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https://www.readbyqxmd.com/read/28211951/semiparametric-regression-analysis-of-interval-censored-competing-risks-data
#1
Lu Mao, Dan-Yu Lin, Donglin Zeng
Interval-censored competing risks data arise when each study subject may experience an event or failure from one of several causes and the failure time is not observed directly but rather is known to lie in an interval between two examinations. We formulate the effects of possibly time-varying (external) covariates on the cumulative incidence or sub-distribution function of competing risks (i.e., the marginal probability of failure from a specific cause) through a broad class of semiparametric regression models that captures both proportional and non-proportional hazards structures for the sub-distribution...
February 17, 2017: Biometrics
https://www.readbyqxmd.com/read/28195811/determinants-of-patient-centered-financial-stress-in-patients-with-locally-advanced-head-and-neck-cancer
#2
Jonas A de Souza, Sunny Kung, Jeremy O'Connor, Bonnie J Yap
PURPOSE: To prospectively estimate patient-centered financial stress and its relationship with health care utilization in patients with head and neck cancer. This was a survey-based, longitudinal, prospective study of treatment-naïve patients with stage III, IVa, or IVb locally advanced head and neck cancer at a single-institution tertiary care hospital from May 2013 to November 2014. With 121 patients approached, 73 (60%) agreed to participate. METHODS: Self-reported data were collected on demographics, income, wealth, cost-coping strategies, out-of-pocket costs, supportive medication compliance, and perceived social isolation...
February 14, 2017: Journal of Oncology Practice
https://www.readbyqxmd.com/read/28195340/preventive-benefit-of-access-to-fluoridated-water-for-young-adults
#3
A John Spencer, Pingzhou Liu, Jason Mathew Armfield, Loc Giang Do
: Water fluoridation has been repeatedly associated with lower caries experience in children but uncertainty still exists on strength and extent of the association into adulthood. OBJECTIVE: To analyze the preventive effect of access to fluoridated water on dental caries among young adults. METHODS: In 1991/92 a cross-section of South Australian children aged 5-17 were recruited. Parents provided information on residential history, socioeconomic status, and behaviors...
February 13, 2017: Journal of Public Health Dentistry
https://www.readbyqxmd.com/read/28194642/are-optimism-and-cynical-hostility-associated-with-smoking-cessation-in-older-women
#4
Ana M Progovac, Yue-Fang Chang, Chung-Chou H Chang, Karen A Matthews, Julie M Donohue, Michael F Scheier, Elizabeth B Habermann, Lewis H Kuller, Joseph S Goveas, Benjamin P Chapman, Paul R Duberstein, Catherine R Messina, Kathryn E Weaver, Nazmus Saquib, Robert B Wallace, Robert C Kaplan, Darren Calhoun, J Carson Smith, Hilary A Tindle
BACKGROUND: Optimism and cynical hostility independently predict morbidity and mortality in Women's Health Initiative (WHI) participants and are associated with current smoking. However, their association with smoking cessation in older women is unknown. PURPOSE: The purpose of this study is to test whether optimism (positive future expectations) or cynical hostility (mistrust of others) predicts smoking cessation in older women. METHODS: Self-reported smoking status was assessed at years 1, 3, and 6 after study entry for WHI baseline smokers who were not missing optimism or cynical hostility scores (n = 10,242)...
February 13, 2017: Annals of Behavioral Medicine: a Publication of the Society of Behavioral Medicine
https://www.readbyqxmd.com/read/28194581/the-impact-of-massed-and-spaced-out-curriculum-in-oncology-knowledge-acquisition
#5
Dario Cecilio-Fernandes, Wytze S Aalders, Jakob de Vries, René A Tio
Starting in 2009, cancer has been the leading cause of death in the Netherlands. Oncology is therefore an important part of the medical curriculum in undergraduate education. It is crucial that medical students know about cancer, since doctors will encounter many cases of oncology. We have compared the influence that teaching oncology has when spread over a 3-year curriculum versus concentrated in one semester. The participants comprised 525 medical students from one medical school with comprehensive integrated curricula...
