statistical modeling

统计建模
  • 文章类型: Journal Article
    这项研究是为了研究不吃早餐(BKS)的频率,相关因素,Covid-19大流行期间的健康后果和本科生学业成绩是最早关注这一领域的研究。对2225名本科生进行了横断面研究。这项研究是在2020年15月1日至2020年3月4日之间进行的,使用在线自我报告早餐饮食习惯调查(BEHS)。BEHS调查分为两个部分。第一部分包括社会人口统计信息(性别,BMI,年龄,吸烟,residence,父母教育,家庭收入,学习系统和阶段(公共或私人),和学习机构(大学或研究所)的学习成绩。第二部分包括有关早餐饮食习惯的问题,包括不吃饭的频率,与BKS健康后果和零食类型相关的因素。逻辑回归是用于对落入1和0范围内的结果进行建模的常用技术。为此,我们进行了逻辑回归,以找出调整后的比值比和粗比值比.结果显示,大多数参与者是女性(1238人,55.7%)。在2,224名学生中,2059的年龄在18至24岁之间。大多数参与者来自第一级(26.5%),第二级(32.8%),第三级(17.6%)或第四级(21.3%)。超过92%的参与者是单身,约68%来自中等收入家庭。统计分析表明,住在住宿的学生中,BKS的几率降低了54%(优势比=54%,CI(41-71%),p值=0.000)。看来,低收入和正常或更高BMI的学生更有可能更经常地不吃早餐。BMI为18-24.9的学生不吃早餐的几率降低了41%(赔率=59%,CI(27%-93%),p值=0.027),并且BMI为25-29.9的学生的BKS几率降低了45%(赔率比=55%,CI(31-95%)。此外,与低收入学生相比,中等或高收入学生更有可能不吃早餐两倍(中等收入(赔率=1.85,CI(1.08-3.17)),p值=0.024),高收入(赔率比=1.98,CI(1.12-3.51),p值=0.019)。包括不吃早餐的最常见原因包括时间限制,不饿,早餐还没准备好,害怕超重和缺乏食欲。不吃早餐的后果是一整天都感到饥饿,感到疲倦,上课不注意,学习成绩低。最后,Covid-19期间的BKS在BMI较高的学生中更常见,更高的收入和住宿。主要原因是时间限制,最常见的健康问题是疲劳和注意力的运气。
    The study was conducted in order to study breakfast skipping (BKS) frequency, factors associated with, health consequence and undergraduate students academic performance during Covid-19 pandemic as earliest studies focusing on this area. A cross-sectional study was carried out among 2225 of undergraduate students. The study was carried between the period of 15/1/2020 to 3/4/2020 using an online self-report Breakfast Eating Habit Survey (BEHS). The BEHS survey was divided into two sections. The first sections included sociodemographic information (gender, BMI, age, smoking, residency, parental education, family income, studying system and stage (public or private), and studying institution (university or institute) academic performance. The second part included questions regarding breakfast eating habits including frequency of skipping meals, factors related to BKS health consequences and types of snacks. Logistic regression is a common technique used for modeling outcomes that fall into the range of 1 and 0. For this purpose, a logistic regression was performed to find adjusted odds ratio and crude odds ratio. The results showed that the majority of participants were female (1238, 55.7%). Out of 2,224 students, 2059 are aged between 18 to 24 years. Most of the participants were from first level (26.5%), second level (32.8%), third level (17.6%) or the fourth level (21.3%). Over 92% of participants were single and about 68% came from families of medium income families. The statistical analysis showed that the odds of BKS is reduced among students who live in accommodation by 54% (odds ratio = 54%, CI (41-71%), p value = 0.000). It seems that students with low income and normal or higher BMI are more likely to skip breakfast more regularly. The odds of skipping breakfast among students with BMI of 18-24.9 is reduced by 41% (odds ratio = 59%, CI (27%-93%), p value = 0.027) and the odds of BKS is reduced among students with BMI of 25-29.9 by 45% (odds ratio = 55%, CI (31-95%). Additionally, students with medium or high incomes are more likely to skip breakfast as much as twofold in comparison with students with low income (medium income (odds ratio = 1.85, CI (1.08-3.17), p-value = 0.024), high income (odds ratio = 1.98, CI (1.12-3.51), p-value = 0.019). The most common reasons for skipping breakfast included include time constraint, not hungry, breakfast is not ready, afraid to be overweight and lack of appetite. The consequences of skipping breakfast were feeling hungry throughout the day, feeling tired, and not paying attention in class and low academic performance. To concluded, BKS during Covid-19 is more common among students with higher BMI, higher income and living in accommodation. The main reason is time constraint and the most common health problems are being tired and luck of attention.
