title: Benchmarking antibiotic use in Finnish acute care hospitals using patient case-mix adjustment.
abstract: OBJECTIVE
  It is difficult to draw conclusions about the prudence of antibiotic use in different hospitals by directly comparing usage figures. We present a patient case-mix adjustment model of antibiotic use to rank hospitals while taking patient characteristics into account.
  
  
  METHODS
  Data on antibiotic use were collected during the national healthcare-associated infection (HAI) prevalence survey in 2005 in Finland in all 5 tertiary care, all 15 secondary care and 10 (25% of 40) other acute care hospitals. The use of antibiotics was measured using use-days/100 patient-days during a 7day period and the prevalence of patients receiving at least two antimicrobials during the study day. Case-mix-adjusted antibiotic use was calculated by using multivariate models and an indirect standardization method. Parameters in the model included age, sex, severity of underlying diseases, intensive care, haematology, preceding surgery, respirator, central venous and urinary catheters, community-associated infection, HAI and contact isolation due to methicillin-resistant Staphylococcus aureus.
  
  
  RESULTS
  The ranking order changed one position in 12 (40%) hospitals and more than two positions in 13 (43%) hospitals when the case-mix-adjusted figures were compared with those observed. In 24 hospitals (80%), the antibiotic use density observed was lower than expected by the case-mix-adjusted use density.
  
  
  CONCLUSIONS
  The patient case-mix adjustment of antibiotic use ranked the hospitals differently from the ranking according to observed use, and may be a useful tool for benchmarking hospital antibiotic use. However, the best set of easily and widely available parameters that would describe both patient material and hospital activities remains to be determined.
authors.affiliation: Finnish Hospital Infection Program (SIRO), National Institute for Health and Welfare (THL), Department of Infectious Disease Surveillance and Control, Helsinki, Finland. mari.kanerva@hus.fi
authors.forename: Mari
authors.initials: M
authors.lastname: Kanerva
authors.forename: Jukka
authors.initials: J
authors.lastname: Ollgren
authors.forename: Outi
authors.initials: O
authors.lastname: Lyytikäinen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D019985:Benchmarking; D003953:Diagnosis-Related Groups; D004334:Drug Administration Schedule; D016903:Drug Monitoring / Q000379:methods*; D004363:Drug Utilization / Q000706:statistics & numerical data*; D005260:Female; D005387:Finland; D006760:Hospitalization; D006761:Hospitals; D006801:Humans; D008297:Male; D008875:Middle Aged; D020379:Risk Adjustment
chemical_list: D000900:Anti-Bacterial Agents