The optimal prophylactic dose of heparin in patients with coronavirus-associated disease 2019 (COVID-19) in the emergency department (ED) is debated. This study aimed to analyze different thromboprophylaxis approaches in unvaccinated COVID-19 patients admitted to ED without initial venous thromboembolism. Retrospectively, the effect of intermediate/high versus low dose heparin treatment was evaluated from December 2020 to July 2021 in a tertiary Academic Hospital in northeast Italy. The primary outcome comprised arterial or venous thromboembolism or all-cause death within 30 days. Secondary outcomes comprised each single primary outcome component or major hemorrhagic event. Cox regression was used to determine predictors of the primary outcome and propensity score weights to balance the effect of heparin treatment on all outcomes. Data of 144 consecutive patients (age 70 ± 13, 33% females) were included in the study. High-dose prophylactic heparin was used in 69%, intermediate in 15%, and low in 17% of patients. The primary outcome occurred in 48 patients. Independent predictors of the primary outcome were COVID-19 severity (hazards ratio (HR) 1.96, 95% confidence interval (CI) 1.05–3.65, p = 0.035) and D-dimer levels (HR each log ng/dl 1.38, 95% CI 1.04–1.84, p = 0.026). Intermediate/high dose heparin did not affect the risk of the primary outcome compared with the low dose (weighted HR 1.39, 95% CI 0.75–2.56, p = 0.292). Intermediate/high heparin increased the risk of major hemorrhagic events (weighted HR 5.92, 95% CI 1.09–32, p = 0.039). In unvaccinated COVID-19 patients admitted to ED, prophylaxis with heparin at the intermediate/high dose did not reduce primary outcome compared with the low dose but increased the risk of major hemorrhagic events.

中文翻译：

---

中/高剂量与低剂量肝素对急诊科未接种 COVID-19 患者血栓栓塞和出血风险的影响

急诊科 (ED) 中 2019 年冠状病毒相关疾病 (COVID-19) 患者的最佳肝素预防剂量存在争议。本研究旨在分析未接种疫苗的 COVID-19 患者在没有初始静脉血栓栓塞的情况下入住 ED 的不同血栓预防方法。回顾性地，于 2020 年 12 月至 2021 年 7 月在意大利东北部的一家三级学术医院评估了中/高剂量与低剂量肝素治疗的效果。主要结局包括 30 天内的动脉或静脉血栓栓塞或全因死亡。次要结局包括每个单一的主要结局成分或主要出血事件。Cox 回归用于确定主要结果的预测因子和倾向评分权重，以平衡肝素治疗对所有结果的影响。该研究包括 144 名连续患者（年龄 70 ± 13 岁，33% 为女性）的数据。69% 的患者使用了高剂量的预防性肝素，15% 的患者使用了中等剂量的肝素，17% 的患者使用了低剂量的肝素。主要结果发生在 48 名患者中。主要结果的独立预测因子是 COVID-19 严重程度（风险比 (HR) 1.96, 95% 置信区间 (CI) 1.05–3.65, p = 0.035）和 D-二聚体水平（HR 每个 log ng/dl 1.38, 95% CI 1.04–1.84，p = 0.026）。与低剂量相比，中/高剂量肝素不影响主要结局的风险（加权 HR 1.39，95% CI 0.75-2.56，p = 0.292）。中/高肝素增加了主要出血事件的风险（加权 HR 5.92，95% CI 1.09-32，p = 0.039）。在收治 ED 的未接种疫苗的 COVID-19 患者中，