Observational studies

观察性研究
  • 文章类型: Journal Article
    这份手稿总结了第一作者在2024年卡尔文·施瓦贝兽医流行病学和预防医学终身成就奖研讨会上发表的演讲,授予JanSargeant博士.流行病学研究在理解暴露与健康结果之间的复杂关系中起着至关重要的作用。然而,从这些调查中得出的结论的准确性取决于对暴露变量的精心选择和测量。适当的暴露变量选择对于了解疾病病因至关重要,但通常情况下,我们无法直接测量感兴趣的风险敞口变量,而是使用代理度量来评估风险敞口。不适当地使用代理措施可能会导致对真正的利益暴露做出错误的结论。这些错误可能导致对风险敞口和结果之间关联的估计有偏差。这种偏见的后果超出了研究的关注,因为可以根据有缺陷的证据做出健康决定。认识到并减轻这些偏见对于提供可靠的证据来指导卫生政策和干预措施至关重要。最终有助于改善人口健康结果。为了应对这些挑战,研究人员必须采用严格的方法进行暴露变量选择和验证研究,以最大程度地减少测量误差。
    This manuscript summarizes a presentation delivered by the first author at the 2024 symposium for the Calvin Schwabe Award for Lifetime Achievement in Veterinary Epidemiology and Preventive Medicine, which was awarded to Dr. Jan Sargeant. Epidemiologic research plays a crucial role in understanding the complex relationships between exposures and health outcomes. However, the accuracy of the conclusions drawn from these investigations relies upon the meticulous selection and measurement of exposure variables. Appropriate exposure variable selection is crucial for understanding disease etiologies, but it is often the case that we are not able to directly measure the exposure variable of interest and use proxy measures to assess exposures instead. Inappropriate use of proxy measures can lead to erroneous conclusions being made about the true exposure of interest. These errors may lead to biased estimates of associations between exposures and outcomes. The consequences of such biases extend beyond research concerns as health decisions can be made based on flawed evidence. Recognizing and mitigating these biases are essential for producing reliable evidence that informs health policies and interventions, ultimately contributing to improved population health outcomes. To address these challenges, researchers must adopt rigorous methodologies for exposure variable selection and validation studies to minimize measurement errors.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    背景:尽管大多数网络荟萃分析(NMA)使用来自随机临床试验(RCT)的汇总数据(AD),其他研究设计(例如,队列研究和其他非随机研究,NRS)可以提供有关相对治疗效果的信息。研究的个体参与者数据(IPD),当可用时,对于调整重要的参与者特征以及更好地处理网络中的异质性和不一致性,都优于AD。
    结果:我们开发了R包crossnma,以执行交叉格式(IPD和AD)和交叉设计(RCT和NRS)NMA和网络元回归(NMR)。在R环境中使用另一个吉布斯采样器(JAGS)软件将模型实现为贝叶斯三级分层模型。R包crossnma包含自动创建JAGS模型的函数,重新格式化数据(基于用户输入),评估收敛性并总结结果。我们通过使用六个比较四个治疗方法的试验网络来证明Crosnma内的工作流程。
    结论:R包crossnma使用户能够在贝叶斯框架中使用不同数据类型执行NMA和NMR,并有助于纳入所有类型的证据,以识别偏差风险的差异。
    BACKGROUND: Although aggregate data (AD) from randomised clinical trials (RCTs) are used in the majority of network meta-analyses (NMAs), other study designs (e.g., cohort studies and other non-randomised studies, NRS) can be informative about relative treatment effects. The individual participant data (IPD) of the study, when available, are preferred to AD for adjusting for important participant characteristics and to better handle heterogeneity and inconsistency in the network.
    RESULTS: We developed the R package crossnma to perform cross-format (IPD and AD) and cross-design (RCT and NRS) NMA and network meta-regression (NMR). The models are implemented as Bayesian three-level hierarchical models using Just Another Gibbs Sampler (JAGS) software within the R environment. The R package crossnma includes functions to automatically create the JAGS model, reformat the data (based on user input), assess convergence and summarize the results. We demonstrate the workflow within crossnma by using a network of six trials comparing four treatments.