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  • 文章类型: Journal Article
    非洲猪瘟(ASF)是一种高死亡率和高传播性的疾病。提前识别高风险集群并了解ASF的传播特征对于防止其在短时间内传播至关重要。这项研究通过分析野猪尸体的监视数据,调查了大韩民国ASF的时空异质性。
    我们观察到了一个明显的年传播模式,随着时间的推移,感染ASF的尸体向南移动。我们开发了一个基于等级的统计模型,通过估计每个地区随时间的每周平均屠体数量来评估风险,允许我们分析和识别ASF的风险集群。我们进行了分析,以确定两个不同时期的风险集群,2022年末和2023年初,利用感染ASF尸体的数据。为了解决由于监测数据不完整而导致的风险和观察误差的低估,我们估计了ASF感染者的数量,并通过不同的监测强度解释了观察误差.
    因此,在2022年末,通过观察到的和估计的感染ASF的尸体数量确定的风险集群几乎相同,特别是在庆北西北部地区,北忠北地区,和西南江原地区。在2023年初,我们观察到类似的模式,在与2022年末相同的地区确定了许多风险集群。
    这种方法增强了我们对ASF空间动力学的理解。此外,它通过突出需要紧急和重点干预的领域,为动物传染病的流行病学和研究做出了贡献。通过为疾病管理和预防措施有针对性地分配资源提供关键数据,我们的发现为改进ASF管理策略奠定了重要的基础,最终帮助遏制和控制这种毁灭性的疾病。
    UNASSIGNED: African swine fever (ASF) is a disease with a high mortality rate and high transmissibility. Identifying high-risk clusters and understanding the transmission characteristics of ASF in advance are essential for preventing its spread in a short period of time. This study investigated the spatial and temporal heterogeneity of ASF in the Republic of Korea by analyzing surveillance data on wild boar carcasses.
    UNASSIGNED: We observed a distinct annual propagation pattern, with the occurrence of ASF-infected carcasses trending southward over time. We developed a rank-based statistical model to evaluate risk by estimating the average weekly number of carcasses per district over time, allowing us to analyze and identify risk clusters of ASF. We conducted an analysis to identify risk clusters for two distinct periods, Late 2022 and Early 2023, utilizing data from ASF-infected carcasses. To address the underestimation of risk and observation error due to incomplete surveillance data, we estimated the number of ASF-infected individuals and accounted for observation error via different surveillance intensities.
    UNASSIGNED: As a result, in Late 2022, the risk clusters identified by observed and estimated number of ASF-infected carcasses were almost identical, particularly in the northwestern Gyeongbuk region, north Chungbuk region, and southwestern Gangwon region. In Early 2023, we observed a similar pattern with numerous risk clusters identified in the same regions as in Late 2022.
    UNASSIGNED: This approach enhances our understanding of ASF spatial dynamics. Additionally, it contributes to the epidemiology and study of animal infectious diseases by highlighting areas requiring urgent and focused intervention. By providing crucial data for the targeted allocation of resources for disease management and preventive measures, our findings lay vital groundwork for improving ASF management strategies, ultimately aiding in the containment and control of this devastating disease.
