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BMC Medical Research Methodology

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https://www.readbyqxmd.com/read/28629314/erratum-to-standardizing-effect-size-from-linear-regression-models-with-log-transformed-variables-for-meta-analysis
#1
Miguel Rodríguez-Barranco, Aurelio Tobías, Daniel Redondo, Elena Molina-Portillo, María José Sánchez
No abstract text is available yet for this article.
June 19, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28610631/simulation-of-complex-data-structures-for-planning-of-studies-with-focus-on-biomarker-comparison
#2
Andreas Schulz, Daniela Zöller, Stefan Nickels, Manfred E Beutel, Maria Blettner, Philipp S Wild, Harald Binder
BACKGROUND: There are a growing number of observational studies that do not only focus on single biomarkers for predicting an outcome event, but address questions in a multivariable setting. For example, when quantifying the added value of new biomarkers in addition to established risk factors, the aim might be to rank several new markers with respect to their prediction performance. This makes it important to consider the marker correlation structure for planning such a study. Because of the complexity, a simulation approach may be required to adequately assess sample size or other aspects, such as the choice of a performance measure...
June 13, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28595574/limitations-of-pulmonary-embolism-icd-10-codes-in-emergency-department-administrative-data-let-the-buyer-beware
#3
Kristin Burles, Grant Innes, Kevin Senior, Eddy Lang, Andrew McRae
BACKGROUND: Administrative data is a useful tool for research and quality improvement; however, validity of research findings based on these data depends on their reliability. Diagnoses assigned by physicians are subsequently converted by nosologists to ICD-10 codes (International Statistical Classification of Diseases and Related Health Problems, 10th Revision). Several groups have reported ICD-9 coding errors in inpatient data that have implications for research, quality improvement, and policymaking, but few have assessed ICD-10 code validity in ambulatory care databases...
June 8, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28587662/a-nonparametric-multiple-imputation-approach-for-missing-categorical-data
#4
Muhan Zhou, Yulei He, Mandi Yu, Chiu-Hsieh Hsu
BACKGROUND: Incomplete categorical variables with more than two categories are common in public health data. However, most of the existing missing-data methods do not use the information from nonresponse (missingness) probabilities. METHODS: We propose a nearest-neighbour multiple imputation approach to impute a missing at random categorical outcome and to estimate the proportion of each category. The donor set for imputation is formed by measuring distances between each missing value with other non-missing values...
June 6, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28587598/methodologic-considerations-in-the-design-and-analysis-of-nested-case-control-studies-association-between-cytokines-and-postoperative-delirium
#5
Long H Ngo, Sharon K Inouye, Richard N Jones, Thomas G Travison, Towia A Libermann, Simon T Dillon, George A Kuchel, Sarinnapha M Vasunilashorn, David C Alsop, Edward R Marcantonio
BACKGROUND: The nested case-control study (NCC) design within a prospective cohort study is used when outcome data are available for all subjects, but the exposure of interest has not been collected, and is difficult or prohibitively expensive to obtain for all subjects. A NCC analysis with good matching procedures yields estimates that are as efficient and unbiased as estimates from the full cohort study. We present methodological considerations in a matched NCC design and analysis, which include the choice of match algorithms, analysis methods to evaluate the association of exposures of interest with outcomes, and consideration of overmatching...
June 6, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28587592/bayesian-hierarchical-piecewise-regression-models-a-tool-to-detect-trajectory-divergence-between-groups-in-long-term-observational-studies
#6
Marie-Jeanne Buscot, Simon S Wotherspoon, Costan G Magnussen, Markus Juonala, Matthew A Sabin, David P Burgner, Terho Lehtimäki, Jorma S A Viikari, Nina Hutri-Kähönen, Olli T Raitakari, Russell J Thomson
BACKGROUND: Bayesian hierarchical piecewise regression (BHPR) modeling has not been previously formulated to detect and characterise the mechanism of trajectory divergence between groups of participants that have longitudinal responses with distinct developmental phases. These models are useful when participants in a prospective cohort study are grouped according to a distal dichotomous health outcome. Indeed, a refined understanding of how deleterious risk factor profiles develop across the life-course may help inform early-life interventions...
June 6, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28577547/validity-of-self-reported-weight-and-height-a-cross-sectional-study-among-malaysian-adolescents
#7
C C Kee, K H Lim, M G Sumarni, C H Teh, Y Y Chan, M I Nuur Hafizah, Y K Cheah, E O Tee, Y Ahmad Faudzi, M Amal Nasir
BACKGROUND: Self-reported weight and height are commonly used in lieu of direct measurements of weight and height in large epidemiological surveys due to inevitable constraints such as budget and human resource. However, the validity of self-reported weight and height, particularly among adolescents, needs to be verified as misreporting could lead to misclassification of body mass index and therefore overestimation or underestimation of the burden of BMI-related diseases. The objective of this study was to determine the validity of self-reported weight and height among Malaysian secondary school children...