    CONCLUSIONS: The R package crossnma enables the user to perform NMA and NMR with different data types in a Bayesian framework and facilitates the inclusion of all types of evidence recognising differences in risk of bias.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    谷物是世界上许多日常饮食的基础。最近,由于其植物化学物质的含量,人们对全谷物的有益特性产生了相当大的兴趣,特别是多酚。尽管如此,最全面的数据库中报告的谷物类食品中多酚成分的现有数据仍未更新.许多谷类食品和酚类化合物缺失,包括有色素的.报告谷物多酚摄入量的观察性流行病学研究有限且不一致,尽管实验研究表明膳食多酚对心血管疾病具有保护作用,糖尿病,和癌症。由于食物中存在大量化合物,影响其含量的因素很多,因此估算多酚的摄入量是复杂的,如植物品种,收获季节,食品加工和烹饪,使得消费数据与食品成分数据难以匹配。Further,应该考虑到食物成分表和食用食物以不同的方式分类。本工作概述了几个现有数据库中报告的多酚含量的可用数据,就存在而言,缺少和没有数据,并讨论了评估谷物多酚消费量的方法的优缺点。此外,这篇综述表明,我们更需要纳入最新的谷类食物成分数据,并统一收集谷类食物数据的标准化程序和适当的膳食摄入评估工具.
    Cereals are the basis of much of the world\'s daily diet. Recently, there has been considerable interest in the beneficial properties of wholegrains due to their content of phytochemicals, particularly polyphenols. Despite this, the existing data on polyphenolic composition of cereal-based foods reported in the most comprehensive databases are still not updated. Many cereal-based foods and phenolic compounds are missing, including pigmented ones. Observational epidemiological studies reporting the intake of polyphenols from cereals are limited and inconsistent, although experimental studies suggest a protective role for dietary polyphenols against cardiovascular disease, diabetes, and cancer. Estimating polyphenol intake is complex because of the large number of compounds present in foods and the many factors that affect their levels, such as plant variety, harvest season, food processing and cooking, making it difficult matching consumption data with data on food composition. Further, it should be taken into account that food composition tables and consumed foods are categorized in different ways. The present work provides an overview of the available data on polyphenols content reported in several existing databases, in terms of presence, missing and no data, and discusses the strengths and weaknesses of methods for assessing cereal polyphenol consumption. Furthermore, this review suggests a greater need for the inclusion of most up-to-date cereal food composition data and for the harmonization of standardized procedures in collecting cereal-based food data and adequate assessment tools for dietary intake.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    牛皮癣是一种慢性免疫介导的影响皮肤的疾病,指甲,和/或关节。它与全身性炎症有关,也可能与动脉粥样硬化性心血管疾病(ASCVD)的风险增加有关。这项研究的目的是确定银屑病患者ASCVD的总体风险,并根据ASCVD类型和银屑病的严重程度评估风险。这是一项观察性研究的系统评价和荟萃分析,报告了银屑病与一种或多种ASCVD临床类型之间的关联。我们通过PubMed在线搜索医学文献分析和检索系统(MEDLINE),摘录医学数据库(EMBASE),Scopus,比勒费尔德学术搜索引擎(BASE),和谷歌学者从他们的记录开始到2023年7月的英语相关研究。研究选择和数据提取由四名独立评审员进行。总共21项观察性研究(三项横断面研究,一个病例控制,和17个队列)被包括在这篇综述中,代表总共778,049名牛皮癣患者和16,881,765名无牛皮癣的对照受试者。纳入的研究有不同程度的协变量调整,因此,他们的发现可能会受到残留的混淆。所有荟萃分析都使用调整后的效应大小,并基于随机效应模型。然而,队列研究与非队列研究(病例对照和横断面研究)分开分析.银屑病和ASCVD之间存在显著关联(队列研究:风险比(HR),1.21;95%置信区间(CI),1.14至1.28;I2=63%;p<0.001;非队列研究:比值比(OR),1.60;95%CI,1.34至1.92;I2=31%;p=0.23)。