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BMC Medical Research Methodology

Alexis K Huynh, Martin L Lee, Melissa M Farmer, Lisa V Rubenstein
BACKGROUND: Stepped wedge designs have gained recognition as a method for rigorously assessing implementation of evidence-based quality improvement interventions (QIIs) across multiple healthcare sites. In theory, this design uses random assignment of sites to successive QII implementation start dates based on a timeline determined by evaluators. However, in practice, QII timing is often controlled more by site readiness. We propose an alternate version of the stepped wedge design that does not assume the randomized timing of implementation while retaining the method's analytic advantages and applying to a broader set of evaluations...
October 21, 2016: BMC Medical Research Methodology
H Felix Fischer, Matthias Rose
BACKGROUND: Recently, a growing number of Item-Response Theory (IRT) models has been published, which allow estimation of a common latent variable from data derived by different Patient Reported Outcomes (PROs). When using data from different PROs, direct estimation of the latent variable has some advantages over the use of sum score conversion tables. It requires substantial proficiency in the field of psychometrics to fit such models using contemporary IRT software. We developed a web application ( http://www...
October 19, 2016: BMC Medical Research Methodology
Ahmad Reza Hosseinpoor, Devaki Nambiar, Anne Schlotheuber, Daniel Reidpath, Zev Ross
BACKGROUND: It is widely recognised that the pursuit of sustainable development cannot be accomplished without addressing inequality, or observed differences between subgroups of a population. Monitoring health inequalities allows for the identification of health topics where major group differences exist, dimensions of inequality that must be prioritised to effect improvements in multiple health domains, and also population subgroups that are multiply disadvantaged. While availability of data to monitor health inequalities is gradually improving, there is a commensurate need to increase, within countries, the technical capacity for analysis of these data and interpretation of results for decision-making...
October 19, 2016: BMC Medical Research Methodology
Abel Makubi, Philip Sasi, Mariam Ngaeje, Enrico M Novelli, Bruno P Mmbando, Mark T Gladwin, Julie Makani
BACKGROUND: Hydroxyurea (HU) has been demonstrated to be efficacious in reducing complications in individuals with sickle cell anemia (SCA) but poor adherence is a barrier. Directly Observed Therapy (DOT) has been shown to improve adherence in various chronic diseases but there is limited data in adults with SCA. METHODS AND DESIGN: To examine the effect of mobile-directly observed therapy (mDOT) on adherence to HU (mDOT-HuA) in adults with SCA at Muhimbili National Hospital in Tanzania...
October 18, 2016: BMC Medical Research Methodology
George O Agogo, Hilko van der Voet, Pieter van 't Veer, Pietro Ferrari, David C Muller, Emilio Sánchez-Cantalejo, Christina Bamia, Tonje Braaten, Sven Knüppel, Ingegerd Johansson, Fred A van Eeuwijk, Hendriek C Boshuizen
BACKGROUND: Measurement error in self-reported dietary intakes is known to bias the association between dietary intake and a health outcome of interest such as risk of a disease. The association can be distorted further by mismeasured confounders, leading to invalid results and conclusions. It is, however, difficult to adjust for the bias in the association when there is no internal validation data. METHODS: We proposed a method to adjust for the bias in the diet-disease association (hereafter, association), due to measurement error in dietary intake and a mismeasured confounder, when there is no internal validation data...
October 13, 2016: BMC Medical Research Methodology
Jean Joel R Bigna, Jean Jacques N Noubiap, Serra Lem Asangbeh, Lewis N Um, Paule Sandra D Sime, Elvis Temfack, Mathurin Cyrille Tejiokem
BACKGROUND: Sufficiently detailed abstracts of randomized controlled trials (RCTs) are important, because readers often base their assessment of a trial solely on information in the abstract. We aimed at comparing reporting quality of RCTs in HIV/AIDS medicine before and after the publication of the 2008 CONSORT extension for abstracts and to investigate factors associated with better reporting quality. METHODS: We searched PubMed/Medline for HIV/AIDS RCTs published between 2006-07 (Pre-CONSORT) and 2014-15 (Post-CONSORT) in 40 leading general medicine and infectious diseases journals...
