title: The influence of baseline severity on efficacy of escitalopram and citalopram in the treatment of major depressive disorder: an extended analysis.
abstract: OBJECTIVE
  To determine the differences between escitalopram and citalopram in the treatment of patients with major depressive disorder across a range of baseline severity of depression using trend analysis.
  
  
  METHODS
  Data from the three placebo-controlled studies comparing escitalopram to citalopram were analyzed. The pre-specified primary outcome variable was MADRS total score; secondary outcomes included Clinical Global Impression-Severity (CGI-S) and -Improvement (CGI-I) scores. All analyses were based on an intent-to-treat (ITT) population and all direct comparisons were done by ANCOVA adjusting for baseline value and centre.
  
  
  RESULTS
  Analyses of the pooled data (N=1203) show that, while the difference between citalopram and placebo was approximately constant across the range of baseline severity, the difference between escitalopram and placebo (p=0.0010 for no trend) and between escitalopram and citalopram (p=0.0012 for no trend) became greater, the more severely depressed the patients were at baseline. A similar pattern was apparent with the CGI-S and CGI-I results. There was a significant superiority of escitalopram over citalopram in response rate (defined as > or = 50% decrease in MADRS total score), and this difference increased with increasing baseline severity.
  
  
  CONCLUSIONS
  These trend analyses thus indicate that the superiority of escitalopram over citalopram is more apparent as the baseline severity of depression increases.
authors.affiliation: University of British Columbia, Vancouver, British Columbia, Canada. r.lam@ubc.ca
authors.forename: R W
authors.initials: RW
authors.lastname: Lam
authors.forename: H F
authors.initials: HF
authors.lastname: Andersen
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D018687:Antidepressive Agents, Second-Generation / Q000627:therapeutic use*; D015283:Citalopram / Q000627:therapeutic use*; D003865:Major Depressive Disorder / Q000188:drug therapy*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D016032:Randomized Controlled Trials as Topic; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use*; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D018687:Antidepressive Agents, Second-Generation; D015283:Citalopram; D017367:Selective Serotonin Reuptake Inhibitors