口腔正畸拔牙与非拔牙判别的ROC分析

目的 建立上海交通大学医学院附属第九人民医院口腔正畸科79个病例的拔牙指数值,为临床诊断和治疗提供参考.方法 选择符合标准的79个病例,其中男性32例,女性47例,年龄11-16岁,平均年龄12.7岁.计算每个病例治疗前的拔牙指数值.以不同假定判断标准的拔牙指数值获得一系列灵敏度和特异度值,绘制ROC曲线进行分析.结果 拔牙指数为151时,ROC曲线上灵敏度为72.7%,特异度为79.2%,灵敏度与特异度之和最大.结论 拔牙指数临界值为151,在临床应用时结合其他评价指标作出全面准确的判断.

Differentiation between extraction and nonextraction treatment using ROC analysis

Objective To establish the cutoff value of extraction index among 79 patients selected from the Department of Orthodontics, the 9th People's Hospital. Methods The subject's operating characteristic curve was used to measure the cutoff value of extraction index of 79 cases. Among them, 32 were males, 47 females. Their ages ranged from 11 to 16 years with an average age of 12.7 years. By changing the hypothetic cutoff values several times, different pairs of false-positive ratio (1-specificity) and true-positive ratio (sensitivity) were obtained. These pairs were plotted as the X and Y coordinate values on the ROC curve. Both axes of the graph ranged in value from 0 to 1. The plot which reached the maximal sensitivity plus specificity was the cutoff value we needed. Results The cutoff value was 151. The sensitivity and specificity was 72.7% and 79.2% respectively. Conclusions The cutoff value of extraction index established in this paper was 151, which is helpful to determining extraction or nonextraction therapy in clinical orthodontic practice.