Healthcare Costs Among Patients Diagnosed With Estrogen Receptor Positive (ER+) Breast Cancer: Relationship With Comorbid Depression and Adherence to Anti-Depressant Medication

OBJECTIVES: There is a known association between cancer and depression, particularly among women with ER+ breast cancer prescribed estrogen depletion therapy (EDT), which may increase healthcare expenditure. The purpose of this study was to examine the relationship between comorbid depression and antidepressant treatment on healthcare expenditure among women newly diagnosed with ER+ breast cancer.

METHODS: This was a retrospective analysis of the Inovalon MORE² closed claims database of Commercial, Medicare Advantage, and Managed Medicaid beneficiaries between 1/1/2013 and 9/30/2023. Inclusion criteria: ≥1 inpatient or ≥2 outpatient claims with a breast cancer diagnosis (earliest diagnosis=index date), ER+ disease (diagnosis sub-code or lab value), female sex, age 18+ on index, continuous enrollment for 12 months preceding (baseline) and following (follow-up) index, and an absence of baseline depression. Patients were segmented into cohorts based on the presence/absence of a depression diagnosis during follow-up, with the former segmented by adherence status to prescribed anti-depressant therapy (proportion of days covered ≥0.80). Descriptive analyses and general linear models were used to assess relationships between healthcare costs and comorbid depression, anti-depressant adherence, and use of EDT during follow-up.

RESULTS: 91,469 patients qualified for analyses. Patients with a depression diagnosis incurred significantly greater total healthcare costs than those without a diagnosis ($60,924 vs. $45,078; p<0.0001). Among patients with depression prescribed an antidepressant, those adherent with treatment incurred significantly lower healthcare costs than those non-adherent ($61,169 vs. $69,115; p<0.05). The adherence effect was replicated among the subset of patients receiving EDT, and confirmed in general linear models controlling for baseline characteristics.

CONCLUSIONS: Women with ER+ breast cancer and comorbid depression incurred significantly greater healthcare costs compared to women without depression, though adherence to prescribed anti-depressant therapy attenuated the effect on costs. Results highlight the economic benefit associated with adherence to anti-depressant therapy among ER+ breast cancer patients with depression, including those receiving EDT.