The Type of Preoperative Oral Antithrombotics as a Risk Factor for Venous Thromboembolism After Hip Surgery: A Retrospective Study

<i>Background and Objectives</i>: Hip surgery is increasingly performed among elderly patients. Oral antithrombotics, which are taken for patients' underlying diseases, are a main concern regarding perioperative bleeding. Postoperative venous thromboembolism (VTE) is a leading cause of mortality after hip surgery. Therefore, administration of preoperative oral antithrombotics is a double-edged sword in hip surgery. In this study, we examined the correlation between the occurrence of postoperative VTE and the type of oral antithrombotics administered preoperatively. <i>Materials and Methods</i>: We analyzed the medical records of 601 patients aged 19 and over who underwent hip surgery from January 2021 to June 2023. The patients were assigned to two groups as follows: Groups VTE+ (patients who developed postoperative VTE) and VTE- (patients who did not develop postoperative VTE), respectively. <i>Results</i>: Of the 139 patients who had been taking oral antithrombotics for 6 months or more, 24 were allocated to group VTE+ and 115 to group VTE-, respectively. The number of patients who took clopidogrel and cilostazol was significantly higher in groups VTE- and VTE+, respectively (12.5 vs. 33.9%, <i>p</i> = 0.038, odds ratio (OR) = 0.278, 95% confidence interval (CI) = 0.078-0.991; 20.8 vs. 5.2%, <i>p</i> = 0.010, 95% CI = 1.325-17.245; group VTE+ vs. group VTE-). Preoperative albumin levels were significantly lower in group VTE+ (3.4 ± 0.6 g/dL vs. 3.7 ± 0.4 g/dL, <i>p</i> = 0.004, OR = 0.285, 95% CI = 0.115-0.702). In multivariate regression analysis, the results were statistically significant for clopidogrel, cilostazol, and preoperative albumin levels (<i>p</i> = 0.035, OR = 0.237, 95% CI = 0.062-0.901; <i>p</i> = 0.011, OR = 6.479, 95% CI = 1.542-27.226; <i>p</i> = 0.002, OR = 0.211, 95% CI = 0.080-0.558). <i>Conclusions</i>: Among the patients who had been taking oral antithrombotics for ≥6 months, clopidogrel had a prophylactic effect, but cilostazol showed an aggravating effect on postoperative VTE in hip surgery. Preoperative hypoalbuminemia increases the risk of postoperative VTE in hip surgery.