title: Should data monitoring committees assess efficacy when considering safety in trials in acute stroke?
abstract: BACKGROUND
  The primary role of a trial's data monitoring committee (DMC) is to ensure the safety of enrolled patients. In stroke trials, safety is monitored typically by comparing death and stroke-specific events between treatment groups. DMCs may also have the remit for monitoring efficacy depending on the aims of the trial. We hypothesised that functional outcome at the end of follow-up, a measure of efficacy, is also a powerful measure of safety and tested this in a systematic review.
  
  
  METHODS
  Acute stroke trials with a negative outcome or which were stopped prematurely on the grounds of safety were sought systematically from searches of electronic databases and published reviews. Information on early and late death, impairment and functional outcome, and the presence of a DMC, were recorded for each trial. The results for each outcome measure were ranked within each trial to determine which was most statistically efficient in detecting hazard.
  
  
  RESULTS
  Fourteen trials were included. The most efficient outcomes for detecting hazard were late death or disability, six trials; early death, four trials (two of which tested thrombolysis); late death, three trials and late death or impairment, one trial. Early death was insensitive to hazard in all six trials where late death or dependency was most sensitive. Two trials (both phase II) did not report the presence of a DMC.
  
  
  CONCLUSIONS
  Functional outcome at end of follow-up can be sensitive to hazard and should be included in all assessments of safety in stroke trials, whether or not efficacy itself is being assessed.
authors: Institute of Neuroscience, University of Nottingham, Nottingham, UK. philip.bath@nottingham.ac.uk
authors: P M W
authors: PM
authors: Bath
authors: L J
authors: LJ
authors: Gray
authors: N-G
authors: NG
authors: Wahlgren
mesh_terms: D026661:Clinical Trials Data Monitoring Committees; D002986:Clinical Trials as Topic / Q000592:standards; D006801:Humans; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D012449:Safety; D020521:Stroke / Q000188:drug therapy / Q000401:mortality*
chemical_list: D018696:Neuroprotective Agents