http://www.bcshguidelines.com/documents/pre-op_anaemia.pdf
“Anaemia is most often defined in terms of the criteria established by the World Health Organization (WHO) in 1968 (WHO 2011), namely haemoglobin (Hb) concentration of <130 g/l for men and <120 g/l for women. Pre-operative anaemia is common. Its prevalence varies from 5-75% depending on the population studied (Shander et al. 2004). Pre-operative anaemia may significantly affect patient outcomes. Anaemia is an independently predictive risk factor for complications and death (Beattie et al. 2009, Spahn 2010, Musallam et al. 2011). Co-existing anaemia substantially increases health care costs in medical (Ershler et al. 2005, Nissenson et al. 2005, Dowling 2007) as well as surgical (M’Koma et al. 2009) patients, with substantial additional cost incurred out of hospital (Ebinger et al. 2004, Ershler et al. 2005). It further predisposes patients to requiring allogeneic blood transfusion (Shander et al. 2004, Beattie et al. 2009, Spahn 2010, Musallam et al. 2011). (In this guideline, “transfusion” may be taken to mean only allogeneic blood transfusion.)”
Perioperative Complications and Length of Stay After Revision Total Hip and Knee Arthroplasties: An Analysis of the NSQIP Database
Journal of Arthroplasty, November 2015, vol./is. 30/11(1868-1871), 0883-5403;1532-8406 (November 2015)
Liodakis E.; Bergeron S.G.; Zukor D.J.; Huk O.L.; Epure L.M.; Antoniou J.
Goals of this study were (1) to determine the 30-day complications after aseptic revision hip arthroplasty (RHA) and aseptic revision knee arthroplasty (RKA) and (2) to identify patient-related risk factors predicting major complications and prolonged hospital stay beyond 7 days. The National Surgical Quality Improvement Program (NSQIP) database was used to identify patients with RHA (n=2643) or RKA (n=2425) from 2011 to 2012. The 30-day mortality rates for RHA and RKA were 1.0% and 0.1% (P< 0.001) and the overall complication rates were 7.4% and 4.7% (P< 0.001) for RHA and RKA, respectively. Multivariable analysis showed that preoperative anemia is the most important modifiable independent predictor for both major complications and prolonged hospital stay after RHA and RKA.
Baron DM et al. Preoperative anaemia is associated with poor clinical outcome in non- cardiac surgery patients. British Journal Anaesthesia 2014; 113(3): 416-23
http://hospital.blood.co.uk/patient-services/patient-blood-management/pre-operative-anaemia/
https://www.nice.org.uk/guidance/ng45/evidence/full-guideline-87258149468 (Page 140 for anaemia recommendations)