BMC Medical Research Methodology

https://bmcmedresmethodol.biomedcentral.com

List of Papers (Total 1,597)

The relationship between statistical power and predictor distribution in multilevel logistic regression: a simulation-based approach

Despite its popularity, issues concerning the estimation of power in multilevel logistic regression models are prevalent because of the complexity involved in its calculation (i.e., computer-simulation-based approaches). These issues are further compounded by the fact that the distribution of the predictors can play a role in the power to estimate these effects. To address both...

Towards greater understanding of implementation during systematic reviews of complex healthcare interventions: the framework for implementation transferability applicability reporting (FITAR)

There have been calls for greater consideration of applicability and transferability in systematic reviews, to improve their usefulness in informing policy and practice. Understanding how evidence is, or is not applicable and transferable to varying local situations and contexts, is a key challenge for systematic review synthesis in healthcare. Assessing applicability and...

Understanding the importance of key risk factors in predicting chronic bronchitic symptoms using a machine learning approach

Chronic respiratory symptoms involving bronchitis, cough and phlegm in children are underappreciated but pose a significant public health burden. Efforts for prevention and management could be supported by an understanding of the relative importance of determinants, including environmental exposures. Thus, we aim to develop a prediction model for bronchitic symptoms...

A Bayesian hierarchical logistic regression model of multiple informant family health histories

Family health history (FHH) inherently involves collecting proxy reports of health statuses of related family members. Traditionally, such information has been collected from a single informant. More recently, research has suggested that a multiple informant approach to collecting FHH results in improved individual risk assessments. Likewise, recent work has emphasized the...

A methodological systematic review of meta-ethnography conduct to articulate the complex analytical phases

Decision making in health and social care requires robust syntheses of both quantitative and qualitative evidence. Meta-ethnography is a seven-phase methodology for synthesising qualitative studies. Developed in 1988 by sociologists in education Noblit and Hare, meta-ethnography has evolved since its inception; it is now widely used in healthcare research and is gaining...

Likelihood-based random-effects meta-analysis with few studies: empirical and simulation studies

Standard random-effects meta-analysis methods perform poorly when applied to few studies only. Such settings however are commonly encountered in practice. It is unclear, whether or to what extent small-sample-size behaviour can be improved by more sophisticated modeling. We consider likelihood-based methods, the DerSimonian-Laird approach, Empirical Bayes, several adjustment...

Population-based assessment of health, healthcare utilisation, and specific needs of Syrian migrants in Germany: what is the best sampling method?

Studies elucidating health-related information and special needs of Syrian migrants living in Germany are urgently required. However, data is scarce and finding appropriate sampling strategies to obtain representative results is challenging. In order to increase survey response in hard-to-reach populations, new methods were developed. One of them is respondent-driven sampling...

A new approach for sample size calculation in cost-effectiveness studies based on value of information

Value of information is now recognized as a reference method in the decision process underpinning cost-effectiveness evaluation. The expected value of perfect information (EVPI) is the expected value from completely reducing the uncertainty surrounding the cost-effectiveness of an innovative intervention. Among sample size calculation methods used in cost-effectiveness studies...

A comparison of metrics and performance characteristics of different search strategies for article retrieval for a systematic review of the global epidemiology of kidney and urinary diseases

Conducting a systematic review requires a comprehensive bibliographic search. Comparing different search strategies is essential for choosing those that cover all useful data sources. Our aim was to develop search strategies for article retrieval for a systematic review of the global epidemiology of kidney and urinary diseases, and evaluate their metrics and performance...

Primary versus secondary source of data in observational studies and heterogeneity in meta-analyses of drug effects: a survey of major medical journals

The data from individual observational studies included in meta-analyses of drug effects are collected either from ad hoc methods (i.e. “primary data”) or databases that were established for non-research purposes (i.e. “secondary data”). The use of secondary sources may be prone to measurement bias and confounding due to over-the-counter and out-of-pocket drug consumption, or non...

The effect of a voucher incentive on a survey response rate in the clinical setting: a quasi-randomized controlled trial

Financial rewards have been shown to be an important motivator to include normal healthy volunteers in trials. Less emphasis has been put on non-healthy volunteers. No previous study has investigated the impact of a voucher incentive for participants in a cross-sectional study in a clinical setting. The objective of this study was to examine the impact of a small voucher...

Community Assessment of COPD Health Care (COACH) study: a clinical audit on primary care performance variability in COPD care

A thorough evaluation of the adequacy of clinical practice in a designated health care setting and temporal context is key for clinical care improvement. This study aimed to perform a clinical audit of primary care to evaluate clinical care delivered to patients with COPD in routine clinical practice. The Community Assessment of COPD Health Care (COACH) study was an observational...

