Post-Hoc Comparison in Survival Analysis: An Easy Approach

Survival studies mainly deal with distribution of time to event. Often in such studies researchers are interested in comparing several treatment or prognostic groups. At the time of analysis, there is an unmeasured chance of making type I error, or finding a falsely significant difference between any two groups. The chance of making type I error is increased, if multiple groups are compared simultaneously. In this paper, survival analysis with Bonferroni correction is explained in easy way to cope up with this issue. The DLHS-3 data are taken to explain this methodology in the context of neonatal survival. Kaplan-meier plot with three survival comparison test is used to elaborate the application of Bonferroni correction.

Survival Analysis of Victims of Sulfur Oxide Air Pollution Suffering from COPD or Asthma in Yokkaichi, Japan, in Relation to Predisposing Exposure

To investigate the relationships between clinical findings and symptoms and the survival of patients with Yokkaichi Asthma, in relation to predisposing sulfur dioxide (SO2) exposure, we examined records of 1836 patients registered in the city of Yokkaichi during 1973-1988 by “Pollution-Related Health Damage Compensation Law.” Complete records were obtained from 735 patients (352 males and 383 females) until December 31, 2007, and were used for the analysis. Ambient SO2 concentrations in the Yokkaichi area were obtained from the Environmental Numeric Database of the National Institute for Environmental Science, Japan. It was found that severity of clinical symptoms and decreased pulmonary function were significantly correlated with predisposing SO2 exposure. A Cox proportional hazards analysis revealed that among all patients (COPD and asthma), age, forced expiratory volume 1.0 (sec) % and smoking affected mortality for both males and females. Significant associations between mortality, vital capacity (percent predicted) and cough and sputum were observed in males. Thus, the survival of patients with Yokkaichi Asthma was affected by severity of clinical symptoms and decreased pulmonary function, which were related to predisposing SO2 exposure. It appeared that the effects of clinical changes were greater in males than in females.

Survival Analysis of Lung Cancer Patients from TCGA Cohort

Lung cancer is one of the leading causes of death worldwide, accounting for an estimated 2.1 million cases in 2018. To analyze the risk factors behind the lung cancer survival, this paper employs two main models: Kaplan-Meier estimator and Cox proportional hazard model [1]. Also, log-rank test and wald test are utilized to test whether a correlation exists or not, which is discussed in detail in later parts of the paper. The aim is to find out the most influential factors for the survival probability of lung cancer patients. To summarize the results, stage of cancer is always a significant factor for lung cancer survival, and time has to be taken into account when analyzing the survival rate of patients in our data sample, which is from TCGA. Future study on lung cancer is also required to make improvement for the treatment of lung cancer, as our data sample might not represent the overall condition of patients diagnosed with lung cancer;also, more appropriate and advanced models should be employed in order to reflect factors that can affect survival rate of patients with lung cancer in detail.

Change-Point Analysis of Survival Data with Application in Clinical Trials

Effects of many medical procedures appear after a time lag, when a significant change occurs in subjects’ failure rate. This paper focuses on the detection and estimation of such changes which is important for the evaluation and comparison of treatments and prediction of their effects. Unlike the classical change-point model, measurements may still be identically distributed, and the change point is a parameter of their common survival function. Some of the classical change-point detection techniques can still be used but the results are different. Contrary to the classical model, the maximum likelihood estimator of a change point appears consistent, even in presence of nuisance parameters. However, a more efficient procedure can be derived from Kaplan-Meier estimation of the survival function followed by the least-squares estimation of the change point. Strong consistency of these estimation schemes is proved. The finite-sample properties are examined by a Monte Carlo study. Proposed methods are applied to a recent clinical trial of the treatment program for strong drug dependence.

Survival Analysis of Logistics Service Providers: An Empirical Study of Chengdu, Area in China

This paper worked on a sample of 6791 logistics establishments registered in Chengdu, China over the period 1984-2016 to understand the survival status of logistics service providers (LSPs) by non-parametric Kaplan-Meier estimation, together with Cox proportional hazard regression model, to identify factors affecting the failure of LSPs. In particular, it studies the interaction effect between LSPs’ size and entry timing and location. The empirical results show that: 1) Regarding the survival time, 1365 of the 6791 sample LSPs exited from the market by 2017. The exit rate is 20.1%, and the average life of the 6791 LSPs is about 6 years. 2) The survival of LSPs depends on their typology, ownership structure. And there is no significant difference in the probability of survival for both independent LSPs and logistics branches after controlling the effects of other variables. 3) Location and entry timing also play an important role in the survival of small-scale LSPs, but these factors cannot explain large-scale LSPs’ failure.

