Multimorbidity and Its Associations With Anxiety and Depression Among Newly Diagnosed Patients With Breast Cancer: A Retrospective Observational Cohort Study in a US Commercially Insured and Medicare Advantage Population.

Multimorbidity was highly prevalent among patients with breast cancer and was strongly associated with increased risk of anxiety and depression in the first year following breast cancer diagnosis. The presence of multimorbidity, anxiety, and depression should be considered in the context of clinical decision making to optimize cancer care and improve mental health and quality of life.