Articles

Optimizing literature search in systematic reviews – are MEDLINE, EMBASE and CENTRAL enough for identifying effect studies within the area of musculoskeletal disorders?

When conducting systematic reviews, it is essential to perform a comprehensive literature search to identify all published studies relevant to the specific research question. The Cochrane Collaborations Method...

Authors: Thomas Aagaard, Hans Lund and Carsten Juhl

Common data elements for secondary use of electronic health record data for clinical trial execution and serious adverse event reporting

Data capture is one of the most expensive phases during the conduct of a clinical trial and the increasing use of electronic health records (EHR) offers significant savings to clinical research. To facilitate ...

Authors: Philipp Bruland, Mark McGilchrist, Eric Zapletal, Dionisio Acosta, Johann Proeve, Scott Askin, Thomas Ganslandt, Justin Doods and Martin Dugas

Predictors of in-hospital mortality following major lower extremity amputations in type 2 diabetic patients using artificial neural networks

Outcome prediction is important in the clinical decision-making process. Artificial neural networks (ANN) have been used to predict the risk of post-operative events, including survival, and are increasingly b...

Authors: Ana Lopez-de-Andres, Valentin Hernandez-Barrera, Roberto Lopez, Pablo Martin-Junco, Isabel Jimenez-Trujillo, Alejandro Alvaro-Meca, Miguel Angel Salinero-Fort and Rodrigo Jimenez-Garcia

Using cognitive pre-testing methods in the development of a new evidenced-based pressure ulcer risk assessment instrument

Variation in development methods of Pressure Ulcer Risk Assessment Instruments has led to inconsistent inclusion of risk factors and concerns about content validity. A new evidenced-based Risk Assessment Instr...

Authors: S. Coleman, J. Nixon, J. Keen, D. Muir, L. Wilson, E. McGinnis, N. Stubbs, C. Dealey and E. A. Nelson

Does size really matter? A sensitivity analysis of number of seeds in a respondent-driven sampling study of gay, bisexual and other men who have sex with men in Vancouver, Canada

Respondent-driven sampling (RDS) is an increasingly used peer chain-recruitment method to sample “hard-to-reach” populations for whom there are no reliable sampling frames. Implementation success of RDS varies...

Authors: Nathan John Lachowsky, Justin Tyler Sorge, Henry Fisher Raymond, Zishan Cui, Paul Sereda, Ashleigh Rich, Eric A. Roth, Robert S. Hogg and David M. Moore

National weighting of data from the Behavioral Risk Factor Surveillance System (BRFSS)

The Behavioral Risk Factor Surveillance System (BRFSS) is a network of health-related telephone surveys--conducted by all 50 states, the District of Columbia, and participating US territories—that receive tech...

Authors: Ronaldo Iachan, Carol Pierannunzi, Kristie Healey, Kurt J. Greenlund and Machell Town

Improving incidence estimation in practice-based sentinel surveillance networks using spatial variation in general practitioner density

In surveillance networks based on voluntary participation of health-care professionals, there is little choice regarding the selection of participants’ characteristics. External information about participants,...

Authors: Cécile Souty and Pierre-Yves Boëlle

Least absolute shrinkage and selection operator type methods for the identification of serum biomarkers of overweight and obesity: simulation and application

The study of circulating biomarkers and their association with disease outcomes has become progressively complex due to advances in the measurement of these biomarkers through multiplex technologies. The Least...

Authors: Monica M. Vasquez, Chengcheng Hu, Denise J. Roe, Zhao Chen, Marilyn Halonen and Stefano Guerra

Defining the clinical pathway in cochrane diagnostic test accuracy reviews

The value of a medical test depends on the context in which it might be used. Ideally, questions, results and conclusions of a diagnostic test accuracy (DTA) systematic review should be presented in light of t...

Authors: G. Gopalakrishna, Miranda W. Langendam, Rob J. P. M. Scholten, Patrick M. M. Bossuyt and Mariska M. G. Leeflang

Design and development of the Australian and New Zealand (ANZ) myeloma and related diseases registry

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) ...