June 2, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28577540/overview-of-systematic-reviews-of-therapeutic-ranges-methodologies-and-recommendations-for-practice
#8
Lewis Cooney, Yoon K Loke, Su Golder, Jamie Kirkham, Andrea Jorgensen, Ian Sinha, Daniel Hawcutt
BACKGROUND: Many medicines are dosed to achieve a particular therapeutic range, and monitored using therapeutic drug monitoring (TDM). The evidence base for a therapeutic range can be evaluated using systematic reviews, to ensure it continues to reflect current indications, doses, routes and formulations, as well as updated adverse effect data. There is no consensus on the optimal methodology for systematic reviews of therapeutic ranges. METHODS: An overview of systematic reviews of therapeutic ranges was undertaken...
June 2, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28532387/robust-estimation-of-the-expected-survival-probabilities-from-high-dimensional-cox-models-with-biomarker-by-treatment-interactions-in-randomized-clinical-trials
#9
Nils Ternès, Federico Rotolo, Stefan Michiels
BACKGROUND: Thanks to the advances in genomics and targeted treatments, more and more prediction models based on biomarkers are being developed to predict potential benefit from treatments in a randomized clinical trial. Despite the methodological framework for the development and validation of prediction models in a high-dimensional setting is getting more and more established, no clear guidance exists yet on how to estimate expected survival probabilities in a penalized model with biomarker-by-treatment interactions...
May 22, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28494765/duration-of-the-common-cold-and-similar-continuous-outcomes-should-be-analyzed-on-the-relative-scale-a-case-study-of-two-zinc-lozenge-trials
#10
Harri Hemilä
BACKGROUND: The relative scale has been used for decades in analysing binary data in epidemiology. In contrast, there has been a long tradition of carrying out meta-analyses of continuous outcomes on the absolute, original measurement, scale. The biological rationale for using the relative scale in the analysis of binary outcomes is that it adjusts for baseline variations; however, similar baseline variations can occur in continuous outcomes and relative effect scale may therefore be often useful also for continuous outcomes...
May 12, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28486955/changes-in-affect-after-completing-a-mailed-survey-about-trauma-two-pre-and-post-test-studies-in-former-disability-applicants-for-posttraumatic-stress-disorder
#11
Maureen Murdoch, Shannon Marie Kehle-Forbes, Melissa Ruth Partin
BACKGROUND: One potential concern with using mailed surveys containing trauma-related content is the possibility of re-traumatizing survivors without a trained mental health professional present. Prior research provides insufficient guidance regarding the prevalence and magnitude of this risk because the psychological harms of trauma-related surveys have typically been estimated using single post-test observations. Post-test observations cannot quantify magnitude of change in participants' emotional states and may over or under estimate associations between participants' characteristics (risk factors) and post-survey upset...
May 10, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28482809/on-the-impact-of-nonresponse-in-logistic-regression-application-to-the-45-and-up-study
#12
Joanna J J Wang, Mark Bartlett, Louise Ryan
BACKGROUND: In longitudinal studies, nonresponse to follow-up surveys poses a major threat to validity, interpretability and generalisation of results. The problem of nonresponse is further complicated by the possibility that nonresponse may depend on the outcome of interest. We identified sociodemographic, general health and wellbeing characteristics associated with nonresponse to the follow-up questionnaire and assessed the extent and effect of nonresponse on statistical inference in a large-scale population cohort study...
May 8, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28464839/on-comparison-of-net-survival-curves
#13
Klemen Pavlič, Maja Pohar Perme
BACKGROUND: Relative survival analysis is a subfield of survival analysis where competing risks data are observed, but the causes of death are unknown. A first step in the analysis of such data is usually the estimation of a net survival curve, possibly followed by regression modelling. Recently, a log-rank type test for comparison of net survival curves has been introduced and the goal of this paper is to explore its properties and put this methodological advance into the context of the field...
May 2, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28454568/double-adjustment-in-propensity-score-matching-analysis-choosing-a-threshold-for-considering-residual-imbalance
#14
Tri-Long Nguyen, Gary S Collins, Jessica Spence, Jean-Pierre Daurès, P J Devereaux, Paul Landais, Yannick Le Manach
BACKGROUND: Double-adjustment can be used to remove confounding if imbalance exists after propensity score (PS) matching. However, it is not always possible to include all covariates in adjustment. We aimed to find the optimal imbalance threshold for entering covariates into regression. METHODS: We conducted a series of Monte Carlo simulations on virtual populations of 5,000 subjects. We performed PS 1:1 nearest-neighbor matching on each sample. We calculated standardized mean differences across groups to detect any remaining imbalance in the matched samples...
