Increased severity of anemia is associated with postoperative complications following primary total shoulder arthroplasty

Background: Anemia has been demonstrated as a modifiable risk factor for postoperative complications following various types of primary and revision total joint arthroplasties. However, at present, we are not aware of any studies assessing postoperative complications following total shoulder arthroplasty (TSA) in patients with varying severity of anemia. The purpose of this study was to determine the influence of preoperative anemia severity on 30-day postoperative complications following primary TSA. Methods: Adult patients undergoing primary TSA from 2012 to 2018 were identified in the National Surgical Quality Improvement Program database. Patients undergoing TSA were substratified into 3 cohorts: nonanemia (hematocrit >36% for women, >39% for men), mild anemia (hematocrit 33%-36% for women, 33%-39% for men), and moderate to severe anemia (hematocrit <33% for both women and men), based on World Health Organization definitions of anemia. In this analysis, 30-day wound, cardiac, pulmonary, renal, and thromboembolic complications, as well as sepsis, mortality, postoperative transfusion, extended length of stay, and reoperation were assessed. Bivariate analyses, including χ² and analysis of variance, and multivariable logistical regression were performed. Results: Of 13,921 total patients undergoing TSA, 11,330 patients (81.4%) did not have anemia, 1934 (13.9%) had mild anemia, and 657 (4.7%) had moderate to severe anemia. Following adjustment, patients with mild anemia were more likely to have a postoperative blood transfusion (odds ratio [OR] 4.7, P <.001), extended length of stay (OR 1.7, P =.002), and reoperation (OR 1.5, P =.028). Patients with moderate to severe anemia were at increased risk of cardiac complications (OR 3.0, P =.012), pulmonary complications (OR 2.2, P =.015), postoperative blood transfusion (OR 23.8, P <.001), extended length of stay (OR 6.6, P <.001), reoperation (OR 2.2, P =.003), and death (OR 3.8, P =.034). Conclusion: From mild anemia to moderate to severe anemia, there was a stepwise and approximately 2-fold increase in the odds of postoperative complications for patients undergoing primary TSA. Patients with moderate to severe anemia should be medically optimized before they undergo TSA.