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BMC Medical Research Methodology

Oyvind Bjertnaes, Hilde Hestad Iversen, Torild Skrivarhaug
BACKGROUND: The objective of this study was to compare three data collection methods for the measurement of parent experiences with hospital outpatient care for child and adolescent diabetes, based on a randomised national trial in Norway involving both pen-and-paper and electronic response options. METHODS: The sample frame was patients registered in the Norwegian Childhood Diabetes Registry. Parents of patients were randomised into the following groups (n = 2606): group A, who were posted questionnaires with only a pen-and-paper response option (n = 859); group B, who were posted questionnaires with both an electronic and a pen-and-paper response option (n = 886); and group C, who were posted questionnaires with only an electronic response option (n = 861)...
September 20, 2018: BMC Medical Research Methodology
S W English, L McIntyre, V Saigle, M Chassé, D A Fergusson, A F Turgeon, F Lauzier, D Griesdale, A Garland, R Zarychanski, A Algird, C van Walraven
BACKGROUND: Conducting prospective epidemiological studies of hospitalized patients with rare diseases like primary subarachnoid hemorrhage (pSAH) are difficult due to time and budgetary constraints. Routinely collected administrative data could remove these barriers. We derived and validated 3 algorithms to identify hospitalized patients with a high probability of pSAH using administrative data. We aim to externally validate their performance in four hospitals across Canada. METHODS: Eligible patients include those ≥18 years of age admitted to these centres from January 1, 2012 to December 31, 2013...
September 15, 2018: BMC Medical Research Methodology
Carly A Bobak, Paul J Barr, A James O'Malley
BACKGROUND: Intraclass correlation coefficients (ICC) are recommended for the assessment of the reliability of measurement scales. However, the ICC is subject to a variety of statistical assumptions such as normality and stable variance, which are rarely considered in health applications. METHODS: A Bayesian approach using hierarchical regression and variance-function modeling is proposed to estimate the ICC with emphasis on accounting for heterogeneous variances across a measurement scale...
September 12, 2018: BMC Medical Research Methodology
Alden L Gross, Doug Tommet, Madeline D'Aquila, Eva Schmitt, Edward R Marcantonio, Benjamin Helfand, Sharon K Inouye, Richard N Jones
BACKGROUND: This study aimed to describe the level of agreement of three commonly used delirium instruments: the Delirium Rating Scale-Revised-98 (DRS-R-98), Memorial Delirium Assessment Scale (MDAS), and Confusion Assessment Method-Severity (CAM-S). METHODS: We used data from a prospective clinical research study, in which a team of trained lay interviewers administered each instrument along with supporting interview and cognitive assessments in the same group of patients daily while in the hospital (N = 352)...
September 10, 2018: BMC Medical Research Methodology
Jacques-Emmanuel Galimard, Sylvie Chevret, Emmanuel Curis, Matthieu Resche-Rigon
BACKGROUND: Multiple imputation by chained equations (MICE) requires specifying a suitable conditional imputation model for each incomplete variable and then iteratively imputes the missing values. In the presence of missing not at random (MNAR) outcomes, valid statistical inference often requires joint models for missing observations and their indicators of missingness. In this study, we derived an imputation model for missing binary data with MNAR mechanism from Heckman's model using a one-step maximum likelihood estimator...
August 31, 2018: BMC Medical Research Methodology
Antti Malmivaara
BACKGROUND: Randomized trials provide the most valid evidence of effectiveness of interventions. The study aims to determine the primary study question for randomized controlled trials; to evaluate the study questions in trials on effectiveness of arthroscopic meniscectomy for meniscal rupture of the knee; and to explore the clinical and research implications. METHODS: Previous studies on benchmarking controlled trials were utilized. A literature search was undertaken to find the trials on arthroscopic surgery for meniscal rupture of the knee, data was extracted, and checked for accuracy twice...
August 31, 2018: BMC Medical Research Methodology
Alyson J Littman, Gala True, Emily Ashmore, Tracy Wellens, Nicholas L Smith
BACKGROUND: Research participant recruitment is often fraught with obstacles. Poor response rates can reduce statistical power, threaten both internal and external validity, and increase study costs and duration. Military personnel are socialized to a specific set of laws, norms, traditions, and values; their willingness to participate in research may differ from civilians. The aims of this study were to better understand the views of United States (US) Veterans who served in Operation Enduring Freedom (OEF)/ Operation Iraqi Freedom (OIF) on research and motivators for participating in research to inform recruitment for a planned observational study of respiratory health in OEF/OIF Veterans...
