Incidence, Causes and Predictors of 30-Day Readmission After Shoulder Arthroplasty.

BACKGROUND: The Center for Medicare and Medicaid Service has identified several quality metrics, including unplanned readmission within 30 days of surgery, to assess and compare surgeons and hospitals. The purpose of this study was to identify the incidence, causes and risk factors for unplanned 30-day readmission after total shoulder arthroplasty.
METHODS: We identified patients undergoing primary elective shoulder arthroplasty performed at American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) participating hospitals in 2013. Cases were stratified by readmission status. Univariate and multivariate analyses were employed to assess patient demographics, comorbidities and operative variables predicting unplanned readmission.
RESULTS: 2779 patients undergoing shoulder arthroplasty were identified, with 74 (2.66%) requiring unplanned readmissions within 30 days of surgery. The most common surgical causes for unplanned readmission were surgical site infections (18.6%), dislocations (16.3%) and venous thromboembolism (14.0%). Medical causes for readmission were responsible for 51% of unplanned readmissions. Multivariate analysis identified patient age >75 (OR 2.62, 95% CI: 1.27 - 5.41), and ASA class of 3 (OR 1.79, 95% CI: 1.01 - 3.18) or 4 (OR 3.63, 95% CI: 1.31 - 10.08) as independent risk factors for unplanned readmission. Predictive modeling estimated that patients with ASA class of 4 and age >75 are 17.4 times more likely (95% CI 1.77-171.09) to be readmitted within 30 days of shoulder arthroplasty.
CONCLUSION: Unplanned readmission after shoulder arthroplasty is infrequent and medical complications account for more than 50% of occurrences. The risk of readmission exponentially increases when age and preoperative comorbidity burden are increased.