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https://www.readbyqxmd.com/read/27921315/imputing-estrogen-receptor-er-status-in-a-population-based-cancer-registry-a-sensitivity-analysis
#1
Rebecca Andridge, Anne-Michelle Noone, Nadia Howlader
Breast cancers are clinically heterogeneous based on tumor markers. The National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program provides baseline data on these tumor markers for reporting cancer burden and trends over time in the US general population. These tumor markers, however, are often prone to missing observations. In particular, estrogen receptor (ER) status, a key biomarker in the study of breast cancer, has been collected since 1992 but historically was not well-reported, with missingness rates as high as 25% in early years...
December 5, 2016: Statistics in Medicine
https://www.readbyqxmd.com/read/27909127/costs-quality-of-life-and-cost-effectiveness-of-arthroscopic-and-open-repair-for-rotator-cuff-tears-an-economic-evaluation-alongside-the-ukuff-trial
#2
J Murphy, A Gray, C Cooper, D Cooper, C Ramsay, A Carr
AIMS: A trial-based comparison of the use of resources, costs and quality of life outcomes of arthroscopic and open surgical management for rotator cuff tears in the United Kingdom NHS was performed using data from the United Kingdom Rotator Cuff Study (UKUFF) randomised controlled trial. PATIENTS AND METHODS: Using data from 273 patients, healthcare-related use of resources, costs and quality-adjusted life years (QALYs) were estimated at 12 months and 24 months after surgery on an intention-to-treat basis with adjustment for covariates...
December 2016: Bone & Joint Journal
https://www.readbyqxmd.com/read/27902733/single-camera-trap-survey-designs-miss-detections-impacts-on-estimates-of-occupancy-and-community-metrics
#3
Brent S Pease, Clayton K Nielsen, Eric J Holzmueller
The use of camera traps as a tool for studying wildlife populations is commonplace. However, few have considered how the number of detections of wildlife differ depending upon the number of camera traps placed at cameras-sites, and how this impacts estimates of occupancy and community composition. During December 2015-February 2016, we deployed four camera traps per camera-site, separated into treatment groups of one, two, and four camera traps, in southern Illinois to compare whether estimates of wildlife community metrics and occupancy probabilities differed among survey methods...
2016: PloS One
https://www.readbyqxmd.com/read/27892664/breast-cancer-and-modifiable-lifestyle-factors-in-argentinean-women-addressing-missing-data-in-a-case-control-study
#4
Julia Becaria Coquet, Natalia Tumas, Alberto Ruben Osella, Matteo Tanzi, Isabella Franco, Maria Del Pilar Diaz
A number of studies have evidenced the effect of modifiable lifestyle factors such as diet, breastfeeding and nutritional status on breast cancer risk. However, none have addressed the missing data problem in nutritional epidemiologic research in South America. Missing data is a frequent problem in breast cancer studies and epidemiological settings in general. Estimates of effect obtained from these studies may be biased, if no appropriate method for handling missing data is applied. We performed Multiple Imputation for missing values on covariates in a breast cancer case-control study of Córdoba (Argentina) to optimize risk estimates...
January 10, 2016: Asian Pacific Journal of Cancer Prevention: APJCP
https://www.readbyqxmd.com/read/27866307/explicating-the-conditions-under-which-multilevel-multiple-imputation-mitigates-bias-resulting-from-random-coefficient-dependent-missing-longitudinal-data
#5
Nisha C Gottfredson, Sonya K Sterba, Kristina M Jackson
Random coefficient-dependent (RCD) missingness is a non-ignorable mechanism through which missing data can arise in longitudinal designs. RCD, for which we cannot test, is a problematic form of missingness that occurs if subject-specific random effects correlate with propensity for missingness or dropout. Particularly when covariate missingness is a problem, investigators typically handle missing longitudinal data by using single-level multiple imputation procedures implemented with long-format data, which ignores within-person dependency entirely, or implemented with wide-format (i...
