chronic cough is associated with 5.9 fold increased risk of COPD exacerbation, 2.4 fold increased risk of acute pneumonia, 4.0 fold increased risk of COPD hospitalization, and 1.9 fold increased risk of all-cause mortality in the general population.