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  • 文章类型: Journal Article
    放射治疗(RT)是治疗癌症的前线方法。虽然放射剂量输送的目标是肿瘤,剂量不可避免地会泄漏到附近的正常器官,从而引起并发症。这种现象被称为放疗毒性。为了预测毒性的结果,统计模型可以基于正常危险器官(OAR)接收的剂量学变量来建立,称为正常组织并发症概率(NTCP)模型。为了应对剂量变量的高维性和有限的临床样本量的挑战,具有变量选择技术的统计模型是可行的选择。然而,现有的变量选择技术是数据驱动的,没有将医学领域知识集成到模型公式中。我们提出了一个知识约束的广义线性模型(KC-GLM)。KC-GLM包括一个新的数学公式,将三个领域知识转化为非否定性,单调性,以及对模型系数的相邻相似性约束。我们进一步提出了KC-GLM公式的等效转换,这使得使用现有的优化求解器求解模型系数成为可能。此外,我们通过模拟研究和前列腺癌和肺癌的两个真实数据集比较KC-GLM和几种著名的变量选择技术,分别。这些实验表明,KC-GLM选择了具有更好可解释性的变量,避免产生反直觉和误导性的结果,具有较好的预测精度。
    Radiation therapy (RT) is a frontline approach to treating cancer. While the target of radiation dose delivery is the tumor, there is an inevitable spill of dose to nearby normal organs causing complications. This phenomenon is known as radiotherapy toxicity. To predict the outcome of the toxicity, statistical models can be built based on dosimetric variables received by the normal organ at risk (OAR), known as Normal Tissue Complication Probability (NTCP) models. To tackle the challenge of the high dimensionality of dosimetric variables and limited clinical sample sizes, statistical models with variable selection techniques are viable choices. However, existing variable selection techniques are data-driven and do not integrate medical domain knowledge into the model formulation. We propose a knowledge-constrained generalized linear model (KC-GLM). KC-GLM includes a new mathematical formulation to translate three pieces of domain knowledge into non-negativity, monotonicity, and adjacent similarity constraints on the model coefficients. We further propose an equivalent transformation of the KC-GLM formulation, which makes it possible to solve the model coefficients using existing optimization solvers. Furthermore, we compare KC-GLM and several well-known variable selection techniques via a simulation study and on two real datasets of prostate cancer and lung cancer, respectively. These experiments show that KC-GLM selects variables with better interpretability, avoids producing counter-intuitive and misleading results, and has better prediction accuracy.
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  • 文章类型: Journal Article
    将Fe3O4纳米颗粒嵌入海绿石-海藻酸钙(G/CA)基质中,以创建磁性杂化球(MNPs-G/CA),目的是在25、40和50°C的温度下从亚甲蓝(MB)中净化水。使用多种技术对MNPs-G/CA吸附剂进行了表征,包括元素映射,zeta电位,FTIR,FESEM,XRD,EDX,和TEM。在溶液pH8.0,MNPs-G/CA质量(25mg)的确定条件下,达到了最大量的去除MB。相互作用时间(2小时),和200mg/L的MB浓度。在所有测试温度下,MB吸收过程动力学遵循伪二阶方程(R2>0.99)。将平衡数据与Langmuir和Freundlich方程一起拟合到统计物理多层模型中。空间n参数表明MNPs-G/CA吸附剂具有混合吸附取向(即,在各种温度范围从0.69到0.93)。MNPs-G/CA活性位置的量(NM参数)从245mg/g逐渐增加至419mg/g。测得的吸附容量(Qsat)范围为466.49至664.37mg/g,MB分子的去除与吸热相互作用一致。MNPs-G/CA-MB之间的接口主要由静电吸引力决定,正如吸附能(ΔE)的值所证明的那样,从16.75到21.52kJ/mol不等。再生的MNPs-G/CA在第四次吸附-解吸循环后提供了超过80%的吸附强度。这项研究有助于我们了解控制多功能混合吸附剂上MB吸附机理的物理化学参数,比如海绿石之间的界面,海藻酸盐,和MNPs。
    Fe3O4 nanoparticles were embedded within a glauconite‑calcium alginate (G/CA) matrix to create magnetic hybrid spheres (MNPs-G/CA), with the aim of purifying water from methylene blue (MB) at temperatures of 25, 40, and 50 °C. MNPs-G/CA adsorbent was characterized using numerous techniques, including elemental mapping, zeta potential, FTIR, FESEM, XRD, EDX, and TEM. The greatest amount of the removed MB was achieved under definite conditions of solution pH 8.0, MNPs-G/CA mass (25 mg), interaction time (2 h), and 200 mg/L of MB concentration. The MB uptake process kinetic followed a pseudo-second-order equation (R2 > 0.99) at all tested temperatures. The equilibrium data were fitted to a statistical physics multilayer model in conjunction with the Langmuir and Freundlich equations. The steric n parameter reveals that MNPs-G/CA adsorbent possesses a mixed adsorption orientation (i.e., ranging from 0.69 to 0.93) across various temperatures. The amount of MNPs-G/CA active positions (the NM parameter) was progressively increased from 245 mg/g to 419 mg/g. The measured adsorption capacities (Qsat) ranged from 466.49 to 664.37 mg/g, and the removal of MB molecules was consistent with an endothermic interaction. The interface between the MNPs-G/CA-MB was principally dictated by electrostatic attractions, as evidenced by the values of adsorption energies (∆E), which varied from 16.75 to 21.52 kJ/mol. The regenerated MNPs-G/CA offered over 80 % of its adsorption strength after the fourth adsorption-desorption cycle. This study contributes to our understanding of the physicochemical parameters controlling the MB adsorption mechanism on multifunctional hybrid adsorbents, like the interface between glauconite, alginate, and MNPs.