November 19, 2016: Prevention Science: the Official Journal of the Society for Prevention Research
https://www.readbyqxmd.com/read/27859153/integrating-population-dynamics-models-and-distance-sampling-data-a-spatial-hierarchical-state-space-approach
#6
Khurram Nadeem, Jeffrey E Moore, Ying Zhang, Hugh Chipman
Stochastic versions of Gompertz, Ricker, and various other dynamics models play a fundamental role in quantifying strength of density dependence and studying long-term dynamics of wildlife populations. These models are frequently estimated using time series of abundance estimates that are inevitably subject to observation error and missing data. This issue can be addressed with a state-space modeling framework that jointly estimates the observed data model and the underlying stochastic population dynamics (SPD) model...
July 2016: Ecology
https://www.readbyqxmd.com/read/27857074/second-premolar-agenesis-is-associated-with-mandibular-form-a-geometric-morphometric-analysis-of-mandibular-cross-sections
#7
Michael H Bertl, Kristina Bertl, Manuel Wagner, André Gahleitner, Andreas Stavropoulos, Christian Ulm, Philipp Mitteroecker
The aim of this study was to compare mandibular form (i.e., size and shape) between patients with agenesis of the lower second premolar (P2) and a control group with no agenesis. Three hypotheses were tested: (H1) agenesis causes a change in mandibular morphology because of inadequate alveolar ridge development in the area of the missing tooth (mandibular plasticity); (H2) agenesis is caused by spatial limitations within the mandible (dental plasticity); and (H3) common genetic/epigenetic factors cause agenesis and affect mandibular form (pleiotropy)...
November 18, 2016: International Journal of Oral Science
https://www.readbyqxmd.com/read/27856962/analysis-of-an-incomplete-longitudinal-composite-variable-using-a-marginalized-random-effects-model-and-multiple-imputation
#8
Masahiko Gosho, Kazushi Maruo, Ryota Ishii, Akihiro Hirakawa
The total score, which is calculated as the sum of scores in multiple items or questions, is repeatedly measured in longitudinal clinical studies. A mixed effects model for repeated measures method is often used to analyze these data; however, if one or more individual items are not measured, the method cannot be directly applied to the total score. We develop two simple and interpretable procedures that infer fixed effects for a longitudinal continuous composite variable. These procedures consider that the items that compose the total score are multivariate longitudinal continuous data and, simultaneously, handle subject-level and item-level missing data...
November 16, 2016: Statistical Methods in Medical Research
https://www.readbyqxmd.com/read/27833512/impact-of-sociodemographic-attributes-and-dental-caries-on-quality-of-life-of-intellectual-disabled-children-using-ecohis
#9
Vikram Pal Aggarwal, Anmol Mathur, C L Dileep, Manu Batra, Diljot Kaur Makkar
OBJECTIVES: To assess the impact of oral health outcomes on Oral Health-Related Quality of Life (OHRQoL) among intellectual disabled children and their families. METHODOLOGY: OHRQoL based study was conducted among 150 intellectual disabled children students in the North West part of the country, Rajasthan, India. Guardians were asked to complete questionnaire on socioeconomic status and the Early Childhood Oral Health Impact Scale (ECOHIS) on their perception of the children's OHRQoL...
October 2016: International Journal of Health Sciences
https://www.readbyqxmd.com/read/27829038/long-term-secondary-care-costs-of-endometrial-cancer-a-prospective-cohort-study-nested-within-the-united-kingdom-collaborative-trial-of-ovarian-cancer-screening-ukctocs
#10
Mark Pennington, Aleksandra Gentry-Maharaj, Chloe Karpinskyj, Alec Miners, Julie Taylor, Ranjit Manchanda, Rema Iyer, Michelle Griffin, Andy Ryan, Ian Jacobs, Usha Menon, Rosa Legood
BACKGROUND: There is limited evidence on the costs of Endometrial Cancer (EC) by stage of disease. We estimated the long-term secondary care costs of EC according to stage at diagnosis in an English population-based cohort. METHODS: Women participating in UKCTOCS and diagnosed with EC following enrolment (2001-2005) and prior to 31st Dec 2009 were identified to have EC through multiple sources. Survival was calculated through data linkage to death registry. Costs estimates were derived from hospital records accessed from Hospital Episode Statistics (HES) with additional patient level covariates derived from case notes and patient questionnaires...