The Statistical Analysis of Interval-Censored Failure Time Data with Applications

The analysis of survival data is a major focus of statistics. Interval censored data reflect uncertainty as to the exact times the units failed within an interval. This type of data frequently comes from tests or situations where the objects of interest are not constantly monitored. Thus events are known only to have occurred between the two observation periods. Interval censoring has become increasingly common in the areas that produce failure time data. This paper explores the statistical analysis of interval-censored failure time data with applications. Three different data sets, namely Breast Cancer, Hemophilia, and AIDS data were used to illustrate the methods during this study. Both parametric and nonparametric methods of analysis are carried out in this study. Theory and methodology of fitted models for the interval-censored data are described. Fitting of parametric and non-parametric models to three real data sets are considered. Results derived from different methods are presented and also compared.

A MICROCOMPUTER PROGRAM FOR CALCULATINGTHE CONFIDENCE INTERVALS OF SURVIVAL PROBABILITY IN MEDICAL FOLLOW－UP STUDIES

In cancer survival analysis, it is very frequently to estimate the confidence intervals for survival probabilities.But this calculation is not commonly involve in most popular computer packages, or only one methods of estimation in the packages. In the present Paper, we will describe a microcomputer Program for estimating the confidence intervals of survival probabilities, when the survival functions are estimated using Kaplan-Meier product-limit or life-table method. There are five methods of estimation in the program (SPCI), which are the classical(based on Greenwood's formula of variance of S(ti), Rothman-Wilson, arcsin transformation, log(-Iog) transformation, Iogit transformation methods. Two example analysis are given for testing the performances of the program running.

Cox Proportional Hazard Model for Survival Time of Neonatal Mortality in Neonatal Intensive Care Unit of Hospitals in River Nile State-Sudan

Cox Proportional Hazard model is a popular statistical technique for exploring the relationship between the survival time of neonates and several explanatory variables. It provides an estimate of the study variables’ effect on survival after adjustment for other explanatory variables, and allows us to estimate the hazard (or risk) of death of newborn in NICU of hospitals in River Nile State-Sudan for the period (2018-2020). Study Data represented (neonate gender, mode of delivery, birth type, neonate weight, resident type, gestational age, and survival time). Kaplan-Meier method is used to estimate survival and hazard function for survival times of newborns that have not completed their first month. Of 700 neonates in the study area, 25% of them died during 2018-2020. Variables of interest that had a significant effect on neonatal death by Cox Proportional Hazard Model analysis were neonate weight, resident type, and gestational age. In Cox Proportional Hazard Model analysis all the variables of interest had an effect on neonatal death, but the variables with a significant effect included, weight of neonate, resident type and gestational age.

Log-Rank Test for Comparing Survival Curves of Neonatal Mortality Characteristic Groups in River Nile State-Sudan

This paper concerns the Log-rank test for comparing survival curves of neonatal mortality characteristic groups in River Nile State, Sudan. In this paper, log-rank test is used to compare two or more survival curves for the characteristics of newborn associated with newborn death after using Kaplan-Meier methods to estimate and graph survival curves for the variable of interest as (sex of newborn, weight of newborn, gestational age, mode of delivery and resident type), at the hospital of River Nile state—Sudan, with a sample size 700 of newborn in which the admission to the Neonatal Intensive Care Unit (NICU) of those hospitals during the period 2018-2020. In term of risk of death for newborn we found that 25% of sample study for newborns who were born in River Nile State-Sudan died. In addition, we conclude that after the log-rank statistics and Kaplan-Meier methods were applied, gender does not affect the newborn’s risk of survival, while the risk of survival increases when the birth weight is greater than 4.35 kg and the gestational age is greater than 42 weeks. There is no difference in the probability of survival for newborns whether the delivery is normal or cesarean. However, newborns are significantly more likely to survive in urban areas than in rural areas.

Lutetium in prostate cancer: Reconstruction of patient-level data from published trials and generation of a multi-trial Kaplan-Meier curve

BACKGROUND Lutetium has been shown to be an important potential innovation in pre-treated metastatic castration-resistant prostate cancer.Two clinical trials have evaluated lutetium thus far(therap and vision with 99 and 385 patients,respectively),but their results are discordant.AIM To synthetize the available evidence on the effectiveness of lutetium in pre-treated metastatic castration-resistant prostate cancer;and to test the application of a new artificial intelligence technique that synthetizes effectiveness based on reconstructed patient-level data.METHODS We employed a new artificial intelligence method(shiny method)to pool the survival data of these two trials and evaluate to what extent the lutetium cohorts differed from one another.The shiny technique employs an original reconstruction of individual patient data from the Kaplan-Meier curves.The progression-free survival graphs of the two lutetium cohorts were analyzed and compared.RESULTS The hazard ratio estimated was in favor of the vision trial;the difference was statistically significant(P<0.001).These results indicate that further studies on lutetium are needed because the survival data of the two trials published thus far are conflicting.CONCLUSION Our study confirms the feasibility of reconstructing patient-level data from survival graphs in order to generate a survival statistics.

