Sample size calculation in multi-centre clinical trials.

abstract：BACKGROUND:Statistical time series derived from administrative data sets form key indicators in measuring progress in addressing disadvantage in Aboriginal and Torres Strait Islander populations in Australia. However, inconsistencies in the reporting of Indigenous status can cause difficulties in producing reliable ind...

journal_title：BMC medical research methodology

authors： Lawrence D,Christensen D,Mitrou F,Draper G,Davis G,McKeown S,McAullay D,Pearson G,Zubrick SR

更新日期：2012-07-02 00:00:00

abstract：BACKGROUND:Variation in counts between subjects at a given speed or work rate are the most important source of error in physical activity (PA) measurements with accelerometers. The aim of this study was to explore how the use of individual accelerometer cut points (ICPs) affected the analysis of PA field data. METHODS...

journal_title：BMC medical research methodology

authors： Aadland E,Steene-Johannessen J

更新日期：2012-11-15 00:00:00

abstract：BACKGROUND:Health researchers undertake studies which combine qualitative and quantitative methods. Little attention has been paid to the structural issues affecting this mixed methods approach. We explored the facilitators and barriers to undertaking mixed methods studies in health research. METHODS:Face-to-face semi...

journal_title：BMC medical research methodology

authors： O'Cathain A,Nicholl J,Murphy E

更新日期：2009-12-09 00:00:00

abstract：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 o...

journal_title：BMC medical research methodology

authors： Lahr MM,van der Zee DJ,Luijckx GJ,Vroomen PC,Buskens E

更新日期：2017-01-10 00:00:00

abstract：BACKGROUND:We would expect information on adverse drug reactions in randomised clinical trials to be easily retrievable from specific searches of electronic databases. However, complete retrieval of such information may not be straightforward, for two reasons. First, not all clinical drug trials provide data on the fre...

journal_title：BMC medical research methodology

authors： Derry S,Loke YK,Aronson JK

更新日期：2001-01-01 00:00:00

abstract：BACKGROUND:The term 'inequities' refers to avoidable differences rooted in injustice. This review examined whether or not, and how, quantitative studies identifying inequalities in risk factors and health service utilization for asthma explicitly addressed underlying inequities. Asthma was chosen because recent decades...

journal_title：BMC medical research methodology

authors： Greenwood HL,Edwards N,Hoogbruin A,Kahwa EK,Odhiambo ON,Buong JA

更新日期：2011-07-12 00:00:00

abstract：:Clinical Decision Support Systems (CDSS) provide aid in clinical decision making and therefore need to take into consideration human, data interactions, and cognitive functions of clinical decision makers. The objective of this paper is to introduce a high level reference model that is intended to be used as a foundat...

journal_title：BMC medical research methodology

authors： Zikos D,DeLellis N

更新日期：2018-11-16 00:00:00

abstract：BACKGROUND:When multiple endpoints are of interest in evidence synthesis, a multivariate meta-analysis can jointly synthesise those endpoints and utilise their correlation. A multivariate random-effects meta-analysis must incorporate and estimate the between-study correlation (rhoB). METHODS:In this paper we assess ma...

journal_title：BMC medical research methodology

authors： Riley RD,Abrams KR,Sutton AJ,Lambert PC,Thompson JR

更新日期：2007-01-12 00:00:00

abstract：BACKGROUND:Evidence-based health care is informed by results of randomized clinical trials (RCTs) and their syntheses in meta-analyses. When the trial outcomes measured are not clearly described in trial publications, knowledge synthesis, translation, and decision-making may be impeded. While heterogeneity in outcomes ...

journal_title：BMC medical research methodology

authors： Monsour A,Mew EJ,Patel S,Chee-A-Tow A,Saeed L,Santos L,Courtney DB,Watson PN,Monga S,Szatmari P,Offringa M,Butcher NJ

更新日期：2020-05-25 00:00:00

abstract：BACKGROUND:Defeat and entrapment have been shown to be of central relevance to the development of different disorders. However, it remains unclear whether they represent two distinct constructs or one overall latent variable. One reason for the unclarity is that traditional factor analytic techniques have trouble estim...

journal_title：BMC medical research methodology

authors： Forkmann T,Teismann T,Stenzel JS,Glaesmer H,de Beurs D

更新日期：2018-01-25 00:00:00

abstract：BACKGROUND:Biomarkers of exposures such as infection or environmental chemicals can be measured in small volumes of blood extracted from newborn dried blood spots (DBS) underscoring their potential utility for population-based research. However, few studies have evaluated the feasibility and utility of this resource; p...

