Comparison of patient-demographics, causes, and costs of 90-day readmissions following primary total shoulder arthroplasty for glenohumeral osteoarthritis

Introduction: Readmissions following orthopaedic surgery are associated with worse outcomes and increased healthcare costs. Studies investigating trends, causes, and costs of readmissions following primary total shoulder arthroplasty (TSA) for the indication of glenohumeral osteoarthritis (OA) are limited. The objective was to compare: 1) patient-demographics of those readmitted and not readmitted within 90-days following primary TSA for OA; 2) causes of readmissions and 3) associated costs.Methods: A retrospective query from 2005 to 2014 was performed using a nationwide administrative claims database. The study group consisted of patients readmitted within 90-days following primary TSA for glenohumeral OA, whereas patients not readmitted served as controls. Causes of readmission were stratified into the following groups: cardiovascular, hematological, endocrine, gastrointestinal (GI), musculoskeletal (MSK), neoplastic, neurological, pulmonary, infectious, renal, and miscellaneous causes. Patient demographics were compared, in addition to the frequency of the causes of readmissions, and their associated costs. Chi-square analyses compared demographics between groups. Analysis of variance was utilized to determine differences in 90-day costs for the causes of readmission. A p -value less than 0.001 was significant.Results: The overall 90-day readmission rate was 2.4% (3432/143,878). Patients readmitted following primary TSA were more likely to be over the age of 75, female, and higher prevalence of comorbid conditions, including psychiatric and medical conditions. Readmitted patients had a higher overall comorbidity burden per mean Elixhauser-Comorbidity Index (ECI) scores (10 vs. 7,p < .0001). The leading cause of readmissions were due to MSK (17.34%), cardiac (16.28%), infectious (16.26%), and gastrointestinal (11.64%) etiologies. There were differences in the mean 90-day costs of care for the various causes of readmissions, with the leading cost of readmissions being cardiac causes ($10,913.70) and MSK ($10,590.50) etiologies.Conclusion: Patients with greater comorbidities experienced increased incidence of readmission following TSA for glenohumeral OA. Cardiac and MSK etiologies were the primary cause of readmissions. Level of evidence: III.