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  • 文章类型: Journal Article
    因果推理本质上是复杂的,通常依赖于有时被忽视的关键假设。一个这样的假设是潜在的单向或双向因果关系,另一个是人口同质性,这表明两个变量之间的因果方向在整个研究样本中保持一致。识别这些过程需要通过适当的研究设计进行细致的数据收集,并使用合适的软件来定义和拟合替代模型。在精神病学中,不同疾病的共同发生是常见的,可以源于各种起源。被诊断患有两种疾病的患者可能有一种被认为是原发性的,另一种被认为是继发性的,表明人群中存在两种共病。例如,在一些个人中,抑郁症可能导致物质使用,而在别人,物质的使用可能会导致抑郁。识别原发性疾病对于制定有效的治疗计划至关重要。本文探讨了使用有限混合模型来描述样本内的异质性。我们从孪生数据的因果关系方向(DoC)模型开始,并将其扩展到混合分布模型。此扩展允许计算两个交替因果方向的每个个体数据的可能性。给定双胞胎数据,因果方向有四种可能的成对组合。通过模拟,我们研究了由于因果方向变化而导致的双混合方向(mixCLPM)模型检测和建模异质性的潜力。
    Causal inference is inherently complex, often dependent on key assumptions that are sometimes overlooked. One such assumption is the potential for unidirectional or bidirectional causality, while another is population homogeneity, which suggests that the causal direction between two variables remains consistent across the study sample. Discerning these processes requires meticulous data collection through an appropriate research design and the use of suitable software to define and fit alternative models. In psychiatry, the co-occurrence of different disorders is common and can stem from various origins. A patient diagnosed with two disorders might have one recognized as primary and the other as secondary, suggesting the existence of two types of comorbidity within the population. For example, in some individuals, depression might lead to substance use, while in others, substance use could lead to depression. Identifying the primary disorder is crucial for developing effective treatment plans. This article explores the use of finite mixture models to depict within-sample heterogeneity. We begin with the Direction of Causation (DoC) model for twin data and extend it to a mixture distribution model. This extension allows for the calculation of the likelihood of each individual\'s data for the two alternate causal directions. Given twin data, there are four possible pairwise combinations of causal direction. Through simulations, we investigate the Direction of Causation Twin Mixture (mixCLPM) model\'s potential to detect and model heterogeneity due to varying causal directions.
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  • 文章类型: Journal Article
    在肿瘤药物开发中,肿瘤动力学模型被广泛应用于通过参数模型预测患者的总体生存(OS)。然而,当前的建模范式,假设肿瘤动力学和生存率之间存在疾病特异性联系,有其局限性。这在药物开发方案中尤其明显,其中所考虑的临床试验包含具有肿瘤类型的患者,其几乎没有或没有先前的机构数据。在这项工作中,我们建议使用全适应症实体肿瘤机器学习(ML)方法,由此所有三个肿瘤指标(肿瘤收缩率,肿瘤再生长率和肿瘤生长时间)同时用于以独立于肿瘤类型的方式预测患者的OS。我们证明了这种方法在用酪氨酸激酶抑制剂治疗的癌症患者的临床试验中的实用性,普雷替尼。我们比较了参数模型和ML模型,结果表明,所提出的ML方法能够充分预测RET改变的实体肿瘤患者的OS,包括非小细胞肺癌,甲状腺髓样癌以及其他实体瘤。虽然这项研究的结果很有希望,需要进一步的研究来评估ML模型对其他实体瘤类型的普适性.