Authors: Krystal Bergin, Elizabeth Moore, Zoe McQuilten, Erica Wood, Bradley Augustson, Hilary Blacklock, Joy Ho, Noemi Horvath, Tracy King, John McNeil, Peter Mollee, Hang Quach, Christopher M. Reid, Brian Rosengarten, Patricia Walker and Andrew Spencer

Inverse probability weighting to estimate causal effect of a singular phase in a multiphase randomized clinical trial for multiple myeloma

Randomization procedure in randomized controlled trials (RCTs) permits an unbiased estimation of causal effects. However, in clinical practice, differential compliance between arms may cause a strong violation...

Authors: Annalisa Pezzi, Michele Cavo, Annibale Biggeri, Elena Zamagni and Oriana Nanni

Erratum to: A Monte Carlo simulation study comparing linear regression, beta regression, variable-dispersion beta regression and fractional logit regression at recovering average difference measures in a two sample design

Authors: Christopher Meaney and Rahim Moineddin

Autoregressive transitional ordinal model to test for treatment effect in neurological trials with complex endpoints

A number of potential therapeutic approaches for neurological disorders have failed to provide convincing evidence of efficacy, prompting pharmaceutical and health companies to discontinue their involvement in...

Authors: Lorenzo G. Tanadini, John D. Steeves, Armin Curt and Torsten Hothorn

A comparison of time dependent Cox regression, pooled logistic regression and cross sectional pooling with simulations and an application to the Framingham Heart Study

Typical survival studies follow individuals to an event and measure explanatory variables for that event, sometimes repeatedly over the course of follow up. The Cox regression model has been used widely in the...

Authors: Julius S. Ngwa, Howard J. Cabral, Debbie M. Cheng, Michael J. Pencina, David R. Gagnon, Michael P. LaValley and L. Adrienne Cupples

Comparing two sampling methods to engage hard-to-reach communities in research priority setting

Effective community-partnered and patient-centered outcomes research needs to address community priorities. However, optimal sampling methods to engage stakeholders from hard-to-reach, vulnerable communities t...

Authors: Melissa A. Valerio, Natalia Rodriguez, Paula Winkler, Jaime Lopez, Meagen Dennison, Yuanyuan Liang and Barbara J. Turner

Statistical methodology for age-adjustment of the GH-2000 score detecting growth hormone misuse

The GH-2000 score has been developed as a powerful and unique technique for the detection of growth hormone misuse by sportsmen and women. The score depends upon the measurement of two growth hormone (GH) sens...

Authors: Dankmar Böhning, Walailuck Böhning, Nishan Guha, David A. Cowan, Peter H. Sönksen and Richard I. G. Holt

Why sex and gender matter in implementation research

There has been a recent swell in activity by health research funding organizations and science journal editors to increase uptake of sex and gender considerations in study design, conduct and reporting in orde...

Authors: Cara Tannenbaum, Lorraine Greaves and Ian D. Graham

Assessment of predictive performance in incomplete data by combining internal validation and multiple imputation

Missing values are a frequent issue in human studies. In many situations, multiple imputation (MI) is an appropriate missing data handling strategy, whereby missing values are imputed multiple times, the analy...

Authors: Simone Wahl, Anne-Laure Boulesteix, Astrid Zierer, Barbara Thorand and Mark A. van de Wiel

Application of a nonrandomized stepped wedge design to evaluate an evidence-based quality improvement intervention: a proof of concept using simulated data on patient-centered medical homes

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 de...

Authors: Alexis K. Huynh, Martin L. Lee, Melissa M. Farmer and Lisa V. Rubenstein

Health Equity Assessment Toolkit (HEAT): software for exploring and comparing health inequalities in countries

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 inequaliti...

Authors: Ahmad Reza Hosseinpoor, Devaki Nambiar, Anne Schlotheuber, Daniel Reidpath and Zev Ross

www.common-metrics.org: a web application to estimate scores from different patient-reported outcome measures on a common scale

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 usin...

Authors: H. Felix Fischer and Matthias Rose

Rationale and design of mDOT-HuA study: a randomized trial to assess the effect of mobile-directly observed therapy on adherence to hydroxyurea in adults with sickle cell anemia in Tanzania

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 t...

