Comorbidity and stage at diagnosis among lung cancer patients in the US military health system

Purpose: We investigated the association between comorbidities and stage at diagnosis among NSCLC patients in the US Military Health System (MHS), which provides universal health care to its beneficiaries. Methods: The linked data from the Department of Defense’s Central Cancer Registry (CCR) and the MHS Data Repository (MDR) were used. The study included 4768 patients with histologically confirmed primary NSCLC. Comorbid conditions were extracted from the MDR data. Comorbid conditions were those included in the Charlson Comorbidity Index (CCI) and were defined as a diagnosis during a 3-year time frame prior to the NSCLC diagnosis. Multivariable logistic regression was performed to estimate odds ratios (ORs) and 95% confidence intervals (95% CI) of late stage (stages III and IV) versus early stage (stages I and II) in relation to pre-existing comorbidities. Results: Compared to patients with no comorbidities, those with prior comorbidities tended to be less likely to have lung cancer diagnosed at late stage. When specific comorbidities were analyzed, decreased odds of being diagnosed at late stage were observed among those with chronic obstructive pulmonary disease (COPD) (adjusted OR 0.78, 95% CI 0.68 to 0.90). In contrast, patients with a congestive heart failure or a liver cirrhosis/chronic hepatitis had an increased likelihood of being diagnosed at late stage (adjusted OR 1.30, 95% CI 1.00 to 1.69 and adjusted OR 1.87, 95% CI 1.24 to 2.82, respectively). Conclusions: Among NSCLC patients in an equal access health system, the likelihood of late stage at diagnosis differed by specific comorbid diseases.