A CONSORT flow diagram serves as a standardized visual tool in scientific publications, primarily within clinical research. It illustrates the progression of participants through a randomized clinical trial from initial screening to final analysis. This diagram provides a clear overview of participant numbers at each stage of a trial.
What is a CONSORT Flow Diagram?
A CONSORT flow diagram is a graphical representation depicting the journey of participants in a clinical trial. Its purpose is to provide a transparent account of how participants were recruited, assigned to different study groups, monitored, and included in the final data analysis. This diagram is a core component of the Consolidated Standards of Reporting Trials (CONSORT) Statement, an evidence-based set of recommendations for reporting randomized controlled trials. The diagram helps researchers and readers understand the flow of participants and identify any potential deviations from the study protocol.
The diagram enhances the clarity and completeness of trial reports, making it easier to assess the reliability of the study’s results. It visually summarizes the participant journey, from eligibility assessment to study completion, aiding in the evaluation of research findings.
Understanding the Diagram’s Stages
The CONSORT flow diagram typically outlines four distinct stages of participant progression in a clinical trial: Enrollment, Allocation, Follow-up, and Analysis. Each stage provides specific numerical details about the participants.
The Enrollment stage shows the total number of participants assessed for eligibility. It details how many were excluded, with reasons such as not meeting inclusion criteria or declining to participate. Finally, it indicates the number of participants deemed eligible and randomized into the study.
The Allocation stage illustrates how eligible participants were assigned to different intervention groups, such as the experimental treatment group or the control group. It clarifies the number of participants assigned to each arm of the trial and accounts for any who were allocated but did not receive the intended intervention.
The Follow-up stage tracks participants through the study duration after allocation. It shows the number who completed the follow-up period in each group and identifies those lost to follow-up or who discontinued the intervention, along with the reasons for withdrawal.
The Analysis stage specifies the number of participants from each group whose data were included in the primary outcome analysis. It also notes any participants who were excluded from the analysis and the reasons for their exclusion.
Why CONSORT Diagrams Matter
CONSORT diagrams significantly improve the transparency of clinical trial reporting. By visually presenting the participant journey, these diagrams enable readers to quickly understand how many individuals were involved at each study stage. This clarity makes it easier to evaluate the study’s design and execution.
These diagrams also contribute to the reproducibility of research findings. Researchers can assess if participant flow was consistent with the study protocol and identify potential sources of bias. For example, a high number of participants lost to follow-up in one group could indicate bias affecting generalizability. The diagram provides a standardized format for easy comparison across different studies.
Practical Steps for Diagram Creation
Creating a CONSORT flow diagram requires careful tracking of participant data throughout the clinical trial. Researchers need to record the number of individuals at each defined stage: screening, eligibility assessment, randomization, intervention receipt, follow-up, and final analysis. This includes documenting reasons for exclusion or withdrawal at every step.
The data points needed include the initial number of participants screened, the number excluded with specific reasons, and the number randomized. For the allocation phase, the count of participants assigned to each group and any who did not receive the intervention are recorded. During follow-up, the numbers completing the study, those lost, and their reasons are documented. Finally, the number of participants included in the analysis for each group is reported. Various software tools, such as Microsoft PowerPoint, specialized diagramming software, or online templates, can assist in constructing these diagrams.
References
1. Schulz, K. F., Altman, D. G., Moher, D., & CONSORT Group. (2010). CONSORT 2010 statement: updated guidelines for reporting parallel group randomised trials. BMJ, 340, c332.
2. Moher, D., Hopewell, A., Schulz, K. F., Montori, V., Gøtzsche, P. C., Devereaux, P. J., … & Altman, D. G. (2010). CONSORT 2010 explanation and elaboration: updated guidelines for reporting parallel group randomised trials. BMJ, 340, c869.