Association between preoperative anemia and revision risk after total shoulder arthroplasty: a multi-institutional cohort study.

This retrospective cohort study explored the association between preoperative anemia and the risk of revision surgery following total shoulder arthroplasty (TSA). Using the TriNetX database, we analyzed patients aged ≥ 50 years who underwent primary TSA between 2010 and 2024. Patients were classified as anemic (hemoglobin 8-12 g/dL) or non-anemic (≥ 12 g/dL), and propensity score matching was applied in a 1:1 ratio. After matching, 10,838 patients were included (5,419 per group). At three-year follow-up, patients with preoperative anemia demonstrated significantly higher risks of TSA revision (hazard ratio [HR]: 1.58, p < 0.001), periprosthetic joint infection (HR: 1.98, p < 0.001), mortality (HR: 2.65, p < 0.001), pneumonia (HR: 1.66, p < 0.001), and emergency department visits (HR: 1.18, p < 0.001). One-year results showed consistent trends, with mortality risk being notably higher (HR: 3.29 vs. 2.65). Sensitivity analyses restricted to academic medical centers, patients with minimum three-year survival, and individuals with mild anemia consistently reinforced these findings. A validation cohort from the pre-COVID-19 era confirmed the associations. These findings suggest that preoperative anemia may represent an opportunity for risk stratification and optimization following TSA. Whether preoperative correction of anemia can reduce these risks warrants investigation in prospective interventional studies.