Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 10.211
Filtrar
3.
Zhonghua Liu Xing Bing Xue Za Zhi ; 41(4): 585-588, 2020 Apr 10.
Artigo em Chinês | MEDLINE | ID: mdl-32344486

RESUMO

Observational study has been viewed as the most convenient method in designing etiological studies. However, the presence of confounders always challenge the researchers in study design, since unadjusted confounders may lead to biased results. The traditional definition of a confounder is not intuitional in application and sometimes leading to inappropriate adjustment of nonexistent "confounders" which might induce new bias to merge. The use of directed acyclic graphs (DAGs) may identify confounders easier and more intuitional, as well as avoiding superfluous adjustment. It can also contribute to the identification of adjustment methods, and be useful in causal inference of observational studies.


Assuntos
Viés , Gráficos por Computador , Fatores de Confusão Epidemiológicos , Interpretação Estatística de Dados , Humanos , Modelos Estatísticos , Projetos de Pesquisa , Pesquisadores
4.
Zhonghua Liu Xing Bing Xue Za Zhi ; 41(4): 594-598, 2020 Apr 10.
Artigo em Chinês | MEDLINE | ID: mdl-32344488

RESUMO

Negative control methods (NCM) are developed based on the idea that negative controls should be tested with negative results. It also extends to the multiple comparison groups and used for specificity of association in population studies. Negative controls do not take part in studying the causal hypothesis but sharing the same potential bias structures. Under different purposes, NCM can be divided into methods on negative exposure, negative period or negative outcome controls. They are mainly used to detect and control bias, such as: selection bias, confounding bias and measurement bias, but leaving the sample size at secondary importance. Rational application of NCM can help improving the accuracy of causal inference in both experimental and observational processes.


Assuntos
Viés , Fatores de Confusão Epidemiológicos , Viés de Seleção , Humanos , Projetos de Pesquisa , Tamanho da Amostra
7.
Ann Allergy Asthma Immunol ; 124(6): 583-588, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32217188

RESUMO

BACKGROUND: Cefazolin is a first-line prophylactic antibiotic used to prevent surgical site infections (SSIs) in cardiac surgery. Patients with a history of penicillin allergy often receive less effective second-line antibiotics, which is associated with an increased SSI risk. OBJECTIVE: To describe the impact of preoperative penicillin allergy evaluation on perioperative cefazolin use in patients undergoing cardiac surgery. METHODS: We performed a retrospective cohort study of patients with a documented penicillin allergy who underwent cardiac surgery at the Massachusetts General Hospital from September 2015 to December 2018. We describe penicillin allergy evaluation assessment and outcomes. We evaluated the association between preoperative penicillin allergy evaluation and first-line perioperative antibiotic use using a multivariable logistic regression model. RESULTS: Of 3802 cardiac surgical patients, 510 (13%) had a documented penicillin allergy; 165 (33%) were referred to allergy and immunology practitioners. Of 160 patients (31%) who underwent penicillin allergy evaluation (ie, penicillin skin testing and, if results were negative, an amoxicillin challenge), 154 (97%) were found not to have a penicillin allergy. Patients who underwent preoperative penicillin allergy evaluation were more likely to receive the first-line perioperative antibiotic (92% vs 38%, P < .001). After adjusting for potential confounders, patients who underwent preoperative penicillin allergy evaluation had higher odds of first-line perioperative antibiotic use (adjusted odds ratio, 26.6; 95% CI, 12.8-55.2). CONCLUSION: Integrating penicillin allergy evaluation into routine preoperative care ensured that almost all evaluated patients undergoing cardiac surgery received first-line antibiotic prophylaxis, a critical component of SSI risk reduction. Further efforts are needed to increase access to preoperative allergy evaluation.


Assuntos
Antibacterianos/efeitos adversos , Hipersensibilidade a Drogas/diagnóstico , Hipersensibilidade a Drogas/prevenção & controle , Penicilinas/efeitos adversos , Cuidados Pré-Operatórios , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Fatores de Confusão Epidemiológicos , Hipersensibilidade a Drogas/imunologia , Feminino , Humanos , Masculino , Razão de Chances , Avaliação de Resultados em Cuidados de Saúde , Estudos Retrospectivos
8.
Community Dent Health ; 37(1): 84-89, 2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32031350

RESUMO

Confounding can make an association seem bigger when the true effect is smaller or vice-versa and it can also make it appear negative when it may actually be positive. In short, both the direction and the magnitude of an association are dependent on confounding. Therefore, understanding and adjusting for confounding in epidemiological research is central to addressing whether an observed association is causal or not. Moreover, unmeasured confounding in observational studies can give rise to biased estimates. Several techniques have been developed to account for bias and conducting sensitivity analysis. Using an hypothetical example this paper illustrates application of simple methods for conducting sensitivity analysis for unmeasured confounder(s).


