Impact of Bupivacaine Liposomal Injectable Suspension on Hospital Length of Stay and Home Discharge among Medicare Patients Undergoing Total Knee Arthroplasty

Under the Medicare Comprehensive Care for Joint Replacement (CJR), hospitals will receive a bundled payment to cover services from admission to 90 days for TKA; reducing hospital LOS and increasing home discharge are known to decrease total costs. This study examined the impact of using BLIS on LOS and home discharge in Medicare patients undergoing TKA. This analysis used hospital chargemaster data from Premier, focusing on hospitals with >500 Medicare primary TKA patients who received BLIS from 7/1/2013 to 3/31/2015; controls without BLIS from the same hospitals were included from 1/1/2011 to 3/31/2015. Descriptive, univariate, and multivariate analyses were conducted to compare outcomes; log transformation was applied to LOS with gamma distribution, while logit link with binary distribution was used for home discharge. Independent variables were age, gender, race, and Charlson Comorbidity Index (CCI), with hospital for random effects. The analysis included five hospitals (urban: n=5, 101-500 beds: n=5, academic: n=2); two were in the Northeast, and one each in the Midwest, South, and West. The study included 3,359 patients with BLIS and 5,785 controls, with no differences between groups in age, gender, or CCI, but more whites in the BLIS group. In univariate analyses, the BLIS group had a lower LOS (mean 2.5 vs. 2.9 days; Wilcoxon p<0.001), higher discharge within 2.0 days (58.1% vs. 32.2%; chi-square p<0.001), and higher home discharge (68.1% vs. 56.7%; chi-square p<0.001). In multivariate analyses, use of BLIS reduced LOS by 0.5 days (p<0.001) and increased the odds of home discharge by 1.57 (95% confidence interval 1.43-1.73). At midsize urban hospitals, Medicare patients undergoing TKA had a shorter LOS and were more likely to be discharged home when receiving BLIS. These differences could materially impact total hospital costs for TKA at 90 days under CJR.