August 29, 2018: BMC Medical Research Methodology
Catherine A Welch, Séverine Sabia, Eric Brunner, Mika Kivimäki, Martin J Shipley
BACKGROUND: Informative attrition occurs when the reason participants drop out from a study is associated with the study outcome. Analysing data with informative attrition can bias longitudinal study inferences. Approaches exist to reduce bias when analysing longitudinal data with monotone missingness (once participants drop out they do not return). However, findings may differ when using these approaches to analyse longitudinal data with non-monotone missingness. METHODS: Different approaches to reduce bias due to informative attrition in non-monotone longitudinal data were compared...
August 29, 2018: BMC Medical Research Methodology
Ines Rombach, Alastair M Gray, Crispin Jenkinson, David W Murray, Oliver Rivero-Arias
BACKGROUND: Missing data can introduce bias in the results of randomised controlled trials (RCTs), but are typically unavoidable in pragmatic clinical research, especially when patient reported outcome measures (PROMs) are used. Traditionally applied to the composite PROMs score of multi-item instruments, some recent research suggests that multiple imputation (MI) at the item level may be preferable under certain scenarios. This paper presents practical guidance on the choice of MI models for handling missing PROMs data based on the characteristics of the trial dataset...
August 28, 2018: BMC Medical Research Methodology
Dawid Pieper, Nina Kotte, Peggy Ober
BACKGROUND: Financial rewards have been shown to be an important motivator to include normal healthy volunteers in trials. Less emphasis has been put on non-healthy volunteers. No previous study has investigated the impact of a voucher incentive for participants in a cross-sectional study in a clinical setting. The objective of this study was to examine the impact of a small voucher incentive on a survey response rate in a clinical setting at the point-of-care in a quasi-randomized controlled trial (q-RCT)...
August 16, 2018: BMC Medical Research Methodology
Chris Cooper, Andrew Booth, Jo Varley-Campbell, Nicky Britten, Ruth Garside
BACKGROUND: Systematic literature searching is recognised as a critical component of the systematic review process. It involves a systematic search for studies and aims for a transparent report of study identification, leaving readers clear about what was done to identify studies, and how the findings of the review are situated in the relevant evidence. Information specialists and review teams appear to work from a shared and tacit model of the literature search process. How this tacit model has developed and evolved is unclear, and it has not been explicitly examined before...
August 14, 2018: BMC Medical Research Methodology
Nicola Creighton, Stuart Purdie, Matthew Soeberg, Richard Walton, Deborah Baker, Jane Young
BACKGROUND: In contrast to aetiological associations, there is little empirical evidence for generalising health service use associations from cohort studies. We compared the health service use of cohort study participants diagnosed with bowel or lung cancer to the source population of people diagnosed with these cancers in New South Wales (NSW), Australia to assess the representativeness of health service use of the cohort study participants. METHODS: Population-based cancer registry data for NSW residents aged ≥45 years at diagnosis of bowel or lung cancer were linked to the 45 and Up Study, a NSW population-based cohort study (N~ 267,000)...
August 8, 2018: BMC Medical Research Methodology
Haifang Ni, Rolf H H Groenwold, Mirjam Nielen, Irene Klugkist
BACKGROUND: Random effects modelling is routinely used in clustered data, but for prediction models, random effects are commonly substituted with the mean zero after model development. In this study, we proposed a novel approach of including prior knowledge through the random effects distribution and investigated to what extent this could improve the predictive performance. METHODS: Data were simulated on the basis of a random effects logistic regression model. Five prediction models were specified: a frequentist model that set the random effects to zero for all new clusters, a Bayesian model with weakly informative priors for the random effects of new clusters, Bayesian models with expert opinion incorporated into low informative, medium informative and highly informative priors for the random effects...
