Clinical Trials

❘❙❚■ Chapter 33 | Trial ProfileFigure 2. Trial profile for a parallel design study investigating the use of Mycobacterium vaccae in thetreatment of pulmonary tuberculosis (TB) [2].484 eligible patients374 randomized110 excluded10 excluded• 1 did nothave TB185 receivedplacebo189 receivedvaccine17 excluded• 1 did nothave TB• 9 resistantorganism175 analyzed forprimary endpoint172 analyzed forprimary endpoint• 16 resistantorganismReprinted with permission from Elsevier (Lancet 1999;354:116–19).are excluded after allocation and are not available for follow-up (eg, because of aside-effect of treatment, or worsening of the disease process) might not be typicalof the other participants in the study and this can bias the results. The trial profilewill allow the reader to determine whether an analysis is intention-to-treat –ie, whether the analysis has been performed on all those patients who wererandomized to the group they were originally allocated to (regardless of theirsubsequent treatment) or only on those who completed the entire study (perprotocol analysis).It might be necessary to adapt the flow chart to suit the needs of a particular trial.For example, there may be a large number of patients who do not receive theallocated treatment as planned, so that the box describing treatment allocationwould need to be expanded to describe the reasons for this and the number ofpatients for each reason (categorized into broad divisions if needed).Examples of trial profilesIn this section, three trial profiles from published studies with different trial designswill be described: a two-way parallel design, a 2 × 2 factorial design, and a two-waycrossover design. Although the CONSORT guidelines on trial profiles were designedfor reporting parallel-group randomized controlled trials, the profile can be adaptedto describe the flow of participants in factorial and crossover design trials.380