PMD146 - HEALTH CARE RESOURCE UTILIZATION AND COSTS AMONG PATIENTS WITH ASEPTIC LOOSENING AFTER PRIMARY TOTAL KNEE ARTHROPLASTY

Abstract

Aseptic loosening (AL) is a common mechanism of failure in patients with primary total knee arthroplasty (TKA). This study compared the health care resource utilization and costs among patients with aseptic loosening (AL) versus those without AL following primary TKA in the United States. This retrospective observational cohort study used Truven MarketScan® Commercial claims database. Patients with diagnosis of AL (index) between 2010 and 2014 and a prior record of TKA with knee osteoarthritis (OA) were identified. The comparison cohort comprised patients without AL diagnosis but a record of TKA with knee OA. Direct and propensity score matching were used to maximize the similarities between the patients with and without AL. The outcomes of interest were rates of inpatient stay, revision TKA, narcotic prescriptions and the total all-cause payments during one-year follow-up from the index. Generalized linear models were used to adjust for the variables not balanced after matching. A total of 2,094 patients (1,047 per cohort) were included after patient matching; mean(SD) age at primary TKA was 54.4 (5.5) years and majority were females (57.4%). Adjusted rates of inpatient stays (80.8% vs 14.7%) and revision TKA (77.0% vs 1.7%) were significantly higher at one-year follow-up (both p<0.0001) in patients with AL compared to patients without AL. The adjusted proportion of patients receiving narcotic prescriptions was nearly 32 percentage points higher in the AL cohort (75.1% vs. 42.8%, p<0.0001). The adjusted mean all-cause payments for patients with AL were nearly four times higher than those for patients without AL ($58,622 vs. $14,201, p<0.0001). After using a doubly robust methodology incorporating both matching and regression, patients with diagnosis of AL following primary TKA had significantly increased healthcare utilization and costs during the one year follow-up than patients without AL in the United States.