Does it matter whether the recipient of patient questionnaires in general practice is the general practitioner or an independent researcher? The REPLY randomised trial.

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:Given an observed test statistic and its degrees of freedom, one may compute the observed P value with most statistical packages. It is unknown to what extent test statistics and P values are congruent in published medical papers. METHODS:We checked the congruence of statistical results reported in all the ...

journal_title：BMC medical research methodology

authors： García-Berthou E,Alcaraz C

更新日期：2004-05-28 00:00:00

abstract：BACKGROUND:In the era of evidence based medicine, with systematic reviews as its cornerstone, adequate quality assessment tools should be available. There is currently a lack of a systematically developed and evaluated tool for the assessment of diagnostic accuracy studies. The aim of this project was to combine empiri...

journal_title：BMC medical research methodology

authors： Whiting P,Rutjes AW,Reitsma JB,Bossuyt PM,Kleijnen J

更新日期：2003-11-10 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:In a random effects meta-analysis model, true treatment effects for each study are routinely assumed to follow a normal distribution. However, normality is a restrictive assumption and the misspecification of the random effects distribution may result in a misleading estimate of overall mean for the treatmen...

journal_title：BMC medical research methodology

authors： Yamaguchi Y,Maruo K,Partlett C,Riley RD

更新日期：2017-07-19 00:00:00

abstract：BACKGROUND:Recruitment to clinical trials can be challenging. Methods that improve the efficiency of trial recruitment are needed to increase successful study completions. The aim of this study was to ascertain whether sending an audio-visual presentation on a digital versatile disc (DVD), along with usual study invita...

journal_title：BMC medical research methodology

authors： Rogers A,Flynn RWV,Mackenzie IS,MacDonald TM

更新日期：2019-01-30 00:00:00

abstract：BACKGROUND:Quantitative Microbial Risk Assessment (QMRA), a modelling approach, is used to assess health risks. Inputs into the QMRA process include data that characterise the intensity, frequency and duration of exposure to risk(s). Data gaps for water exposure assessment include the duration and frequency of urban no...

journal_title：BMC medical research methodology

authors： O'Toole JE,Sinclair MI,Leder K

更新日期：2009-11-09 00:00:00

abstract：BACKGROUND:In clinical trials, study designs may focus on assessment of superiority, equivalence, or non-inferiority, of a new medicine or treatment as compared to a control. Typically, evidence in each of these paradigms is quantified with a variant of the null hypothesis significance test. A null hypothesis is assume...

journal_title：BMC medical research methodology

authors： van Ravenzwaaij D,Monden R,Tendeiro JN,Ioannidis JPA

更新日期：2019-03-29 00:00:00

abstract：BACKGROUND:For practical reasons it is not easy to obtain fasting samples in large population health surveys. Non-fasting triglyceride (Tg) values are difficult to interpret. The authors compared the accuracy of statistically corrected non-fasting Tg values with true fasting values and estimated the misclassification o...

journal_title：BMC medical research methodology

authors： Sundvall J,Leiviskä J,Laatikainen T,Peltonen M,Salomaa V,Vanhala M,Korpi-Hyövälti E,Lauronen J,Alfthan G

更新日期：2011-05-10 00:00:00

abstract：BACKGROUND:Controlled clinical trials of health care interventions are either explanatory or pragmatic. Explanatory trials test whether an intervention is efficacious; that is, whether it can have a beneficial effect in an ideal situation. Pragmatic trials measure effectiveness; they measure the degree of beneficial ef...

journal_title：BMC medical research methodology

authors： Godwin M,Ruhland L,Casson I,MacDonald S,Delva D,Birtwhistle R,Lam M,Seguin R

更新日期：2003-12-22 00:00:00

abstract：BACKGROUND:The use of health-related quality of life (HRQoL) as an endpoint in cancer clinical trials is growing rapidly. Hence, research into the statistical approaches used to analyze HRQoL data is of major importance, and could lead to a better understanding of the impact of treatments on the everyday life and care ...

journal_title：BMC medical research methodology

authors： Barbieri A,Peyhardi J,Conroy T,Gourgou S,Lavergne C,Mollevi C

更新日期：2017-09-26 00:00:00

abstract：BACKGROUND:Primary care databases are a major source of data for epidemiological and health services research. However, most studies are based on coded information, ignoring information stored in free text. Using the early presentation of rheumatoid arthritis (RA) as an exemplar, our objective was to estimate the exten...

journal_title：BMC medical research methodology

authors： Ford E,Nicholson A,Koeling R,Tate A,Carroll J,Axelrod L,Smith HE,Rait G,Davies KA,Petersen I,Williams T,Cassell JA

更新日期：2013-08-21 00:00:00

abstract：BACKGROUND:Many biological variables sampled from human subjects show a diurnal pattern, which poses special demands on the techniques used to analyze such data. Furthermore, most biological variables belong to nonlinear dynamical systems, which may make linear statistical techniques less suitable to analyze their dyna...

journal_title：BMC medical research methodology

authors： Toonen RB,Wardenaar KJ,Bos EH,van Ockenburg SL,de Jonge P

更新日期：2018-03-21 00:00:00

abstract：BACKGROUND:Researchers and policy makers have determined that accounting for productivity costs, or "indirect costs," may be as important as including direct medical expenditures when evaluating the societal value of health interventions. These costs are also important when estimating the global burden of disease. The ...

journal_title：BMC medical research methodology

authors： Menzin J,Marton JP,Menzin JA,Willke RJ,Woodward RM,Federico V

更新日期：2012-06-25 00:00:00

abstract：BACKGROUND:Clinical quality registries and other systems that conduct routine post-discharge surveillance of patient outcomes following surgery may have difficulty surveying patients who have limited proficiency in the language of the healthcare provider. Interpreter proxies (family and carers) are often used due to li...

