The impact of the mode of survey administration on estimates of daily smoking for mobile phone only users

Over the past decade, there have been substantial changes in landline and mobile phone ownership, with a substantial increase in the proportion of mobile-only households. Estimates of daily smoking rates for t...

Authors: Joseph Hanna, Damien V. Cordery, David G. Steel, Walter Davis and Timothy C. Harrold

Impact of correlation of predictors on discrimination of risk models in development and external populations

The area under the ROC curve (AUC) of risk models is known to be influenced by differences in case-mix and effect size of predictors. The impact of heterogeneity in correlation among predictors has however bee...

Authors: Suman Kundu, Madhu Mazumdar and Bart Ferket

Grey literature in systematic reviews: a cross-sectional study of the contribution of non-English reports, unpublished studies and dissertations to the results of meta-analyses in child-relevant reviews

Systematic reviews (SRs) are an important source of information about healthcare interventions. A key component of a well-conducted SR is a comprehensive literature search. There is limited evidence on the con...

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

Kappa statistic to measure agreement beyond chance in free-response assessments

The usual kappa statistic requires that all observations be enumerated. However, in free-response assessments, only positive (or abnormal) findings are notified, but negative (or normal) findings are not. This...

Authors: Marc Carpentier, Christophe Combescure, Laura Merlini and Thomas V. Perneger

Protocol for the development of a salutogenic intrapartum core outcome set (SIPCOS)

Maternity intrapartum care research and clinical care more often focus on outcomes that minimise or prevent adverse health rather than on what constitutes positive health and wellbeing (salutogenesis). This wa...

Authors: Valerie Smith, Deirdre Daly, Ingela Lundgren, Tine Eri, Cecily Begley, Mechthild M. Gross, Soo Downe, Zarko Alfirevic and Declan Devane

Review and evaluation of performance measures for survival prediction models in external validation settings

When developing a prediction model for survival data it is essential to validate its performance in external validation settings using appropriate performance measures. Although a number of such measures have ...

Authors: M. Shafiqur Rahman, Gareth Ambler, Babak Choodari-Oskooei and Rumana Z. Omar

Clinical patient registry recruitment and retention: a survey of patients in two chronic disease registries

The collection of routine clinical data in the setting of research registries can serve an important role in understanding real world care. However, relatively little is known about the patient experience in r...

Authors: Daniel H. Solomon, Nancy A. Shadick, Michael E. Weinblatt, Michelle Frits, Christine Iannaccone, Agnes Zak and Joshua R. Korzenik

Practical application of opt-out recruitment methods in two health services research studies

Participant recruitment is an ongoing challenge in health research. Recruitment may be especially difficult for studies of access to health care because, even among those who are in care, people using services...

Authors: Christopher J. Miller, James F. Burgess Jr., Ellen P. Fischer, Deborah J. Hodges, Lindsay K. Belanger, Jessica M. Lipschitz, Siena R. Easley, Christopher J. Koenig, Regina L. Stanley and Jeffrey M. Pyne

Statistical evaluation of adding multiple risk factors improves Framingham stroke risk score

Framingham Stroke Risk Score (FSRS) is the most well-regarded risk appraisal tools for evaluating an individual’s absolute risk on stroke onset. However, several widely accepted risk factors for stroke were no...

Authors: Xiao-Hua Zhou, Xiaonan Wang, Ashlee Duncan, Guizhou Hu and Jiayin Zheng

Evidence synthesis to inform model-based cost-effectiveness evaluations of diagnostic tests: a methodological review of health technology assessments

Evaluations of diagnostic tests are challenging because of the indirect nature of their impact on patient outcomes. Model-based health economic evaluations of tests allow different types of evidence from vario...

Authors: Bethany Shinkins, Yaling Yang, Lucy Abel and Thomas R. Fanshawe

Estimating the standardized incidence ratio (SIR) with incomplete follow-up data

A standard parameter to compare the disease incidence of a cohort relative to the population is the standardized incidence ratio (SIR). For statistical inference is commonly assumed that the denominator, the e...

Authors: Heiko Becher and Volker Winkler

Comparison of surveillance-based metrics for the assessment and monitoring of disease detection: simulation study about type 2 diabetes

Screening and detection of cases are a common public health priority for treatable chronic conditions with long subclinical periods. However, the validity of commonly-used metrics from surveillance systems for...

Authors: Ralph Brinks, Annika Hoyer, Deborah B. Rolka, Oliver Kuss and Edward W. Gregg

Time-dependent ROC curve analysis in medical research: current methods and applications

ROC (receiver operating characteristic) curve analysis is well established for assessing how well a marker is capable of discriminating between individuals who experience disease onset and individuals who do n...