Recipient functional status impacts on short and long-term intestinal transplant outcomes in United States adults

BACKGROUND Recipient functional status prior to transplantation has been found to impact post-transplant outcomes in heart,liver and kidney transplants.However,information on how functional status,before and after transplant impacts post-transplant survival outcomes is lacking.AIM To investigate the impact of recipient functional status on short and long term intestinal transplant outcomes in United States adults.METHODS We conducted a retrospective cohort study on 1254 adults who underwent first-time intestinal transplantation from 2005 to 2022.The primary outcome was mortality.Using the Karnofsky Performance Status,functional impairment was categorized as severe,moderate and normal.Analyses were conducted using Kaplan-Meier curves and multivariable Cox regression.RESULTS The median age was 41 years,majority(53.4%)were women.Severe impairment was present in 28.3%of recipients.The median survival time was 906.6 days.The median survival time was 1331 and 560 days for patients with normal and severe functional impairment respectively.Recipients with severe impairment had a 56%higher risk of mortality at one year[Hazard ratio(HR)=1.56;95%CI:1.23–1.98;P<0.001]and 58%at five years(HR=1.58;95%CI:1.24–2.00;P<0.001)compared to patients with no functional impairment.Recipients with worse functional status after transplant also had poor survival outcomes.CONCLUSION Pre-and post-transplant recipient functional status is an important prognostic indicator for short-and long-term intestinal transplant outcomes.

目标体温管理对体外心肺复苏患者神经功能结局和出院生存率影响的系统评价

目的系统评价目标体温管理对体外心肺复苏(extracorporeal cardiopulmonary resuscitation,ECPR)患者神经功能结局和出院生存率的影响。方法计算机检索PubMed、Cochrane Library、Elsevier、Web of Science、Ovid、中国知网、万方、SinoMed、中华医学期刊全文数据库中关于目标体温管理对ECPR患者结局指标影响的文献,检索时限均从建库至2023年6月1日。严格按照纳入排除标准进行筛选,提取资料,评价文献质量,采用RevMan 5.3软件对纳入研究进行Meta分析。结果共纳入8篇研究,包括3687例ECPR患者。与非目标体温管理组比较,目标体温管理未能显著改善患者神经功能结局(OR=1.37,95%CI 0.89~2.13,P=0.16)和出院生存率(OR=0.98,95%CI 0.82~1.15,P=0.77),且两组出血、下肢缺血、肾损伤和感染等ECMO相关并发症发生率差异无统计学意义(OR=1.24,95%CI 0.91~1.68,P=0.17)。结论目标体温管理对ECPR患者的神经结局和出院生存率无显著改善作用,但不会加重ECMO相关并发症的发生。

间充质干细胞来源外泌体治疗动物急性肝衰竭的Meta分析

目的:评价间充质干细胞来源外泌体治疗急性肝衰竭动物模型的效果。方法:检索PubMed、Web of Science、Embase、The Cochrane Library、CBM、CNKI、万方、维普数据库,收集各数据库建库至2023-01-16期间有关间充质干细胞外泌体治疗急性肝衰竭的动物实验。由2名研究人员独立筛选文献并提取数据,应用SYRCLE工具评估偏倚风险。提取的数据由Revman 5.4.1软件和Stata 17.0软件进行分析。结果:共检索出241篇相关文献,筛选9篇动物实验纳入分析,共219只动物:模型组110只,外泌体组109只。研究结果显示外泌体组动物生存率较模型组显著提高[RR=9.34,95%CI(3.91,22.29),P<0.001],血清丙氨酸氨基转移酶水平[SMD=-5.31,95%CI(-7.43,-3.19),P<0.001]及天门冬氨酸氨基转移酶水平[SMD=-4.47,95%CI(-5.85,-3.10),P<0.001]明显降低,白细胞介素1β[SMD=-11.54,95%CI(-18.12,-4.95),P=0.0006]、白细胞介素6[SMD=-5.75,95%CI(-8.08,-3.41),P<0.001]、肿瘤坏死因子α[SMD=-4.46,95%CI(-6.83,-2.09),P=0.0002]等促炎因子的表达水平明显降低。结论:间充质干细胞外泌体有助于抑制炎症反应,改善急性肝衰竭动物的肝功能,并提高其生存率。亚组分析结果提示,动物生存时间较短(≤24 h)、外泌体移植剂量较小(<1 mg/kg)及外泌体来源(脂肪间充质干细胞)可能会影响间充质干细胞外泌体治疗急性肝衰竭动物模型的疗效。该结论及临床转化仍需大样本量、高质量的随机对照研究予以证实。

