COPD With Lung Cancer Among Older United States Adults: Prevalence, Diagnostic Timeliness, and Association With Earlier Stage Tumors.

Rationale: Chronic obstructive pulmonary disease (COPD) is a common comorbidity among patients with lung cancer, and an important determinant of their outcomes, however, it is commonly underdiagnosed. Objective: Our objective was to estimate the prevalence of COPD among a cohort of U.S. lung cancer patients, the timing of a COPD diagnosis relative to their lung cancer diagnosis, and the association between an earlier diagnosis of COPD and stage of lung cancer, with consideration of patient sociodemographic modifying factors. Methods: We conducted an analysis of the Medicare-linked Surveillance, Epidemiology, and End Results database including patients aged 68+ years who were diagnosed with lung cancer between 2008 to 2017. Exposure: Prevalence of COPD was identified using claims and subclassified based on the timing of its diagnosis relative to the lung cancer diagnostic episode-"preexisting" if diagnosed > 3 months before lung cancer, and "concurrent" if diagnosed around the same time as the lung cancer (+/-3 months). Outcome: The stage of cancer at diagnosis (early versus late) was the outcome. Results: Among 159,542 patients with lung cancer, 73.5% had COPD. Among those with COPD, 34.4% were diagnosed within 3 months of their lung cancer diagnosis and considered to have "concurrent COPD." We observed a positive association between preexisting COPD diagnosis and early-stage lung cancer (prevalence ratio= 1.27; 95% confidence interval= 1.23-1.30), in adjusted models which were stronger for male, non-Hispanic Black, and Hispanic patients. Conclusions: Seven out of 10 patients with lung cancer have COPD, however, many do not receive their COPD diagnosis until around the time of their lung cancer diagnosis. Among these patients, an early COPD diagnosis may improve early detection of lung cancer.