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BMC Medical Research Methodology

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https://www.readbyqxmd.com/read/28077079/a-double-simex-approach-for-bivariate-random-effects-meta-analysis-of-diagnostic-accuracy-studies
#1
Annamaria Guolo
BACKGROUND: Bivariate random-effects models represent a widely accepted and recommended approach for meta-analysis of test accuracy studies. Standard likelihood methods routinely used for inference are prone to several drawbacks. Small sample size can give rise to unreliable inferential conclusions and convergence issues make the approach unappealing. This paper suggests a different methodology to address such difficulties. METHODS: A SIMEX methodology is proposed...
January 11, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28077076/estimating-a-population-cumulative-incidence-under-calendar-time-trends
#2
Stefan N Hansen, Morten Overgaard, Per K Andersen, Erik T Parner
BACKGROUND: The risk of a disease or psychiatric disorder is frequently measured by the age-specific cumulative incidence. Cumulative incidence estimates are often derived in cohort studies with individuals recruited over calendar time and with the end of follow-up governed by a specific date. It is common practice to apply the Kaplan-Meier or Aalen-Johansen estimator to the total sample and report either the estimated cumulative incidence curve or just a single point on the curve as a description of the disease risk...
January 11, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28073360/centralising-and-optimising-decentralised-stroke-care-systems-a-simulation-study-on-short-term-costs-and-effects
#3
Maarten M H Lahr, Durk-Jouke van der Zee, Gert-Jan Luijckx, Patrick C A J Vroomen, Erik Buskens
BACKGROUND: Centralisation of thrombolysis may offer substantial benefits. The aim of this study was to assess short term costs and effects of centralisation of thrombolysis and optimised care in a decentralised system. METHODS: Using simulation modelling, three scenarios to improve decentralised settings in the North of Netherlands were compared from the perspective of the policy maker and compared to current decentralised care: (1) improving stroke care at nine separate hospitals, (2) centralising and improving thrombolysis treatment to four, and (3) two hospitals...
January 10, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28068901/development-of-a-microsoft-excel-tool-for-one-parameter-rasch-model-of-continuous-items-an-application-to-a-safety-attitude-survey
#4
Tsair-Wei Chien, Yang Shao, Shu-Chun Kuo
BACKGROUND: Many continuous item responses (CIRs) are encountered in healthcare settings, but no one uses item response theory's (IRT) probabilistic modeling to present graphical presentations for interpreting CIR results. A computer module that is programmed to deal with CIRs is required. To present a computer module, validate it, and verify its usefulness in dealing with CIR data, and then to apply the model to real healthcare data in order to show how the CIR that can be applied to healthcare settings with an example regarding a safety attitude survey...
January 10, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28068910/outcome-sensitive-multiple-imputation-a-simulation-study
#5
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/28068905/g-computation-of-average-treatment-effects-on-the-treated-and-the-untreated
#6
Aolin Wang, Roch A Nianogo, Onyebuchi A Arah
BACKGROUND: Average treatment effects on the treated (ATT) and the untreated (ATU) are useful when there is interest in: the evaluation of the effects of treatments or interventions on those who received them, the presence of treatment heterogeneity, or the projection of potential outcomes in a target (sub-) population. In this paper we illustrate the steps for estimating ATT and ATU using g-computation implemented via Monte Carlo simulation. METHODS: To obtain marginal effect estimates for ATT and ATU we used a three-step approach: fitting a model for the outcome, generating potential outcome variables for ATT and ATU separately, and regressing each potential outcome variable on treatment intervention...
January 9, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28056835/clinical-prediction-in-defined-populations-a-simulation-study-investigating-when-and-how-to-aggregate-existing-models
#7
Glen P Martin, Mamas A Mamas, Niels Peek, Iain Buchan, Matthew Sperrin
BACKGROUND: Clinical prediction models (CPMs) are increasingly deployed to support healthcare decisions but they are derived inconsistently, in part due to limited data. An emerging alternative is to aggregate existing CPMs developed for similar settings and outcomes. This simulation study aimed to investigate the impact of between-population-heterogeneity and sample size on aggregating existing CPMs in a defined population, compared with developing a model de novo. METHODS: Simulations were designed to mimic a scenario in which multiple CPMs for a binary outcome had been derived in distinct, heterogeneous populations, with potentially different predictors available in each...
