Faculty of Health and Medical Sciences

Bias minimisation

Study Reporting

Reporting of follow-up, dropouts, and crossover is important because there may be a systematic reason for loss of follow-up or dropout from one arm of a study, or for patients to not undergo one of two diagnostic tests under comparison. The study report should transparently account for all patients. Reports of randomised controlled trials are now required to include a CONSORT diagram by the ICMJE.

This diagram, represented as a series of boxes containing patient numbers, describes how many patients withdrew, crossed over, or were lost to follow up, often with reasons for these events. Duration and completeness of follow-up should be sufficient and of the right time frame to see the effect being looked for.

CONSORT diagram from an RCT of a supporting care intervention in advanced cancer patients

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Figure 1: CONSORT diagram from an RCT of a supporting care intervention in advanced cancer patients. It clearly shows where patients died, were lost to follow up, or stopped treatment. Text explanation would be complex and difficult to follow. Reprinted from The Lancet Oncology 2007:8: 603-12 with permission from Elsevier http://www.thelancet.com/journals/lanonc.


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