February 13, 2017: Journal of Cancer Education: the Official Journal of the American Association for Cancer Education
https://www.readbyqxmd.com/read/28099744/a-retrospective-cohort-study-of-hemostatic-agent-use-during-hysterectomy-and-risk-of-post-operative-complications
#6
John A Harris, Shitanshu Uppal, Neil Kamdar, Carolyn W Swenson, Darrell Campbell, Daniel M Morgan
OBJECTIVE: To determine if the use of intraoperative hemostatic agents was a risk factor for post-operative adverse events within 30 days of patients undergoing hysterectomy. METHOD: A population-based retrospective cohort study included data from patients undergoing hysterectomy for any indication between January 1, 2013, and December 31, 2014, at 52 hospitals in Michigan, USA. Any individuals with missing covariate data were excluded, and multivariable logistic regression and propensity score-matching were used to estimate the rate of post-operative adverse events associated with intra-operative hemostatic agents independent of demographic and surgical factors...
February 2017: International Journal of Gynaecology and Obstetrics
https://www.readbyqxmd.com/read/28092105/effectiveness-of-water-fluoridation-in-the-prevention-of-dental-caries-across-adult-age-groups
#7
Loc Do, Diep Ha, Marco A Peres, John Skinner, Roy Byun, A John Spencer
BACKGROUND: Lifetime access to fluoridated water (FW) is associated with lower caries experience. However, assessing this association in adults is likely affected by age. Cohort stratification and categorization of per cent lifetime access to fluoridated water (% LAFW) within cohorts are current approaches to this assessment. These approaches require an examination of the % LAFW and caries experience variation within and across age groups and their association to inform future analyses...
January 16, 2017: Community Dentistry and Oral Epidemiology
https://www.readbyqxmd.com/read/28088357/joint-genome-wide-prediction-in-several-populations-accounting-for-randomness-of-genotypes-a-hierarchical-bayes-approach-ii-multivariate-spike-and-slab-priors-for-marker-effects-and-derivation-of-approximate-bayes-and-fractional-bayes-factors-for-the-complete
#8
Carlos Alberto Martínez, Kshitij Khare, Arunava Banerjee, Mauricio A Elzo
This study corresponds to the second part of a companion paper devoted to the development of Bayesian multiple regression models accounting for randomness of genotypes in across population genome-wide prediction. This family of models considers heterogeneous and correlated marker effects and allelic frequencies across populations, and has the ability of considering records from non-genotyped individuals and individuals with missing genotypes in any subset of loci without the need for previous imputation, taking into account uncertainty about imputed genotypes...
January 12, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28076925/the-association-between-electronic-bullying-and-school-absenteeism-among-high-school-students-in-the-united-states
#9
Erin Grinshteyn, Y T Yang
BACKGROUND: We examined the relationship between exposure to electronic bullying and absenteeism as a result of being afraid. METHODS: This multivariate, multinomial regression analysis of the 2013 Youth Risk Behavior Survey data assessed the association between experiencing electronic bullying in the past year and how often students were absent in the last month due to feeling unsafe at/in transit to school. The model controlled for other predictors of school absence including demographics, physical/behavioral health, and risk factors...
February 2017: Journal of School Health
https://www.readbyqxmd.com/read/28074600/analyzing-multiple-endpoints-in-a-confirmatory-randomized-clinical-trial-an-approach-that-addresses-stratification-missing-values-baseline-imbalance-and-multiplicity-for-strictly-ordinal-outcomes
#10
Hengrui Sun, Atsushi Kawaguchi, Gary Koch
Confirmatory randomized clinical trials with a stratified design may have ordinal response outcomes, ie, either ordered categories or continuous determinations that are not compatible with an interval scale. Also, multiple endpoints are often collected when 1 single endpoint does not represent the overall efficacy of the treatment. In addition, random baseline imbalances and missing values can add another layer of difficulty in the analysis plan. Therefore, the development of an approach that provides a consolidated strategy to all issues collectively is essential...
