title: Facility characteristics do not explain higher false-positive rates in diagnostic mammography at facilities serving vulnerable women.
abstract: BACKGROUND
  Facilities serving vulnerable women have higher false-positive rates for diagnostic mammography than facilities serving nonvulnerable women. False positives lead to anxiety, unnecessary biopsies, and higher costs.
  
  
  OBJECTIVE
  Examine whether availability of on-site breast ultrasound or biopsy services, academic medical center affiliation, or profit status explains differences in false-positive rates.
  
  
  METHODS
  We examined 78,733 diagnostic mammograms performed to evaluate breast problems at Breast Cancer Surveillance Consortium facilities from 1999 to 2005. We used logistic-normal mixed effects regression to determine if adjusting for facility characteristics accounts for observed differences in false-positive rates.
  
  
  METHODS
  Facilities were characterized as serving vulnerable women based on the proportion of mammograms performed on racial/ethnic minorities, women with lower educational attainment, limited household income, or rural residence.
  
  
  RESULTS
  Although the availability of on-site ultrasound and biopsy services was associated with greater odds of a false positive in most models [odds ratios (OR) ranging from 1.24 to 1.88; P<0.05], adjustment for these services did not attenuate the association between vulnerability and false-positive rates. Estimated ORs for the effect of vulnerability indexes on false-positive rates unadjusted for facility services were: lower educational attainment [OR 1.33; 95% confidence intervals (CI), 1.03-1.74]; racial/ethnic minority status (OR 1.33; 95% CI, 0.98-1.80); rural residence (OR 1.56; 95% CI, 1.26-1.92); limited household income (OR 1.38; 95% CI, 1.10-1.73). After adjustment, estimates remained relatively unchanged.
  
  
  CONCLUSIONS
  On-site diagnostic service availability may contribute to unnecessary biopsies, but does not explain the higher diagnostic mammography false-positive rates at facilities serving vulnerable women.
authors.affiliation: Department of Medicine, University of California San Francisco, San Francisco, CA 94110, USA. legoldman@medsfgh.ucsf.edu
authors.forename: L Elizabeth
authors.initials: LE
authors.lastname: Goldman
authors.forename: Rod
authors.initials: R
authors.lastname: Walker
authors.forename: Diana L
authors.initials: DL
authors.lastname: Miglioretti
authors.forename: Rebecca
authors.initials: R
authors.lastname: Smith-Bindman
authors.forename: And Karla
authors.initials: AK
authors.lastname: Kerlikowske
mesh_terms: D000046:Academic Medical Centers / Q000458:organization & administration; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D001943:Breast Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging; D005189:False Positive Reactions; D005260:Female; D006268:Health Facilities / Q000592:standards; D058016:Health Facility Administration / Q000592:standards; D006801:Humans; D008327:Mammography / Q000592:standards* / Q000706:statistics & numerical data; D008403:Mass Screening / Q000458:organization & administration / Q000592:standards; D008875:Middle Aged; D011787:Quality of Health Care / Q000458:organization & administration / Q000592:standards; D012959:Socioeconomic Factors; D014463:Ultrasonography; D014481:United States; D035862:Vulnerable Populations