Role of preoperative anemia for risk of transfusion and postoperative morbidity in fast-track hip and knee arthroplasty.

Patients scheduled for major elective orthopedic procedures frequently present with preoperative anemia. Preoperative anemia in itself has been linked to poor postoperative outcome, but is also a major independent predictive factor for the need of perioperative allogeneic blood transfusion (ABT), which in turn is associated with increased rates of morbidity and mortality.

In this paper, Jans et al have analyzed a prospective observational database of over 5,000 elective fast-track hip and knee arthroplasty procedures (January 2010‒December 2011) performed at six high-volume Danish surgical centers. They found that “preoperative anemia is prevalent before elective fast-track THA and TKA and is associated with increased risk of receiving ABT during admission and risk of prolonged length of hospital stay (LOS) and 90-day readmission”. These findings deserve some brief comments:

1. Using the WHO criteria, anemia was present in 12.8% of procedures. However, if women presenting with hemoglobin concentration >12 g/dL but <13 g/dL (the cut-off for the risk of transfusion and for recombinant human erythropoietin administration) are included, the overall prevalence “suboptimal preoperative hemoglobin” would be close to 20%. Thus the dimension of the problem in bigger. 2. Overall, 11% of the patients received 1 or more RBC units during primary admission, but anemic patients were at 4-fold higher risk (32% vs. 8.1%; p<0.001). Additionally, the median number of transfused RBC units per transfused patient was 2 (IQR 2-4), suggesting that there might be room for improvement by increasing the use of single unit transfusions. 3. This study also showed that preoperative anemia increased median LOS by 1 day (2 [2-3] vs. 3 [3-4]; p<0.001), the risk for LOS >5 days by 3, and the risk for 90-day readmission by 1.5. Although strongly influenced by ABT, extended LOS and increased rates of hospital readmission should be considered surrogate indicators of postoperative morbidity in anemic patients, with clear implications for both the patients (well-being) and the health care system (costs). These important issues have been frequently overlooked in most studies.

In summary, this important study highlights the impact of preoperative anemia on patients’ outcomes in everyday surgical practice, and the importance of its correction prior to admission into the operating room. To attain this goal, patients undergoing hip or knee arthroplasty and presenting with “suboptimal” hemoglobin levels should receive preoperative treatment for stimulating erythropoiesis, in addition to the standardized, short-stay, multimodal fast-track regimen.

– Manuel Muñoz