竞争风险下Fine-Gray模型与Cox模型的比较与评价

在生存分析中经常会遇到存在竞争风险的情形,在存在竞争风险情形下,比较Cox模型与Fine-Gray模型估计的分析效果。本文介绍了在存在竞争风险情形下的Fine-Gray模型,举例说明了Fine-Gray模型风险集的定义以及权重计算方法,并利用Cox模型与Fine-Gray模型对实际存在竞争风险的数据集进行了实例分析,结果表明,Fine-Gray模型与Cox模型分析结果不同,尤其是Cox模型会高估事件的累计发生率。因此,在生存分析中存在竞争风险时,选择Fine-Gray模型进行建模是更适合的。

Liquid Phase Behavior during Elevated Temperature Deformation of the Fine-Grained 5083 Al Alloy

The liquid phase behavior of the fine-grained 5083 AI alloy obtained through thermomechanical process was investigated during the tensile tests in a temperature range of 380-570℃ and strain rate range of 4.17× 10^-4- 1.0× 10^-2 s^-1. The maximum elongation 530% of the fine-grained 5083 AI alloy was obtained at 550℃ and 4.17× 10^-4 s^-1. Fracture analysis by scanning electron microscopy （SEM） indicated that the formation of filament （formed by liquid phase） was greatly affected by the tensile temperature and strain rate. The results also showed that the optimum morphology of formed filament was obtained at 550℃ and a strain rate of 4.17× 10^-4 s^-1. The effect of liquid phase on superplastic deformation of the alloy was further discussed.

Risk of cardiovascular death in patients with hepatocellular carcinoma based on the Fine-Gray model

BACKGROUND Hepatocellular carcinoma(HCC)is one of the most common types of cancers worldwide,ranking fifth among men and seventh among women,resulting in more than 7 million deaths annually.With the development of medical tech-nology,the 5-year survival rate of HCC patients can be increased to 70%.How-ever,HCC patients are often at increased risk of cardiovascular disease(CVD)death due to exposure to potentially cardiotoxic treatments compared with non-HCC patients.Moreover,CVD and cancer have become major disease burdens worldwide.Thus,further research is needed to lessen the risk of CVD death in HCC patient survivors.METHODS This study was conducted on the basis of the Surveillance,Epidemiology,and End Results database and included HCC patients with a diagnosis period from 2010 to 2015.The independent risk factors were identified using the Fine-Gray model.A nomograph was constructed to predict the CVM in HCC patients.The nomograph performance was measured using Harrell’s concordance index(C-index),calibration curve,receiver operating characteristic(ROC)curve,and area under the ROC curve(AUC)value.Moreover,the net benefit was estimated via decision curve analysis(DCA).RESULTS The study included 21545 HCC patients,of whom 619 died of CVD.Age(<60)[1.981(1.573-2.496),P<0.001],marital status(married)[unmarried:1.370(1.076-1.745),P=0.011],alpha fetoprotein(normal)[0.778(0.640-0.946),P=0.012],tumor size(≤2 cm)[(2,5]cm:1.420(1.060-1.903),P=0.019;>5 cm:2.090(1.543-2.830),P<0.001],surgery(no)[0.376(0.297-0.476),P<0.001],and chemotherapy(none/unknown)[0.578(0.472-0.709),P<0.001]were independent risk factors for CVD death in HCC patients.The discrimination and calibration of the nomograph were better.The C-index values for the training and validation sets were 0.736 and 0.665,respectively.The AUC values of the ROC curves at 2,4,and 6 years were 0.702,0.725,0.740 in the training set and 0.697,0.710,0.744 in the validation set,respectively.The calibration curves showed that the predicted probab-ilities of the CVM prediction model in the training set vs the validation set were largely consistent with the actual probabilities.DCA demonstrated that the prediction model has a high net benefit.CONCLUSION Risk factors for CVD death in HCC patients were investigated for the first time.The nomograph served as an important reference tool for relevant clinical management decisions.

放射治疗后直肠癌患者发生第二原发妇科恶性肿瘤的风险评价

研究放射治疗与直肠癌患者发生第二原发妇科恶性肿瘤风险之间的关系。方法 首先利用Fine-Gray竞争风险回归模型估计第二原发妇科恶性肿瘤的累积发病率,其次利用逻辑斯蒂回归评估接受放疗的患者与未接受放疗的患者中发生第二原发妇科恶性肿瘤的风险,最后利用logrank检验放射治疗与发生第二原发妇科恶性肿瘤的相关性。结果 本研究共纳入27466例直肠癌患者。通过构建竞争风险回归模型分析发现,接受放射治疗的直肠癌患者子宫体癌和宫颈癌的累积发病率显著高于未接受放射治疗的直肠癌患者,根据逻辑斯蒂回归计算放疗与未放疗发生第二原发妇科恶性肿瘤的OR值,其中发生子宫体癌的OR值为2.89,P<0.001;发生宫颈癌的OR值为5.21,P<0.001。结论 放射治疗会导致直肠癌患者发生子宫体癌和宫颈癌的风险增加。

竞争风险模型在肠造口旁疝发病风险及影响因素分析中的应用

目的应用竞争风险模型评估肠造口旁疝(parastomal hernia,PSH)的发病风险及影响因素。方法回顾性分析2015年至2019年735例行肠造口术患者的临床资料。通过Cox模型评估PSH的累计发生率。当死亡和回纳作为竞争事件出现时,采用Fine-Gray模型进行分析。结果中位随访17.1个月,其间,136例(18.5%)发生PSH,PSH出现的中位时间为10个月。单因素Cox回归分析和单因素Gray检验显示,年龄、术前体质指数(BMI)、高血压、前列腺肥大、造口途径与PSH的发生相关。多因素Cox回归分析和多因素Fine-Gray模型均显示,年龄≥60岁、术前BMI≥25 kg/m2和经腹膜外造口术是PSH发生的独立影响因素。此外,多因素Fine-Gray模型显示,乙状结肠造口也是PSH的独立影响因素。使用Kaplan-Meier法分析发现,肠造口患者随访1年、2年和5年的PSH累计发生率分别为20.5%、29.8%和37.6%;使用Fine-Gray模型分析发现,肠造口患者随访1年、2年和5年的PSH累计发生率分别为13.69%、20.07%和25.31%。与Kaplan-Meier或Cox法相比,Fine-Gray模型对PSH累计发生率的估计始终较低。结论在存在竞争风险的情况下,相比于Kaplan-Meier和Cox模型,Fine-Gray模型能更准确地评估与PSH发生相关的高危因素以及PSH的累计发生率。