银屑病也与心肌梗死显著相关(队列研究:HR,1.20;95%CI,1.10~1.31;I2=60%;p<0.001;非队列研究:OR,1.57;95%CI,1.15至2.15;I2=74%;p=0.05),冠状动脉疾病(队列研究:HR,1.20;95%CI,1.13~1.28;I2=67%;p<0.001;非队列研究:OR,1.60;95%CI,1.34至1.92;I2=31%;p=0.23),主动脉瘤(HR,1.45;95%CI,1.04至2.02;I2=67%;p=0.08),但与缺血性卒中无关(HR,1.14;95%CI,0.96至1.36;I2=44%;p=0.17)。就银屑病的严重程度进行汇总分析显示,两者均为轻度(队列研究:HR,1.17;95%CI,1.08~1.26;I2=74%;p<0.001;非队列研究:OR,1.54;95%CI,1.25至1.90;I2=0%;p=0.50)和严重(队列研究:HR,1.43;95%CI,1.23~1.65;I2=65%;p<0.001;非队列研究:OR,1.65;95%CI,1.29~2.12;I2=25%;p=0.26)银屑病与ASCVD显著相关。银屑病(包括轻度和重度疾病)与ASCVD的风险增加有关。包括冠状动脉疾病(CAD)和主动脉瘤(AA)。所有成人银屑病患者应优先考虑ASCVD风险评估和预防。未来的观察性研究调查银屑病和ASCVD之间的关联应该进行更全面的协变量调整。
    Psoriasis is a chronic immune-mediated disease affecting the skin, nails, and/or joints. It is associated with systemic inflammation and may also be linked to an increased risk of atherosclerotic cardiovascular disease (ASCVD). The objectives of this study were to determine the overall risk of ASCVD in patients with psoriasis and to evaluate the risk according to ASCVD type and the severity of psoriasis. This was a systematic review and meta-analysis of observational studies reporting the association between psoriasis and one or more of the clinical types of ASCVD. We searched Medical Literature Analysis and Retrieval System Online (MEDLINE) via PubMed, Excerpta Medica Database (EMBASE), Scopus, Bielefeld Academic Search Engine (BASE), and Google Scholar for relevant studies in the English language from the beginning of their records to July 2023. Study selection and data extraction were conducted by four independent reviewers. A total of 21 observational studies (three cross-sectional, one case-control, and 17 cohort) were included in this review, representing a total of 778,049 patients with psoriasis and 16,881,765 control subjects without psoriasis. The included studies had varying degrees of covariate adjustment, and thus, their findings may have been subject to residual confounding. All the meta-analyses used the adjusted effect sizes and were based on the random-effects model. However, the cohort studies were analysed separately from the non-cohort studies (the case-control and cross-sectional studies). There was a significant association between psoriasis and ASCVD (cohort studies: hazard ratio (HR), 1.21; 95% confidence interval (CI), 1.14 to 1.28; I2 = 63%; p < 0.001; non-cohort studies: odds ratio (OR), 1.60; 95% CI, 1.34 to 1.92; I2 = 31%; p = 0.23). Psoriasis was also significantly associated with myocardial infarction (cohort studies: HR, 1.20; 95% CI, 1.10 to 1.31; I2 = 60%; p < 0.001; non-cohort studies: OR, 1.57; 95% CI, 1.15 to 2.15; I2 = 74%; p = 0.05), coronary artery disease (cohort studies: HR, 1.20; 95% CI, 1.13 to 1.28; I2 = 67%; p < 0.001; non-cohort studies: OR, 1.60; 95% CI, 1.34 to 1.92; I2 = 31%; p = 0.23), aortic aneurysm (HR, 1.45; 95% CI, 1.04 to 2.02; I2 = 67%; p = 0.08) but not with ischaemic stroke (HR, 1.14; 95% CI, 0.96 to 1.36; I2 = 44%; p = 0.17). Pooled analysis in terms of the severity of psoriasis showed that both mild (cohort studies: HR, 1.17; 95% CI, 1.08 to 1.26; I2 = 74%; p < 0.001; non-cohort studies: OR, 1.54; 95% CI, 1.25 to 1.90; I2 = 0%; p = 0.50) and severe (cohort studies: HR, 1.43; 