Clinical Trials

❘❙❚■ Chapter 35 | Use of TablesThe CONSORT (Consolidated Standards of Reporting Trials) guidelines forreporting of clinical trials state that the number of participants (denominator) in eachgroup included in each analysis must be reported, as well as whether the analysiswas by ‘intention-to-treat’ (see Chapter 22) [1]. The guidelines also suggest that theresults should be stated in absolute numbers when feasible (eg, 10/20, not 50%),although giving both can be considered good practice. For each primary andsecondary outcome, the report should quote a summary of results for each group,and the estimated effect size and its precision (eg, 95% CI as in Table 1).Authors must address multiplicity by reporting any other analyses performed,including subgroup analyses and adjusted analyses, indicating those that wereprespecified and those that were exploratory (see Chapters 23, 25, and 29). Allimportant adverse events or side-effects in each intervention group also need to bereported. International journals such as The Lancet require that all contributorsabide by such guidelines.Detailed advice on constructing a tableOnce you are ready to construct a table, there are a number of guidelines to helpproduce the best format.OverviewPurposeDecide on the purpose of the table and what information should be includedwithin it. For clinical trials, this is generally a comparison between two treatmentgroups, and the table will contain summary statistics for each treatment, as well asinformation directly comparing the two treatments.Table sizeSmaller tables can draw readers in more clearly to the main issue you want to getacross, although a single row table might be best incorporated in the text. In ajournal with a double-column page, a single-column table should not exceed60 characters (and equivalent spaces) and a full-width table should not exceed120 characters [6].Unnecessary informationThe best tables contain information that will be useful to the reader. Avoidrepeating information in figures or text, other than the key outcomes. Balance themerits of giving the readers additional information with the possibility that thereaders will feel overwhelmed if faced with too much information. This is oftenthe case in tables of clinical characteristics.400