Authors: Adina Najwa Kamarudin, Trevor Cox and Ruwanthi Kolamunnage-Dona

The importance of censoring in competing risks analysis of the subdistribution hazard

The analysis of time-to-event data can be complicated by competing risks, which are events that alter the probability of, or completely preclude the occurrence of an event of interest. This is distinct from ce...

Authors: Mark W. Donoghoe and Val Gebski

Practical partnered research to improve weight loss among overweight/obese veterans: lessons from the trenches

Obesity and obesity-related conditions, such as type 2 diabetes, are a major issue for Veteran health. Veterans Health Administration (VA) researchers and health systems leaders have worked separately and toge...

Authors: Mona AuYoung, Laura J. Damschroder, Linda Kinsinger, Tannaz Moin and Caroline R. Richardson

Erratum to: What impact do assumptions about missing data have on conclusions? a practical sensitivity analysis for a cancer survival registry

Authors: M. Smuk, J. R. Carpenter and T. P. Morris

The effect of postal questionnaire burden on response rate and answer patterns following admission to intensive care: a randomised controlled trial

The effects of postal questionnaire burden on return rates and answers given are unclear following treatment on an intensive care unit (ICU). We aimed to establish the effects of different postal questionnaire...

Authors: Robert Hatch, Duncan Young, Vicki Barber, David A Harrison and Peter Watkinson

Evaluation of AMSTAR to assess the methodological quality of systematic reviews in overviews of reviews of healthcare interventions

Overviews of reviews (overviews) compile information from multiple systematic reviews (SRs) to provide a single synthesis of relevant evidence for decision-making. It is recommended that authors assess and rep...

Authors: Michelle Pollock, Ricardo M. Fernandes and Lisa Hartling

Erratum to: Evaluation of biases present in the cohort multiple randomised controlled trial design: a simulation study

Authors: Jane Candlish, Alexander Pate, Matthew Sperrin and Tjeerd van Staa

Methods for conceptualising ‘visual ability’ as a measurable construct in children with cerebral palsy

Vision influences functioning and disability of children with cerebral palsy, so there is a growing need for psychometrically robust tools to advance assessment of children’s vision abilities in clinical pract...

Authors: Belinda Deramore Denver, Margareta Adolfsson, Elspeth Froude, Peter Rosenbaum and Christine Imms

Incorporating nonlinearity into mediation analyses

Mediation is an important issue considered in the behavioral, medical, and social sciences. It addresses situations where the effect of a predictor variable X on an outcome variable Y is explained to some extent ...

Authors: George J. Knafl, Kathleen A. Knafl, Margaret Grey, Jane Dixon, Janet A. Deatrick and Agatha M. Gallo

Standardizing effect size from linear regression models with log-transformed variables for meta-analysis

Meta-analysis is very useful to summarize the effect of a treatment or a risk factor for a given disease. Often studies report results based on log-transformed variables in order to achieve the principal assum...

Authors: Miguel Rodríguez-Barranco, Aurelio Tobías, Daniel Redondo, Elena Molina-Portillo and María José Sánchez

Implementation of clinical research trials using web-based and mobile devices: challenges and solutions

With the increasing implementation of web-based, mobile health interventions in clinical trials, it is crucial for researchers to address the security and privacy concerns of patient information according to h...

Authors: Roy Eagleson, Luis Altamirano-Diaz, Alex McInnis, Eva Welisch, Stefanie De Jesus, Harry Prapavessis, Meghan Rombeek, Jamie A. Seabrook, Teresa Park and Kambiz Norozi

The feasibility of matching on a propensity score for acupuncture in a prospective cohort study of patients with chronic pain

Propensity scores are typically applied in retrospective cohort studies. We describe the feasibility of matching on a propensity score derived from a retrospective cohort and subsequently applied in a prospect...

Authors: Eric S. Johnson, John F. Dickerson, William M. Vollmer, Alee M. Rowley, Cheryl Ritenbaugh, Richard A. Deyo and Lynn DeBar

Assignment of adverse event indexing terms in randomized clinical trials involving spinal manipulative therapy: an audit of records in MEDLINE and EMBASE databases

Reporting of adverse events in randomized clinical trials (RCTs) is encouraged by the authors of The Consolidated Standards of Reporting Trials (CONSORT) statement. With robust methodological design and adequa...

Authors: Lindsay M. Gorrell, Roger M. Engel, Reidar P. Lystad and Benjamin T. Brown