95% CI, 1.23 to 1.65; I2 = 65%; p < 0.001; non-cohort studies: OR, 1.65; 95% CI, 1.29 to 2.12; I2 = 25%; p = 0.26) psoriasis were significantly associated with ASCVD. Psoriasis (including mild and severe disease) is associated with an increased risk of ASCVD, including coronary artery disease (CAD) and aortic aneurysm (AA). ASCVD risk assessment and prevention should be prioritised in all adult psoriasis patients. Future observational studies investigating the association between psoriasis and ASCVD should conduct a more comprehensive adjustment of covariates.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Editorial
    暂无摘要。
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Systematic Review
    吸入皮质类固醇(ICS)治疗已被证明可以降低COPD加重的风险。应仅适用于未通过双重长效支气管扩张剂治疗得到充分控制且每年加重≥2次,血液嗜酸性粒细胞计数≥300个细胞/µL的COPD患者。ICS治疗在COPD患者的指南之外广泛使用,使ICS退出成为一个重要的考虑因素。本系统综述旨在对ICS戒断对加重频率的影响进行最新分析。肺功能(FEV1)的变化,并确定停药后恢复ICS治疗的COPD患者的比例。
    纳入比较ICS停药与ICS继续治疗的随机对照试验(RCT)和观察性研究。CochraneCentral,WebofScience,CINHAL,搜索Embase和OVIDMedline。使用CochraneRoB2工具和纽卡斯尔-渥太华量表评估偏倚风险。采用GRADE对随机对照试验进行质量评价。ICS戒断RCT事后分析的荟萃分析,通过血液嗜酸性粒细胞计数(BEC)分层,进行了。
    10项随机对照试验(6642例患者随机分组)和6项观察性研究(160,029例患者)纳入结果。当停用ICS并维持长效支气管扩张剂治疗时,ICS退出试验组和继续试验组的加重频率或肺功能变化无一致差异.这些影响的证据质量中等。对于停药后恢复ICS治疗的患者比例(估计范围为12-93%的参与者),没有足够的证据得出确切的结论。
    COPD患者退出ICS治疗是安全可行的,但应同时维持支气管扩张治疗以获得最佳结果。
    UNASSIGNED: Inhaled corticosteroid (ICS) therapy has been demonstrated to reduce the risk of COPD exacerbations. It should only be prescribed to COPD patients who are not adequately controlled by dual long-acting bronchodilator therapy and who have ≥2 exacerbations per year and a blood eosinophil count ≥300cells/µL. ICS therapy is widely prescribed outside guidelines to COPD patients, making ICS withdrawal an important consideration. This systematic review aims to provide an up-to-date analysis of the effect of ICS withdrawal on exacerbation frequency, change in lung function (FEV1) and to determine the proportion of COPD patients who resume ICS therapy following withdrawal.
    UNASSIGNED: Randomised controlled trials (RCTs) and observational studies which compared ICS withdrawal with ICS continuation treatment were included. Cochrane Central, Web of Science, CINHAL, Embase and OVID Medline were searched. Risk of bias was assessed using the Cochrane RoB2 tool and the Newcastle-Ottawa Scale. Quality assessment of RCTs was conducted using GRADE. Meta-analysis of post-hoc analyses of RCTs of ICS withdrawal, stratified by blood eosinophil count (BEC), was undertaken.
    UNASSIGNED: Ten RCTs (6642 patients randomised) and 6 observational studies (160,029 patients) were included in the results. When ICS was withdrawn and long-acting bronchodilator therapy was maintained, there was no consistent difference in exacerbation frequency or lung function change between the ICS withdrawal and continuation trial arms. The evidence for these effects was of moderate quality. There was insufficient evidence to draw a firm conclusion on the proportion of patients who resumed ICS therapy following withdrawal (estimated range 12-93% of the participants).