    In oncology drug development, tumor dynamics modeling is widely applied to predict patients\' overall survival (OS) via parametric models. However, the current modeling paradigm, which assumes a disease-specific link between tumor dynamics and survival, has its limitations. This is particularly evident in drug development scenarios where the clinical trial under consideration contains patients with tumor types for which there is little to no prior institutional data. In this work, we propose the use of a pan-indication solid tumor machine learning (ML) approach whereby all three tumor metrics (tumor shrinkage rate, tumor regrowth rate and time to tumor growth) are simultaneously used to predict patients\' OS in a tumor type independent manner. We demonstrate the utility of this approach in a clinical trial of cancer patients treated with the tyrosine kinase inhibitor, pralsetinib. We compared the parametric and ML models and the results showed that the proposed ML approach is able to adequately predict patient OS across RET-altered solid tumors, including non-small cell lung cancer, medullary thyroid cancer as well as other solid tumors. While the findings of this study are promising, further research is needed for evaluating the generalizability of the ML model to other solid tumor types.
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  • 文章类型: Journal Article
    在墨西哥加勒比海的中美洲珊瑚礁系统中存在加勒比海绿海龟(Cheloniamydas)的重要觅食和筑巢栖息地。在过去的25年里,金塔纳罗奥的城市发展和旅游活动急剧增加,墨西哥。此外,在过去的十年里,大量的中上层马尾藻繁殖也困扰着这个地区;然而,缺乏有关这些输入的加勒比绿龟的生化反应的信息。这项研究旨在评估绿海龟红细胞中的氧化应激指标是否是该地区人类影响程度的有价值的生物标志物。在2015-2018年期间,还在自由生活的绿龟的血浆中测量了持久性有机污染物(POPs),以进一步表征这些栖息地。作为生化生物标志物,超氧自由基(O2·-)的产生速率,羰基化蛋白质含量,和脂质过氧化(TBARS)水平,和超氧化物歧化酶的活性,谷胱甘肽S-转移酶(GST),过氧化氢酶,在红细胞中测量谷胱甘肽过氧化物酶。发现纤维乳头状瘤病(FP)的发生率为15%,在受影响的个体中,肿瘤大小与CAT活性呈正相关。包括所有氧化应激标记的多变量分析区分了捕获年份之间的绿海龟(p<0.001),2015年采样的O2·-产量最高(p=0.001),GST活性(p<0.001),TBARS(p<0.001)和羰基化蛋白(p=0.02)的水平。这些局部和时间的生化反应与第一个大量的Sargessumspp相吻合。据报道,该地区有bloom。这项研究的结果证实了氧化应激指标作为环境条件(马尾藻花和POPs)的生物标志物在绿龟作为哨兵物种中的实用性。
    Important foraging and nesting habitats for Caribbean green sea turtles (Chelonia mydas) exist within the Mesoamerican Reef System in the Mexican Caribbean. During the last 25 years, urban development and touristic activities have drastically increased in Quintana Roo, Mexico. Moreover, in the last decade, massive pelagic sargasso blooms have also afflicted this region; however, information about the biochemical responses of Caribbean green turtles to these inputs is absent. This study aimed to assess if the oxidative stress indicators in the red blood cells of green turtles are valuable biomarkers of the extent of the anthropic impact in this region. Persistent organic pollutants (POPs) were also measured in the plasma of free-living green turtles during 2015-2018 to characterize these habitats further. As biochemical biomarkers, the production rate of superoxide radical (O2•-), carbonylated protein content, and lipid peroxidation (TBARS) levels, and the activities of superoxide dismutase, glutathione S-transferase (GST), catalase, glutathione peroxidase were measured in erythrocytes. A 15 % occurrence of fibropapillomatosis (FP) was revealed, with tumor size being positively correlated with CAT activity in the affected individuals. A multivariate analysis embracing all oxidative stress markers discriminated green turtles between years of capture (p < 0.001), with those sampled during 2015 presenting the highest production of O2•- (p = 0.001), activities of GST (p < 0.001), levels of TBARS (p < 0.001) and carbonylated proteins (p = 0.02). These local and temporal biochemical responses coincided with the first massive Sargassum spp. bloom reported in the region. The results of this study corroborate the utility of the oxidative stress indicators as biomarkers of environmental conditions (sargasso blooms and POPs) in the green turtle as sentinel species.
