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likelihood ratios test

Sebastian Schneeweiss, Wesley Eddings, Robert J Glynn, Elisabetta Patorno, Jeremy Rassen, Jessica M Franklin
BACKGROUND: Data-adaptive approaches to confounding adjustment may improve performance beyond expert knowledge when analyzing electronic healthcare databases and have additional practical advantages for analyzing multiple databases in rapid cycles. Improvements seemed possible if outcome predictors were reliably identified empirically and adjusted. METHODS: In five cohort studies from diverse healthcare databases, we implemented a base-case high-dimensional propensity score algorithm with propensity score decile-adjusted outcome models to estimate treatment effects among prescription drug initiators...
October 21, 2016: Epidemiology
Nawal Salahuddin, Alaa Mohamed, Nadia Alharbi, Hamad Ansari, Khaled J Zaza, Qussay Marashly, Iqbal Hussain, Othman Solaiman, Torbjorn V Wetterberg, Khalid Maghrabi
BACKGROUND: Unexplained coma after critical illness can be multifactorial. We evaluated the diagnostic ability of bedside Optic Nerve Sheath Diameter [ONSD] as a screening test for non-traumatic radiographic cerebral edema. METHODS: In a prospective study, mixed medical-surgical intensive care units [ICU] patients with non-traumatic coma [GCS < 9] underwent bedside ultrasonographic ONSD measurements. Non-traumatic radiographic cerebral edema [NTRCE] was defined as > 5 mm midline shift, cisternal, sulcal effacement, or hydrocephalus on CT...
October 25, 2016: BMC Anesthesiology
Katarzyna Filipiak, Daniel Klein, Anuradha Roy
The problem of testing the separability of a covariance matrix against an unstructured variance-covariance matrix is studied in the context of multivariate repeated measures data using Rao's score test (RST). The RST statistic is developed with the first component of the separable structure as a first-order autoregressive (AR(1)) correlation matrix or an unstructured (UN) covariance matrix under the assumption of multivariate normality. It is shown that the distribution of the RST statistic under the null hypothesis of any separability does not depend on the true values of the mean or the unstructured components of the separable structure...
October 24, 2016: Biometrical Journal. Biometrische Zeitschrift
Akin Ojagbemi, Robin Emsley, Oye Gureje
OBJECTIVES: The time required in completing the 26 items of neurological examinations in the standard Neurological Evaluation Scale (NES) may limit its utility in pragmatic clinical situations. We propose the Short Neurological Evaluation Scale (S-NES) for use in busy clinical settings, and in research. METHODS: Using confirmatory factor analyses, we identified 12 items of neurological examination showing significant overlap with previously reported theoretical and empirical categories of neurological soft signs (NSS) in schizophrenia...
October 24, 2016: Acta Neuropsychiatrica
Fen Peng, Songyun Chu, Wenhui Ding, Lin Liu, Jing Zhao, Xiaojing Cui, Renxu Li, Jie Wang
Catestatin (CST) is a proteolytic fragment of Chromogranin A with a broad spectrum of activities in the cardiovascular system. The level of plasma CST increases in chronic heart failure patients, but its potential relationship to patient prognosis is unknown. In this study, we measured plasma CST levels in 202 chronic heart failure patients and followed them for a median of 52.5 months. The plasma CST level was higher in patients with all-cause death and cardiac death than in survivors. According to univariate COX regression, higher plasma CST levels predicted increased risk of all-cause and cardiac death...
October 19, 2016: Peptides
Maoqi Xu, Liang Chen
The individual sample heterogeneity is one of the biggest obstacles in biomarker identification for complex diseases such as cancers. Current statistical models to identify differentially expressed genes between disease and control groups often overlook the substantial human sample heterogeneity. Meanwhile, traditional nonparametric tests lose detailed data information and sacrifice the analysis power, although they are distribution free and robust to heterogeneity. Here, we propose an empirical likelihood ratio test with a mean-variance relationship constraint (ELTSeq) for the differential expression analysis of RNA sequencing (RNA-seq)...
October 21, 2016: Briefings in Bioinformatics
Tânia Nobre, Manuela Oliveira, Birgit Arnholdt-Schmitt
By definition, the domestication process leads to an overall reduction of crop genetic diversity. This lead to the current search of genomic regions in wild crop relatives (CWR), an important task for modern carrot breeding. Nowadays massive sequencing possibilities can allow for discovery of novel genetic resources in wild populations, but this quest could be aided by the use of a surrogate gene (to first identify and prioritize novel wild populations for increased sequencing effort). Alternative oxidase (AOX) gene family seems to be linked to all kinds of abiotic and biotic stress reactions in various organisms and thus have the potential to be used in the identification of CWR hotspots of environment-adapted diversity...
