title: Preoperative anaemia and newly diagnosed cancer 1 year after elective total hip and knee arthroplasty.
abstract: BACKGROUND
  Preoperative anaemia is a well-established risk factor for use of blood transfusions and postoperative morbidity. Consequently, focus on preoperative evaluation of haemoglobin levels is increasing. In this context, iron deficiency anaemia may be a symptom of undiscovered gastrointestinal (GI) cancer requiring further investigation. However, the association between preoperative anaemia and cancer 1 year after elective total hip (THA) and total knee arthroplasty (TKA) is unknown. We evaluated 1-year cancer diagnoses, particularly GI cancers, in anaemic and non-anaemic THA and TKA patients.
  
  
  METHODS
  A prospective database on preoperative patient characteristics from six Danish orthopaedic centres was cross-referenced with the Danish Cancer Registry for information on diagnoses of new cancers 1 year after surgery. Crude cancer risk estimates were calculated using chi-square and Fisher's exact test in the total study cohort. Adjusted risk estimates were obtained using propensity scores and the Mantel-Haenzel statistic.
  
  
  RESULTS
  Of 5400 procedures, 731 (13·5%) were in anaemic patients. These were older and had more comorbidity than non-anaemic patients. There were 17 (2·3%) and 79 (1·6%) new cancers in anaemic and non-anaemic patients, respectively (OR: 1·38; 95% CI: 0·81-2·35, P = 0·228). After propensity matching of 661 anaemic and 1305 non-anaemic patients, we found no association between preoperative anaemia and cancer (OR: 0·94; 95% CI: 0·51-1·73, P = 0·837) or with GI cancers specifically (OR: 0·80; 95% CI: 0·25-2·56, P = 0·707).
  
  
  CONCLUSIONS
  Preoperative anaemia per se may not be related to being diagnosed with cancer 1 year after THA and TKA. The optimal criteria for preoperative referral of anaemic patients to gastroenterologist in elective THA and TKA need further investigation.
authors.affiliation: Section for Surgical Pathophysiology 4074, Rigshospitalet, Copenhagen University, Copenhagen, Denmark.|The Lundbeck Foundation Centre for Fast-track Hip and Knee Replacement, Copenhagen, Denmark.
authors.forename: C C
authors.identifier: http://orcid.org/0000-0001-6902-8181
authors.initials: CC
authors.lastname: Jørgensen
authors.affiliation: Section for Surgical Pathophysiology 4074, Rigshospitalet, Copenhagen University, Copenhagen, Denmark.|The Lundbeck Foundation Centre for Fast-track Hip and Knee Replacement, Copenhagen, Denmark.
authors.forename: Ø
authors.identifier: http://orcid.org/0000-0001-8466-1217
authors.initials: Ø
authors.lastname: Jans
authors.affiliation: The Lundbeck Foundation Centre for Fast-track Hip and Knee Replacement, Copenhagen, Denmark.
authors.forename: H
authors.initials: H
authors.lastname: Kehlet
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D019644:Arthroplasty, Replacement, Hip; D019645:Arthroplasty, Replacement, Knee; D001803:Blood Transfusion; D015331:Cohort Studies; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors
keywords: cancer risk; hip arthroplasty; knee arthroplasty; preoperative anaemia; preoperative evaluation