    UNASSIGNED: Withdrawal of ICS therapy from patients with COPD is safe and feasible but should be accompanied by maintenance of bronchodilation therapy for optimal outcomes.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    背景:生活质量指标对于肿瘤患者以及死亡率和疾病进展等传统终点越来越重要。统计工具,如WinRatio,赢得赔率,和净效益优先考虑使用复合终点的临床显著结果。在随机试验中,Win统计提供治疗组和对照组之间的公平比较。然而,它们在观察性研究中的使用因混杂变量而变得复杂。倾向得分(PS)匹配减轻了混杂变量,但可能会减少样本量,影响必胜统计分析的力量。或者,PS匹配可以对样本进行分层,保留样本量。本研究旨在评估这些方法对决策的长期影响,尤其是结直肠癌患者。方法:一个激励的例子涉及来自ReSARCh观察性研究(2016-2021)的局部晚期直肠腺癌患者队列,位于12厘米的肛门边缘。这些患者接受了观察和等待方法(WW)或经肛门局部切除术(LE)。Win统计数据比较了WW和LE对复合结局的影响(总生存期,复发,造口术的存在,和直肠切除术)。对于匹配的获胜统计数据,我们使用了Matsouaka等人提出的鲁棒推理技术。(2022),对于分层的胜利统计数据,我们应用了Dong等人提出的方法。(2018)。一项模拟研究评估了平衡和不平衡组中匹配和分层获胜统计数据的覆盖概率,计算置信区间包含WR真实值的频率,NB,和WO跨越1000次模拟。结果:结果表明,当单独考虑疗效结果时,LE方法的疗效更好(WR:0.47(0.01至1.14);NB:-0.16(-0.34至0.02);WO:0.73(0.5至1.05))。然而,当QoL结果包括在分析中时,估计更接近1(WR:0.87(0.06至2.06);WO:0.93(0.61至1.4))和0(NB:-0.04(-0.25至0.17)),这表明LE对造口术和直肠切除的治疗效果有负面影响。此外,基于仿真研究,我们的发现强调了与分层获胜统计相比,匹配在覆盖概率方面的卓越表现(匹配WR:97%与分层WR:在高不平衡情况下为33.3%;匹配WR:98%与分层WR:中等不平衡情况下的34.4%;匹配WR:99.2%与分层WR:在低不平衡设置中为37.4%)。结论:总之,我们的研究从统计意义上解释了winstatistics的结果,提供对成对比较在观测设置中的应用的见解,促进其使用,以改善癌症患者的预后。
    Background: Quality-of-life metrics are increasingly important for oncological patients alongside traditional endpoints like mortality and disease progression. Statistical tools such as Win Ratio, Win Odds, and Net Benefit prioritize clinically significant outcomes using composite endpoints. In randomized trials, Win Statistics provide fair comparisons between treatment and control groups. However, their use in observational studies is complicated by confounding variables. Propensity score (PS) matching mitigates confounding variables but may reduce the sample size, affecting the power of win statistics analyses. Alternatively, PS matching can stratify samples, preserving the sample size. This study aims to assess the long-term impact of these methods on decision making, particularly in colorectal cancer patients. Methods: A motivating example involves a cohort of patients from the ReSARCh observational study (2016-2021) with locally advanced adenocarcinoma of the rectum, situated up to 12 cm from the anal verge. These patients underwent either a watch-and-wait approach (WW) or trans-anal local excision (LE). Win statistics compared the effects of WW and LE on a composite outcome (overall survival, recurrence, presence of ostomy, and rectum excision). For matched win statistics, we used robust inference techniques proposed by Matsouaka et al. (2022), and for stratified win statistics, we applied the method proposed by Dong et al. (2018). A simulation study assessed the coverage probability of matched and stratified win statistics in balanced and unbalanced groups, calculating how often the confidence intervals included the true values of WR, NB, and WO across 1000 simulations. Results: The results suggest a better efficacy of the LE approach when considering efficacy outcomes alone (WR: 0.47 (0.01 to 1.14); NB: -0.16 (-0.34 to 0.02); and WO: 0.73 (0.5 to 1.05)). However, when QoL outcomes are included in the analyses, the estimates are closer