2016: PloS One
Claire Montlahuc, Emmanuel Curis, Sarah Flora Jonas, Frank Bellivier, Sylvie Chevret
Gaussian mixture analysis is frequently used to model the age-at-onset (AAO) in bipolar I disorder and identify homogeneous subsets of patients. This study aimed to examine whether, using admixture analysis of AAO, cross-sectional designs (which cause right truncation), unreliable diagnosis for individuals younger than 10 years old (which causes left truncation) and the selection criterion used for admixture analysis impact the number of identified subsets. A simulation study was performed. Different criteria - the likelihood ratio test (LRT), the Akaike information criterion (AIC), and the Bayesian information criterion (BIC) - were compared using no, left and/or right truncation simulated data...
October 21, 2016: International Journal of Methods in Psychiatric Research
Kongkiat Chaikriangkrai, Ghanshyam Palamaner Subash Shantha, Hye Yeon Jhun, Patompong Ungprasert, Gardar Sigurdsson, Faisal Nabi, John J Mahmarian, Su Min Chang
STUDY OBJECTIVE: Coronary artery calcium score (CACS) is a well-established test for risk stratifying asymptomatic patients. Recent studies also indicate that CACS may accurately risk stratify stable patients presenting to the emergency department (ED) with acute chest pain; however, many were underpowered. The purpose of this systematic review and meta-analysis is to evaluate the prognostic value and accuracy of a zero (normal) CACS for identifying patients at acceptable low risk for future cardiovascular events who might be safely discharged home from the ED...
October 10, 2016: Annals of Emergency Medicine
Yohannes W Woldeamanuel, Peter R Kamerman, Demetri G A Veliotes, Tudor J Phillips, David Asboe, Marta Boffito, Andrew S C Rice
HIV-associated sensory peripheral neuropathy (HIV-SN) afflicts approximately 50% of patients on antiretroviral therapy, and is associated with significant neuropathic pain. Simple accurate diagnostic instruments are required for clinical research and daily practice in both high- and low-resource setting. A 4-item clinical tool (CHANT: Clinical HIV-associated Neuropathy Tool) assessing symptoms (pain and numbness) and signs (ankle reflexes and vibration sense) was developed by selecting and combining the most accurate measurands from a deep phenotyping study of HIV positive people (Pain In Neuropathy Study-HIV-PINS)...
2016: PloS One
Xu Steven Xu, Min Yuan, Haitao Yang, Yan Feng, Jinfeng Xu, Jose Pinheiro
Covariate analysis based on population pharmacokinetics (PPK) is used to identify clinically relevant factors. The likelihood ratio test (LRT) based on nonlinear mixed effect model fits is currently recommended for covariate identification, whereas individual empirical Bayesian estimates (EBEs) are considered unreliable due to the presence of shrinkage. The objectives of this research were to investigate the type I error for LRT and EBE approaches, to confirm the similarity of power between the LRT and EBE approaches from a previous report and to explore the influence of shrinkage on LRT and EBE inferences...
October 19, 2016: AAPS Journal
Ruth C Travis, Angela Balkwill, Georgina K Fensom, Paul N Appleby, Gillian K Reeves, Xiao-Si Wang, Andrew W Roddam, Toral Gathani, Richard Peto, Jane Green, Timothy J Key, Valerie Beral
BACKGROUND: It has been proposed that night shift work could increase breast cancer incidence. A 2007 World Health Organization review concluded, mainly from animal evidence, that shift work involving circadian disruption is probably carcinogenic to humans. We therefore aimed to generate prospective epidemiological evidence on night shift work and breast cancer incidence. METHODS: Overall, 522 246 Million Women Study, 22 559 EPIC-Oxford, and 251 045 UK Biobank participants answered questions on shift work and were followed for incident cancer...
December 2016: Journal of the National Cancer Institute
C-M Chu, K-C Kao, S-H Huang, D-Y Chuang, H-P Wu
Severe sepsis is associated with significant mortality and massive immune cell lose, or apoptosis. It is unclear whether plasma apoptosis biomarkers could be used as a diagnostic test for severe sepsis. Forty patients with severe sepsis and 35 healthy controls were enrolled. The percentage and apoptosis of monocytes and lymphocytes were detected by flow cytometric analysis. Plasma levels of tumor necrosis factor (TNF)-α, soluble TNF receptor (sTNFR), soluble Fas (sFas), Fas ligand (FasL), caspase-1, and procalcitonin (PCT) were measured...
