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https://www.readbyqxmd.com/read/28340126/association-between-socioeconomic-status-and-access-to-care-and-quitting-smoking-with-and-without-assistance
#1
Sarah A Edwards, Russell C Callaghan, Robert E Mann, Susan J Bondy
Introduction: Socio-economic disparities in smoking rates persist, in Ontario, despite public health care and universal tobacco control policies. Mechanisms for continuing disparities are not fully understood. Unequal access or utilization of assistance for cessation may contribute. The objective of this research was to use longitudinal data on smokers to examine the associations between socioeconomic status (SES) and access to care measures and assisted and unassisted quit attempts. Methods: Data were taken from 3578 smokers with at least one follow-up interview participating in the Ontario Tobacco Survey (OTS)...
March 10, 2017: Nicotine & Tobacco Research: Official Journal of the Society for Research on Nicotine and Tobacco
https://www.readbyqxmd.com/read/28334230/guided-bayesian-imputation-to-adjust-for-confounding-when-combining-heterogeneous-data-sources-in-comparative-effectiveness-research
#2
Joseph Antonelli, Corwin Zigler, Francesca Dominici
In comparative effectiveness research, we are often interested in the estimation of an average causal effect from large observational data (the main study). Often this data does not measure all the necessary confounders. In many occasions, an extensive set of additional covariates is measured for a smaller and non-representative population (the validation study). In this setting, standard approaches for missing data imputation might not be adequate due to the large number of missing covariates in the main data relative to the smaller sample size of the validation data...
March 3, 2017: Biostatistics
https://www.readbyqxmd.com/read/28327265/association-between-body-mass-index-and-caries-experience-in-brazilian-children-and-adolescents
#3
Raquel Assed Bezerra da Silva, Driely Barreiros, Sara Oliveira, Lea Assed Bezerra da Silva, Paulo Nelson-Filho, Erika Calvano Küchler
PURPOSE: The purpose of this study was to evaluate the association between caries and body mass index (BMI) deviations in Brazilian schoolchildren and adolescents. METHODS: A total of 237 three- to 15-year-old children, all undergoing treatment in a university pediatric dental clinic, was evaluated. Caretakers answered a questionnaire on sociodemographic, ethnicity, oral hygiene, and dietary information. The children's height was measured in centimeters, the weight in kilograms, and BMIs were calculated...
September 15, 2016: Journal of Dentistry for Children
https://www.readbyqxmd.com/read/28281937/sensitivity-analysis-for-missing-dichotomous-outcome-data-in-multi-visit-randomized-clinical-trial-with-randomization-based-covariance-adjustment
#4
Siying Li, Gary G Koch, John S Preisser, Diana Lam, Matilde Sanchez-Kam
Dichotomous endpoints in clinical trials have only two possible outcomes, either directly or via categorization of an ordinal or continuous observation. It is common to have missing data for one or more visits during a multi-visit study. This paper presents a closed form method for sensitivity analysis of a randomized multi-visit clinical trial that possibly has missing not at random (MNAR) dichotomous data. Counts of missing data are redistributed to the favorable and unfavorable outcomes mathematically to address possibly informative missing data...
February 8, 2017: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28281895/randomization-based-adjustment-of-multiple-treatment-hazard-ratios-for-covariates-with-missing-data
#5
Diana Lam, Gary G Koch, John S Preisser, Benjamin R Saville, Michael A Hussey
Clinical trials are designed to compare treatment effects when applied to samples from the same population. Randomization is used so that the samples are not biased with respect to baseline covariates that may influence the efficacy of the treatment. We develop randomization-based covariance adjustment methodology to estimate the log hazard ratios and their confidence intervals of multiple treatments in a randomized clinical trial with time-to-event outcomes and missingness among the baseline covariates. The randomization-based covariance adjustment method is a computationally straight-forward method for handling missing baseline covariate values...
February 8, 2017: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28267796/multivariate-normative-comparisons-using-an-aggregated-database
#6
Joost A Agelink van Rentergem, Jaap M J Murre, Hilde M Huizenga
In multivariate normative comparisons, a patient's profile of test scores is compared to those in a normative sample. Recently, it has been shown that these multivariate normative comparisons enhance the sensitivity of neuropsychological assessment. However, multivariate normative comparisons require multivariate normative data, which are often unavailable. In this paper, we show how a multivariate normative database can be constructed by combining healthy control group data from published neuropsychological studies...
2017: PloS One
https://www.readbyqxmd.com/read/28258365/dosing-and-switching-strategies-for-paliperidone-palmitate-3-month-formulation-in-patients-with-schizophrenia-based-on-population-pharmacokinetic-modeling-and-simulation-and-clinical-trial-data
#7
REVIEW
Mats O Magnusson, Mahesh N Samtani, Elodie L Plan, E Niclas Jonsson, Stefaan Rossenu, An Vermeulen, Alberto Russu
Paliperidone palmitate 3-month formulation (PP3M), a long-acting injectable atypical antipsychotic, was recently approved in the US and Europe for the treatment of schizophrenia in adult patients who have already been treated with paliperidone palmitate 1-month formulation (PP1M) for ≥4 months. This article reviews the pharmacokinetic rationale for the approved dosing regimens for PP3M, dosing windows, management of missed doses and treatment discontinuation, switching to other formulations, and dosing in special populations...
