Imputation of a true endpoint from a surrogate: application to a cluster randomized controlled trial with partial information on the true endpoint.

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:Systematic reviews (SRs) must be of high quality. The purpose of our research was to compare the methodological and reporting quality of original versus updated Cochrane SRs to determine whether updating had improved these two quality dimensions. METHODS:We identified updated Cochrane SRs published in issue...

journal_title：BMC medical research methodology

authors： Shea B,Boers M,Grimshaw JM,Hamel C,Bouter LM

更新日期：2006-06-13 00:00:00

abstract：BACKGROUND:Recruitment to health research remains a major challenge. Innovation is required to meet policy commitments to help patients take part in health research. One innovation that may help meet those policy goals is the development of 'consent to contact' systems, where people give generic consent to be contacted...

journal_title：BMC medical research methodology

authors： Grady K,Gibson M,Bower P

更新日期：2019-10-22 00:00:00

abstract：BACKGROUND:Missing data present a challenge to many research projects. The problem is often pronounced in studies utilizing self-report scales, and literature addressing different strategies for dealing with missing data in such circumstances is scarce. The objective of this study was to compare six different imputatio...

journal_title：BMC medical research methodology

authors： Shrive FM,Stuart H,Quan H,Ghali WA

更新日期：2006-12-13 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:Multiple Imputation as usually implemented assumes that data are Missing At Random (MAR), meaning that the underlying missing data mechanism, given the observed data, is independent of the unobserved data. To explore the sensitivity of the inferences to departures from the MAR assumption, we applied the meth...

journal_title：BMC medical research methodology

authors： Héraud-Bousquet V,Larsen C,Carpenter J,Desenclos JC,Le Strat Y

更新日期：2012-06-08 00:00:00

abstract：BACKGROUND:The study design and protocol that underpin a randomised controlled trial (RCT) are critical for the ultimate success of the trial. Although RCTs are considered the gold standard for research, there are multiple threats to their validity such as participant recruitment and retention, identifying a meaningful...

journal_title：BMC medical research methodology

authors： Hall CL,Brown S,James M,Martin JL,Brown N,Selby K,Clarke J,Williams L,Sayal K,Hollis C,Groom MJ

更新日期：2019-06-18 00:00:00

abstract：BACKGROUND:This paper focuses on measuring the efficiency and effectiveness of two diagramming methods employed in key informant interviews with clinicians and health care administrators. The two methods are 'participatory diagramming', where the respondent creates a diagram that assists in their communication of answe...

journal_title：BMC medical research methodology

authors： Umoquit MJ,Dobrow MJ,Lemieux-Charles L,Ritvo PG,Urbach DR,Wodchis WP

更新日期：2008-08-08 00:00:00

abstract：BACKGROUND:Dichotomisation of continuous outcomes has been rightly criticised by statisticians because of the loss of information incurred. However to communicate a comparison of risks, dichotomised outcomes may be necessary. Peacock et al. developed a distributional approach to the dichotomisation of normally distribu...

journal_title：BMC medical research methodology

authors： Sauzet O,Ofuya M,Peacock JL

更新日期：2015-04-24 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:To assess cross-cultural validity between Dutch and English versions of the FVQ_CYP, a patient-reported outcome measure developed in the United Kingdom (UK) for children and adolescents with (severe) visual impairment or blindness (VI for brevity) to measure functional vision. METHODS:The 36-item FVQ_CYP wa...

journal_title：BMC medical research methodology

authors： Elsman EBM,Tadić V,Peeters CFW,van Rens GHMB,Rahi JS,van Nispen RMA

更新日期：2019-12-03 00:00:00

abstract：BACKGROUND:Information and theory beyond copula concepts are essential to understand the dependence relationship between several marginal covariates distributions. In a therapeutic trial data scheme, most of the time, censoring occurs. That could lead to a biased interpretation of the dependence relationship between ma...

journal_title：BMC medical research methodology

authors： Fontaine C,Daurès JP,Landais P

更新日期：2017-02-15 00:00:00

abstract：BACKGROUND:Outcomes in observational studies may not best estimate those expected in the HIV vaccine efficacy trials. We compared retention in Simulated HIV Vaccine Efficacy Trials (SiVETs) and observational cohorts drawn from two key populations in Uganda. METHODS:Two SiVETs were nested within two observational cohor...

journal_title：BMC medical research methodology

authors： Abaasa A,Todd J,Nash S,Mayanja Y,Kaleebu P,Fast PE,Price M

更新日期：2020-02-12 00:00:00

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: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:The most commonly used survey methods are self-administered questionnaires, telephone interviews, and a mixture of both. But until now evidence out of randomised controlled trials as to whether patient responses differ depending on the survey mode is lacking. Therefore this study assessed whether patient res...

