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

## TL;DR

This study found that the type of preoperative oral antithrombotics affects the risk of blood clots after hip surgery, with clopidogrel reducing and cilostazol increasing the risk.

## Contribution

The study identifies specific antithrombotic drugs as risk factors for postoperative venous thromboembolism in hip surgery patients.

## Key findings

- Clopidogrel was associated with a lower risk of postoperative VTE compared to other antithrombotics.
- Cilostazol was linked to a higher risk of postoperative VTE.
- Low preoperative albumin levels increased the risk of VTE after hip surgery.

## Abstract

Background and Objectives: 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. Materials and Methods: 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. Results: 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%, p = 0.038, odds ratio (OR) = 0.278, 95% confidence interval (CI) = 0.078–0.991; 20.8 vs. 5.2%, p = 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, p = 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 (p = 0.035, OR = 0.237, 95% CI = 0.062–0.901; p = 0.011, OR = 6.479, 95% CI = 1.542–27.226; p = 0.002, OR = 0.211, 95% CI = 0.080–0.558). Conclusions: 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.