to 1 (WR: 0.87 (0.06 to 2.06); WO: 0.93 (0.61 to 1.4)) and to 0 (NB: -0.04 (-0.25 to 0.17)), indicating a negative impact of the treatment effect of LE regarding the presence of ostomy and the excision of the rectum. Moreover, based on the simulation study, our findings underscore the superior performance of matched compared to stratified win statistics in terms of coverage probability (matched WR: 97% vs. stratified WR: 33.3% in a high-imbalance setting; matched WR: 98% vs. stratified WR: 34.4% in a medium-imbalance setting; and matched WR: 99.2% vs. stratified WR: 37.4% in a low-imbalance setting). Conclusions: In conclusion, our study sheds light on the interpretation of the results of win statistics in terms of statistical significance, providing insights into the application of pairwise comparison in observational settings, promoting its use to improve outcomes for cancer patients.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    本研究旨在基于随机对照试验(RCT)和观察性研究,探讨沙库巴曲/缬沙坦治疗肾功能异常(eGFR<60ml/min/1.73m2)合并心力衰竭患者的疗效和安全性。
    Embase,从成立之初到2023年12月,对PubMed和Cochrane图书馆进行了相关研究。二分变量被描述为具有比值比(OR)和95%置信区间(CI)值的事件计数。连续变量表示为平均值±标准差(SD),95%CI。
    共纳入6项RCT和8项观察性研究,涉及17335eGFR低于60ml/min/1.73m2合并心力衰竭的患者。就功效而言,我们分析了心血管事件的发生率,发现沙库巴曲/缬沙坦可显著降低慢性肾脏病(CKD)3~5期心力衰竭患者的心血管死亡或心力衰竭住院风险(OR:0.65,95CI:0.54~0.78).此外,沙库必曲/缬沙坦可预防血清肌酐升高(OR:0.81,95CI:0.68-0.95),eGFR下降(OR:0.83,95%CI:0.73-0.95)和该人群终末期肾病的发展(OR:0.73,95CI:0.60-0.89).至于安全结果,我们未发现在CKD3~5期心力衰竭患者中,沙库巴曲/缬沙坦组高钾血症(OR:1.31,95CI:0.79~2.17)和低血压(OR:1.57,95CI:0.94~2.62)的发生率增加.
    我们的荟萃分析证明,沙库巴曲/缬沙坦对肾功能异常合并心力衰竭患者的心功能具有良好的作用,没有明显的不良事件风险,这表明沙库必曲/缬沙坦有可能成为这些患者的前瞻性治疗。
    UNASSIGNED: This study aimed to investigate the efficacy and safety of sacubitril/valsartan in abnormal renal function (eGFR < 60 ml/min/1.73m2) patients combined with heart failure based on randomized controlled trials (RCTs) and observational studies.
    UNASSIGNED: The Embase, PubMed and the Cochrane Library were searched for relevant studies from inception to December 2023. Dichotomous variables were described as event counts with the odds ratio (OR) and 95% confidence interval (CI) values. Continuous variables were expressed as mean standard deviation (SD) with 95% CIs.
    UNASSIGNED: A total of 6 RCTs and 8 observational studies were included, involving 17335 eGFR below 60 ml/min/1.73m2 patients combined with heart failure. In terms of efficacy, we analyzed the incidence of cardiovascular events and found that sacubitril/valsartan significantly reduced the risk of cardiovascular death or heart failure hospitalization in chronic kidney disease (CKD) stages 3-5 patients with heart failure (OR: 0.65, 95%CI: 0.54-0.78). Moreover, sacubitril/valsartan prevented the serum creatinine elevation (OR: 0.81, 95%CI: 0.68-0.95), the eGFR decline (OR: 0.83, 95% CI: 0.73-0.95) and the development of end-stage renal disease in this population (OR:0.73, 95%CI:0.60-0.89). As for safety outcomes, we did not find that the rate of hyperkalemia (OR:1.31, 95%CI:0.79-2.17) and hypotension (OR:1.57, 95%CI:0.94-2.62) were increased in sacubitril/valsartan group among CKD stages 3-5 patients with heart failure.
