title: Preoperative anemia in total joint arthroplasty: is it associated with periprosthetic joint infection?
abstract: BACKGROUND
  Anemia is common in patients undergoing total joint arthroplasty (TJA). Numerous studies have associated anemia with increased risk of infection, length of hospital stay, and mortality in surgical populations. However, it is unclear whether and to what degree preoperative anemia in patients undergoing TJA influences postoperative periprosthetic joint infection (PJI) and mortality.
  
  
  OBJECTIVE
  We therefore (1) determined the incidence of preoperative anemia in patients undergoing TJA; (2) assessed the possible association between preoperative anemia and subsequent PJI; and (3) explored the relationship between preoperative anemia with postoperative mortality.
  
  
  METHODS
  We identified 15,722 patients who underwent TJA from January 2000 to June 2007. Anemia was defined as hemoglobin < 12 g/dL in women and hemoglobin < 13 g/dL in men. We determined the effect of preoperative anemia, demographics, and comorbidities on postoperative complications.
  
  
  RESULTS
  Of the 15,222 patients, 19.6% presented with preoperative anemia. PJI occurred more frequently in anemic patients at an incidence of 4.3% in anemic patients compared with 2% in nonanemic patients. Thirty-day (0.4%), 90-day (0.6%), and 1-year (1.8%) mortality rates were not higher in patients with preoperative anemia. Forty-four percent of anemic patients received an allogenic transfusion compared with only 13.4% of nonanemic patients. Anemic patients had increased hospital stays averaging 4.3 days compared with 3.9 days in nonanemic patients. Anemia did not predict cardiac complications.
  
  
  CONCLUSIONS
  Our data demonstrate that preoperative anemia is associated with development of subsequent PJI. Preoperative anemia was not associated with 30-day, 60-day, or 1-year mortality in this cohort.
  
  
  METHODS
  Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.
authors: The Rothman Institute of Orthopaedics at Thomas Jefferson University Hospital, 925 Chestnut Street, 5th Floor, Philadelphia, PA 19107, USA.
authors: Max
authors: M
authors: Greenky
authors: Kishor
authors: K
authors: Gandhi
authors: Luis
authors: L
authors: Pulido
authors: Camilo
authors: C
authors: Restrepo
authors: Javad
authors: J
authors: Parvizi
mesh_terms: D000368:Aged; D000740:Anemia / Q000150:complications* / Q000453:epidemiology*; D019644:Arthroplasty, Replacement, Hip; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D007720:Knee Prosthesis / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D016459:Prosthesis-Related Infections / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D013997:Time Factors