January 6, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28031023/can-longitudinal-generalized-estimating-equation-models-distinguish-network-influence-and-homophily-an-agent-based-modeling-approach-to-measurement-characteristics
#8
Kori Sauser Zachrison, Theodore J Iwashyna, Achamyeleh Gebremariam, Meghan Hutchins, Joyce M Lee
BACKGROUND: Connected individuals (or nodes) in a network are more likely to be similar than two randomly selected nodes due to homophily and/or network influence. Distinguishing between these two influences is an important goal in network analysis, and generalized estimating equation (GEE) analyses of longitudinal dyadic network data are an attractive approach. It is not known to what extent such regressions can accurately extract underlying data generating processes. Therefore our primary objective is to determine to what extent, and under what conditions, does the GEE-approach recreate the actual dynamics in an agent-based model...
December 28, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27978818/multiple-and-mixed-methods-in-formative-evaluation-is-more-better-reflections-from-a-south-african-study
#9
Willem Odendaal, Salla Atkins, Simon Lewin
BACKGROUND: Formative programme evaluations assess intervention implementation processes, and are seen widely as a way of unlocking the 'black box' of any programme in order to explore and understand why a programme functions as it does. However, few critical assessments of the methods used in such evaluations are available, and there are especially few that reflect on how well the evaluation achieved its objectives. This paper describes a formative evaluation of a community-based lay health worker programme for TB and HIV/AIDS clients across three low-income communities in South Africa...
December 15, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27931207/a-comparative-study-classification-vs-user-based-collaborative-filtering-for-clinical-prediction
#10
Fang Hao, Rachael Hageman Blair
BACKGROUND: Recommender systems have shown tremendous value for the prediction of personalized item recommendations for individuals in a variety of settings (e.g., marketing, e-commerce, etc.). User-based collaborative filtering is a popular recommender system, which leverages an individuals' prior satisfaction with items, as well as the satisfaction of individuals that are "similar". Recently, there have been applications of collaborative filtering based recommender systems for clinical risk prediction...
December 8, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27927178/inter-rater-reliability-of-the-quis-as-an-assessment-of-the-quality-of-staff-inpatient-interactions
#11
Ines Mesa-Eguiagaray, Dankmar Böhning, Chris McLean, Peter Griffiths, Jackie Bridges, Ruth M Pickering
BACKGROUND: Recent studies of the quality of in-hospital care have used the Quality of Interaction Schedule (QuIS) to rate interactions observed between staff and inpatients in a variety of ward conditions. The QuIS was developed and evaluated in nursing and residential care. We set out to develop methodology for summarising information from inter-rater reliability studies of the QuIS in the acute hospital setting. METHODS: Staff-inpatient interactions were rated by trained staff observing care delivered during two-hour observation periods...
December 7, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27919233/sexual-health-questions-included-in-the-health-behaviour-in-school-aged-children-hbsc-study-an-international-methodological-pilot-investigation
#12
Honor Young, András Költő, Marta Reis, Elizabeth M Saewyc, Nathalie Moreau, Lorraine Burke, Alina Cosma, Béat Windlin, Saoirse Nic Gabhainn, Emmanuelle Godeau
BACKGROUND: This paper describes the methodological developments of the sexual health items included in the Health Behaviour in School-aged Children (HBSC) study since their mandatory inclusion in the study in 2002. The current methodological, ethical and pedagogical challenges in measuring young people's sexual health behaviours are discussed along with the issues associated with the sexual health items introduced to the HBSC study in 2002. The development and piloting of new cross-national items for use in the 2013/14 HBSC data collection are presented and discussed...
December 5, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27919231/erratum-to-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 A van de Wiel
No abstract text is available yet for this article.
December 5, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27919221/joint-models-for-longitudinal-and-time-to-event-data-a-review-of-reporting-quality-with-a-view-to-meta-analysis
#14
Maria Sudell, Ruwanthi Kolamunnage-Dona, Catrin Tudur-Smith
BACKGROUND: Joint models for longitudinal and time-to-event data are commonly used to simultaneously analyse correlated data in single study cases. Synthesis of evidence from multiple studies using meta-analysis is a natural next step but its feasibility depends heavily on the standard of reporting of joint models in the medical literature. During this review we aim to assess the current standard of reporting of joint models applied in the literature, and to determine whether current reporting standards would allow or hinder future aggregate data meta-analyses of model results...
