Testing the agreement of medical instruments: Overestimation of bias in the Bland–Altman analysis

ObjectivesThe Bland–Altman method is the most popular method used to assess the agreement of medical instruments. The main concern about this method is the presence of proportional bias. The slope of the regression line fitted to the Bland–Altman plot should be tested to exclude proportional bias. The aim of this study was to determine whether the overestimation of bias in the Bland–Altman analysis is still present even when the proportional bias has been excluded.MethodsData were collected from participants attending a workplace health screening program in a public university in Malaysia between 2009 and 2010. Variables collected were blood glucose level, body weight and systolic blood pressure (n = 300 per variable). Readings from the original clinical dataset were compared with twenty randomly generated datasets for each variable. The Bland–Altman limits of agreement was used to determine the agreement. The presence of proportional bias was excluded for all datasets using the recommended method.ResultsThe range of predicted bias was higher than the simulated bias for all datasets. The overestimation of bias increased as the range of actual bias increased.ConclusionTesting the slope of regression line of the Bland–Altman plot does not remove the artifactual bias in the prediction.     

眉区不同部位切口的选择与应用

目的 为眉周美容手术提供一个理想的切口选择.方法 根据患者的脸型、眉区情况、患者的治疗目的,要解决那些问题进行评估制定方案,选择不同切口:A、全眉切口;B、部分眉切口;C、眉上切口;D、眉下切口;E、眉内切口.结果 本组158例,均为Ⅰ期愈合,3个月至半年均可稳定,晚期眉切口痕迹难以察觉,效果满意.结论 通过眉切口可以进行多种面部美容手术,也能进行多种美容项目的联合手术,我们认为,它已成为面部上1/3美容手术的主要切口.     

克隆性造血对肿瘤体细胞突变检测的影响

克隆性造血（clonal hematopoiesis，CH）突变是造血干细胞（hematopoietic stem cell，HSC）携带的突变，是年龄和外在环境（吸烟、放化疗等）共同作用的结果。随着肿瘤基因研究的进展，基因检测已成为实体瘤患者全病程管理中一个重要的环节。目前CH在实体瘤中的价值越来越受到关注。将围绕CH的检出，详细阐述实体瘤患者组织样本及循环肿瘤DNA （circulating tumor DNA，ctDNA）样本中CH的检测方法，探讨CH对肿瘤体细胞突变检测的影响和挑战。     

新式带锁抢救车的设计与临床应用

目的:探讨新设计的新式带锁抢救车的临床应用价值。方法:设计一种带状态开关锁的新式带锁抢救车,并与传统开放式抢救车比较药品和物品合格率、护士清点和交接抢救车的耗时的差异。结果:新式带锁抢救车与传统开放式抢救车相比,药品合格率由90.42%提升至100%(P0.01),物品合格率由94.98%提升至100%(P0.05),护士每月平均清点时间由(34.88±1.95) h降至(4.92±1.03) h(P0.05),平均交接班时间由(16.00±0.77) min降至(2.00±0.17) min(P0.05)。结论:新式带锁抢救车便于管理、省时省力、安全便捷,可有效保障临床抢救,具有良好的应用推广价值。