Modifiable Risk Factors Increase Length of Stay and 90-Day Cost of Care After Shoulder Arthroplasty.

BACKGROUND Baseline health conditions can negatively impact cost of care and risk of complications after joint replacement, necessitating additional care and incurring higher costs. Bundled payments have been utilized for hip and knee replacement and CMS (Centers for Medicare and Medicaid Services) is testing bundled payments for upper extremity arthroplasty. The purpose of this study was to determine the impact of pre-defined modifiable risk factors (MRF) on total encounter charges, hospital length of stay (LOS), related emergency department (ED) visits and charges, and related hospital readmissions within 90 days after shoulder arthroplasty. METHODS We queried the electronic medical record (EPIC) for all shoulder arthroplasty cases under DRG 483 within a regional seven-hospital system between October 2015 and December 2019. Data was used to calculate mean LOS, total 90-day charges, related emergency department (ED) visits and charges, and related hospital readmissions after shoulder arthroplasty. Data for patients who had one or more modifiable risk factors, defined as anemia (Hg 40kg/m2), uncontrolled diabetes (random glucose >180mg/dL or HgA1C>8.0%), tobacco use (ICD 10 code indicating patient is a smoker) and opioid use (opioid prescription within 90 days of surgery), were evaluated as potential covariates to assess the relationship between MRF and total encounter charges, LOS, ED visits, ED charges, and hospital readmissions. RESULTS 1317 shoulder arthroplasty patients were identified. Multivariable analysis demonstrated that anemia (+$19,847, CI: $15,743, $23,951, p<.001), malnutrition (+$5,850, CI: $3712, $7988, p<.001), and obesity (+$2,762, CI: $766, $4758, p=.007) independently contributed to higher charges after shoulder arthroplasty. Mean LOS was higher in patients with anemia (5.0 ± 4.0 days vs. 2.2 ± 1.6 days, p<.001), malnutrition (3.7 ± 2.8 days vs. 2.2 ± 1.5 days, p<.001) and uncontrolled diabetes (2.8 ± 2.8 days vs. 2.3 ± 1.7 days p=.019). Univariate risk factors associated with a significant increase in total 90-day encounter charges included anemia (+$19,345; n=37, p<.001), malnutrition (+$6,971; n=116, p<.001), obesity (+$2,615; n=184, p=.011), and uncontrolled diabetes (+$4,377, n=66, p=.011). Univariate risk for readmission within 90 days was higher in patients with malnutrition (OR 3.0, CI 1.8, 4.9, p<.001). CONCLUSION Malnutrition, obesity and anemia contribute to significantly higher costs after shoulder arthroplasty. Medical strategies to optimize patients before shoulder arthroplasty are warranted to reduce total 90-day encounter charges, length of stay, and risk of readmission within 90 days of surgery. Optimizing patient health before shoulder surgery will positively impact outcomes and cost containment for patients, institutions, and payors after shoulder arthroplasty.