Effects of Patient Comorbidities and Demographics on Episode-of-Care Costs Following Total Shoulder Arthroplasty

Abstract

Background: As demand for shoulder arthroplasty grows, adequate cost containment is of importance. Given the historical use of bundle payments for lower extremity arthroplasty, it is reasonable to anticipate that such programs will be universally implemented in shoulder arthroplasty. This project evaluates how patient demographics, medical comorbidities, and surgical variables affect episode-of-care costs in an effort to ensure accurate reimbursement scales and equitable access to care. Methods: Consecutive series of primary total shoulder arthroplasty (anatomic and reverse) procedures were retrospectively reviewed at a single academic institution from 2014 to 2020 using claims cost data from Medicare and a private insurer. Patient demographics, comorbidities, and clinical outcomes were collected. A stepwise multivariate regression was performed to determine the independent effect of comorbidities and demographics on 90-day episode-of-care costs. Results: Overall, 1,452 shoulder arthroplasty patients were identified (1,402 Medicare and 50 private payer patients). The mean 90-day cost for Medicare and private payers was $25,822 and $31,055, respectively. Among Medicare patients, dementia ($3,407, P = 0.003), history of stroke ($3,182, P = 0.005), chronic pulmonary disease ($1,958, P = 0.007), anemia ($1,772, P = 0.039), and heart disease ($1,699, P = 0.014) were associated with significantly increased costs. Demographics that significantly increased costs included advanced age ($199 per year in age, P < 0.001) and elevated body mass index ($183 per point, P < 0.001). Among private payers, hyperlipidemia ($6,254, P = 0.031) and advanced age ($713 per year, P < 0.001) were associated with an increase in total costs. Conclusion: Providers should be aware that certain demographic variables and comorbidities (history of stroke, dementia, chronic pulmonary disease, anemia, heart disease, advanced age, and elevated body mass index) are associated with an increase in total costs following primary shoulder arthroplasty. Further study is required to determine whether bundled payment target costs should be adjusted to better compensate for specific comorbidities. Level of Evidence: Level IV case series.