The use of propensity score methods with survival or time‐to‐event outcomes: reporting measures of effect similar to those used in randomized experiments

Propensity score methods are increasingly being used to estimate causal treatment effects in observational studies. In medical and epidemiological studies, outcomes are frequently time‐to‐event in nature. Propensity‐score methods are often applied incorrectly when estimating the effect of treatment on time‐to‐event outcomes. This article describes how two different propensity score methods (matching and inverse probability of treatment weighting) can be used to estimate the measures of effect that are frequently reported in randomized controlled trials: (i) marginal survival curves, which describe survival in the population if all subjects were treated or if all subjects were untreated; and (ii) marginal hazard ratios. The use of these propensity score methods allows one to replicate the measures of effect that are commonly reported in randomized controlled trials with time‐to‐event outcomes: both absolute and relative reductions in the probability of an event occurring can be determined. We also provide guidance on variable selection for the propensity score model, highlight methods for assessing the balance of baseline covariates between treated and untreated subjects, and describe the implementation of a sensitivity analysis to assess the effect of unmeasured confounding variables on the estimated treatment effect when outcomes are time‐to‐event in nature. The methods in the paper are illustrated by estimating the effect of discharge statin prescribing on the risk of death in a sample of patients hospitalized with acute myocardial infarction. In this tutorial article, we describe and illustrate all the steps necessary to conduct a comprehensive analysis of the effect of treatment on time‐to‐event outcomes. © 2013 The authors. Statistics in Medicine published by John Wiley & Sons, Ltd.     

大量输注多种抗体红细胞但无不良反应的输血分析

目的分析一例临床配血不合的不明抗体的成分和来源,探讨大量输注配血不合红细胞而没有导致输血不良反应的原因。方法对患者血浆做血型鉴定、直抗、抗筛、抗体鉴定和抗体效价测定等血清学试验。结果患者血浆中同时存在效价高达1∶1024的抗-I为主的多种抗体,包括特异性抗体和药物抗体且已激活补体,造成配血不合。结论大量配血不合红细胞的输注并没有引起明显输血不良反应,临床输血应根据患者病情灵活调整输血方案。     

不同粘接剂对全瓷修复体颜色影响的实验研究

目的：研究粘接剂对两种全瓷修复体颜色的影响。方法：应用色差仪测试不同粘结剂对相同厚度的两种全瓷修复体颜色的影响,分别采用国际照明委员会（CIE）1976L＊a＊b标准色度系统及L＊C＊H表色系统进行评价。结果：In-Ceram、Cergogold两种瓷修复体厚度为1．5nm时,在标准黑、白背景下的色差值分别为△E=1．57、2．15。不同粘接剂对两种全瓷材料的各项色度值均有影响。结论：临床在选择不同全瓷修复材料时,应根据材料的透性选择不同的粘接剂,以达到最佳的美学效果。     

原位心脏移植的初步体会

目的总结9例原位心脏移植经验,探讨该方法的近、远期疗效。方法心脏移植病人9例,均患终末期扩张型心肌病,术前射血分数(ejection fraction,EF)为0．10-0．29(0．21±0．03),均有频发室性期前收缩。用标准法处理5例,用双腔静脉法4例。供心热缺血时间2．6-6．7(4．2±1．0)min,冷缺血时间110- 175(141±16)min。抗排斥反应采用环孢素、麦考酚酸酯和甲泼尼龙三联方案,以环孢素为主。维持其血药浓度200μg／L;综合临床表现、超声心动图和心电图观察排斥反应,必要时行心内膜活检。结果手术全部成功,病人均在术后1-3月内出院,出院时心功能均恢复到0-Ⅰ级。随访4-42(27±20)个月,除1例病人在8个月时自行停服免疫抑制药因排斥反应死亡外,其余8例病人健康状况良好,6例病人已恢复工作。结论原位心脏移植是治疗终末期心脏病的有效手段。术前认真选择供体和受体,并造好血液配型及组织配型,移植过程中尽量缩短热、冷缺血时间和良好吻合是手术成功的关键。术后应用免疫抑制药和密切观察排斥反应是取得远期疗效的重点。     

HLA-A/B、DR抗原的基因配型对穿透性角膜移植免疫排斥反应影响的研究

目的 探讨HLA-A/B、DR抗原的基因配型对穿透性角膜移植术后免疫排斥的影响。设计实验研究。研究对象北京同仁医院穿透性角膜移植角膜供受体材料150对。方法 回顾角膜供受体的基本信息、免疫排斥反应发生情况、可能引起排斥反应的高危因素。对供体角膜环和受体病变组织采用多聚酶链式反应-序列特异性引物(PCR-SS)法进行HLA-A/B、DR抗原的基因检测及配型。根据供体与受体HLA配型是否一致分为配型符合组及配型不符合组。采用χ²检验对组间排斥反应率进行比较。采用Logistic回归分析基因配型及其他相关危险因素对发生排斥反应的发生风险。主要指标不同HLA抗原基因配型的排斥反应发生率;发生排斥反应的OR值。结果 150对角膜组织中HLA-A/B配型符合组64例,3例(4.69%)发生免疫排斥反应;配型不符合组86例中23例(33.72%)发生排斥反应(χ²=18.430,P<0.001)。HLA-DR配型符合组34例,9例(25.71%)发生免疫排斥反应,配型不符合组115例,23例(20%)发生免疫排斥反应(χ²=0....     

Impact of body mass index in elderly patients treated with laparoscopic liver resection for hepatocellular carcinoma

BACKGROUND The impact of obesity on surgical outcomes in elderly patients candidate for liver surgery is still debated.AIM To evaluate the impact of high body mass index(BMI) on perioperative and oncological outcome in elderly patients(> 70 years old) treated with laparoscopic liver resection for hepatocellular carcinoma(HCC).METHODS Retrospective multicenter study including 224 elderly patients(> 70 years old) operated by laparoscopy for HCC(196 with a BMI < 30 and 28 with BMI ≥ 30), o...     

膝关节镜的手术配合体会

目的探讨膝关节镜的手术护理配合的重要性。方法回顾80例膝关节镜的手术的配合情况。结果掌握病人的心理情况,台上、台下熟练操作,注意高标准、严要求,就能达到预期的效果。     

The roles of the LpSTS and DLPFC in self‐prioritization: A transcranial magnetic stimulation study

The Self‐Attention Network (SAN) has been proposed to describe the underlying neural mechanism of the self‐prioritization effect, yet the roles of the key nodes in the SAN—the left posterior superior temporal sulcus (LpSTS) and the dorsolateral prefrontal cortex (DLPFC)—still need to be clarified. One hundred and nine participants were randomly assigned into the LpSTS group, the DLPFC group, or the sham group. We used the transcranial magnetic stimulation (TMS) technique to selectively disrupt the functions of the corresponding targeted region, and observed its impacts on self‐prioritization effect based on the difference between the performance of the self‐matching task before and after the targeted stimulation. We analyzed both model‐free performance measures and HDDM‐based performance measures for the self‐matching task. The results showed that the inhibition of LpSTS could lead to reduced performance in processing self‐related stimuli, which establishes a causal role for the LpSTS in self‐related processing and provide direct evidence to support the SAN framework. However, the results of the DLPFC group from HDDM analysis were distinct from the results based on response efficiency. Our investigation further the understanding of the differentiated roles of key nodes in the SAN in supporting the self‐salience in information processing.