title: The cost effectiveness of vancomycin for preventing infections after shoulder arthroplasty: a break-even analysis.
abstract: BACKGROUND
  Increasing methicillin resistance and recognition of Propionibacterium acnes as a cause of infection in shoulder arthroplasty has led to the adoption of local vancomycin powder application as a more effective method to prevent expensive periprosthetic infections. However, no study has analyzed the cost effectiveness of vancomycin powder for preventing infection after shoulder replacement.
  
  
  METHODS
  Cost data for infection-related care of 16 patients treated for deep periprosthetic shoulder infection was collected from our institution for the break-even analysis. An equation was developed and applied to the data to determine how effective vancomycin powder would need to be at reducing a baseline infection rate to make prophylactic use cost effective.
  
  
  RESULTS
  The efficacy of vancomycin (absolute risk reduction [ARR]) was evaluated at different unit costs, baseline infection rates, and average costs of treating infection. We determined vancomycin to be cost effective if the initial infection rate decreased by 0.04% (ARR). Using the current costs of vancomycin reported in the literature (range: $2.50/1000 mg to $44/1000 mg), we determined vancomycin to be cost effective with an ARR range of 0.01% at a cost of $2.50/1000 mg to 0.19% at $44/1000 mg. Baseline infection rate does not influence the ARR obtained at any specific cost of vancomycin or the cost of treating infection.
  
  
  CONCLUSIONS
  We have derived and used a break-even equation to assess efficacy of prophylactic antibiotics during shoulder surgery. We further demonstrated the prophylactic administration of local vancomycin powder during shoulder arthroplasty to be a highly cost-effective practice.
authors.affiliation: Department of Orthopaedic Surgery, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: M Daniel
authors.initials: MD
authors.lastname: Hatch
authors.affiliation: Department of Orthopaedic Surgery, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Daniels
authors.affiliation: Department of Orthopaedic Surgery, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Kimberly M
authors.initials: KM
authors.lastname: Glerum
authors.affiliation: Department of Orthopaedic Surgery, Brigham and Women's Hospital, Boston, MA, USA. Electronic address: ldhiggins@partners.org.
authors.forename: Laurence D
authors.initials: LD
authors.lastname: Higgins
mesh_terms: D000900:Anti-Bacterial Agents / Q000191:economics* / Q000627:therapeutic use; D019072:Antibiotic Prophylaxis / Q000191:economics*; D000072228:Arthroplasty, Replacement, Shoulder; D003362:Cost-Benefit Analysis; D006801:Humans; D013530:Surgical Wound Infection / Q000191:economics / Q000517:prevention & control*; D014481:United States; D014640:Vancomycin / Q000191:economics* / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin
keywords: Infection; break-even analysis; cost-benefit analysis; prophylaxis; shoulder arthroplasty infection; vancomycin