Comparing performance between log-binomial and robust Poisson regression models for estimating risk ratios under model misspecification

Log-binomial and robust (modified) Poisson regression models are popular approaches to estimate risk ratios for binary response variables. Previous studies have shown that comparatively they produce similar point estimates and standard errors. However, their performance under model misspecification is poorly understood. In this simulation study, the statistical performance of the...

Comparison of response rates on invitation mode of a web-based survey on influenza vaccine adverse events among healthcare workers: a pilot study

Web-based surveys have become increasingly popular but response rates are low and may be prone to selection bias. How people are invited to participate may impact response rates and needs further study as previous evidence is contradictory. The purpose of this study was to determine whether response to a web-based survey of healthcare workers would be higher with a posted or an...

Analysis of randomised trials with long-term follow-up

Randomised trials with long-term follow-up can provide estimates of the long-term effects of health interventions. However, analysis of long-term outcomes in randomised trials may be complicated by problems with the administration of treatment such as non-adherence, treatment switching and co-intervention, and problems obtaining outcome measurements arising from loss to follow-up...

The appropriateness of Bland-Altman’s approximate confidence intervals for limits of agreement

Percentiles are widely used as reference limits for determining the relative magnitude and substantial importance of quantitative measurements. An important application is the advocated Bland-Altman limits of agreement. To contribute to the data analysis and design planning of reference limit or percentile research, the purpose of this paper is twofold. The first is to clarify...

Influence of blinding on treatment effect size estimate in randomized controlled trials of oral health interventions

Recent methodologic evidence suggests that lack of blinding in randomized trials can result in under- or overestimation of the treatment effect size. The objective of this study is to quantify the extent of bias associated with blinding in randomized controlled trials of oral health interventions. We selected all oral health meta-analyses that included a minimum of five...

Comparison of methodological quality rating of systematic reviews on neuropathic pain using AMSTAR and R-AMSTAR

Systematic reviews (SRs) in the field of neuropathic pain (NeuP) are increasingly important for decision-making. However, methodological flaws in SRs can reduce the validity of conclusions. Hence, it is important to assess the methodological quality of NeuP SRs critically. Additionally, it remains unclear which assessment tool should be used. We studied the methodological quality...

Advantages of a multi-state approach in surgical research: how intermediate events and risk factor profile affect the prognosis of a patient with locally advanced rectal cancer

Standard survival analysis fails to give insight into what happens to a patient after a first outcome event (like first relapse of a disease). Multi-state models are a useful tool for analyzing survival data when different treatments and results (intermediate events) can occur. Aim of this study was to implement a multi-state model on data of patients with rectal cancer to...

The management of children with bronchiolitis in the Australasian hospital setting: development of a clinical practice guideline

Bronchiolitis is the commonest respiratory infection in children less than 12 months and cause of hospitalisation in infants under 6 months of age in Australasia. Unfortunately there is substantial variation in management, despite high levels of supporting evidence. This paper reports on the process, strengths and challenges of the hybrid approach used to develop the first...

Using an onset-anchored Bayesian hierarchical model to improve predictions for amyotrophic lateral sclerosis disease progression

Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s disease, is a rare disease with extreme between-subject variability, especially with respect to rate of disease progression. This makes modelling a subject’s disease progression, which is measured by the ALS Functional Rating Scale (ALSFRS), very difficult. Consider the problem of predicting a subject’s ALSFRS score...

Evaluating screening approaches for hepatocellular carcinoma in a cohort of HCV related cirrhosis patients from the Veteran’s Affairs Health Care System

Hepatocellular carcinoma (HCC) has limited treatment options in patients with advanced stage disease and early detection of HCC through surveillance programs is a key component towards reducing mortality. The current practice guidelines recommend that high-risk cirrhosis patients are screened every six months with ultrasonography but these are done in local hospitals with...

Multiple Score Comparison: a network meta-analysis approach to comparison and external validation of prognostic scores

Prediction models and prognostic scores have been increasingly popular in both clinical practice and clinical research settings, for example to aid in risk-based decision making or control for confounding. In many medical fields, a large number of prognostic scores are available, but practitioners may find it difficult to choose between them due to lack of external validation as...

On the use of the outcome variable “small for gestational age” when gestational age is a potential mediator: a maternal asthma perspective

The variable “small for gestational age,” frequently defined as birth weight below the 10th percentile in a gestational age and sex-normalized population, is nowadays generally perceived as a more adequate measure than birth weight or low birth weight (birth weight < 2500 g) to capture fetal growth. However, the use of small for gestational age rather than birth weight or low...

Methods to perform systematic reviews of patient preferences: a literature survey

Systematic reviews are a commonly used research design in the medical field to synthesize study findings. At present—although several systematic reviews of patient preference studies are published—there is no clear guidance available for researchers to conduct this type of systematic review. The aim of our study was to learn the most current practice of conducting these...