Systematic reviewers are advised to search trials registers to minimise risk of reporting biases. However, there has been little research on the impact of searching trials registers on the results of meta-analyses. We aimed to evaluate the impact of searching clinical trials registers for systematic reviews of pharmaceutical or non-pharmaceutical…

A substantial proportion of trial registrations are not linked to corresponding published articles, limiting analyses and new tools. Our aim was to develop a method for finding articles reporting the results of trials that are registered on ClinicalTrials.gov when they do not include metadata links. We used a set of 27,280 trial registration and…

The practice of prospectively registering the details of intervention studies in a public database or registry is gaining momentum across disciplines as a strategy for increasing the transparency, credibility, and accessibility of study findings. In this article, we consider five registries that may be relevant for registration of intervention…

Network meta-analysis is a popular method to synthesize the information obtained in a systematic review of studies (e.g., randomized clinical trials) involving subsets of multiple treatments of interest. The dominant method of analysis employs within-study information on treatment contrasts and integrates this over a network of studies. One…

Many randomized trials evaluate an intervention effect on time-to-event outcomes. Individual participant data (IPD) from such trials can be obtained and combined in a so-called IPD meta-analysis (IPD-MA), to summarize the overall intervention effect. We performed a narrative literature review to provide an overview of methods for conducting an…

Meta-analyses of clinical trials targeting rare events face particular challenges when the data lack adequate numbers of events for all treatment arms. Especially when the number of studies is low, standard random-effects meta-analysis methods can lead to serious distortions because of such data sparsity. To overcome this, we suggest the use of…

This article offers a longitudinal computational-rhetorical analysis of biomedical writing on opioids. Using a corpus of 1,467 articles and essays published in the "New England Journal of Medicine" and the "Journal of the American Medical Association" between 1959 and May 2019, this study evaluates diachronic shifts in (a) the…

Clinical trial data are essential for assessments of the effectiveness of health care interventions. Information about ongoing or completed, but not yet formally published, trials has been more difficult to identify until the development of clinical trials registers and portals. This paper summarises research evidence on identifying sources of…

Statistical methods for sequential meta-analysis have applications also for the design of new trials. Existing methods are based on group sequential methods developed for single trials and start with the calculation of a required information size. This works satisfactorily within the framework of fixed effects meta-analysis, but conceptual…

Secretin is used in the United States for diagnosis of pancreatic gastrointestinal (GI) dysfunction and disease. Repeated therapeutic use has not been approved. Widespread interest in secretin as a treatment for autism followed media reports of behavioral improvements in an autistic child who received the hormone during a GI diagnostic procedure.…