journal_title：BMC medical research methodology

authors： Yeung EH,Louis GB,Lawrence D,Kannan K,McLain AC,Caggana M,Druschel C,Bell E

更新日期：2016-02-04 00:00:00

abstract：BACKGROUND:In longitudinal studies where subjects experience recurrent incidents over a period of time, such as respiratory infections, fever or diarrhea, statistical methods are required to take into account the within-subject correlation. METHODS:For repeated events data with censored failure, the independent increm...

journal_title：BMC medical research methodology

authors： Villegas R,Julià O,Ocaña J

更新日期：2013-07-24 00:00:00

abstract：BACKGROUND:To determine if the search technique that is used to sample randomized controlled trial (RCT) manuscripts from a field of medical science can influence the measurement of the change in quality over time in that field. METHODS:RCT manuscripts in the field of brain injury were identified using two readily-ava...

journal_title：BMC medical research methodology

authors： Borsody MK,Yamada C

更新日期：2005-02-07 00:00:00

abstract：BACKGROUND:One of the main challenges for drug evaluation in rare diseases is the often heterogeneous course of these diseases. Traditional outcome measures may not be applicable for all patients, when they are in different stages of their disease. For instance, in Duchenne Muscular Dystrophy, the Six Minute Walk Test ...

journal_title：BMC medical research methodology

authors： Gaasterland CM,Jansen-van der Weide MC,Weinreich SS,van der Lee JH

更新日期：2016-08-17 00:00:00

abstract：BACKGROUND:This article describes the design and baseline sample of a single-site trial comparing Individual Placement and Support (IPS) supported employment delivered within a Veterans Health Administration (VHA) primary care Patient Aligned Care Team (PACT) to treatment-as-usual vocational rehabilitation (TAU-VR) tha...

journal_title：BMC medical research methodology

authors： Davis LL,Blansett CM,Mumba MN,MacVicar D,Toscano R,Pilkinton P,Gay W,Bartolucci A

更新日期：2020-02-17 00:00:00

abstract：BACKGROUND:Joint models of longitudinal and time-to-event data are increasingly used to perform individual dynamic prediction of a risk of event. However the difficulty to perform inference in nonlinear models and to calculate the distribution of individual parameters has long limited this approach to linear mixed-effe...

journal_title：BMC medical research methodology

authors： Desmée S,Mentré F,Veyrat-Follet C,Sébastien B,Guedj J

更新日期：2017-07-17 00:00:00

abstract：BACKGROUND:Chemotherapy is expected to reduce cancer deaths (CD), while possibly being harmful in terms of non-cancer deaths (NCD) because of toxicity. Peto's log-rank test is popular in the medical literature, but its operating characteristics are barely known. We compared this test to the most common ones in the stat...

journal_title：BMC medical research methodology

authors： Rotolo F,Michiels S

更新日期：2014-05-29 00:00:00

abstract：BACKGROUND:Plasma cell dyscrasias (PCD) are a spectrum of disorders resulting from the clonal expansion of plasma cells, ranging from the pre-malignant condition monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM). MM generates a significant burden of disease on the community and it is pr...

journal_title：BMC medical research methodology

authors： Bergin K,Moore E,McQuilten Z,Wood E,Augustson B,Blacklock H,Ho J,Horvath N,King T,McNeil J,Mollee P,Quach H,Reid CM,Rosengarten B,Walker P,Spencer A

更新日期：2016-11-09 00:00:00

abstract：BACKGROUND:The aim was to describe a strategy for recruitment of healthy volunteers (HV) to a randomized trial that assessed the efficacy of different telephone techniques to assist HV in performing cardiac massage for vital emergency. Participation in the randomized trial was not financially compensated, however HV we...

journal_title：BMC medical research methodology

authors： Luzurier Q,Damm C,Lion F,Daniel C,Pellerin L,Tavolacci MP

更新日期：2015-01-05 00:00:00

abstract：BACKGROUND:In Routine Outcome Monitoring (ROM) there is a high demand for short assessments. Computerized Adaptive Testing (CAT) is a promising method for efficient assessment. In this article, the efficiency of a CAT version of the Mood and Anxiety Symptom Questionnaire, - Anhedonic Depression scale (MASQ-AD) for use ...

journal_title：BMC medical research methodology

authors： Smits N,Zitman FG,Cuijpers P,den Hollander-Gijsman ME,Carlier IV

更新日期：2012-01-10 00:00:00

abstract：BACKGROUND:How overall physical activity relates to specific activities and how reported activity changes over time may influence interpretation of observed associations between physical activity and health. We examine the relationships between various physical activities self-reported at different times in a large coh...

journal_title：BMC medical research methodology

authors： Armstrong ME,Cairns BJ,Green J,Reeves GK,Beral V,Million Women Study Collaborators.