Authors: Abel Makubi, Philip Sasi, Mariam Ngaeje, Enrico M. Novelli, Bruno P. Mmbando, Mark T. Gladwin and Julie Makani

Abstracts reporting of HIV/AIDS randomized controlled trials in general medicine and infectious diseases journals: completeness to date and improvement in the quality since CONSORT extension for abstracts

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 reporti...

Authors: Jean Joel R. Bigna, Jean Jacques N. Noubiap, Serra Lem Asangbeh, Lewis N. Um, Paule Sandra D. Sime, Elvis Temfack and Mathurin Cyrille Tejiokem

A method for sensitivity analysis to assess the effects of measurement error in multiple exposure variables using external validation data

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 b...

Authors: 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 and Hendriek C. Boshuizen

Impact of socioeconomic inequalities on geographic disparities in cancer incidence: comparison of methods for spatial disease mapping

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 ...

Authors: Juste Aristide Goungounga, Jean Gaudart, Marc Colonna and Roch Giorgi

Differences in reported sepsis incidence according to study design: a literature review

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 desc...

Authors: Saga Elise Mariansdatter, Andreas Halgreen Eiset, Kirstine Kobberøe Søgaard and Christian Fynbo Christiansen

A consumer register: an acceptable and cost-effective alternative for accessing patient populations

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...

Authors: Jamie Bryant, Rob Sanson-Fisher, Elizabeth Fradgley, Breanne Hobden, Alison Zucca, Frans Henskens, Andrew Searles, Brad Webb and Christopher Oldmeadow

A P-value model for theoretical power analysis and its applications in multiple testing procedures

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 ...

Authors: Fengqing Zhang and Jiangtao Gou

Mechanisms and direction of allocation bias in randomised clinical trials

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 an...

Authors: Asger Paludan-Müller, David Ruben Teindl Laursen and Asbjørn Hróbjartsson

Improving measurement-invariance assessments: correcting entrenched testing deficiencies

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...

Authors: Leslie A. Hayduk

Measurement of adherence in a randomised controlled trial of a complex intervention: supported self-management for adults with learning disability and type 2 diabetes

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 routi...

Authors: Liz Graham, Judy Wright, Rebecca Walwyn, Amy M. Russell, Louise Bryant, Amanda Farrin and Allan House

Methods for network meta-analysis of continuous outcomes using individual patient data: a case study in acupuncture for chronic pain

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 evid...

Authors: Pedro Saramago, Beth Woods, Helen Weatherly, Andrea Manca, Mark Sculpher, Kamran Khan, Andrew J. Vickers and Hugh MacPherson

Adjusting for overdispersion in piecewise exponential regression models to estimate excess mortality rate in population-based research

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. Ho...

Authors: Miguel Angel Luque-Fernandez, Aurélien Belot, Manuela Quaresma, Camille Maringe, Michel P. Coleman and Bernard Rachet

Improving prediction models with new markers: a comparison of updating strategies

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.

Authors: D. Nieboer, Y. Vergouwe, Danna P. Ankerst, Monique J. Roobol and Ewout W. Steyerberg

The contribution of databases to the results of systematic reviews: a cross-sectional study

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 empir...

Authors: Lisa Hartling, Robin Featherstone, Megan Nuspl, Kassi Shave, Donna M. Dryden and Ben Vandermeer

The use of relative incidence ratios in self-controlled case series studies: an overview

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...

Authors: Steven Hawken, Beth K. Potter, Julian Little, Eric I. Benchimol, Salah Mahmud, Robin Ducharme and Kumanan Wilson

Description and initial evaluation of incorporating electronic follow-up of study participants in a longstanding multisite cohort study

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...

Authors: Kiarri N. Kershaw, Kiang Liu, David C. Goff Jr., Donald M. Lloyd-Jones, Laura J. Rasmussen-Torvik, Jared P. Reis, Pamela J. Schreiner, Daniel B. Garside and Stephen Sidney

Feasibility and validity of a statistical adjustment to reduce self-report bias of height and weight in wave 1 of the Add Health study

Bias in adolescent self-reported height and weight is well documented. Given the importance and widespread use of the National Longitudinal Study of Adolescent to Adult Health (Add Health) data for obesity res...