March 4, 2017: CNS Drugs
https://www.readbyqxmd.com/read/28255988/differences-between-proxy-and-patient-assessments-of-cancer-care-experiences-and-quality-ratings
#8
Jessica K Roydhouse, Roee Gutman, Nancy L Keating, Vincent Mor, Ira B Wilson
OBJECTIVE: To assess the impact of proxy survey responses on cancer care experience reports and quality ratings. DATA SOURCES/STUDY SETTING: Secondary analysis of data from Cancer Care Outcomes Research and Surveillance (CanCORS). Recruitment occurred from 2003 to 2005. STUDY DESIGN: The study was a cross-sectional observational study. The respondents were patients with incident colorectal or lung cancer or their proxies. DATA COLLECTION/EXTRACTION METHODS: Analyses used linear regression models with an independent variable for proxy versus patient responses as well as study site and clinical covariates...
March 2, 2017: Health Services Research
https://www.readbyqxmd.com/read/28239457/covariate-selection-for-multilevel-models-with-missing-data
#9
Miguel Marino, Orfeu M Buxton, Yi Li
Missing covariate data hampers variable selection in multilevel regression settings. Current variable selection techniques for multiply-imputed data commonly address missingness in the predictors through list-wise deletion and stepwise-selection methods which are problematic. Moreover, most variable selection methods are developed for independent linear regression models and do not accommodate multilevel mixed effects regression models with incomplete covariate data. We develop a novel methodology that is able to perform covariate selection across multiply-imputed data for multilevel random effects models when missing data is present...
2017: Stat: the ISI's Journal for Rapid Dissemination of Statistics Research
https://www.readbyqxmd.com/read/28239197/linear-regression-with-a-randomly-censored-covariate-application-to-an-alzheimer-s-study
#10
Folefac D Atem, Jing Qian, Jacqueline E Maye, Keith A Johnson, Rebecca A Betensky
The association between maternal age of onset of dementia and amyloid deposition (measured by in vivo positron emission tomography (PET) imaging) in cognitively normal older offspring is of interest. In a regression model for amyloid, special methods are required due to the random right censoring of the covariate of maternal age of onset of dementia. Prior literature has proposed methods to address the problem of censoring due to assay limit of detection, but not random censoring. We propose imputation methods and a survival regression method that do not require parametric assumptions about the distribution of the censored covariate...
2017: Journal of the Royal Statistical Society. Series C, Applied Statistics
https://www.readbyqxmd.com/read/28229396/statistical-approaches-to-longitudinal-data-analysis-in-neurodegenerative-diseases-huntington-s-disease-as-a-model
#11
REVIEW
Tanya P Garcia, Karen Marder
Understanding the overall progression of neurodegenerative diseases is critical to the timing of therapeutic interventions and design of effective clinical trials. Disease progression can be assessed with longitudinal study designs in which outcomes are measured repeatedly over time and are assessed with respect to risk factors, either measured repeatedly or at baseline. Longitudinal data allows researchers to assess temporal disease aspects, but the analysis is complicated by complex correlation structures, irregularly spaced visits, missing data, and mixtures of time-varying and static covariate effects...
February 2017: Current Neurology and Neuroscience Reports
https://www.readbyqxmd.com/read/28226391/closed-form-reml-estimators-and-sample-size-determination-for-mixed-effects-models-for-repeated-measures-under-monotone-missingness
#12
Yongqiang Tang
We derive the closed-form restricted maximum likelihood estimator and Kenward-Roger's variance estimator for fixed effects in the mixed effects model for repeated measures (MMRM) when the missing data pattern is monotone. As an important application of the analytic result, we present the formula for calculating the power of treatment comparison using the Wald t-test with the Kenward-Roger adjusted variance estimate in MMRM. It allows adjustment for baseline covariates without the need to specify the covariate distribution in randomized trials...
February 22, 2017: Statistics in Medicine
https://www.readbyqxmd.com/read/28223781/factors-influencing-the-exit-knowledge-of-patients-for-dispensed-drugs-at-outpatient-pharmacy-of-hiwot-fana-specialized-university-hospital-eastern-ethiopia
#13
Nigatu Hirko, Dumessa Edessa
BACKGROUND: A satisfactory counseling process between the patient and pharmacist is critical for rational use of dispensed drug(s) and is highly influenced by many factors including the experience of pharmacist in dispensing process. To improve patients' knowledge of dispensed drugs, it is necessary to understand the factors that optimize a pharmacist interaction with a patient in each activity of the dispensing process. Therefore, the aim of this study was to identify the pharmacist and patient factors that influence knowledge of dispensed drugs by ambulatory patients at Hiwot Fana Specialized University Hospital, Harar, Ethiopia...
2017: Patient Preference and Adherence
https://www.readbyqxmd.com/read/28211951/semiparametric-regression-analysis-of-interval-censored-competing-risks-data
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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