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  • 文章类型: Journal Article
    在衰老中,生理网络的功能下降速度在个体之间不同,产生广泛的寿命分布。尽管70%的人类寿命差异仍然无法由遗传因素解释,关于衰老生理异质性的内在来源知之甚少。要了解复杂的生理网络如何产生寿命变化,需要新的方法。这里,我们提出Asynch-seq,一种使用等基因种群内基因表达异质性来研究产生寿命变异的过程的方法。通过收集数千个单个转录组,我们捕获了秀丽隐杆线虫“泛转录组”-非遗传变异的高度分辨图谱。我们使用我们的地图集来指导大规模的扰动筛选,确定种系和体细胞之间的总mRNA含量的解耦是衰老中生理异质性的最大来源。由多效基因驱动,这些基因的敲除大大降低了寿命差异。我们的工作证明了如何应用生理异质性的系统映射来减少衰老中的个体间差异。
    In aging, physiologic networks decline in function at rates that differ between individuals, producing a wide distribution of lifespan. Though 70% of human lifespan variance remains unexplained by heritable factors, little is known about the intrinsic sources of physiologic heterogeneity in aging. To understand how complex physiologic networks generate lifespan variation, new methods are needed. Here, we present Asynch-seq, an approach that uses gene-expression heterogeneity within isogenic populations to study the processes generating lifespan variation. By collecting thousands of single-individual transcriptomes, we capture the Caenorhabditis elegans \"pan-transcriptome\"-a highly resolved atlas of non-genetic variation. We use our atlas to guide a large-scale perturbation screen that identifies the decoupling of total mRNA content between germline and soma as the largest source of physiologic heterogeneity in aging, driven by pleiotropic genes whose knockdown dramatically reduces lifespan variance. Our work demonstrates how systematic mapping of physiologic heterogeneity can be applied to reduce inter-individual disparities in aging.
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  • 文章类型: Journal Article
    两项随机试验(SPCG4和PIVOT)比较了手术和保守治疗局部前列腺癌。这些试验对当代实践的适用性仍然不确定。我们的目的是开发一种个体化的前列腺癌死亡率预测模型,将在高容量中心的即时手术与主动监测进行比较。
    我们确定手术与观察的前列腺癌死亡率的相对风险是否随基线风险而变化。然后,我们使用各种相对风险估计来估计有或没有手术的15年死亡率,作为预测器,从模型计算的生化复发风险。
    我们没有看到相对风险随基线风险而变化的证据,支持使用恒定的相对风险。与观察相比,对于GradeGroup(GG)1疾病(15年死亡率降低0.2%)患者,手术获益可忽略不计,而对于PSA和分期较低(死亡率降低≤5%)的GG2患者,手术获益较小.GG3或GG4患者的获益更大(6%-9%),但仍不明显。但根据手术风险比的选择(绝对风险降低6%-36%),效果估计差异很大.
    对于患有低风险(GG1)前列腺癌的男性和许多患有GG2疾病的男性,应避免手术。在高风险疾病的男性中,手术益处更大。将研究结果与预期寿命模型相结合,将使患者能够根据肿瘤风险做出明智的治疗决定,其他原因死亡的风险,和手术的估计效果。
    UNASSIGNED: Two randomized trials (SPCG4 and PIVOT) have compared surgery to conservative management for localized prostate cancer. The applicability of these trials to contemporary practice remains uncertain. We aimed to develop an individualized prediction model for prostate cancer mortality comparing immediate surgery at a high-volume center to active surveillance.
    UNASSIGNED: We determined whether the relative risk of prostate cancer mortality with surgery vs observation varied by baseline risk. We then used various estimates of relative risk to estimate 15-year mortality with and without surgery using, as a predictor, risk of biochemical recurrence calculated from a model.
    UNASSIGNED: We saw no evidence that relative risk varied by baseline risk, supporting the use of a constant relative risk. Compared with observation, surgery was associated with negligible benefit for patients with Grade Group (GG) 1 disease (0.2% mortality reduction at 15 years) and small benefit for patients with GG2 with lower PSA and stage (≤5% mortality reduction). Benefit was greater (6%-9%) for patients with GG3 or GG4 though still modest, but effect estimates varied widely depending on choice of hazard ratio for surgery (6%-36% absolute risk reduction).
