University of Connecticut School of Pharmacy, Storrs, CT, USA.
Mayo Clin Proc. 2011 Jun;86(6):509-21. doi: 10.4065/mcp.2010.0755.
To determine the strength of evidence supporting an accentuated bleeding risk when patients with CHADS(2) risk factors (chronic heart failure, hypertension, advanced age, diabetes, and prior stroke/transient ischemic attack) receive warfarin.
A systematic literature search of MEDLINE (January 1, 1950, through December 22, 2009) and Cochrane CENTRAL (through December 22, 2009) was conducted to identify studies that reported multivariate results on the association between CHADS(2) covariates and risk of bleeding in patients receiving warfarin. Each covariate was evaluated for its association with a specific type of bleeding. Individual evaluations were rated as good, fair, or poor using methods consistent with those recommended by the Agency for Healthcare Research and Quality. The strength of the associations between each CHADS(2) covariate and a specific type of bleeding was determined using Grading of Recommendations Assessment, Development and Evaluation criteria as insufficient, very low, low, moderate, or high for the entire body of evidence.
Forty-one studies were identified, reporting 127 multivariate evaluations of the association between a CHADS(2) covariate and bleeding risk. No CHADS(2) covariate had a high strength of evidence for association with any bleeding type. For the vast majority of evaluations, the strength of evidence between covariates and bleeding was low. Advanced age was the only covariate that had a moderate strength of evidence for association; this was the strongest independent positive predictor for major bleeding. Similar findings were observed regardless of whether all included studies, or only those evaluating patients with atrial fibrillation, were assessed.
The associations between CHADS(2) covariates and increased bleeding risk were weak, with the exception of age. Given the known association of the CHADS(2) score and stroke risk, the decision to prescribe warfarin should be driven more by patients' risk of stroke than by the risk of bleeding.
确定 CHADS（2）危险因素（充血性心力衰竭、高血压、高龄、糖尿病和既往卒中和短暂性脑缺血发作）的患者服用华法林时出血风险增加的证据强度。
系统检索 MEDLINE（1950 年 1 月 1 日至 2009 年 12 月 22 日）和 Cochrane CENTRAL（2009 年 12 月 22 日），以确定报道 CHADS（2）变量与接受华法林治疗的患者出血风险之间关联的多变量研究。评估每个协变量与特定类型出血的相关性。采用与美国医疗保健研究与质量局推荐方法一致的方法，对个体评估结果进行了良好、中等和差的分级。使用推荐分级评估、制定与评价（Grading of Recommendations Assessment, Development and Evaluation）标准，根据每个 CHADS（2）变量与特定类型出血之间的关联强度，将证据强度分为不足、极低、低、中或高。
共确定了 41 项研究，报告了 127 项 CHADS（2）变量与出血风险之间关联的多变量评估。没有 CHADS（2）变量的证据强度足以与任何出血类型相关联。对于大多数评估，变量与出血之间的证据强度较低。高龄是唯一与出血相关的证据强度为中度的变量；这是发生主要出血的最强独立阳性预测因素。无论评估是否包括所有纳入的研究，还是仅评估心房颤动患者，都观察到了类似的结果。
CHADS（2）变量与出血风险增加之间的关联较弱，只有年龄除外。鉴于 CHADS（2）评分与中风风险的已知关联，开处方华法林的决定应更多地取决于患者中风的风险，而不是出血的风险。
