China
Africa
Explore chapters and articles related to this topic
Cluster Randomized Trials
Published in Susan Halabi, Stefan Michiels, Textbook of Clinical Trials in Oncology, 2019
Stepped-wedge trials: A stepped-wedge trial is similar to a crossover trial except that the crossovers are all in one direction, from control to intervention condition, and are staggered over time. Clusters are randomized to cross over to the intervention at time points called steps, and all clusters end the trial in the intervention condition. Stepped-wedge trials are discussed in several articles [62–65].
Alternative Study Designs
Published in Richard J. Hayes, Lawrence H. Moulton, Cluster Randomised Trials, 2017
Richard J. Hayes, Lawrence H. Moulton
In terms of statistical efficiency, the stepped wedge design’s effect estimator can have a much larger variance than that of the simple parallel group design. This is easy to see because, in general, the variance of an observed difference between two treatment arms is minimised when there is an equal number of observations (or person-time) in each arm. In a stepped wedge trial, if the analysis is based on between-cluster comparisons within each time-slice (‘vertical’ approach), this will only be the case in the ‘middle time-slice’ where there are equal numbers of clusters in the intervention and control arms. In all other time-slices, the variance of the difference will be greater than for a parallel group design. Similarly, if the analysis is based on before–after comparisons within each cluster (‘horizontal’ approach), there are many clusters with very little time in the control phase, and others with little time in the intervention phase. This built-in inefficiency of the design, however, diminishes and can even reverse if there is enough within-cluster correlation over time. Any proper analysis will account for such possible correlation, and in so doing, will increase relative efficiency as the correlation increases. A stepped wedge trial can be thought of as a kind of pair-matched design, with each cluster providing a pair of observations before and after the introduction of the intervention. At some point, analogous to a paired t-test compared with an unpaired t-test, accounting for the pairing will be the more efficient choice (Woertman et al. 2013; Hemming and Girling 2013).
The Association Between Suicide-Related Media Coverage and Suicide: A Cross-Sectional Observational Study
Published in Archives of Suicide Research, 2022
Emma Hofstra, Marjan Bakker, Chiara A. M. Diepstraten, Iman Elfeddali, Mathilde S. Lucas, Chijs van Nieuwenhuizen, Christina M. van der Feltz-Cornelis
Although some literature suggests that there is a small effect of media portrayal on actual suicide, no evidence for such an association is found in this study. The exact role of media on suicide, in relation to other risk factors of suicide, is yet unknown. A recommendation for practice is to better implement the protective media guidelines, such as stimulating help-seeking behavior, so that the potential preventive effect of media on suicide can be better investigated. For future research, it is recommended to perform more controlled studies to the association between the quality of media reports and actual suicides. This would imply performing a study in a region or country that is well known for low adherence to media guidelines, and then educating the media to improve their reporting. Evaluation studies to the use and effectiveness of media guidelines have been performed (Bohanna & Wang, 2012), also in the context of a multilevel intervention for suicide prevention by the European Alliance Against Depression (Hegerl et al., 2008; 2009). However, to enable evaluation to establish a causal relationship, a study involving multiple regions and a stepped wedge trial might be needed, as this provides an ethical research design to investigate this issue in a controlled setting. Also, in such a study, other variables influencing the decision to attempt suicide should be taken into account as much as possible.
Expanding syphilis testing: a scoping review of syphilis testing interventions among key populations
Published in Expert Review of Anti-infective Therapy, 2018
Jason J. Ong, Hongyun Fu, M. Kumi Smith, Joseph D. Tucker
We define new communication technologies as mass communication using digital technologies such as social networking platforms. Public campaigns through targeted messaging interventions have been used to increase syphilis knowledge and testing. These programs have focused on MSM and transgender people [110,113,114]. Mixed findings were reported. For example, a syphilis awareness public campaign targeting MSM in eight U.S. cities using social marketing approach reported an increased awareness of syphilis in some cities and increased syphilis testing associated with campaign participation [113]. However, the “Check Yourself “public campaign conducted in Los Angeles in the U.S. did not find a significant association between campaign awareness and syphilis testing in MSM [114]. Among technology-focused testing strategies, crowdsourcing is another approach to developing new syphilis testing campaigns. Crowdsourcing is the process of having a group solve a problem and then sharing the solution with the public [115]. Crowdsourcing has been used to solicit novel content for promotional images, videos, and HIV testing strategies. A stepped wedge trial randomized controlled trial evaluating this approach is underway and includes syphilis testing as a secondary outcome [116]. Cross-sectional data from this study suggested that dual HIV/syphilis self-testing promoted through the internet could be a feasible approach for increasing syphilis testing among MSM [117].
Association of education and feedback on hypertension management with risk for stroke and cardiovascular disease
Published in Blood Pressure, 2022
Mattias Brunström, Nawi Ng, John Dahlström, Lars H. Lindholm, Margareta Norberg, Lennarth Nyström, Lars Weinehall, Bo Carlberg
The current study illustrates the difficulties of assessing complex health care interventions using observational data and methods. Although many are enthusiastic about the potential for real-world evidence, causal inference from observational data relies on strong assumptions about exchangeability between comparison groups, assumptions that rarely hold in practice. Although individual-level randomisation may not be possible for public health interventions, cluster-randomisation or quasi-experimental approaches, like the stepped-wedge trial, are alternatives available today that would have reduced the risk of bias substantially compared to the methods employed in this paper.