title: Socioeconomic Disparities in Mortality Among Women With Incident Breast Cancer Before and After Implementation of Medicare Part D.
abstract: Breast cancer patients exhibit survival disparities based on socioeconomic status (SES). Disparities may be attributable to access to expensive oral endocrine agents.
  
  
  
  Define recent socioeconomic disparities in breast cancer survival and determine whether these improved after implementation of the Medicare Part D program.
  
  
  
  Difference-in-difference natural experiment of women diagnosed and treated before or after implementation of Medicare Part D.
  
  
  
  Female Medicare beneficiaries with early-stage breast cancer: 54,772 diagnosed in 2001 and 46,371 in 2007.
  
  
  
  SES was based on Medicaid enrollment and zip code per capita income, all-cause mortality from Medicare, and cause of death from National Death Index.
  
  
  
  Among women diagnosed pre-Part D, 40.5% of poor beneficiaries had died within 5 years compared with 20.3% of high-income women (P<0.0001). Post-Part D, 33.6% of poor women and 18.4% of high-income women died by 5 years. After adjustment for potential confounders, improvement in all-cause mortality post-Part D was greater for poorer women compared with more affluent women (P=0.002). However, absolute improvement in breast cancer-specific mortality was 1.8%, 1.2%, and 0.8% (P=0.88 for difference in improvement by SES), respectively for poor, near-poor, and high-income women, whereas analogous improvement in mortality from other causes was 5.1%, 3.8%, and 0.9% (P=0.067 for difference in improvement by SES).
  
  
  
  Large survival disparities by SES exist among breast cancer patients. The Part D program successfully ameliorated SES disparities in all-cause mortality. However, improvement was concentrated in causes of death other than breast cancer, suggesting remaining gaps in care.
authors.affiliation: *Department of Medicine, Medical College of Wisconsin †Center for Patient Care and Outcomes Research, Medical College of Wisconsin ‡Division of Biostatistics, Institute for Health and Society, Medical College of Wisconsin, Milwaukee, WI.
authors.forename: Ann B
authors.initials: AB
authors.lastname: Nattinger
authors.forename: Erica M
authors.initials: EM
authors.lastname: Wozniak
authors.forename: Emily L
authors.initials: EL
authors.lastname: McGinley
authors.forename: Jianing
authors.initials: J
authors.lastname: Li
authors.forename: Purushottam
authors.initials: P
authors.lastname: Laud
authors.forename: Liliana E
authors.initials: LE
authors.lastname: Pezzin
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality* / Q000628:therapy*; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D006297:Health Services Accessibility / Q000706:statistics & numerical data*; D054625:Healthcare Disparities / Q000706:statistics & numerical data*; D006801:Humans; D054524:Medicare Part D / Q000706:statistics & numerical data*; D008875:Middle Aged; D011203:Poverty; D012923:Social Class; D014481:United States