title: Critical care trial design and interpretation: a primer.
abstract: OBJECTIVE
  Better understanding of the pathophysiology of critical illness has led to an increase in clinical trials designed to improve the clinical care and outcomes of patients with life-threatening illness. Knowledge of basic principles of clinical trial design and interpretation will assist the clinician in better applying the results of these studies into clinical practice.
  
  
  METHODS
  We review selected clinical trials to highlight important design features that will improve understanding of the results of critical care clinical trials designed to improve clinical care of the critically ill.
  
  
  RESULTS
  Trial design features such as patient selection, bias, sample size calculation, selection of subjects and controls, and primary outcome measure may influence the results of a critical care clinical trial designed to test a therapy targeting improved clinical care. In conjunction with trial design knowledge, understanding the size of the anticipated treatment effect, the importance of any clinical end point achieved, and whether patients in the trial are representative of typical patients with the illness will assist the reader in determining whether the results should be applied to specific patients or usual clinical practice.
  
  
  CONCLUSIONS
  Better understanding of important aspects of trial design and interpretation, such as whether patients enrolled in both intervention arms were comparable and whether the primary outcome of the trial is clinically important, will assist the bedside clinician in determining whether to apply the findings from the clinical study into clinical practice.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland, USA. jsevran1@jhmi.edu
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Sevransky
authors.forename: William
authors.initials: W
authors.lastname: Checkley
authors.forename: Greg S
authors.initials: GS
authors.lastname: Martin
mesh_terms: D002986:Clinical Trials as Topic; D003422:Critical Care; D006801:Humans; D012107:Research Design