Association of hyperlipidemia with post-operative complications following total knee arthroplasty: A nationwide propensity score-matched cohort study in Japan

The impact of hyperlipidemia on post-operative outcomes in orthopedic surgery remains unclear, particularly in total knee arthroplasty (TKA). This study aimed to evaluate the association between hyperlipidemia and in-hospital complications following TKA in a Japanese population. A retrospective nationwide cohort study was conducted using Japan's national Diagnosis Procedure Combination database, including 228,595 patients who underwent TKA between April 2016 and March 2023. Hyperlipidemia was identified using ICD-10 codes E78.0–E78.5. One-to-one propensity score (PS) matching was performed, adjusting for age, sex, body mass index, type of anesthesia, Charlson comorbidity index, and comorbidities. Post-operative complications were compared between patients with and without hyperlipidemia. Given the large sample size in the analysis, the significance level was set at p < 0.001. After PS matching, each group included 45,049 patients. The incidence of deep vein thrombosis (DVT) was 11.2% in the hyperlipidemia group versus 9.8% in the control group [odds ratio (OR) 1.16, 95% confidence interval (CI) 1.11–1.21; p < 0.0001). Surgical site infection (SSI) occurred in 1.6% of hyperlipidemia patients compared with 1.3% without hyperlipidemia (OR 1.23, 95% CI 1.10–1.37; p = 0.0002). Pulmonary embolism showed a non-significant trend (OR 1.37, 95% CI 1.10–1.71; p = 0.005). Hyperlipidemia was associated with an increased risk of DVT and SSI following TKA. Although the absolute differences were modest, these findings suggest that hyperlipidemia may be associated with peri-operative risk profiles in patients undergoing TKA. • Nationwide Japanese DPC database enabled propensity score-matched analysis. • Hyperlipidemia increased deep vein thrombosis risk after total knee arthroplasty. • Surgical site infection risk was higher in patients with hyperlipidemia. • Pre-operative metabolic optimization may reduce post-operative complications.