Reporting the results of a controlled trial

Randomized controlled trials (RCTs) are considered the gold standard for evaluation of healthcare interventions. Biases introduced by inadequate methods, however, affect rigor of evidence from RCTs. Thus, a complete and transparent reporting of methods and results is needed to help readers to evaluate the quality of evidence from RCTs. Results section is the most important part of the manuscript reporting findings from an RCT where the effect of an intervention on outcomes is presented along with necessary information needed for interpretation of results. CONSORT (Consolidated Standards of Reporting Trials)statement provides a framework of essential elements for reporting of RCT.1 Recent reviews assessing quality of reporting of RCTs have suggested that although CONSORT statement has improved reporting consistency, not all published papers adhere to reporting standards and completeness of reporting is suboptimal.2-6 In this second commentary of our two part series,7 we provide a summary of essential elements of an RCT results that should be reported in the manuscript. We have drawn on CONSORT statement for this commentary. 1,8 We have also included the fictive example from our previous commentary which refers to a comparison of clinical efficacy of drug "B" with drug "A" using randomized controlled design.7 The essential subsections of RCT results described here are participants' flow, baseline characteristics, primary analyses, additional analyses, adherence, and harmful effects. Participant flow through the study The RCT manuscript should describe participant flow starting with numbers screened for eligibility to those included in the primary analysis, presenting all exclusions and losses and reasons for losses throughout the study. This information is important for interpretation of results to assess validity of findings and potential for selection bias related to withdrawal from the study after randomization/treatment allocation, loss to follow-up across study arms, and exclusion from main analysis, all impacting results of the study. The CONSORT statement recommends a figure presenting the flow of participants. 1,8 In this figure, authors should provide number of participants screened for eligibility and provide number for major conditions for ineligibility. Then in the diagram, authors should describe that of eligible participants how many were randomized intervention or comparator, and briefly describe the reasons of non-randomization. Then, the diagram should include the numbers of those who had received intervention or comparator, and the numbers of those who completed study treatments (intervention or control). A description of those completing planned follow-up or not by treatment arm (intervention or control), and those included in the final analyses should be available in the diagram and text. Periods of enrollment and follow-up provide historical context for interpretation and relevance of findings, and therefore must be included in methods or results section. Please see Figure-1 adapted from CONSORT guidelines based on our fictive example of comparison of drugs "A" and "B." The diagram is divided into four sections which are enrollment, allocation, follow up and analyses to describe exclusions and losses and the reasons for losses during each step of the study.