January 11, 2017: Pharmaceutical Statistics
https://www.readbyqxmd.com/read/28068910/outcome-sensitive-multiple-imputation-a-simulation-study
#11
Evangelos Kontopantelis, Ian R White, Matthew Sperrin, Iain Buchan
BACKGROUND: Multiple imputation is frequently used to deal with missing data in healthcare research. Although it is known that the outcome should be included in the imputation model when imputing missing covariate values, it is not known whether it should be imputed. Similarly no clear recommendations exist on: the utility of incorporating a secondary outcome, if available, in the imputation model; the level of protection offered when data are missing not-at-random; the implications of the dataset size and missingness levels...
January 9, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28065879/structural-zeros-in-high-dimensional-data-with-applications-to-microbiome-studies
#12
Abhishek Kaul, Ori Davidov, Shyamal D Peddada
SUMMARYThis paper is motivated by the recent interest in the analysis of high-dimensional microbiome data. A key feature of these data is the presence of "structural zeros" which are microbes missing from an observation vector due to an underlying biological process and not due to error in measurement. Typical notions of missingness are unable to model these structural zeros. We define a general framework which allows for structural zeros in the model and propose methods of estimating sparse high-dimensional covariance and precision matrices under this setup...
January 8, 2017: Biostatistics
https://www.readbyqxmd.com/read/28065470/the-rare-variant-generalized-disequilibrium-test-for-association-analysis-of-nuclear-and-extended-pedigrees-with-application-to-alzheimer-disease-wgs-data
#13
Zongxiao He, Di Zhang, Alan E Renton, Biao Li, Linhai Zhao, Gao T Wang, Alison M Goate, Richard Mayeux, Suzanne M Leal
Whole-genome and exome sequence data can be cost-effectively generated for the detection of rare-variant (RV) associations in families. Causal variants that aggregate in families usually have larger effect sizes than those found in sporadic cases, so family-based designs can be a more powerful approach than population-based designs. Moreover, some family-based designs are robust to confounding due to population admixture or substructure. We developed a RV extension of the generalized disequilibrium test (GDT) to analyze sequence data obtained from nuclear and extended families...
February 2, 2017: American Journal of Human Genetics
https://www.readbyqxmd.com/read/28057876/academic-performance-in-adolescents-born-after-art-a-nationwide-registry-based-cohort-study
#14
A L Spangmose, S S Malchau, L Schmidt, D Vassard, S Rasmussen, A Loft, J Forman, A Pinborg
STUDY QUESTION: Is academic performance in adolescents aged 15-16 years and conceived after ART, measured as test scores in ninth grade, comparable to that for spontaneously conceived (SC) adolescents? SUMMARY ANSWER: ART singletons had a significantly lower mean test score in the adjusted analysis when compared with SC singletons, yet the differences were small and probably not of clinical relevance. WHAT IS KNOWN ALREADY: Previous studies have shown similar intelligence quotient (IQ) levels in ART and SC children, but only a few have been on adolescents...
January 5, 2017: Human Reproduction
https://www.readbyqxmd.com/read/28056955/development-of-an-algorithm-for-determining-smoking-status-and-behaviour-over-the-life-course-from-uk-electronic-primary-care-records
#15
Mark D Atkinson, Jonathan I Kennedy, Ann John, Keir E Lewis, Ronan A Lyons, Sinead T Brophy
BACKGROUND: Patients' smoking status is routinely collected by General Practitioners (GP) in UK primary health care. There is an abundance of Read codes pertaining to smoking, including those relating to smoking cessation therapy, prescription, and administration codes, in addition to the more regularly employed smoking status codes. Large databases of primary care data are increasingly used for epidemiological analysis; smoking status is an important covariate in many such analyses. However, the variable definition is rarely documented in the literature...