癌症中甲基化改变对增强子活性的影响

目的 分析识别癌症中甲基化改变对增强子活性的影响。方法 分别从人类增强子数据库FANTOM5、甲基化DNA结合转录因子数据库MeDReaders及分子特征数据库MSigDB中获取增强子、转录因子结合位点及分子通路数据等信息,识别受甲基化影响的活性增强子、正常与癌症差异甲基化增强子和探针,并在CpG Island上注释,根据增强子和基因的共表达情况进一步识别增强子甲基化调控的靶基因并在泛癌模块中进行功能富集分析,最后进行COX比例风险回归分析与功能分析模式的识别。结果 共识别出1 155个受甲基化调控的增强子,其对应的探针大部分是在癌症中表现差异甲基化的探针,少数在癌症中受甲基化调控的增强子所对应的探针没有表现出差异甲基化。根据增强子和基因的共表达筛选出的靶基因和癌症相关通路有关,这些基因还参与到癌症相关(P53通路)、转录相关(transcript通路)、信号转导相关以及代谢相关等重要功能的通路中;在膀胱尿路上皮癌中存在很多三元组合与生存相关,这些靶基因还分布在癌症相关通路以及其他生命健康相关通路中。结论 本研究系统分析了癌症中受甲基化影响的增强子调控,识别了关键的增强子通过调控重要的靶基因参与癌症发生发展的功能。

早期多次血液灌流与血液透析对百草枯中毒病人的血气分析和预后效果分析

目的探讨早期多次血液灌流联合血液透析对百草枯中毒患者的治疗效果。方法回顾性分析我院2021年2月至2023年1月治疗的124例百草枯中毒患者资料,其中50例接受常规治疗与早期多次血液灌流作为对照组,74例在对照组治疗基础上加用血液透析作为观察组。比较两组患者临床疗效、肝肾功能、血气指标变化及90天生存情况。结果与对照组相比,观察组临床疗效明显增强,总有效率分别为93.24%和76.00%(P<0.05);肝功能指标AST、ALT和ALP较对照组显著降低(P<0.05);肾功能指标BUN和Cr较对照组显著降低(P<0.05);PaO_(2)、PaO_(2)/FiO_(2)较对照组显著升高,PaCO_(2)较对照组显著降低(P<0.05);90天生存率显著升高,死亡率分别为25.68%和66.00%(P<0.001)。结论早期多次血液灌流联合血液透析可显著提高百草枯中毒患者临床疗效、改善肝肾功能和血气指标,并提高患者短期生存率。

基于网络拓扑分析识别非小细胞肺癌的关键基因

目的:通过分析非小细胞肺癌(Non-small cell lung cancer,NSCLC)的差异基因蛋白质互作网络和加权基因共表达网络,挖掘NSCLC潜在的生物标志物。方法:从公共数据库收集3套NSCLC的表达谱数据集为研究对象,首先利用NSCLC中发生差异表达的基因构建蛋白质-蛋白质互作网络,并根据网络的拓扑结构挖掘网络中的关键基因。再通过构建NSCLC加权基因共表达网络对关键基因进一步验证。最后,利用Logistic回归、功能富集、生存分析等方法评估关键基因作为NSCLC生物标志物的潜力。结果:在3套独立的NSCLC数据集中,通过差异基因蛋白互作网络和加权基因共表达网络的筛选,共得到6个与NSCLC相关的关键基因,分别为CDK1、CCNA2、CDC20、TOP2A、KIF11和BUB1B。Logistic回归分析表明,这些关键基因具有良好的NSCLC预测潜能,其在3套数据集中的平均AUC为0.945(范围为0.895~1)。利用KM-Plotter在线生存分析网站进行分析,发现这6个关键基因的表达水平均与NSCLC患者的预后显著相关。功能富集分析结果显示,这些基因主要在细胞周期、细胞衰老等癌症相关的生物学通路中富集。结论:基因CDK1、CCNA2、CDC20、TOP2A、KIF11、BUB1B与NSCLC发生发展密切相关,可能是其潜在的生物标志物。

