Lack of association between sputum atypia and chronic obstructive pulmonary disease mortality

Chronic obstructive pulmonary disease (COPD) and lung cancer are thought to share common elements in pathogenesis. The authors hypothesized that sputum atypia would reflect the processes leading to progressive airflow obstruction and might be a novel biomarker of more rapidly progressive COPD.

The authors analyzed the association between COPD death and sputum cytologic atypia in an ongoing cohort of 2013 smokers with varying degrees of airflow obstruction during the period between January 1, 1993, and July 1, 2001.

There were 326 deaths attributed to COPD over 4495 person-years, giving a COPD death rate of 7.25 deaths per 100 person-years, which is highly elevated compared with fewer than 0.2 COPD deaths per 100 person-years for the United States population aged between 65 and 74 years. Sputum atypia was not associated with either the degree of airflow obstruction or death from COPD. COPD death was associated with age and degree of airflow obstruction, as expected.

Sputum cytologic atypia is not predictive of death from COPD. As sputum cytologic grades of moderate or worse atypia are associated with a significant increase in the risk for lung cancer and do not denote a group with increased competing death rates from COPD, patients with sputum atypia are a good high risk group in whom chemoprevention and early detection studies can be conducted.