The hidden influence of communities in collaborative funding of clinical science

Every year the National Institutes of Health allocates $10.7 billion (one-third of its funds) for clinical science research while the pharmaceutical companies spend $52.9 billion (90% of its annual budget). However, we know little about funder collaborations and the impact of collaboratively funded projects. As an initial effort towards this, we examine the co-funding network, where a funder represents a node and an edge signifies collaboration. Our core data include all papers that cite and receive citations by the Cochrane Database of Systemic Reviews, a prominent clinical review journal. We find that 65% of clinical papers have multiple funders and discover communities of funders that are formed by national boundaries and funding objectives. To quantify success in funding, we use a g -index metric that indicates efficiency of funders in supporting clinically relevant research. After controlling for authorship, we find that funders generally achieve higher success when collaborating than when solo-funding. We also find that as a funder, seeking multiple, direct connections with various disconnected funders may be more beneficial than being part of a densely interconnected network of co-funders. The results of this paper indicate that collaborations can potentially accelerate innovation, not only among authors but also funders.

Effectiveness of Dental and Maxillary Transverse Changes in Tooth-Borne, Bone-Borne, and Hybrid Palatal Expansion through Cone-Beam Tomography: A Systematic Review of the Literature

Background and Objectives: Palatal expansion is a common orthodontic technique able to increase the transverse changes for subjects with constricted maxillary arches. The aim of the present investigation was to evaluate through a systematic review the tomography effectiveness of different palatal expander approaches. Materials and Methods: The database used to perform the screening and determine the eligibility of the clinical papers was PubMed (Medline). Results: The database search included a total of 284 results, while 271 articles were excluded. A total of 14 articles were included for the qualitative assessment. Conclusions: The effectiveness of the present studies reported that skeletal expansion was a useful approach to increase the transverse changes for subjects with constricted maxillary arches.

Reflections on modern methods: demystifying robust standard errors for epidemiologists

All statistical estimates from data have uncertainty due to sampling variability. A standard error is one measure of uncertainty of a sample estimate (such as the mean of a set of observations or a regression coefficient). Standard errors are usually calculated based on assumptions underpinning the statistical model used in the estimation. However, there are situations in which some assumptions of the statistical model including the variance or covariance of the outcome across observations are violated, which leads to biased standard errors. One simple remedy is to userobust standard errors, which are robust to violations of certain assumptions of the statistical model. Robust standard errors are frequently used in clinical papers (e.g. to account for clustering of observations), although the underlying concepts behind robust standard errors and when to use them are often not well understood. In this paper, we demystify robust standard errors using several worked examples in simple situations in which model assumptions involving the variance or covariance of the outcome are misspecified. These are: (i) when the observed variances are different, (ii) when the variance specified in the model is wrong and (iii) when the assumption of independence is wrong.

Factors Affecting the Number of Citations to Clinical Therapeutic Articles Mentioning Level of Evidence

Background: Level of evidence (LoE) is a hierarchical system for classifying the quality of studies. Objectives: This study examined the factors affecting the number of citations to clinical articles related to the treatment of human diseases that have included the LoE in their abstracts. Methods: A total of 3,683 therapeutic articles published between 2011 and 2013 that mentioned the LoE in their abstract and were indexed in PubMed and Web of Science were retrieved. The LoE and type of study design were extracted from abstracts and other bibliographic and citation information was obtained from PubMed and Web of Science databases. Independent samples t-test, one-way ANOVA, Pearson correlation test and linear regression were used to analyze the relationship between the variables. Results: Articles with level I evidence had the lowest frequency (290, 7.9%) and articles with level IV had the highest frequency (1,831, 49.7%). Five-year citations ranged from zero to 215, with a median of 13 citations. The median values of five-year citations from level I to level V were 20.5, 15, 14, 11, and 6 citations, respectively. Evaluation of the models to examine the factors affecting the number of citations showed that the change of evidence-level from level I to V reduced the number of citations (P < 0.001). Conclusions: Journal Impact Factor, LoE, number of references, number of authors, number of title words, number of pages, article type and subject category accounted for about 25% of the variation in five-year citations of clinical papers. Clinical papers with high LoE (levels I & II) received more citations over a five-year period than those with lower LoE (levels III & IV).

The ESC Textbook of Sports Cardiology

Sport and exercise have been intensely advocated as protective lifestyle measures, preventing or reducing the risk of severe health issues including cardiovascular disease. More extreme forms of sport (for instance at high altitudes) have been identified as an important way of promoting cardiovascular adaptation, but have also been associated with adverse effects and even major cardiovascular events. More commonplace sport and exercise may also increase an individual’s risk of cardiac events. This publication is timely in the light of an increasing number of clinical papers in this field. The textbook provides an overview of prevention, detection, and treatment for elite athletes and young sports professionals in training which will be useful for clinical cardiologists, sports physicians, and general physicians alike. Split into eleven key areas in sports cardiology, ranging from sudden cardiac death in athletes to cardiovascular effects of substance of abuse/doping, the text is an invaluable resource covering all aspects of sports cardiology.

The Omental Free Flap—A Review of Usage and Physiology

Background The omental flap has a rich history of use over the last century, and specifically as a free flap in the last four decades. It has a wide variety of applications in reconstructive surgery and has shown itself to be a reliable donor tissue. We seek to review the properties that make the omental free flap a valuable tool in reconstruction, as well as its many surgical applications in all anatomic regions of the body. Methods We conducted a narrative review of the literature on Medline and Google Scholar. We reviewed basic science articles discussing the intrinsic properties of omental tissue, along with clinical papers describing its applications. Results The omental free flap is anatomically suitable for harvest and wound coverage and has molecular properties that promote healing and improve function at recipient sites. It has demonstrated utility in a wide variety of reconstructive procedures spanning the head and neck, extremities, and viscera and for several purposes, including wound coverage, lymphedema treatment, and vascularization. It is also occasionally employed in the thoracic cavity and chest wall, though more often as a pedicled flap. More novel uses include its use for cerebrospinal fluid leaks. Conclusions The omental free flap is a valuable option for reconstructive efforts in nearly all anatomic regions. This is a result of its inherent anatomy and vascularity, and its angiogenic, immunogenic, and lymphatic properties.

Vector velocity estimation of blood flow – A new application in medical ultrasound

Vector flow techniques in the field of ultrasound encompass different pulse emission and estimation strategies. Numerous techniques have been introduced over the years, and recently commercial implementations usable in the clinic have been made. A number of clinical papers using different vector velocity approaches have been published. This review will give an overview of the most significant in vivo results achieved with ultrasound vector flow techniques, and will outline some of the possible clinical applications for vector velocity estimation in the future.