塔里木河上游灰胡杨种群生存分析

Six plots were investigated and field data were obtained with the contiguous grid quadrate method in a natural Populus euphratica forest in the upper reaches of the Tarim river.We developed a static life table and a survival function of Populus pruinosa population based on the population life table and a theory of survival analysis.Survivorship curves,and the mortality rate were determined,and population dynamics were analyzed by using the spectral analysis.The results showed that:1)Survival numbers of P.pruinosa populations were decreased with the increasing of age,and the expecting life of individuals with DBH larger than 40 cm declined obviously.2)The Survivorship curve of the populations was Deevey Ⅲ.Four survival functions showed that the P.pruinosa population declined in young age and stabilized in old age.3)There were two peaks of mortality rate existed in the lifespan:respectively occarred at the first and 11th age class periods.Seedling shortage was the restricting factor of development.4) The spectral analysis of the populations showed that there was a marked periodic fluctuation in the process of natural regeneration.5)The higher mortality rate of P.pruinosa seedlings might be integrated by the interplay of biological characteristics of P.pruinosa and deteriorating habitat(groundwater level decreasing).

手术加放射治疗与单纯喉部分切除术治疗喉癌的疗效比较

目的 探讨手术加放射治疗能否比单纯部分喉手术提高疗效。方法 1 71例喉癌随机分为单纯手术、手术加术后放射治疗 (剂量 5 1～ 70Gy)和放射治疗加手术 (剂量 40～ 5 0Gy) 3组 ,前瞻性观察各组的治疗效果。术式包括 :声带切除术、垂直半喉切除术、水平半喉切除术、次全喉切除术。结果 单纯手术组 (5 6例 )、手术加术后放射治疗组 (6 5例 )和术前放射治疗加手术组 (5 0例 )的 5年生存率分别为 85 7% (42 / 49)、80 7% (46 / 5 7)和 79 5 % (35 / 44 ) ,经 χ2 检验 ,差异无显著性 (χ2 =0 70 3,P =0 70 4)。三组总的 5年生存率为 82 0 % (1 2 3/ 1 5 0 )。临床I、II、III、IV期的 5年生存率分别为91 9%、85 1 %、6 8 4 %和 0 %。经 χ2 检验 (χ2 =1 2 2 48,P =0 0 0 7) ,差异有显著性。全组 1 71例 (除 3例次全喉切除术病例外 )均获得良好或较好的发音效果。结论 手术联合术前放射治疗或术后放射治疗均未能提高 5年生存率 ;部分喉切除术的各种术式除次全喉切除术外 ,所获得的发音功能均较满意。

塔里木河下游珍稀濒危植物胡杨的种群生存特征研究

该研究以种群生命表和生存分析理论为基础,采用空间代替时间法和分段均滑技术,编制了塔里木河下游地区胡杨种群特定时间生命表,绘制了胡杨种群的存活曲线、死亡率曲线,并分析了种群数量动态变化过程。结果表明:(1)胡杨种群的存活曲线属于凹型,Ⅰ~Ⅲ龄级死亡率在20%以下,从Ⅲ龄级到Ⅷ龄级死亡率增加迅速,并在Ⅷ龄级达到高峰,之后一直保持在50%以上。(2)胡杨种群累积死亡率从Ⅰ~Ⅷ龄级增加了75.79%,Ⅸ~Ⅻ龄级累积死亡率仅增加5.07%,胡杨幼苗和幼树的死亡率高;种群危险率在第Ⅶ龄级已经达到0.142 3,至第Ⅻ龄级达到0.217 4,表明随着胡杨年龄的增加,危险率也增加;死亡密度在Ⅶ龄级与Ⅸ龄级之间减少了0.018 7,说明从Ⅶ龄级到Ⅸ龄级有大量的胡杨死亡。(3)胡杨种群数量动态除了受基波的影响外,在第Ⅵ龄级处还有一个明显的小周期波动,这也许与该龄级胡杨的生理特性或人为干扰有关。

慢性阻塞性肺疾病患者家庭长期氧疗的临床研究

目的:探讨家庭长期氧疗(LTOT)对慢性阻塞性肺疾病(COPD)患者的疗效。方法:将我院同期住院病人随机分为LTOT组(51人),对照组(52人)。全部病例在缓解期及治疗后每年测定PaO2、PaCO2、FVC、FEV1、HB、HCT的数值及每年住院次数。结果:①氧疗后12、、3、4、5年与氧疗前比较,低氧血症改善,FEV1明显提高,HB、HCT明显减少;每年住院次数减少;②LTOT组5年生存率62.75%,对照组5年生存率46.15%,差异有显著性(p<0.05)。结论:合理使用LTOT对COPD患者有良好的治疗作用,可提高患者的5年生存率。