应用受试者工作曲线确定国际标准化比率诊断非瓣膜心房颤动患者华法林抗凝出血的最佳临界值

Detecting optimal cut-off value of international normalized ration by receiver operator characteristic curve in diagnosis of hemorrhage in patients with nonvalvular atrial fibrillation receiving wafarin

目的 使用受试者工作曲线（ROC曲线）法,评价非瓣膜性心房颤动（房颤）患者在华法林抗凝治疗中国际标准化比率（INR）对出血事件的预测和诊断价值,确定INR预测出血事件的最佳临界值. 方法 通过回顾性分析,选择华法林抗凝治疗的非瓣膜房颤患者231例,发生出血事件患者93例（出血组）,未有出血患者138例（未出血组）作为对照.采用Sysmex CA-500检测仪检测凝血酶原时间（PT）和INR,用Medcalc软件绘制ROC曲线. 结果 其ROC曲线下面积（AUC%）为0.822,95%CI为0.717～0.900,最佳临界值为2.71,敏感性为77.40%,特异性为78.30%. 结论 通过ROC曲线评价,INR对华法林引起的出血事件预测价值较好,当患者INR值≥2.71时,出血风险明显增大,应警惕有出血风险.因此可以通过INR切值来区别服用华法林患者是否容易有出血倾向,可以指导临床内科医生预测发生出血事件的危险性,并指导临床医生用药.

Objective To evaluate the value of international normalized ratio （INR） in predicting and diagnosing hemorrhagic events in patients with nonvalvular atrial fibrillation （NVAF）receiving wafarin, to determine the optimal cut-off value of INR for predicting hemorrhagic events by receiver operator characteristic （ROC） curve. Methods The data of 231 patients with NVAF receiving wafarin were retrospectively analyzed, including 93 patients with hemorrhagic events and 138cases without hemorrhagic events as control group. The PT and INR were detected by Sysmex CA-500 with Medcalc software plotting ROC curve. Results The area under the ROC curve for INR was 0. 822 （95%CI： 0. 717-0. 900）, the analysis of ROC curve revealed the optimal cut-off value of INR was 2.71, which presented a sensitivity of 77.40% and a specificity of 78.30%. Conclusions Through evaluation by ROC curve, the new cut-off value provides substantial improvement in sensitivity, with an acceptable loss of specificity. The value on predicting hemorrhagic events is better, the discriminative power of INR between hemorrhagic events and nonhemorrhagic events is satisfactory. The cut-off value of INR can guide the clinical physicians to predict the risks of hemorrhagic and promote proper use of clinical medications.