The Impact of Depression on Patient Outcomes among Older Adults with Lung Cancer

Background: Depression is a common malady among older adults, and as the incidence of cancer increases with age, older adults may be living with both cancer and depression. Previous studies have assessed the impact of depression on patient outcomes when depression is measured around the time of a cancer diagnosis or during cancer treatment, but we know very little about how depression preceding the cancer diagnosis affects patient outcomes during the course of cancer treatment. Using the example of lung cancer, the most common cause of cancer death among older adults, we examined the association between pre-existing depression and cancer stage at diagnosis, survival, and health care utilization.;Methods: We used the national Surveillance, Epidemiology, and End Results (SEER) database, linked to Medicare healthcare and prescription claims, to examine the association between pre-existing depression and patient outcomes for older adults with non-small cell lung cancer (NSCLC) diagnosed between 2008-2011 with claims from 2007-2013. We used multivariate logistic regression models to investigate the association of pre-existing depression, advanced NSCLC stage at diagnosis, and receipt of aggressive end-of-life care. We estimated multivariate Cox proportional hazards models to examine the association of pre-existing depression and overall survival. We utilized competing risk regression models to examine the relationship between pre-existing depression and time to anticancer therapy or hospice enrollment.;Results: We included 24,666 people in our analysis. Older adults with pre-existing depression were less likely to be diagnosed with advanced stage NSCLC (OR 0.76, 95% CI 0.68-0.85). Of the 8,873 older adults with stages 1-3A NSCLC, persons with pre-existing depression and stage 1 NSCLC had a higher risk of death compared to those without depression (OR 1.19, 95% CI 1.01-1.41). We found similar patterns of anticancer therapy receipt between older adults with or without pre-existing depression, and no significant difference in time to first anticancer treatment, accounting for the competing risk of death. Among 14,385 decedents with stage 3B or 4 NSCLC, those with pre-existing depression were more likely to enroll in hospice than persons without depression (SHR 1.16, 95% CI 1.06-1.28). We found no difference in utilization of inpatient hospitalizations, emergency room use, or chemotherapy receipt in the last 30 days of life, comparing those with versus those without pre-existing depression.;Discussion: In a national sample of older adults with NSCLC, pre-existing depression was associated with earlier stage at cancer diagnosis, shorter survival among those with early stage NSCLC and higher hospice utilization among persons with advanced NSCLC. These findings indicate the importance of screening for and treating depression during cancer therapy. As people with pre-existing depression are more likely to enroll in hospice, it is important that hospice organizations and caregivers have sufficient support to address cancer and mental health concerns at end-of-life.