April 28, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28446140/measurement-properties-of-the-danish-version-of-the-awareness-and-beliefs-about-cancer-abc-measure
#15
Line Hvidberg, Anette Fischer Pedersen, Christian Nielsen Wulff, Anders Helles Carlsen, Peter Vedsted
BACKGROUND: The International Cancer Benchmarking Partnership aims to study international differences in cancer survival and the possible causes. Participating countries are Australia, Canada, Norway, Sweden, Denmark and the UK and a particular focus area is differences in awareness and beliefs about cancer. In this connection, the Awareness and Beliefs about Cancer (ABC) measure has been translated into multiple languages. The aim of this study is to appraise the translation process and measurement properties of the Danish version of the ABC measure...
April 26, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28446138/assessing-the-complexity-of-interventions-within-systematic-reviews-development-content-and-use-of-a-new-tool-icat_sr
#16
Simon Lewin, Maggie Hendry, Jackie Chandler, Andrew D Oxman, Susan Michie, Sasha Shepperd, Barnaby C Reeves, Peter Tugwell, Karin Hannes, Eva A Rehfuess, Vivien Welch, Joanne E Mckenzie, Belinda Burford, Jennifer Petkovic, Laurie M Anderson, Janet Harris, Jane Noyes
BACKGROUND: Health interventions fall along a spectrum from simple to more complex. There is wide interest in methods for reviewing 'complex interventions', but few transparent approaches for assessing intervention complexity in systematic reviews. Such assessments may assist review authors in, for example, systematically describing interventions and developing logic models. This paper describes the development and application of the intervention Complexity Assessment Tool for Systematic Reviews (iCAT_SR), a new tool to assess and categorise levels of intervention complexity in systematic reviews...
April 26, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28446131/the-effectiveness-of-a-monetary-incentive-offer-on-survey-response-rates-and-response-completeness-in-a-longitudinal-study
#17
Shengchao Yu, Howard E Alper, Angela-Maithy Nguyen, Robert M Brackbill, Lennon Turner, Deborah J Walker, Carey B Maslow, Kimberly C Zweig
BACKGROUND: Achieving adequate response rates is an ongoing challenge for longitudinal studies. The World Trade Center Health Registry is a longitudinal health study that periodically surveys a cohort of ~71,000 people exposed to the 9/11 terrorist attacks in New York City. Since Wave 1, the Registry has conducted three follow-up surveys (Waves 2-4) every 3-4 years and utilized various strategies to increase survey participation. A promised monetary incentive was offered for the first time to survey non-respondents in the recent Wave 4 survey, conducted 13-14 years after 9/11...
April 26, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28446127/sample-size-and-power-determination-when-limited-preliminary-information-is-available
#18
Christine E McLaren, Wen-Pin Chen, Thomas D O'Sullivan, Daniel L Gillen, Min-Ying Su, Jeon H Chen, Bruce J Tromberg
BACKGROUND: We describe a novel strategy for power and sample size determination developed for studies utilizing investigational technologies with limited available preliminary data, specifically of imaging biomarkers. We evaluated diffuse optical spectroscopic imaging (DOSI), an experimental noninvasive imaging technique that may be capable of assessing changes in mammographic density. Because there is significant evidence that tamoxifen treatment is more effective at reducing breast cancer risk when accompanied by a reduction of breast density, we designed a study to assess the changes from baseline in DOSI imaging biomarkers that may reflect fluctuations in breast density in premenopausal women receiving tamoxifen...
April 26, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28441932/an-experimental-comparison-of-web-push-vs-paper-only-survey-procedures-for-conducting-an-in-depth-health-survey-of-military-spouses
#19
Hope Seib McMaster, Cynthia A LeardMann, Steven Speigle, Don A Dillman
BACKGROUND: Previous research has found that a "web-push" approach to data collection, which involves contacting people by mail to request an Internet survey response while withholding a paper response option until later in the contact process, consistently achieves lower response rates than a "paper-only" approach, whereby all respondents are contacted and requested to respond by mail. METHOD: An experiment was designed, as part of the Millennium Cohort Family Study, to compare response rates, sample representativeness, and cost between a web-push and a paper-only approach; each approach comprised 3 stages of mail contacts...
April 26, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28431517/sharp-bounds-on-sufficient-cause-interactions-under-the-assumption-of-no-redundancy
#20
Wen-Chung Lee
BACKGROUND: Sufficient-cause interaction is a type of interaction that has received much attention recently. The sufficient component cause model on which the sufficient-cause interaction is based is however a non-identifiable model. Estimating the interaction parameters from the model is mathematically impossible. METHODS: In this paper, I derive bounding formulae for sufficient-cause interactions under the assumption of no redundancy. RESULTS: Two real data sets are used to demonstrate the method (R codes provided)...
April 21, 2017: BMC Medical Research Methodology
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