journal_title：BMC medical research methodology

authors： Xue D,Churches T,Armstrong E,Mittal R,Naylor JM,Harris IA

更新日期：2019-11-14 00:00:00

abstract：BACKGROUND:Although some nonparametric methods have been proposed in the literature to test for the equality of median survival times for censored data in medical research, in general they have inflated type I error rates, which make their use limited in practice, especially when the sample sizes are small. METHODS:In...

journal_title：BMC medical research methodology

authors： Chen Z,Zhang G

更新日期：2016-03-16 00:00:00

abstract：BACKGROUND:The "real" effect size of a medical therapy is constant over time. In contrast, the effect size reported in randomised controlled trials (RCTs) may change over time because the sum of all kinds of bias influencing the reported effectiveness is not necessarily constant. As this would affect the validity of me...

journal_title：BMC medical research methodology

authors： Gehr BT,Weiss C,Porzsolt F

更新日期：2006-05-11 00:00:00

abstract：BACKGROUND:The Computer Adaptive Test version of the Community Reintegration of Injured Service Members measure (CRIS-CAT) consists of three scales measuring Extent of, Perceived Limitations in, and Satisfaction with community integration. The CRIS-CAT was developed using item response theory methods. The purposes of t...

journal_title：BMC medical research methodology

authors： Resnik L,Borgia M,Ni P,Pirraglia PA,Jette A

更新日期：2012-09-17 00:00:00

abstract：BACKGROUND:Claims databases are generally considered inadequate for obesity research due to suboptimal capture of body mass index (BMI) measurements. This might not be true for bariatric surgery because of reimbursement requirements and changes in coding systems. We assessed the availability and validity of claims-base...

journal_title：BMC medical research methodology

authors： Li X,Lewis KH,Callaway K,Wharam JF,Toh S

更新日期：2020-09-07 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:Persistent Pseudomonas aeruginosa (PPA) infection promotes lung function deterioration in children with cystic fibrosis (CF). Although early CF diagnosis through newborn screening (NBS) has been shown to provide nutritional/growth benefit, it is unclear whether NBS lowers the risk of PPA infection and how th...

journal_title：BMC medical research methodology

authors： Wang W,Chen MH,Chiou SH,Lai HC,Wang X,Yan J,Zhang Z

更新日期：2016-09-17 00:00:00

abstract：BACKGROUND:The prevailing view in therapeutic clinical research today is that observational studies are useful for generating new hypotheses and that controlled experiments (i.e., randomized clinical trials, RCTs) are the most appropriate method for assessing and confirming the efficacy of interventions. DISCUSSION:Th...

journal_title：BMC medical research methodology

authors： Sacristán JA

更新日期：2011-04-25 00:00:00

abstract：BACKGROUND:The collection of individual-level pandemic (H1N1) 2009 influenza immunization data was considered important to facilitate optimal vaccine delivery and accurate assessment of vaccine coverage. These data are also critical for research aimed at evaluating the new vaccine's safety and effectiveness. Systems us...

journal_title：BMC medical research methodology

authors： Pereira JA,Quach S,Heidebrecht C,Foisy J,Quan S,Finkelstein M,Sikora CA,Bettinger JA,Buckeridge DL,McCarthy A,Deeks S,Kwong JC,Public Health Agency of Canada\/Canadian Institutes of Health Research Influenza Research Network Vacc

更新日期：2010-06-08 00:00:00

abstract：BACKGROUND:Randomised controlled trials (RCTs) are the gold standard for evidence-based practice. However, RCTs can have limitations. For example, translation of findings into practice can be limited by design features, such as inclusion criteria, not accurately reflecting clinical populations. In addition, it is expen...

journal_title：BMC medical research methodology

authors： Lemanska A,Byford RC,Cruickshank C,Dearnaley DP,Ferreira F,Griffin C,Hall E,Hinton W,de Lusignan S,Sherlock J,Faithfull S

更新日期：2020-07-25 00:00:00

abstract：BACKGROUND:The likelihood ratio function (LR), the ratio of conditional probabilities of obtaining a specific marker value among those with the event of interest over those without, provides an easily interpretable way to quantify the update of the risk prediction due to the knowledge of the marker value. The LR has be...

journal_title：BMC medical research methodology

authors： Smith AM,Christodouleas JP,Hwang WT

更新日期：2019-05-22 00:00:00

abstract：BACKGROUND:Posttraumatic growth is the positive change resulting from traumatic experiences and is typically assessed with retrospective measures like the Posttraumatic Growth Inventory (PTGI). The PTGI was designed to include reference to a specific traumatic event, making it difficult to implement, without change, in...

journal_title：BMC medical research methodology

authors： Kaur N,Porter B,LeardMann CA,Tobin LE,Lemus H,Luxton DD,Millennium Cohort Study Team.

更新日期：2017-04-20 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:The Pathobiology of Prediabetes in A Biracial Cohort study is a prospective evaluation of the transition from normal to impaired glucose regulation among African American and Caucasian adults with parental type 2 diabetes. This report describes recruitment strategies and relative yields for the 376 enrolled ...

journal_title：BMC medical research methodology

authors： Ebenibo S,Edeoga C,Ammons A,Egbuonu N,Dagogo-Jack S,Pathobiology of Prediabetes in a Biracial Cohort (POP-ABC) Research Group.

更新日期：2013-05-10 00:00:00

abstract：BACKGROUND:To accurately predict the response to treatment, we need a stable and effective risk score that can be calculated from patient characteristics. When we evaluate such risks from time-to-event data with right-censoring, Cox's proportional hazards model is the most popular for estimating the linear risk score. ...

journal_title：BMC medical research methodology

authors： Omae K,Eguchi S

更新日期：2020-07-06 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