以前的研究对于癌症相关静脉血栓栓塞的复发预测因素存在不一致。为了提供改善风险分层的数据，我们描述了在具有活动性癌症的全国队列患者中，根据年龄、性别、日历期、癌症类型、渥太华风险评分、癌症分期和癌症治疗的不同风险，对于复发性静脉血栓栓塞的整体风险。通过使用丹麦的行政登记，我们确定了2003年至2018年期间，所有具有活动性癌症和首次诊断为静脉血栓栓塞的成年患者队列。我们考虑了死亡的竞争风险，并计算了六个月内复发静脉血栓栓塞的绝对风险。 研究人群包括34,072名具有活动性癌症和静脉血栓栓塞的患者。六个月内的复发风险在泌尿系统癌症（6.5%）、肺癌（6.1%）、消化系统癌症（5.6%）、脑癌（5.2%）和血液系统癌症（5.1%）的患者中高于妇科癌症（4.7%）、乳腺癌（4.1%）和其他癌症类型（4.8%）的患者。男性（5.2%）和女性（4.9%）的复发风险相似，在有无化疗的情况下（5.1%），渥太华风险评分组之间（低：5.0%；高：5.1%）和日历时期之间的复发风险也相似，但随着癌症分期的增加而增加。总体而言，六个月内的全因死亡风险为26%，肺癌患者最高（49%），乳腺癌患者最低（4.1%）。 首次癌症相关静脉血栓栓塞后六个月的复发风险很高，并且根据癌症类型和患者特征有所不同。通过细化复发风险分层，可以改善对癌症相关血栓栓塞治疗持续时间的决策。版权所有©2023 Elsevier B.V.出版。

Predictive factors for recurrent cancer-associated venous thromboembolism have been inconsistent across previous studies. To provide data for improved risk stratification, we described the risk of recurrent venous thromboembolism overall and across age, sex, calendar period, cancer type, Ottawa risk score, cancer stage, and cancer treatment in a nationwide cohort of patients with active cancer.Using Danish administrative registries, we identified a cohort of all adult patients with active cancer and a first-time diagnosis of venous thromboembolism during 2003-2018. We accounted for the competing risk of death and calculated absolute risks of recurrent venous thromboembolism at six months.The population included 34,072 patients with active cancer and venous thromboembolism. Recurrence risks at six months were higher for patients with genitourinary cancer (6.5%), lung cancer (6.1%), gastrointestinal cancer (5.6%), brain cancer (5.2%), and hematological cancer (5.1%) than for patients with gynecological cancer (4.7%), breast cancer (4.1%), and other cancer types (4.8%). Recurrence risks were similar for men (5.2%) and women (4.9%), with and without chemotherapy (5.1%), across Ottawa risk score group (low: 5.0%; high: 5.1%) and across calendar periods but increased with increasing cancer stage. The overall six-month all-cause mortality risk was 26%, and highest for patients with lung cancer (49%) and lowest among breast cancer patients (4.1%).Six-month recurrence risk after first-time cancer-associated venous thromboembolism was high and varied by cancer type and patient characteristics. Refining risk stratification for recurrence may improve decision-making regarding treatment duration after cancer-associated thromboembolism.Copyright © 2023. Published by Elsevier B.V.