August 6, 2018: BMC Medical Research Methodology
Katrin Haeussler, Ardo van den Hout, Gianluca Baio
BACKGROUND: Health economic evaluations of interventions in infectious disease are commonly based on the predictions of ordinary differential equation (ODE) systems or Markov models (MMs). Standard MMs are static, whereas ODE systems are usually dynamic and account for herd immunity which is crucial to prevent overestimation of infection prevalence. Complex ODE systems including distributions on model parameters are computationally intensive. Thus, mainly ODE-based models including fixed parameter values are presented in the literature...
August 2, 2018: BMC Medical Research Methodology
Massimiliano Giacalone, Zirilli Agata, Paolo Carmelo Cozzucoli, Angela Alibrandi
BACKGROUND: Statistical methodology is a powerful tool in the health research; however, there is wide accord that statistical methodologies are not usually used properly. In particular when multiple comparisons are needed, it is necessary to check the rate of false positive results and the potential inflation of type I errors. In this case, permutation testing methods are useful to check the simultaneous significance level and identify the most significant factors. METHODS: In this paper an application of permutation tests, in the medical context of Inflammatory Bowel Diseases, is performed...
July 20, 2018: BMC Medical Research Methodology
Inga Poguntke, Martin Schumacher, Jan Beyersmann, Martin Wolkewitz On Behalf Of Combacte-Magnet Consortium
BACKGROUND: We evaluate three methods for competing risks analysis with time-dependent covariates in comparison with the corresponding methods with time-independent covariates. METHODS: We used cause-specific hazard analysis and two summary approaches for in-hospital death: logistic regression and regression of the subdistribution hazard. We analysed real hospital data (n=1864) and considered pneumonia on admission / hospital-acquired pneumonia as time-independent / time-dependent covariates for the competing events 'discharge alive' and 'in-hospital death'...
July 16, 2018: BMC Medical Research Methodology
Kristel Vlot-van Anrooij, Hilde Tobi, Thessa I M Hilgenkamp, Geraline L Leusink, Jenneken Naaldenberg
BACKGROUND: The lack of suitable and reliable scales to measure self-reported health and health behaviour among people with intellectual disabilities (ID) is an important methodological challenge in health research. This study, which was undertaken together with co-researchers with ID, explores possibilities for self-reported health scales by adjusting, testing, and reflecting on three self-reported health scales. METHODS: In an inclusive process, the researchers and co-researchers with ID adjusted the SBQ (sedentary behaviour), SQUASH (physical activity), and SRH (self-reported health) scales, after which a test-retest study among adults with ID was performed...
July 16, 2018: BMC Medical Research Methodology
Joaquín Moncho, Pamela Pereyra-Zamora, Nayara Tamayo-Fonseca, Manuel Giron, Manuel Gómez-Beneyto, Andreu Nolasco
BACKGROUND: We explored the impact of 2008 recession on the prevalence of mental health problems in Spain. METHODS: Repeated cross-sectional survey design. Datasets from 2006 and 2011 were used, and temporal change was examined. The study was conducted on the economically active population (16-64 years old). The two surveys included 29,478 and 21,007 people, obtaining a 96 and 89.6% response rate, respectively. Multiple logistic regression models were adjusted to identify poor mental health risk factors...
July 13, 2018: BMC Medical Research Methodology
Jeffrey Gu, Gary Groot
BACKGROUND: Clinical medicine has lagged behind other fields in understanding and utilizing frameworks to guide research. In this article, we introduce a new framework to examine why women choose mastectomy versus breast conserving therapy in early stage breast cancer, and highlight the importance of utilizing a conceptual framework to guide clinical research. METHODS: The framework we present was developed through integrating previous literature, frameworks, theories, models, and the author's past research...
July 9, 2018: BMC Medical Research Methodology
Helene Karcher, Shuai Fu, Jie Meng, Mikkel Zöllner Ankarfeldt, Orestis Efthimiou, Mark Belger, Josep Maria Haro, Lucien Abenhaim, Clementine Nordon
BACKGROUND: Phase III randomized controlled trials (RCT) typically exclude certain patient subgroups, thereby potentially jeopardizing estimation of a drug's effects when prescribed to wider populations and under routine care ("effectiveness"). Conversely, enrolling heterogeneous populations in RCTs can increase endpoint variability and compromise detection of a drug's effect. We developed the "RCT augmentation" method to quantitatively support RCT design in the identification of exclusion criteria to relax to address both of these considerations...
July 6, 2018: BMC Medical Research Methodology
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