2016: PloS One
https://www.readbyqxmd.com/read/27807470/a-bayesian-hierarchical-spatial-model-for-dental-caries-assessment-using-non-gaussian-markov-random-fields
#11
Ick Hoon Jin, Ying Yuan, Dipankar Bandyopadhyay
Research in dental caries generates data with two levels of hierarchy: that of a tooth overall and that of the different surfaces of the tooth. The outcomes often exhibit spatial referencing among neighboring teeth and surfaces, i.e., the disease status of a tooth or surface might be influenced by the status of a set of proximal teeth/surfaces. Assessments of dental caries (tooth decay) at the tooth level yield binary outcomes indicating the presence/absence of teeth, and trinary outcomes at the surface level indicating healthy, decayed, or filled surfaces...
2016: Annals of Applied Statistics
https://www.readbyqxmd.com/read/27787564/effect-of-cranberry-capsules-on-bacteriuria-plus-pyuria-among-older-women-in-nursing-homes-a-randomized-clinical-trial
#12
Manisha Juthani-Mehta, Peter H Van Ness, Luann Bianco, Andrea Rink, Sabina Rubeck, Sandra Ginter, Stephanie Argraves, Peter Charpentier, Denise Acampora, Mark Trentalange, Vincent Quagliarello, Peter Peduzzi
Importance: Bacteriuria plus pyuria is highly prevalent among older women living in nursing homes. Cranberry capsules are an understudied, nonantimicrobial prevention strategy used in this population. Objective: To test the effect of 2 oral cranberry capsules once a day on presence of bacteriuria plus pyuria among women residing in nursing homes. Design, Setting, and Participants: Double-blind, randomized, placebo-controlled efficacy trial with stratification by nursing home and involving 185 English-speaking women aged 65 years or older, with or without bacteriuria plus pyuria at baseline, residing in 21 nursing homes located within 50 miles (80 km) of New Haven, Connecticut (August 24, 2012-October 26, 2015)...
November 8, 2016: JAMA: the Journal of the American Medical Association
https://www.readbyqxmd.com/read/27782817/assessment-of-predictive-performance-in-incomplete-data-by-combining-internal-validation-and-multiple-imputation
#13
Simone Wahl, Anne-Laure Boulesteix, Astrid Zierer, Barbara Thorand, Mark Avan de Wiel
BACKGROUND: Missing values are a frequent issue in human studies. In many situations, multiple imputation (MI) is an appropriate missing data handling strategy, whereby missing values are imputed multiple times, the analysis is performed in every imputed data set, and the obtained estimates are pooled. If the aim is to estimate (added) predictive performance measures, such as (change in) the area under the receiver-operating characteristic curve (AUC), internal validation strategies become desirable in order to correct for optimism...
October 26, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27777471/minimax-rate-optimal-estimation-of-high-dimensional-covariance-matrices-with-incomplete-data
#14
T Tony Cai, Anru Zhang
Missing data occur frequently in a wide range of applications. In this paper, we consider estimation of high-dimensional covariance matrices in the presence of missing observations under a general missing completely at random model in the sense that the missingness is not dependent on the values of the data. Based on incomplete data, estimators for bandable and sparse covariance matrices are proposed and their theoretical and numerical properties are investigated. Minimax rates of convergence are established under the spectral norm loss and the proposed estimators are shown to be rate-optimal under mild regularity conditions...
September 2016: Journal of Multivariate Analysis
https://www.readbyqxmd.com/read/27770238/pharmacokinetic-and-pharmacodynamic-study-of-doxorubicin-in-children-with-cancer-results-of-a-european-pediatric-oncology-off-patents-medicines-consortium-trial
#15
Miriam Krischke, Georg Hempel, Swantje Völler, Nicolas André, Maurizio D'Incalci, Gianni Bisogno, Wolfgang Köpcke, Matthias Borowski, Ralf Herold, Alan V Boddy, Joachim Boos
PURPOSE: Doxorubicin is a key component in many pediatric oncology treatment regimens; still pharmacology data on which current dosing regimens are based are very limited. METHODS: We conducted a multinational pharmacokinetic study investigating age dependency of doxorubicin metabolism and elimination in children with cancer. One hundred and one patients treated with doxorubicin according to a cancer-specific national or European therapeutic trial were recruited...