Assuntos
Saúde Bucal , Viés , Fatores de Confusão Epidemiológicos , Estudos Epidemiológicos , Humanos
9.
Zhonghua Liu Xing Bing Xue Za Zhi ; 41(1): 111-114, 2020 Jan 10.
Artigo em Chinês | MEDLINE | ID: mdl-32062952

RESUMO

In prospective cohort study, multi follow up is often necessary for study subjects, and the observed values are correlated with each other, usually resulting in time-dependent confounding. In this case, the data generally do not meet the application conditions of traditional multivariate regression analysis. Sequential conditional mean model (SCMM) is a new approach that can deal with time-dependent confounding. This paper mainly summarizes the basic theory, steps and characteristics of SCMM.


Assuntos
Fatores de Confusão Epidemiológicos , Exposição Ambiental , Modelos Estatísticos , Humanos , Análise Multivariada , Estudos Prospectivos
12.
Anesth Analg ; 130(3): 635, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32068590
14.
Plast Reconstr Surg ; 145(3): 574e-582e, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32097318

RESUMO

BACKGROUND: Dupuytren's disease is a common, chronic, fibroproliferative disease of the palmar fascia. The cause is unclear but includes genetic predisposition alongside environmental factors. Several studies have suggested an association between Dupuytren's disease and excess mortality. The authors aimed to evaluate this association in adult patients in the United Kingdom and identify the causes of mortality. METHODS: The authors used a large primary care database (Clinical Practice Research Datalink) linked to the Office of National Statistics to identify patients with Dupuytren's disease between January 1, 1995, and December 31, 2013. Each patient was matched by age, sex, and general practitioner to five control patients without the disease. Cox regression models were used to study the association between Dupuytren's disease and all-cause and cause-specific mortality, adjusting for confounders. RESULTS: A total of 41,965 Dupuytren's disease patients and 209,825 control patients were identified. The all-cause mortality rate was increased in both unadjusted (hazard ratio, 1.48; 99% CI, 1.29 to 1.70; p < 0.0001) and multivariable adjusted (hazard ratio, 1.43; 99% CI, 1.25 to 1.65; p < 0.0001) models in patients with Dupuytren's disease, 12 years after diagnosis. Excess mortality was secondary to a wide range of causes, including cancer (hazard ratio, 1.66; 99% CI, 1.27 to 2.17; p < 0.0001), an effect that persisted after adjustment for confounders. CONCLUSIONS: There is excess mortality associated with Dupuytren's disease that can be partially explained through environmental factors. From time of diagnosis in primary care, there is a 12-year window of opportunity for intervention to reduce the impact of these factors. The authors observed an increased risk of cancer mortality independent of confounders, and hypothesize a shared genetic risk between Dupuytren's disease and cancer. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.


Assuntos
Causas de Morte , Contratura de Dupuytren/epidemiologia , Neoplasias/mortalidade , Idoso , Fatores de Confusão Epidemiológicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Medição de Risco , Fatores de Risco , Reino Unido/epidemiologia
15.
Nat Med ; 26(1): 110-117, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31932804

RESUMO

Progress in high-throughput metabolic profiling provides unprecedented opportunities to obtain insights into the effects of drugs on human metabolism. The Biobanking BioMolecular Research Infrastructure of the Netherlands has constructed an atlas of drug-metabolite associations for 87 commonly prescribed drugs and 150 clinically relevant plasma-based metabolites assessed by proton nuclear magnetic resonance. The atlas includes a meta-analysis of ten cohorts (18,873 persons) and uncovers 1,071 drug-metabolite associations after evaluation of confounders including co-treatment. We show that the effect estimates of statins on metabolites from the cross-sectional study are comparable to those from intervention and genetic observational studies. Further data integration links proton pump inhibitors to circulating metabolites, liver function, hepatic steatosis and the gut microbiome. Our atlas provides a tool for targeted experimental pharmaceutical research and clinical trials to improve drug efficacy, safety and repurposing. We provide a web-based resource for visualization of the atlas (http://bbmri.researchlumc.nl/atlas/).


Assuntos
Estudos Epidemiológicos , Microbioma Gastrointestinal/genética , Metaboloma/genética , Preparações Farmacêuticas , Índice de Massa Corporal , Fatores de Confusão Epidemiológicos , Endofenótipos , Humanos , Fígado/metabolismo , Modelos Biológicos , Mapas de Interação de Proteínas
16.
PLoS One ; 15(1): e0227696, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31940406