    UNASSIGNED: Surgery should be avoided for men with low-risk (GG1) prostate cancer and for many men with GG2 disease. Surgical benefits are greater in men with higher-risk disease. Integration of findings with a life expectancy model will allow patients to make informed treatment decisions given their oncologic risk, risk of death from other causes, and estimated effects of surgery.
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  • 文章类型: Journal Article
    从历史对照数据(HCD)创建的虚拟对照组(VCG)可以将调节毒性研究所需的并发对照组动物的数量减少多达25%。这项研究调查了VCG对传统研究中治疗组和对照组之间体重发展的统计结果的表现。目的是在用虚拟对照组代替并发对照组后,重现28天亚慢性研究(传统研究)的统计结果。在啮齿动物毒性研究中,初始体重用作动物年龄的替代。为了评估VCG采样方法,探索了三种不同的方法:(i)从整个HCD中采样VCG,忽略了传统研究的初始体重信息,(ii)从HCD中取样,与传统研究的初始体重相匹配,和(iii)从HCD采样,分配的统计权重来自传统研究的初始体重信息。结果表明,通过虚拟对照重现统计结果的能力主要取决于传统研究和HCD权重分布之间的一致性:无论选择哪种方法,当传统研究的初始体重分布与HCD相似时,VCG重现统计结果的能力良好.当传统研究的初始体重范围处于HCD分布的极端时,加权抽样方法更优。本文通过传统研究的初始体重强调了适当的HCD匹配的重要性,并讨论了准确复制体重发展所需的条件。
    以标准化方式进行的过去研究的动物对照数据可用于创建虚拟对照组(VCG),以用于新研究而不是对照动物。这种方法可以将研究动物的数量减少多达25%。这项研究评估了在大鼠研究中通过体重选择的VCG的性能。目的是在用来自历史对照值池的VCG替换原始对照组值后,尽可能紧密地再现原始研究结果。比较了几种选择对照动物数据以产生VCG的方法。其中,为采样池分配统计权重可获得最佳性能。理想地,在研究的第1天,VCG和原始研究动物之间的体重分布应该是相似的。本文表明,适当选择VCG可以用更少的动物产生可靠的研究数据。
    Virtual control groups (VCGs) created from historical control data (HCD) can reduce the number of concurrent control group animals needed in regulatory toxicity studies by up to 25%. This study investigates the performance of VCGs on statistical outcomes of body weight development between treatment and control groups in legacy studies. The objective is to reproduce the statistical outcomes of 28-day sub-chronic studies (legacy studies) after replacing the concurrent control group with virtual ones. In rodent toxicity studies initial body weight is used as surrogate for the age of animals. For the assessment of VCG-sampling methods three different approaches are explored: (i) sampling VCGs from the entire HCD ignoring initial body weight information of the legacy study, (ii) sampling from HCD matching the legacy study\'s initial body weights, and (iii) sampling from HCD with assigned statistical weights derived from legacy study initial body weight information. It is shown that the ability to reproduce statistical outcomes by virtual controls is mainly determined by the congruence between the legacy study and the HCD weight distribution: regardless of the chosen approach, the ability to reproduce statistical outcomes was well for VCGs when the legacy study\'s initial-body-weight distribution was similar to the HCD\'s. When the initial body weight range of the legacy study was at the extreme ends of the HCD\'s distribution, the weighted-sampling approach was superior. This article highlights the importance of proper HCD-matching by the legacy study\'s initial body weight and discusses required conditions to accurately reproduce body weight development.
    Animal control data from past studies performed in a standardized manner can be used to create virtual control groups (VCGs) to use in new studies instead of control animals. This approach can reduce the number of study animals by up to 25%. This study assesses the performance of VCGs selected by body weight in rat studies. The objective was to reproduce the original study results as closely as possible after replacing the original control group values with VCGs from a pool of historical control values. Several methods for selecting control animal data to create VCGs were compared. Among these, assigning statistical weights to the sampling pool yielded the best performance. Ideally the body weight distributions on day 1 of the study should be similar between the VCG and the original study animals. This article shows that proper selection VCGs can yield reliable study data with fewer animals.
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