October 13, 2016: BMC Medical Research Methodology
Saga Elise Mariansdatter, Andreas Halgreen Eiset, Kirstine Kobberøe Søgaard, Christian Fynbo Christiansen
BACKGROUND: Sepsis and severe sepsis are common conditions in hospital settings, and are associated with high rates of morbidity and mortality, but reported incidences vary considerably. In this literature review, we describe the variation in reported population-based incidences of sepsis and severe sepsis. We also examine methodological and demographic differences between studies that may explain this variation. METHODS: We carried out a literature review searching three major databases and reference lists of relevant articles, to identify all original studies reporting the incidence of sepsis or severe sepsis in the general population...
October 12, 2016: BMC Medical Research Methodology
Juste Aristide Goungounga, Jean Gaudart, Marc Colonna, Roch Giorgi
BACKGROUND: The reliability of spatial statistics is often put into question because real spatial variations may not be found, especially in heterogeneous areas. Our objective was to compare empirically different cluster detection methods. We assessed their ability to find spatial clusters of cancer cases and evaluated the impact of the socioeconomic status (e.g., the Townsend index) on cancer incidence. METHODS: Moran's I, the empirical Bayes index (EBI), and Potthoff-Whittinghill test were used to investigate the general clustering...
October 12, 2016: BMC Medical Research Methodology
Jamie Bryant, Rob Sanson-Fisher, Elizabeth Fradgley, Breanne Hobden, Alison Zucca, Frans Henskens, Andrew Searles, Brad Webb, Christopher Oldmeadow
BACKGROUND: Population-based registries are increasingly used to recruit patient samples for research, however, they have several limitations including low consent and participation rates, and potential selection bias. To improve access to samples for research, the utility of a new model of recruitment termed the 'Consumer Register', that allows for direct patient recruitment from hospitals, was examined. This paper reports: (i) consent rates onto the register; (ii) preferred methods and frequency of contact; and (iii) the feasibility of establishing the register, including: (a) cost per person recruited to the register; (b) the differential cost and consent rates of volunteer versus paid data collectors; and (c) participant completion rates...
October 10, 2016: BMC Medical Research Methodology
Fengqing Zhang, Jiangtao Gou
BACKGROUND: Power analysis is a critical aspect of the design of experiments to detect an effect of a given size. When multiple hypotheses are tested simultaneously, multiplicity adjustments to p-values should be taken into account in power analysis. There are a limited number of studies on power analysis in multiple testing procedures. For some methods, the theoretical analysis is difficult and extensive numerical simulations are often needed, while other methods oversimplify the information under the alternative hypothesis...
October 10, 2016: BMC Medical Research Methodology
Asger Paludan-Müller, David Ruben Teindl Laursen, Asbjørn Hróbjartsson
BACKGROUND: Selective allocation of patients into the compared groups of a randomised trial may cause allocation bias, but the mechanisms behind the bias and its directionality are incompletely understood. We therefore analysed the mechanisms and directionality of allocation bias in randomised clinical trials. METHODS: Two systematic reviews and a theoretical analysis. We conducted one systematic review of empirical studies of motives/methods for deciphering patient allocation sequences; and another review of methods publications commenting on allocation bias...
October 7, 2016: BMC Medical Research Methodology
Pedro Saramago, Beth Woods, Helen Weatherly, Andrea Manca, Mark Sculpher, Kamran Khan, Andrew J Vickers, Hugh MacPherson
BACKGROUND: Network meta-analysis methods, which are an extension of the standard pair-wise synthesis framework, allow for the simultaneous comparison of multiple interventions and consideration of the entire body of evidence in a single statistical model. There are well-established advantages to using individual patient data to perform network meta-analysis and methods for network meta-analysis of individual patient data have already been developed for dichotomous and time-to-event data...
October 6, 2016: BMC Medical Research Methodology
Leslie A Hayduk
BACKGROUND: Factor analysis historically focused on measurement while path analysis employed observed variables as though they were error-free. When factor- and path-analysis merged as structural equation modeling, factor analytic notions dominated measurement discussions - including assessments of measurement invariance across groups. The factor analytic tradition fostered disregard of model testing and consequently entrenched this deficiency in measurement invariance assessments. DISCUSSION: Applying contemporary model testing requirements to the so-called configural model initiating invariance assessments will improve future assessments but a substantial backlog of deficient assessments remain to be overcome...
October 6, 2016: BMC Medical Research Methodology
Liz Graham, Judy Wright, Rebecca Walwyn, Amy M Russell, Louise Bryant, Amanda Farrin, Allan House
BACKGROUND: Reporting adherence to intervention delivery and uptake is a detailed way of describing what was actually delivered and received, in comparison to what was intended. Measuring and reporting adherence is not routinely done well in complex interventions. The OK Diabetes trial (ISRCTN41897033) aimed to develop and subsequently test the feasibility of implementing a supported self-management intervention in adults with a learning disability and type 2 diabetes. A key study objective was to develop a measure of adherence to the intervention...