journal_title：BMC medical research methodology

authors： Lungenhausen M,Lange S,Maier C,Schaub C,Trampisch HJ,Endres HG

更新日期：2007-11-22 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:The weighted estimators generally used for analyzing case-cohort studies are not fully efficient and naive estimates of the predictive ability of a model from case-cohort data depend on the subcohort size. However, case-cohort studies represent a special type of incomplete data, and methods for analyzing inc...

journal_title：BMC medical research methodology

authors： Marti H,Carcaillon L,Chavance M

更新日期：2012-03-09 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:Occupational stress and specifically job anxiety are crucial factors in determining health outcomes, job satisfaction as well as performance. In order to assess this phenomenon, the Job Anxiety Scale is one of the instruments available. It consists of 70 items that are clustered in 14 subscales and five dime...

journal_title：BMC medical research methodology

authors： Schmalbach B,Kalkbrenner A,Bassler M,Hinz A,Petrowski K

更新日期：2020-04-21 00:00:00

abstract：BACKGROUND:The effectiveness of multiple innovative recruitment strategies for enrolling Black/African American participants to the Adventist Health Study-2 (AHS-2) is described. The study's focus is diet and breast, prostate and colon cancer. METHODS:Promotions centered on trust, relationship building and incentives ...

journal_title：BMC medical research methodology

authors： Herring P,Butler T,Hall S,Bennett H,Montgomery SB,Fraser G

更新日期：2014-04-03 00:00:00

abstract：BACKGROUND:Dynamic risk models, which incorporate disease-free survival and repeated measurements over time, might yield more accurate predictions of future health status compared to static models. The objective of this study was to develop and apply a dynamic prediction model to estimate the risk of developing type 2 ...

journal_title：BMC medical research methodology

authors： Parast L,Mathews M,Friedberg MW

更新日期：2019-08-14 00:00:00

abstract：BACKGROUND:Evidence syntheses, and in particular systematic reviews (SRs), have become one of the cornerstones of evidence-based health care. The Assessment of Multiple Systematic Reviews (AMSTAR) tool has become the most widely used tool for investigating the methodological quality of SRs and is currently undergoing r...

journal_title：BMC medical research methodology

authors： Wegewitz U,Weikert B,Fishta A,Jacobs A,Pieper D

更新日期：2016-08-26 00:00:00

abstract：BACKGROUND:Generic quality of life (QoL) instruments provide important measures of self-reported wellbeing that can be compared across healthy and clinical populations. The aim of this analysis is to validate the ten-item QoL instrument "QOL10", as well as to confirm the validity of the embedded "QOL5" questionnaire an...

journal_title：BMC medical research methodology

authors： Muller AE,Skurtveit S,Clausen T

更新日期：2016-05-23 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:The rationale for commissioning community pulmonary rehabilitation programmes is based on evidence from randomised clinical trials. However, there are a number of reasons why similar programmes might be less effective outside the environment of a clinical trial. These include a less highly selected patient g...

journal_title：BMC medical research methodology

authors： Goyder EC,Strong M,Green A,Holmes MW,Miles G,Reddington O,Lawson R,Lee A,Basran G

更新日期：2013-08-13 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 prognostic studies model instability and missing data can be troubling factors. Proposed methods for handling these situations are bootstrapping (B) and Multiple imputation (MI). The authors examined the influence of these methods on model composition. METHODS:Models were constructed using a cohort of 58...

journal_title：BMC medical research methodology

authors： Vergouw D,Heymans MW,Peat GM,Kuijpers T,Croft PR,de Vet HC,van der Horst HE,van der Windt DA

更新日期：2010-09-17 00:00:00

abstract：BACKGROUND:The construction of prediction intervals (PIs) for future body mass index (BMI) values of individual children based on a recent German birth cohort study with n = 2007 children is problematic for standard parametric approaches, as the BMI distribution in childhood is typically skewed depending on age. METHO...

journal_title：BMC medical research methodology

authors： Mayr A,Hothorn T,Fenske N

更新日期：2012-01-25 00:00:00

abstract：BACKGROUND:Methods for describing one's confidence in the available evidence are useful for end-users of evidence reviews. Analysts inevitably make judgments about the quality, quantity consistency, robustness, and magnitude of effects observed in the studies identified. The subjectivity of these judgments in several a...

journal_title：BMC medical research methodology

authors： Treadwell JR,Tregear SJ,Reston JT,Turkelson CM

更新日期：2006-10-19 00:00:00