Authors: Janet M. Liechty, Xuan Bi and Annie Qu

Predictor characteristics necessary for building a clinically useful risk prediction model: a simulation study

Compelled by the intuitive appeal of predicting each individual patient’s risk of an outcome, there is a growing interest in risk prediction models. While the statistical methods used to build prediction model...

Authors: Laura Schummers, Katherine P. Himes, Lisa M. Bodnar and Jennifer A. Hutcheon

Onset of persistent pseudomonas aeruginosa infection in children with cystic fibrosis with interval censored data

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 provi...

Authors: Wenjie Wang, Ming-Hui Chen, Sy Han Chiou, Hui-Chuan Lai, Xiaojing Wang, Jun Yan and Zhumin Zhang

Combined models for pre- and post-treatment longitudinal biomarker data: an application to CD4 counts in HIV-patients

There has been some debate in the literature as to whether baseline values of a measurement of interest at treatment initiation should be treated as an outcome variable as part of a model for longitudinal chan...

Authors: Oliver T. Stirrup, Abdel G. Babiker and Andrew J. Copas

IDGenerator: unique identifier generator for epidemiologic or clinical studies

Creating study identifiers and assigning them to study participants is an important feature in epidemiologic studies, ensuring the consistency and privacy of the study data. The numbering system for identifier...

Authors: Matthias Olden, Rolf Holle, Iris M. Heid and Klaus Stark

Searching for the optimal measuring frequency in longitudinal studies -- an example utilizing short message service (SMS) to collect repeated measures among patients with low back pain

Mobile technology has opened opportunities within health care and research to allow for frequent monitoring of patients. This has given rise to detailed longitudinal information and new insights concerning beh...

Authors: Iben Axén and Lennart Bodin

Joint modelling of time-to-event and multivariate longitudinal outcomes: recent developments and issues

Available methods for the joint modelling of longitudinal and time-to-event outcomes have typically only allowed for a single longitudinal outcome and a solitary event time. In practice, clinical studies are l...

Authors: Graeme L. Hickey, Pete Philipson, Andrea Jorgensen and Ruwanthi Kolamunnage-Dona

Confidence intervals for the between-study variance in random-effects meta-analysis using generalised heterogeneity statistics: should we use unequal tails?

Confidence intervals for the between study variance are useful in random-effects meta-analyses because they quantify the uncertainty in the corresponding point estimates. Methods for calculating these confiden...

Authors: Dan Jackson and Jack Bowden

Multiple time scales in modeling the incidence of infections acquired in intensive care units

When patients are admitted to an intensive care unit (ICU) their risk of getting an infection will be highly depend on the length of stay at-risk in the ICU. In addition, risk of infection is likely to vary ov...

Authors: Martin Wolkewitz, Ben S. Cooper, Mercedes Palomar-Martinez, Francisco Alvarez-Lerma, Pedro Olaechea-Astigarraga, Adrian G. Barnett and Martin Schumacher

Managing distance and covariate information with point-based clustering

Geographic perspectives of disease and the human condition often involve point-based observations and questions of clustering or dispersion within a spatial context. These problems involve a finite set of poin...

Authors: Peter A. Whigham, Brandon de Graaf, Rashmi Srivastava and Paul Glue

A systematic approach to designing statistically powerful heteroscedastic 2 × 2 factorial studies while minimizing financial costs

The 2 × 2 factorial design is widely used for assessing the existence of interaction and the extent of generalizability of two factors where each factor had only two levels. Accordingly, research problems asso...

Authors: Show-Li Jan and Gwowen Shieh

Performance of models for estimating absolute risk difference in multicenter trials with binary outcome

Reporting of absolute risk difference (RD) is recommended for clinical and epidemiological prospective studies. In analyses of multicenter studies, adjustment for center is necessary when randomization is stra...

Authors: Claudia Pedroza and Van Thi Thanh Truong

Time-varying SMART design and data analysis methods for evaluating adaptive intervention effects

In a standard two-stage SMART design, the intermediate response to the first-stage intervention is measured at a fixed time point for all participants. Subsequently, responders and non-responders are re-random...

Authors: Tianjiao Dai and Sanjay Shete