Chen Qiang, Xu Xiang-huai, Yu Li, Liang Si-wei, Lü Han-jing, Qiu Zhong-min
Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China.
Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China. Email:
Zhonghua Jie He He Hu Xi Za Zhi. 2013 Oct;36(10):746-50.
To explore the optimal cut-off point of symptom association probability (SAP) in the diagnosis of gastroesophageal reflux-induced chronic cough (GERC) and therefore to improve the diagnostic accuracy.
Patients with suspected GERC consecutively referred to our respiratory clinic were enrolled into this prospective study between July 2011 and February 2013. After multi-channel intraluminal esophageal impedance and pH monitoring, SAP was calculated by associating the cough recordings on the patients' diary with the detected reflux. GERC was confirmed when there was a favorable response to the following anti-reflux therapy despite the laboratory findings. The optimal cutoff point of SAP was defined according to the highest Youden index. Then, the sensitivity, specificity, positive and negative predictive values, the area under the curve of ROC, and the Kappa value for the optimal cut-off point of SAP was calculated and compared to those of SAP standards currently used in China or generally accepted in the diagnosis of GERC.
During the study period, 103 patients with suspected GERC were recruited. Among them, GERC was confirmed in 87 patients (84.5%), including 54 patients (62.1%) due to acid reflux and 33 patients (37.9%) due to non-acid reflux. The optimal cut-off point of SAP was defined at ≥ 80% based on the highest Youden index of 0.372. For the diagnosis of GERC, SAP ≥ 80% had the area under the curve of ROC of 0.686, the Kappa value of 0.264, the sensitivity of 74.7%, the specificity of 62.5%, positive predictive value of 91.5% and negative predictive value of 31.3% respectively, which were superior to those of SAP ≥ 75% currently used in China, and to those of SAP ≥ 95% ( the generally accepted cut-off) in that the balance between higher sensitivity and higher specificity was maintained. When combined with DeMeester score ≥ 12.7, the diagnostic accuracy of SAP ≥ 80% was further improved, with the area under the curve of ROC of 0.820, the Kappa value of 0.689, the sensitivity of 87.0%, the specificity of 76.0%, positive predictive value of 94.1% and negative predictive value of 80.0%.
SAP ≥ 80% may be a more suitable standard for the diagnosis of GERC.
探讨症状关联概率（SAP）在胃食管反流性慢性咳嗽（GERC）诊断中的最佳截断点，以提高诊断准确性。
2011年7月至2013年2月，将连续转诊至我院呼吸科门诊的疑似GERC患者纳入本前瞻性研究。在进行多通道腔内食管阻抗和pH监测后，通过将患者日记中的咳嗽记录与检测到的反流情况相关联来计算SAP。尽管实验室检查结果未明确，但如果对以下抗反流治疗有良好反应，则确诊为GERC。根据最高约登指数确定SAP的最佳截断点。然后，计算SAP最佳截断点的敏感性、特异性、阳性和阴性预测值、ROC曲线下面积以及Kappa值，并与我国目前使用的SAP标准或GERC诊断中普遍接受的标准进行比较。
研究期间，共纳入103例疑似GERC患者。其中，87例（84.5%）确诊为GERC，包括54例（62.1%）因酸反流和33例（37.9%）因非酸反流所致。基于最高约登指数0.372，将SAP的最佳截断点定义为≥80%。对于GERC的诊断，SAP≥80%的ROC曲线下面积为0.686，Kappa值为0.264，敏感性为74.7%，特异性为62.5%，阳性预测值为91.5%，阴性预测值为31.3%，分别优于我国目前使用的SAP≥75%以及普遍接受的截断值SAP≥95%，因为其在更高的敏感性和更高的特异性之间保持了平衡。当与DeMeester评分≥12.7相结合时，SAP≥80%的诊断准确性进一步提高，ROC曲线下面积为0.820，Kappa值为0.689，敏感性为87.0%，特异性为76.0%，阳性预测值为94.1%，阴性预测值为80.0%。
SAP≥80%可能是诊断GERC更合适的标准。
