Venous thromboembolism (VTE) is a relatively common complication among patients undergoing primary total knee arthroplasty (TKA). This complication occurs in a spectrum of severity ranging from an incidental finding to serious readmission-requiring events. To date, the risk factors of serious VTE that require readmission have not been characterized. This study examines the patient and hospital characteristics associated with readmission for serious VTE after TKA. The National Readmission Database (NRD) from the Agency of Healthcare Research and Quality (AHRQ) was queried for patients who underwent primary TKA from January 2016-December 2018. The study population consisted of patients who were readmitted within 90 days following primary TKA with a primary diagnosis of VTE. Multivariable regression models were constructed to evaluate patient characteristics (age, sex, insurance, elective nature of procedure, hospital characteristics, discharge status, income, and comorbidities) associated with higher risk of developing readmission-requiring VTE. Readmission rates for VTE exhibited a higher incidence in patients older than 61 (compared with 40 and under), males (OR:1.08, 95%CI [1.03–1.14]), patients with nonelective procedures (OR:20.21, 95% CI [19.16–21.32]), patients at large hospitals(OR:1.17, 95% CI [1.09–1.25]), patients at private hospitals (OR:1.19, 95% CI [1.09–1.29]), and patients with non-home discharge statuses. Comorbidities of paralysis (OR:1.52, 95% CI [1.19–1.94]), neurological disorders (OR:1.12, 95% CI [1.02–1.23]), metastatic cancer (OR:1.48, 95% CI [1.01–2.17]), obesity (OR:1.11, 95% CI [1.06–1.17]), fluid and electrolyte imbalance (OR:1.28, 95% CI [1.18–1.38]), blood loss anemia (OR:1.29, 95% CI [1.02–1.64]), and iron deficiency anemia (OR:1.24, 95 % CI [1.15–1.33]) increased risk of VTE. Certain comorbidities requiring chronic anticoagulation were associated with lower risk of VTE. Insurance status and patient income did not exhibit any correlation with VTE incidence. Patient characteristics of male sex, age > 61, and baseline comorbidities (paralysis, neurological disorders, metastatic cancer, obesity, fluid and electrolyte imbalance, and blood loss/iron deficiency anemia) were at an increased risk of developing serious VTE. Patients without continued supervision at their discharge environment were at higher risk of developing serious VTE. Extra prophylaxis and special protocols may be warranted in these patients to prevent VTE complications.

静脉血栓栓塞（VTE）是初次全膝关节置换术（TKA）患者中相对常见的并发症。这种并发症的严重程度多种多样，从偶然发现到严重的需要重新入院的事件。迄今为止，需要重新入院的严重 VTE 的危险因素尚未确定。本研究探讨了 TKA 后因严重 VTE 再入院相关的患者和医院特征。医疗保健研究与质量局 (AHRQ) 的国家再入院数据库 (NRD) 查询了 2016 年 1 月至 2018 年 12 月期间接受初次 TKA 的患者。研究人群包括初次 TKA 后 90 天内再次入院的患者VTE 的初步诊断。构建多变量回归模型来评估与发生需要再入院的 VTE 较高风险相关的患者特征（年龄、性别、保险、手术的选择性性质、医院特征、出院状况、收入和合并症）。VTE 再入院率在 61 岁以上患者（与 40 岁及以下患者相比）、男性（OR：1.08，95% CI [1.03-1.14]）、接受非选择性手术的患者（OR：20.21，95% CI [ 19.16–21.32]）、大医院患者（OR：1.17，95% CI [1.09–1.25]）、私立医院患者（OR：1.19，95% CI [1.09–1.29]）、非居家患者放电状态。瘫痪合并症（OR：1.52，95% CI [1.19–1.94]）、神经系统疾病（OR：1.12，95% CI [1.02–1.23]）、转移性癌症（OR：1.48，95% CI [1.01–2.17] ）、肥胖（OR：1.11，95% CI [1.06–1.17]）、液体和电解质失衡（OR：1.28，95% CI [1.18–1.38]）、失血性贫血（OR：1.29，95% CI [1.02] –1.64]）和缺铁性贫血（OR：1.24，95 % CI [1.15–1.33]）会增加 VTE 风险。某些需要长期抗凝治疗的合并症与较低的 VTE 风险相关。保险状况和患者收入与 VTE 发生率没有任何相关性。男性、年龄 > 61 岁和基线合并症（瘫痪、神经系统疾病、转移性癌症、肥胖、液体和电解质失衡以及失血/缺铁性贫血）的患者特征发生严重 VTE 的风险增加。在出院环境中没有持续监督的患者发生严重 VTE 的风险较高。这些患者可能需要额外的预防措施和特殊方案，以预防 VTE 并发症。