Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
Am J Med. 2018 Aug;131(8):972.e1-972.e7. doi: 10.1016/j.amjmed.2018.03.031. Epub 2018 Apr 13.
Anemia is a common finding and independent predictor for adverse outcomes in hospitalized patients with medical illness. It remains unclear whether anemia is a risk factor for venous thromboembolism and whether the presence of anemia can refine risk assessment for prediction of venous thromboembolism, thereby adding incremental utility to a validated model.
In the Acute Medically Ill Venous Thromboembolism Prevention with Extended Duration Betrixaban trial (APEX), 7513 hospitalized medical patients were randomized to receive either betrixaban or standard-of-care enoxaparin for thromboprophylaxis. Baseline hemoglobin concentrations were obtained in 6861 patients, with a follow-up of 77 days. Symptomatic venous thromboembolism events, including symptomatic deep vein thrombosis, pulmonary embolism, and venous thromboembolism-related mortality, were compared between low-hemoglobin and normal-hemoglobin groups (normal range: 12.5-17.0 g/dL for males and 11.0-15.5 g/dL for females). The relationship between anemia and venous thromboembolism events was assessed by fitting a univariable and multivariable logistic regression model composed of thromboprophylaxis and risk factors. Venous thromboembolism risk refinement by hemoglobin measurement was evaluated in the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) risk assessment model.
Low hemoglobin at baseline was associated with a greater risk of symptomatic venous thromboembolism (relative risk [RR] 1.94 [95% confidence interval, 1.27-2.98]; P = .002), symptomatic deep vein thrombosis (RR 2.29 [1.12-4.68]; P = .019), and nonfatal pulmonary embolism (RR 2.63 [1.22-5.65]; P = .010) but not venous thromboembolism-related mortality (RR 1.47 [0.71-3.04]; P = .30). After adjusting for thromboprophylaxis, history of previous venous thromboembolism, intensive or coronary unit admission, and D-dimer, low hemoglobin (as a categorical or continuous variable) remained associated with an increased likelihood of venous thromboembolism (adjusted odds ratio 1.71 [95% confidence interval, 1.09-2.69]; P = .020). Low hemoglobin also improved risk discrimination and reclassification after inclusion in the IMPROVE model.
Anemia was independently associated with a greater risk of symptomatic venous thromboembolism among acutely ill medical patients despite the provision of thromboprophylaxis. Hemoglobin measurement also improved risk stratification by the IMPROVE venous thromboembolism risk score.
贫血是住院患者常见的病症，也是不良预后的独立预测因素。目前尚不清楚贫血是否是静脉血栓栓塞的危险因素，以及贫血的存在是否可以改善静脉血栓栓塞的风险评估，从而为验证后的模型增加增量效用。
在急性内科疾病静脉血栓栓塞预防中延长达比加群疗程的研究（APEX）中，7513 例住院内科患者被随机分配接受贝曲西班或标准治疗依诺肝素进行血栓预防。在 6861 例患者中获得了基线血红蛋白浓度，并进行了 77 天的随访。比较低血红蛋白和正常血红蛋白组之间的症状性静脉血栓栓塞事件（包括症状性深静脉血栓形成、肺栓塞和静脉血栓栓塞相关死亡率）（正常范围：男性 12.5-17.0g/dL，女性 11.0-15.5g/dL）。通过拟合由血栓预防和危险因素组成的单变量和多变量逻辑回归模型来评估贫血与静脉血栓栓塞事件之间的关系。通过国际静脉血栓栓塞预防登记处（IMPROVE）风险评估模型评估血红蛋白测量对静脉血栓栓塞风险的细化作用。
基线时低血红蛋白与症状性静脉血栓栓塞（相对风险 [RR] 1.94 [95%置信区间，1.27-2.98]；P =.002）、症状性深静脉血栓形成（RR 2.29 [1.12-4.68]；P =.019）和非致命性肺栓塞（RR 2.63 [1.22-5.65]；P =.010）的风险增加相关，但与静脉血栓栓塞相关死亡率（RR 1.47 [0.71-3.04]；P =.30）无关。在调整了血栓预防、静脉血栓栓塞史、重症监护或冠心病单元入院和 D-二聚体后，低血红蛋白（作为分类或连续变量）仍与静脉血栓栓塞的可能性增加相关（调整后的优势比 1.71 [95%置信区间，1.09-2.69]；P =.020）。低血红蛋白在纳入 IMPROVE 模型后也改善了风险区分度和重新分类。
尽管进行了血栓预防，但贫血与急性内科疾病患者的症状性静脉血栓栓塞风险增加独立相关。血红蛋白测量也改善了 IMPROVE 静脉血栓栓塞风险评分的风险分层。