RESUMO

INTRODUCTION: The relationship between benzodiazepines, opioids and tricyclic antidepressants and trauma is of great importance because of increased consumption and the growing evidence of a positive association among older adults. The objective of this study was to determine the effect size of the association between the consumption of psychotropic medications /opioids and falls in patients who have suffered trauma by studying the role of other variables in this relationship. METHOD: From 2011 to 2016, the presence of benzodiazepines, opioids and tricyclic antidepressants and other drugs in 1060 patients admitted for trauma at a level I trauma hospital was analysed. Multivariate models were used to measure the adjusted effect size of the association between consumption of benzodiazepines, opioids and tricyclic antidepressants and falls, and the effect of age on this association was studied. RESULTS: A total of 192 patients tested positive for benzodiazepines, opioids and tricyclic antidepressants, with same-level falls being the most frequent mechanism of injury in this group (40.1%), with an odds ratio of 1.96 (1.40-2.75), p < 0.001. Once other covariates were introduced, this association was not observed, leaving only age, gender (woman) and, to a lesser extent, sensory conditions as variables associated with falls. Age acted as an effect modifier between benzodiazepines, opioids and tricyclic antidepressants and falls, with significant effect sizes starting at 51.9 years of age. CONCLUSIONS: The association between the consumption of benzodiazepines, opioids and tricyclic antidepressants and falls in patients admitted for trauma is conditioned by other confounding variables, with age being the most influential confounding variable.


Assuntos
Acidentes por Quedas/prevenção & controle , Ferimentos e Lesões/etiologia , Acidentes por Quedas/estatística & dados numéricos , Fatores Etários , Idoso , Analgésicos Opioides/efeitos adversos , Antidepressivos Tricíclicos/efeitos adversos , Benzodiazepinas/efeitos adversos , Fatores de Confusão Epidemiológicos , Feminino , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Fatores de Risco , Espanha , Ferimentos e Lesões/complicações
19.
J Surg Res ; 245: 244-248, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31421369

RESUMO

BACKGROUND: Chronic lymphocytic thyroiditis (CLT) increases cytologic atypia on fine-needle aspiration of thyroid nodules, and its effect on rate of malignancy in atypia of undetermined significance (AUS)/follicular lesions of undetermined significance (FLUS) thyroid nodules remains unclear. This study evaluates the effect of concomitant CLT on malignancy rates of AUS/FLUS thyroid nodules in surgical patients. METHODS: Retrospective review of 1061 patients who underwent thyroidectomy for a dominant thyroid nodule from a single institution was performed. Fine-needle aspiration was classified according to the Bethesda System for Reporting Thyroid Cytopathology. Patients with AUS/FLUS cytopathology were classified into two cohorts: AUS/FLUS with CLT and AUS/FLUS without CLT. Final pathology was reviewed, and the cohorts were further stratified into benign and malignant subgroups. When applicable, patients with gene expression classifier (GEC) testing were reviewed and the positive predictive value (PPV) was calculated. RESULTS: Of the entire surgical series, 293 (28%) patients had AUS/FLUS cytopathology with a rate of malignancy of 56% (163/293) on final pathology. Seventy-three (25%) patients had AUS/FLUS with CLT, of which 44% (n = 32) were malignant by final pathology. The remaining 75% (n = 220) had AUS/FLUS without CLT, 60% (n = 131) of which were malignant. GEC testing was performed in 36 of the AUS/FLUS with CLT patients, where of the 33 suspicious results, 17 were malignant on final pathology, yielding a PPV of 52%. CONCLUSIONS: The rate of malignancy for AUS/FLUS thyroid nodules is lower with coexisting CLT, and similar to previous studies, the PPV of GEC testing is approximately 50%. Cytologic atypia due to CLT may increase more AUS/FLUS results in thyroid nodules, which may lead to overestimation of malignancy rates in this patient population.


Assuntos
Doença de Hashimoto/diagnóstico , Glândula Tireoide/patologia , Nódulo da Glândula Tireoide/epidemiologia , Tireoidectomia/estatística & dados numéricos , Adulto , Biópsia por Agulha Fina , Fatores de Confusão Epidemiológicos , Diagnóstico Diferencial , Feminino , Doença de Hashimoto/complicações , Doença de Hashimoto/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Nódulo da Glândula Tireoide/complicações , Nódulo da Glândula Tireoide/patologia , Nódulo da Glândula Tireoide/cirurgia
20.
Zhonghua Liu Xing Bing Xue Za Zhi ; 40(11): 1450-1455, 2019 Nov 10.
Artigo em Chinês | MEDLINE | ID: mdl-31838820

RESUMO

Observational study of therapy efficacy comparison has been widely conducted to provide the additional efficacy evidence to support randomized control study. Statistical adjustment for unmeasured confounders is a major challenge in observational study of therapy efficacy comparison. This paper summarizes and evaluates the relative statistical methods. Currently, the most commonly used methods include instrumental variable, difference-in-differences (DiD) model and prior event rate ratio (PERR) adjustment. The instrumental variable method skill fully escapes unmeasured confounders through model structure, but it is not easy to obtain satisfied instrumental variables. Both PERR and DiD require the data prior to exposure which are not always collected in observational studies. Unmeasured confounders could result in new requirements and pose new challenges for statistical methods, which needs further study and improvement.


Assuntos
Biometria , Pesquisa Comparativa da Efetividade , Modelos Estatísticos , Estudos Observacionais como Assunto , Viés , Fatores de Confusão Epidemiológicos , Humanos , Pontuação de Propensão , Projetos de Pesquisa
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA