A systematic review of the usage of flow diagram in cluster randomized trials

Abstract

Flow diagram represent an integral part of consolidated standards of reporting trials (CONSORT). Its use in reporting cluster randomization trials is highly recommended. The aim of this article is to present frequency of the use of flow diagram in cluster randomized trials in accordance with standards of reporting. The team has researched Medline database and singled-out 474 studies with cluster randomization for analysis. The studies were reviewed to identify the use of graphic representation, compliance with standards of reporting and the date when study was published. Depending from its duration, studies were divided on completed, and those still ongoing. Usage of CONSORT is recorded in 145 (31%) literature units. Frequency of flow diagram was statistically much higher in studies which were in compliance with standards (86,2%), in comparison to those which did not use CONSORT guidelines (71,4%), as well as in completed studies (81,2%) in comparison to pilot project studies (54,3%). Number of cluster randomized trials gathered through MEDLINE's search of key words 'cluster randomized trial [ti]' and 'cluster randomised trial [ti]', as well as the use of CONSORT in the reports of cluster randomized trials, are showing linear growth over time (p<0,001). Frequency of flow diagram is higher in the reports of cluster randomized trials that were done in accordance with the standards of reporting.