October 6, 2016: BMC Medical Research Methodology
Miguel Angel Luque-Fernandez, Aurélien Belot, Manuela Quaresma, Camille Maringe, Michel P Coleman, Bernard Rachet
BACKGROUND: In population-based cancer research, piecewise exponential regression models are used to derive adjusted estimates of excess mortality due to cancer using the Poisson generalized linear modelling framework. However, the assumption that the conditional mean and variance of the rate parameter given the set of covariates x i are equal is strong and may fail to account for overdispersion given the variability of the rate parameter (the variance exceeds the mean). Using an empirical example, we aimed to describe simple methods to test and correct for overdispersion...
October 1, 2016: BMC Medical Research Methodology
D Nieboer, Y Vergouwe, Danna P Ankerst, Monique J Roobol, Ewout W Steyerberg
BACKGROUND: New markers hold the promise of improving risk prediction for individual patients. We aimed to compare the performance of different strategies to extend a previously developed prediction model with a new marker. METHODS: Our motivating example was the extension of a risk calculator for prostate cancer with a new marker that was available in a relatively small dataset. Performance of the strategies was also investigated in simulations. Development, marker and test sets with different sample sizes originating from the same underlying population were generated...
September 27, 2016: BMC Medical Research Methodology
Lisa Hartling, Robin Featherstone, Megan Nuspl, Kassi Shave, Donna M Dryden, Ben Vandermeer
BACKGROUND: One of the best sources for high quality information about healthcare interventions is a systematic review. A well-conducted systematic review includes a comprehensive literature search. There is limited empiric evidence to guide the extent of searching, in particular the number of electronic databases that should be searched. We conducted a cross-sectional quantitative analysis to examine the potential impact of selective database searching on results of meta-analyses. METHODS: Our sample included systematic reviews (SRs) with at least one meta-analysis from three Cochrane Review Groups: Acute Respiratory Infections (ARI), Infectious Diseases (ID), Developmental Psychosocial and Learning Problems (DPLP) (n = 129)...
September 26, 2016: BMC Medical Research Methodology
Nicole M Rankin, Deborah McGregor, Phyllis N Butow, Kate White, Jane L Phillips, Jane M Young, Sallie A Pearson, Sarah York, Tim Shaw
BACKGROUND: There are a variety of methods for priority setting in health research but few studies have addressed how to prioritise the gaps that exist between research evidence and clinical practice. This study aimed to build a suite of robust, evidence based techniques and tools for use in implementation science projects. We applied the priority setting methodology in lung cancer care as an example. METHODS: We reviewed existing techniques and tools for priority setting in health research and the criteria used to prioritise items...
August 26, 2016: BMC Medical Research Methodology
Kiarri N Kershaw, Kiang Liu, David C Goff, Donald M Lloyd-Jones, Laura J Rasmussen-Torvik, Jared P Reis, Pamela J Schreiner, Daniel B Garside, Stephen Sidney
BACKGROUND: The objective of this study was to evaluate a pilot program that allowed Chicago field center participants of the Coronary Artery Risk Development in Young Adults (CARDIA) study to submit follow-up information electronically (eCARDIA). METHODS: Chicago field center participants who provided email addresses were invited to complete contact information and follow-up questionnaires on medical conditions electronically in 2012-2013. Sociodemographic characteristics were compared between those who did and did not complete follow-up electronically...
2016: BMC Medical Research Methodology
Steven Hawken, Beth K Potter, Julian Little, Eric I Benchimol, Salah Mahmud, Robin Ducharme, Kumanan Wilson
BACKGROUND: The self-controlled case series (SCCS) is a useful design for investigating associations between outcomes and transient exposures. The SCCS design controls for all fixed covariates, but effect modification can still occur. This can be evaluated by including interaction terms in the model which, when exponentiated, can be interpreted as a relative incidence ratio (RIR): the change in relative incidence (RI) for a unit change in an effect modifier. METHODS: We conducted a scoping review to investigate the use of RIRs in published primary SCCS studies, and conducted a case-study in one of our own primary SCCS studies to illustrate the use of RIRs within an SCCS analysis to investigate subgroup effects in the context of comparing whole cell (wcp) and acellular (acp) pertussis vaccines...
2016: BMC Medical Research Methodology
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