更新日期：2011-06-22 00:00:00

abstract：BACKGROUND:Diabetes-related lower limb amputations are associated with considerable morbidity and mortality and are usually preceded by foot ulceration. The available systematic reviews of aggregate data are compromised because the primary studies report both adjusted and unadjusted estimates. As adjusted meta-analyses...

journal_title：BMC medical research methodology

authors： Crawford F,Anandan C,Chappell FM,Murray GD,Price JF,Sheikh A,Simpson CR,Maxwell M,Stansby GP,Young MJ,Abbott CA,Boulton AJ,Boyko EJ,Kastenbauer T,Leese GP,Monami M,Monteiro-Soares M,Rith-Najarian SJ,Veves A,Coates N

更新日期：2013-02-15 00:00:00

abstract：BACKGROUND:When discussing results medical research articles often tear substantive and statistical (methodical) contributions apart, just as if both were independent. Consequently, reasoning on bias tends to be vague, unclear and superficial. This can lead to over-generalized, too narrow and misleading conclusions, es...

journal_title：BMC medical research methodology

authors： Höfler M,Venz J,Trautmann S,Miller R

更新日期：2018-04-17 00:00:00

abstract：BACKGROUND:Cancer relapses may be useful to predict the risk of death. To take into account relapse information, the Landmark approach is popular. As an alternative, we propose the joint frailty model for a recurrent event and a terminal event to derive dynamic predictions of the risk of death. METHODS:The proposed pr...

journal_title：BMC medical research methodology

authors： Mauguen A,Rachet B,Mathoulin-Pélissier S,Lawrence GM,Siesling S,MacGrogan G,Laurent A,Rondeau V

更新日期：2015-04-01 00:00:00

abstract：BACKGROUND:The aim of this study was to examine the relationship between mortality and statin adherence using two different approaches to adherence measurement (summary versus repeated-measures). METHODS:A retrospective cohort study was conducted using administrative data from Saskatchewan, Canada between 1994 and 200...

journal_title：BMC medical research methodology

authors： Alsabbagh MW,Eurich D,Lix LM,Wilson TW,Blackburn DF

更新日期：2017-04-20 00:00:00

abstract：BACKGROUND:Cluster randomised controlled trials (CRCTs) are frequently used in health service evaluation. Assuming an average cluster size, required sample sizes are readily computed for both binary and continuous outcomes, by estimating a design effect or inflation factor. However, where the number of clusters are fix...

journal_title：BMC medical research methodology

authors： Hemming K,Girling AJ,Sitch AJ,Marsh J,Lilford RJ

更新日期：2011-06-30 00:00:00

abstract：BACKGROUND:Social-environmental data obtained from the US Census is an important resource for understanding health disparities, but rarely is the full dataset utilized for analysis. A barrier to incorporating the full data is a lack of solid recommendations for variable selection, with researchers often hand-selecting ...

journal_title：BMC medical research methodology

authors： Handorf E,Yin Y,Slifker M,Lynch S

更新日期：2020-12-10 00:00:00

abstract：BACKGROUND:Growth Mixture Modeling (GMM) is commonly used to group individuals on their development over time, but convergence issues and impossible values are common. This can result in unreliable model estimates. Constraining variance parameters across classes or over time can solve these issues, but can also serious...

journal_title：BMC medical research methodology

authors： Sijbrandij JJ,Hoekstra T,Almansa J,Peeters M,Bültmann U,Reijneveld SA

更新日期：2020-11-12 00:00:00

abstract：BACKGROUND:Most electronic search efforts directed at identifying primary studies for inclusion in systematic reviews rely on the optimal Boolean search features of search interfaces such as DIALOG and Ovid. Our objective is to test the ability of an Ultraseek search engine to rank MEDLINE records of the included studi...

journal_title：BMC medical research methodology

authors： Sampson M,Barrowman NJ,Moher D,Clifford TJ,Platt RW,Morrison A,Klassen TP,Zhang L

更新日期：2006-02-24 00:00:00

abstract：BACKGROUND:Clinical practice guidelines have become increasingly widely used to guide quality improvement of clinical practice. Qualitative research may be a useful way to improve the quality and implementation of guidelines. The methodology for qualitative evidence used in guidelines development is worthy of further r...

journal_title：BMC medical research methodology

authors： Wang YY,Liang DD,Lu C,Shi YX,Zhang J,Cao Y,Fang C,Huang D,Jin YH

更新日期：2020-06-17 00:00:00