January 5, 2017: BMC Medical Informatics and Decision Making
https://www.readbyqxmd.com/read/28045979/intensive-patient-education-improves-glycaemic-control-in-diabetes-compared-to-conventional-education-a-randomised-controlled-trial-in-a-nigerian-tertiary-care-hospital
#16
Okon Essien, Akaninyene Otu, Victor Umoh, Ofem Enang, Joseph Paul Hicks, John Walley
BACKGROUND: Diabetes is now a global epidemic, but most cases are now in low- and middle-income countries. Diabetes self-management education (DSME) is key to enabling patients to manage their chronic condition and can reduce the occurrence of costly and devastating complications. However, there is limited evidence on the effectiveness of different DSME programmes in resource limited settings. METHODS: We conducted an unblinded, parallel-group, individually-randomised controlled trial at the University of Calabar Teaching Hospital (Nigeria) to evaluate whether an intensive and systematic DSME programme, using structured guidelines, improved glycaemic control compared to the existing ad hoc patient education (clinical practice was unchanged)...
2017: PloS One
https://www.readbyqxmd.com/read/28045978/cord-blood-acute-phase-reactants-predict-early-onset-neonatal-sepsis-in-preterm-infants
#17
Leena B Mithal, Hannah L Palac, Ram Yogev, Linda M Ernst, Karen K Mestan
BACKGROUND: Early onset sepsis (EOS) is a major cause of morbidity and mortality in preterm infants, yet diagnosis remains inadequate resulting in missed cases or prolonged empiric antibiotics with adverse consequences. Evaluation of acute phase reactant (APR) biomarkers in umbilical cord blood at birth may improve EOS detection in preterm infants with intrauterine infection. METHODS: In this nested case-control study, infants (29.7 weeks gestation, IQR: 27.7-32...
2017: PloS One
https://www.readbyqxmd.com/read/28039292/to-condition-or-not-condition-analysing-change-in-longitudinal-randomised-controlled-trials
#18
Cynthia J Coffman, David Edelman, Robert F Woolson
OBJECTIVE: The statistical analysis for a 2-arm randomised controlled trial (RCT) with a baseline outcome followed by a few assessments at fixed follow-up times typically invokes traditional analytic methods (eg, analysis of covariance (ANCOVA), longitudinal data analysis (LDA)). 'Constrained' longitudinal data analysis (cLDA) is a well-established unconditional technique that constrains means of baseline to be equal between arms. We use an analysis of fasting lipid profiles from the Group Medical Clinics (GMC) longitudinal RCT on patients with diabetes to illustrate applications of ANCOVA, LDA and cLDA to demonstrate theoretical concepts of these methods including the impact of missing data...
December 30, 2016: BMJ Open
https://www.readbyqxmd.com/read/28004848/analysing-animal-social-network-dynamics-the-potential-of-stochastic-actor-oriented-models
#19
David N Fisher, Amiyaal Ilany, Matthew J Silk, Tom Tregenza
Animals are embedded in dynamically changing networks of relationships with conspecifics. These dynamic networks are fundamental aspects of their environment, creating selection on behaviours and other traits. However, most social network-based approaches in ecology are constrained to considering networks as static, despite several calls for such analyses to become more dynamic. There are a number of statistical analyses developed in the social sciences that are increasingly being applied to animal networks, of which stochastic actor-oriented models (SAOMs) are a principal example...
December 22, 2016: Journal of Animal Ecology
https://www.readbyqxmd.com/read/28002546/use-of-risk-models-to-predict-death-in-the-next-year-among-individual-ambulatory-patients-with-heart-failure
#20
Larry A Allen, Daniel D Matlock, Susan M Shetterly, Stanley Xu, Wayne C Levy, Laura B Portalupi, Colleen K McIlvennan, Jerry H Gurwitz, Eric S Johnson, David H Smith, David J Magid
Importance: The clinical practice guidelines for heart failure recommend the use of validated risk models to estimate prognosis. Understanding how well models identify individuals who will die in the next year informs decision making for advanced treatments and hospice. Objective: To quantify how risk models calculated in routine practice estimate more than 50% 1-year mortality among ambulatory patients with heart failure who die in the subsequent year. Design, Setting, and Participants: Ambulatory adults with heart failure from 3 integrated health systems were enrolled between 2005 and 2008...
December 21, 2016: JAMA Cardiology
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