September 30, 2016: Cellular and Molecular Biology
John S Nemer, Gavriel D Kohlberg, Dean M Mancuso, Brianna M Griffin, Michael V Certo, Stephanie Y Chen, Michael B Chun, Jaclyn B Spitzer, Anil K Lalwani
OBJECTIVE: Cochlear implantation is associated with poor music perception and enjoyment. Reducing music complexity has been shown to enhance music enjoyment in cochlear implant (CI) recipients. In this study, we assess the impact of harmonic series reduction on music enjoyment. STUDY DESIGN: Prospective analysis of music enjoyment in normal-hearing (NH) individuals and CI recipients. SETTING: Single tertiary academic medical center. PATIENTS: NH adults (N = 20) and CI users (N = 8) rated the Happy Birthday song on three validated enjoyment modalities-musicality, pleasantness, and naturalness...
October 12, 2016: Otology & Neurotology
Allen O Eghrari, Shivakumar Vasanth, Jiangxia Wang, Farnoosh Vahedi, S Amer Riazuddin, John D Gottsch
PURPOSE: Fuchs dystrophy is the leading indication of corneal transplantation in the United States. A CTG18.1 trinucleotide repeat in TCF4 correlates with increased severity in Fuchs dystrophy; however, quantitative estimates of increased transplantation risk, including effects of age and sex, are unclear. METHODS: In a tertiary institution clinical practice, 574 participants were enrolled in a longitudinal study of Fuchs dystrophy after slit-lamp biomicroscopy confirmed significant central guttae and/or corneal transplantation in both eyes...
October 14, 2016: Cornea
Benjamin Margolin Rottman
Whether humans can accurately make decisions in line with Bayes' rule has been one of the most important yet contentious topics in cognitive psychology. Though a number of paradigms have been used for studying Bayesian updating, rarely have subjects been allowed to use their own preexisting beliefs about the prior and the likelihood. A study is reported in which physicians judged the posttest probability of a diagnosis for a patient vignette after receiving a test result, and the physicians' posttest judgments were compared to the normative posttest calculated from their own beliefs in the sensitivity and false positive rate of the test (likelihood ratio) and prior probability of the diagnosis...
October 17, 2016: Memory & Cognition
Craig Ravesloot, Cathy Berendts, Alex Schiwal
BACKGROUND: Measurement of the environment is taking on increased importance for understanding variability in participation. Most measures of the environment use subjective ratings, yet little is known about how people appraise the environment. OBJECTIVE: /Hypothesis: We conducted this post-hoc study to examine whether or not catastrophizing, an important variable for understanding how pain contributes to disability, may be related to ratings of the environment...
October 5, 2016: Disability and Health Journal
Fernando Guerrero-Romero, Rafael Villalobos-Molina, J Rafael Jiménez-Flores, Luis E Simental-Mendia, René Méndez-Cruz, Miguel Murguía-Romero, Martha Rodríguez-Morán
BACKGROUND AND AIMS: Although the Glucose and Triglyceride levels (TyG) index is useful for identification of insulin resistance (IR) in different ethnic groups, it has not been evaluated in young adults. We undertook this study to evaluate the TyG index as a diagnostic test for IR in young adults. METHODS: A total of 5,538 healthy young adults, 3,795 (68.5%) non-pregnant women and 1,743 (31.5%) men, with an average age of 19.2 ± 1.4 years, were enrolled in a population-based cross-sectional study...
July 2016: Archives of Medical Research
Orsolya Balogh, Marie Roch, Stefanie Keller, Erika Michel, Iris M Reichler
In dogs, there is no diagnostic test to identify and differentiate fetal fluids from maternal urine in the event that a clear-yellowish vulvar discharge is observed pre-whelping. The objective of this study was to find a test that could easily and accurately identify rupture of the fetal membranes preceding parturition. Maternal urine, and amniotic fluid (AMF) and allantoic fluid (ALF) from only one fetus per bitch, were collected intraoperatively during cesarean section. Specific gravity (SG) was analyzed with a refractometer, whereas the presence of leukocytes, protein, glucose, ketones, bilirubin, urobilinogen, nitrite, erythrocyte/hemoglobin (Hb), and the pH were assessed using a urine dipstick (Combur-Test)...
September 21, 2016: Theriogenology
Nicole Niehoff, Alexandra J White, Lauren E McCullough, Susan E Steck, Jan Beyea, Irina Mordukhovich, Jing Shen, Alfred I Neugut, Kathleen Conway, Regina M Santella, Marilie D Gammon
BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) have been linked to breast cancer in many, but not all, previous studies. PAHs are lipophilic and stored in fat tissue, which we hypothesized may result in constant low-dose exposure to these carcinogens. No previous studies have evaluated whether obesity modifies associations between multiple measures of PAHs and breast cancer incidence. METHODS: This population-based study included 1,006 postmenopausal women with first primary in situ or invasive breast cancer and 990 age-frequency matched controls...
October 11, 2016: Environmental Research
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