title: Blood use in the ambulatory setting among elderly in the United States.
abstract: BACKGROUND
  Our study characterizes blood use in the ambulatory setting by US elderly Medicare beneficiaries during 2001. As the US population ages and delivery of health care in outpatient settings is on the rise, ambulatory blood utilization is expected to increase. There is currently a lack of broad population-based studies detailing ambulatory blood utilization patterns among the US elderly.
  
  
  METHODS
  This descriptive cross-sectional study of ambulatory blood utilization in institutional outpatient settings used Medicare administrative data (5% sample of enrollees) for calendar year 2001. Blood use was identified by either the presence of recorded blood units or the procedure code(s) for transfusion of whole blood or red blood cells.
  
  
  RESULTS
  Among 1,368,368 elderly Medicare beneficiaries analyzed, 7054 (0.52%) had blood transfusion in institutional outpatient settings, and 34,186 (2.50%) had blood transfusion in the inpatient setting. Of 10,705 institutional outpatient claims with blood use quantified in this cohort of elderly Medicare beneficiaries, the top 10 principal diagnoses using the largest quantities of blood accounted for 66.3% of total blood units transfused. Nine of these 10 principal diagnoses were either for anemias (51%) or neoplasms (13%) and accounted for 64% of total blood units transfused.
  
  
  CONCLUSIONS
  Our study suggests that most of the ambulatory blood utilization among US elderly is for diagnoses of anemias and neoplasms rather than procedures. Our population-based study provides valuable information on ambulatory blood utilization patterns which may be used to better understand the reasons for transfusion in the ambulatory setting as blood use is expected to grow.
authors.affiliation: Office of Biostatistics and Epidemiology, Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, MD 20852, USA. Mikhail.Menis@fda.hhs.gov
authors.forename: Mikhail
authors.initials: M
authors.lastname: Menis
authors.forename: Dale R
authors.initials: DR
authors.lastname: Burwen
authors.forename: Leslie
authors.initials: L
authors.lastname: Holness
authors.forename: Steven A
authors.initials: SA
authors.lastname: Anderson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000553:Ambulatory Care / Q000706:statistics & numerical data*; D001803:Blood Transfusion / Q000706:statistics & numerical data*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D014481:United States