COPD prevalence is increased in lung cancer, independent of age, sex and smoking history

Chronic obstructive pulmonary disease (COPD) is a common comorbid disease in lung cancer, estimated to affect 40-70% of lung cancer patients, depending on diagnostic criteria. As smoking exposure is found in 85-90% of those diagnosed with either COPD or lung cancer, coexisting disease could merely reflect a shared smoking exposure. Potential confounding by age, sex and pack-yr smoking history, and/or by the possible effects of lung cancer on spirometry, may result in over-diagnosis of COPD prevalence. In the present study, the prevalence of COPD (pre-bronchodilator Global Initiative for Chronic Obstructive Lung Disease 2+ criteria) in patients diagnosed with lung cancer was 50% compared with 8% in a randomly…