The RENAL (Randomised Evaluation of Normal vs. Augmented Level of Replacement Therapy) study: statistical analysis plan

Abstract

Background: The Randomised Evaluation of Normal vs. Augmented Level of Replacement Therapy (RENAL) study is the largest interventional trial ever conducted in patients with acute renal failure.

Objective: To develop and report a pre-determined statistical analysis plan which the investigators will adhere to in analysing the data from the trial.

Methods: The data collected by the researchers as part of the trial protocol was reviewed and formally assessed. Information relevant to baseline characteristics was selected and, for each item, statistically relevant descriptive elements were described. Information relevant to the process of care and delivery of prescribed trial therapy was similarly classified and, for each item, appropriate descriptive statistical analysis was planned with appropriate comparison between groups. Finally, trial outcomes were selected, and an appropriate statistical comparison between groups was planned and described.

Results: A standard analysis plan for the RENAL trial results was developed, which allows a comprehensive description of baseline characteristics, features of the process of care and trial treatment delivery, and pre-determined statistical assessment of relevant outcome measures in a way that is transparent, available to the public, verifiable and predetermined before the actual analysis of data.

Conclusion: We have developed a pre-determined statistical analysis plan for the RENAL trial. This plan will be adhered to in order to avoid introducing any analysis bias associated with prior knowledge of study findings.