    UNASSIGNED: Our meta-analysis proves that sacubitril/valsartan has a favorable effect on cardiac function without obvious risk of adverse events in abnormal renal function patients combined with heart failure, indicating that sacubitril/valsartan has the potential to become perspective treatment for these patients.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    这项研究总结了卡尔文·施瓦贝兽医流行病学和预防医学终身成就奖研讨会上的演讲,授予第一作者。作为流行病学家,我们被教导“相关性并不意味着因果关系。\"虽然真实,确定原因是我们进行的许多研究的关键目标。有经验证据表明,兽医流行病学家正在进行观察性研究,目的是确定原因;许多研究包括对混杂变量的控制,解释研究结果时经常使用因果语言。研究原因的框架包括明确要测试的特定假设,变量选择的方法,暴露与结果之间关系的统计估计方法,并将这种关系解释为因果关系。当比较兽医人群的观察性研究与人群的观察性研究时,这些步骤中的每一个的应用基本上不同。与人类文献相比,在兽医文献的观察性研究中,对感兴趣的暴露-结果对的先验识别不太常见。在大多数人群的观察性研究中,先验知识被用来选择混杂变量,而数据驱动的方法是兽医人群的常态。没有明确的暴露结果假设和使用数据驱动的分析方法的后果包括偏颇结果的可能性增加和结果的可复制性差。有必要由研究人员社区讨论当前在兽医人群的观察性研究中研究原因的方法。
    This study summarizes a presentation at the symposium for the Calvin Schwabe Award for Lifetime Achievement in Veterinary Epidemiology and Preventive Medicine, which was awarded to the first author. As epidemiologists, we are taught that \"correlation does not imply causation.\" While true, identifying causes is a key objective for much of the research that we conduct. There is empirical evidence that veterinary epidemiologists are conducting observational research with the intent to identify causes; many studies include control for confounding variables, and causal language is often used when interpreting study results. Frameworks for studying causes include the articulation of specific hypotheses to be tested, approaches for the selection of variables, methods for statistical estimation of the relationship between the exposure and the outcome, and interpretation of that relationship as causal. When comparing observational studies in veterinary populations to those conducted in human populations, the application of each of these steps differs substantially. The a priori identification of exposure-outcome pairs of interest are less common in observational studies in the veterinary literature compared to the human literature, and prior knowledge is used to select confounding variables in most observational studies in human populations, whereas data-driven approaches are the norm in veterinary populations. The consequences of not having a defined exposure-outcome hypotheses of interest and using data-driven analytical approaches include an increased probability of biased results and poor replicability of results. A discussion by the community of researchers on current approaches to studying causes in observational studies in veterinary populations is warranted.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    评估疫苗和其他传染病预防措施的人群水平效果对公共卫生领域很重要。在传染病研究中,一个人的治疗可能会影响另一个人的结果,也就是说,单位之间可能存在干扰。例如,一个人使用蚊帐预防疟疾可能会对居住在附近的其他个人产生间接影响。在某些设置中,个人可以形成群组或集群,其中干扰只发生在群组内,也就是说,有部分干扰。以前已经开发了逆概率加权估计器,用于部分干扰的观察研究。不幸的是,这些估计器不太适合大型集群的研究。因此,在本文中,扩展了参数g公式以允许部分干扰。针对总体效果,提出了G公式估计器,治疗时的效果,以及未经治疗时的影响。拟议的估计器可以容纳大的簇,并且不会遭受在没有干扰的情况下可能发生的g-null悖论。假设没有未测量的混杂因素,并且部分干扰采用特定形式(称为“弱分层干扰”),则得出所提出的估计量的大样本属性。进行了仿真研究,证明了所提出的估计器的有限样本性能。然后使用拟议的g公式估算器对刚果民主共和国的人口和健康调查进行分析,以评估使用蚊帐对疟疾的影响。
    Assessing population-level effects of vaccines and other infectious disease prevention measures is important to the field of public health. In infectious disease studies, one person\'s treatment may affect another individual\'s outcome, that is, there may be interference between units. For example, the use of bed nets to prevent malaria by one individual may have an indirect effect on other individuals living in close proximity. In some settings, individuals may form groups or clusters where interference only occurs within groups, that is, there is partial interference. Inverse probability weighted estimators have previously been developed for observational studies with partial interference. Unfortunately, these estimators are not well suited for studies with large clusters. Therefore, in this paper, the parametric g-formula is extended to allow for partial interference. G-formula estimators are proposed for overall effects, effects when treated, and effects when untreated. The proposed estimators can accommodate large clusters and do not suffer from the g-null paradox that may occur in the absence of interference. The large sample properties of the proposed estimators are derived assuming no unmeasured confounders and that the partial interference takes a particular form (referred to as \'weak stratified interference\'). Simulation studies are presented demonstrating the finite-sample performance of the proposed estimators. The Demographic and Health Survey from the Democratic Republic of the Congo is then analyzed using the proposed g-formula estimators to assess the effects of bed net use on malaria.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

公众号