A nationwide study of breast cancer, depression, and multimorbidity among hospitalized women and men in the United States.

Breast cancer is the most common and second most deadly cancer for women in the US. Comorbidities like depression exacerbate the burden. This national study provides data on depression and comorbidity for both women and men with breast cancer. We conducted a serial cross-sectional analysis of the 2002-2014 National Inpatient Sample, the largest all-payer inpatient discharge database in the United States. We identified patients with primary site breast cancer, and captured information on their concomitant depression and other major chronic comorbidities. Logistic regression was used to generate adjusted odds ratios representing associations between patient and hospital characteristics and depression. Joinpoint regression was used to estimate temporal trends in depression rates. Depression prevalence was higher for women than men, with little difference between cancer subtypes. Comorbidity burden was nearly twice as high for men. From 2002 to 2014, the average number of comorbidities doubled. Depression rates were highest for patients with four or more chronic comorbidities and those with unplanned hospitalizations. Significant yearly increases of 6-10% in depression were also observed. Breast cancer patient depression rates were higher than the general inpatient population with a strong gradient effect between increasing numbers of comorbidities and the odds of depression. Comorbidities, including mental health-related, negatively impact breast cancer prognosis, increasing cancer-specific mortality as well as mortality for other conditions. Unplanned hospitalization episodes in a patient with breast cancer can be noted as an opportunity for mental health screening and intervention.