December 2016: Cancer Chemotherapy and Pharmacology
https://www.readbyqxmd.com/read/27767106/impact-of-smoking-on-tooth-loss-in-adults
#16
Susan J Carson, Jacqueline Burns
DesignCohort studyCohort selectionParticipants were recruited between 1994 and 1998 from the general population with the preferred ages of 35 to 65 years in women and 40 to 65 years in men.Exposure measurementSmoking was assessed using a questionnaire from which pack years of smoking were calculated. Educational attainment, body mass index, hypertension, diabetes, alcohol consumption and vitamin or mineral supplements were assessed from measurements and questionnaires. Tooth loss was also assessed by questionnaire returned between 2004 and 2006...
September 2016: Evidence-based Dentistry
https://www.readbyqxmd.com/read/27753954/os-08-04-epistatic-and-sex-dependent-association-analyses-of-genes-of-the-renin-angiotensin-aldosterone-system-and-blood-pressure-in-families
#17
Stephen Harrap, Katrina Scurrah, Angela Lamantia, Justine Ellis
OBJECTIVE: Genes encoding key elements of the renin-angiotensin-aldosterone system (RAAS) cascade have been previously but inconsistently associated with blood pressure. Sex-dependency might be important here and functional genetic polymorphisms might exhibit epistatic effects. DESIGN AND METHOD: We assessed variation in the genes encoding renin (REN), angiotensinogen (AGT), angiotensin converting enzyme (ACE), angiotensin II type 1 receptor (AGTR1) and aldosterone synthase (CYP11B2)...
September 2016: Journal of Hypertension
https://www.readbyqxmd.com/read/27747810/estimating-the-economic-burden-of-rheumatoid-arthritis-in-taiwan-using-the-national-health-insurance-database
#18
Bruce C M Wang, Ping-Ning Hsu, Wesley Furnback, John Ney, Ya-Wen Yang, Chi-Hui Fang, Chao-Hsiun Tang
BACKGROUND: Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by inflammation and destruction of the joints. OBJECTIVES: This research aims to estimate the economic burden of RA in Taiwan. METHODS: The National Health Insurance Research Database (NHIRD), a claims-based dataset encompassing 99 % of Taiwan's population, was applied. We used a micro-costing approach for direct healthcare costs and indirect social costs by estimating the quantities and prices of cost categories...
March 2016: Drugs—Real World Outcomes
https://www.readbyqxmd.com/read/27746264/repeated-measure-analyses-which-one-a-survey-of-statistical-models-and-recommendations-for-reporting
#19
Jacques P Maurissen, Thomas J Vidmar
Repeated-measure analysis of variance is a general term that can imply a number of different statistical models used to analyze data from studies in which measurements are taken from each subject on more than one occasion. Repeated-measure analyses encompass univariate models (with or without sphericity adjustment), multivariate models, mixed models, analysis of covariance, multilevel models, latent growth models, and hybrids of these models. These models are based on different assumptions, especially regarding correlations (sphericity) between within-subject factors, which comprise the variance-covariance matrix...
October 13, 2016: Neurotoxicology and Teratology
https://www.readbyqxmd.com/read/27734514/models-for-zero-inflated-correlated-count-data-with-extra-heterogeneity-when-is-it-too-complex
#20
Sammy Chebon, Christel Faes, Frank Cools, Helena Geys
Statistical analysis of count data typically starts with a Poisson regression. However, in many real-life applications, it is observed that the variation in the counts is larger than the mean, and one needs to deal with the problem of overdispersion in the counts. Several factors may contribute to overdispersion: (1) unobserved heterogeneity due to missing covariates, (2) correlation between observations (such as in longitudinal studies), and (3) the occurrence of many zeros (more than expected from the Poisson distribution)...
January 30, 2017: Statistics in Medicine
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