December 5, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27903238/impress-an-implementation-readiness-checklist-developed-using-a-systematic-review-of-randomised-controlled-trials-assessing-cognitive-stimulation-for-dementia
#15
Amy Streater, Aimee Spector, Elisa Aguirre, Jacki Stansfeld, Martin Orrell
BACKGROUND: Research reporting results of clinical trials, psychosocial or technological interventions frequently omit critical details needed to inform implementation in practice. The aim of this article is to develop an Implementation Readiness (ImpRess) checklist, that includes criteria deemed useful in measuring readiness for implementation and apply it to trials of cognitive stimulation in dementia, providing a systematic review of their readiness for widespread implementation. METHODS: Five electronic databases were searched...
December 1, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27899073/recommendations-for-the-analysis-of-individually-randomised-controlled-trials-with-clustering-in-one-arm-a-case-of-continuous-outcomes
#16
Laura Flight, Annabel Allison, Munyaradzi Dimairo, Ellen Lee, Laura Mandefield, Stephen J Walters
BACKGROUND: In an individually randomised controlled trial where the treatment is delivered by a health professional it seems likely that the effectiveness of the treatment, independent of any treatment effect, could depend on the skill, training or even enthusiasm of the health professional delivering it. This may then lead to a potential clustering of the outcomes for patients treated by the same health professional, but similar clustering may not occur in the control arm. Using four case studies, we aim to provide practical guidance and recommendations for the analysis of trials with some element of clustering in one arm...
November 29, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27899067/drug-placebo-interaction-effect-may-bias-clinical-trials-interpretation-hybrid-balanced-placebo-and-randomized-placebo-controlled-design
#17
Muhammad M Hammami, Safa Hammami, Reem Al-Swayeh, Eman Al-Gaai, Faduma Abdi Farah, Sophia J S De Padua
BACKGROUND: Conventional randomized placebo-controlled study design assumes the absence of drug*placebo interaction. We hypothesized the presence of such an interaction and that conventionally estimated drug effect might be biased. The objectives of the study were to determine the drug*placebo interaction effect (main) and compare conventionally estimated and interaction model-estimated drug effects (secondary). METHODS: We used a hybrid of balanced placebo and randomized placebo-controlled designs...
November 29, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27894262/erratum-to-statistical-methodology-for-age-adjustment-of-the-gh-2000-score-detecting-growth-hormone-misuse
#18
Dankmar Böhning, Walailuck Böhning, Nishan Guha, David A Cowan, Peter H Sönksen, Richard I G Holt
No abstract text is available yet for this article.
November 28, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27881091/conducting-a-large-multi-site-survey-about-patients-views-on-broad-consent-challenges-and-solutions
#19
Maureen E Smith, Saskia C Sanderson, Kyle B Brothers, Melanie F Myers, Jennifer McCormick, Sharon Aufox, Martha J Shrubsole, Nanibaá A Garrison, Nathaniel D Mercaldo, Jonathan S Schildcrout, Ellen Wright Clayton, Armand H Matheny Antommaria, Melissa Basford, Murray Brilliant, John J Connolly, Stephanie M Fullerton, Carol R Horowitz, Gail P Jarvik, Dave Kaufman, Terri Kitchner, Rongling Li, Evette J Ludman, Catherine McCarty, Valerie McManus, Sarah Stallings, Janet L Williams, Ingrid A Holm
BACKGROUND: As biobanks play an increasing role in the genomic research that will lead to precision medicine, input from diverse and large populations of patients in a variety of health care settings will be important in order to successfully carry out such studies. One important topic is participants' views towards consent and data sharing, especially since the 2011 Advanced Notice of Proposed Rulemaking (ANPRM), and subsequently the 2015 Notice of Proposed Rulemaking (NPRM) were issued by the Department of Health and Human Services (HHS) and Office of Science and Technology Policy (OSTP)...
November 24, 2016: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/27881078/no-rationale-for-1-variable-per-10-events-criterion-for-binary-logistic-regression-analysis
#20
Maarten van Smeden, Joris A H de Groot, Karel G M Moons, Gary S Collins, Douglas G Altman, Marinus J C Eijkemans, Johannes B Reitsma
BACKGROUND: Ten events per variable (EPV) is a widely advocated minimal criterion for sample size considerations in logistic regression analysis. Of three previous simulation studies that examined this minimal EPV criterion only one supports the use of a minimum of 10 EPV. In this paper, we examine the reasons for substantial differences between these extensive simulation studies. METHODS: The current study uses Monte Carlo simulations to evaluate small sample bias, coverage of confidence intervals and mean square error of logit coefficients...
November 24, 2016: BMC Medical Research Methodology
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