title: Treatment assignment guesses by study participants in a double-blind dose escalation clinical trial of saw palmetto.
abstract: OBJECTIVE
  This report assesses participant perception of treatment assignment in a randomized, double-blind, placebo-controlled trial of saw palmetto for the treatment of benign prostatic hyperplasia (BCM).
  
  
  METHODS
  Participants randomized to receive saw palmetto were instructed to take one 320 mg gelcap daily for the first 24 weeks, two 320 mg gelcaps daily for the second 24 weeks, and three 320 mg gelcaps daily for the third 24 weeks. Study participants assigned to placebo were instructed to take the same number of matching placebo gelcaps in each time period. At 24, 48, and 72 weeks postrandomization, the American Urological Association Symptom Index (AUA-SI) was administered and participants were asked to guess their treatment assignment.
  
  
  METHODS
  The study was conducted at 11 clinical centers in North America.
  
  
  METHODS
  Study participants were men, 45 years and older, with moderate to low severe BPH symptoms, randomized to saw palmetto (N=151) or placebo (N=155).
  
  
  METHODS
  Treatment arms were compared with respect to the distribution of participant guesses of treatment assignment.
  
  
  RESULTS
  For participants assigned to saw palmetto, 22.5%, 24.7%, and 29.8% correctly thought they were taking saw palmetto, and 37.3%, 40.0%, and 44.4% incorrectly thought they were on placebo at 24, 48, and 72 weeks, respectively. For placebo participants, 21.8%, 27.4%, and 25.2% incorrectly thought they were on saw palmetto, and 41.6%, 39.9%, and 42.6% correctly thought they were on placebo at 24, 48, and 72 weeks, respectively. The treatment arms did not vary with respect to the distributions of participants who guessed they were on saw palmetto (p=0.823) or placebo (p=0.893). Participants who experienced an improvement in AUA-SI were 2.16 times more likely to think they were on saw palmetto.
  
  
  CONCLUSIONS
  Blinding of treatment assignment was successful in this study. Improvement in BPH-related symptoms was associated with the perception that participants were taking saw palmetto.
authors: 1 Department of Biostatistics, University of Arkansas for Medical Sciences , Little Rock, AR.
authors: Jeannette Y
authors: JY
authors: Lee
authors: Page
authors: P
authors: Moore
authors: John
authors: J
authors: Kusek
authors: Michael
authors: M
authors: Barry
mesh_terms: D000368:Aged; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D008875:Middle Aged; D010919:Placebos; D010936:Plant Extracts / Q000008:administration & dosage*; D011470:Prostatic Hyperplasia / Q000188:drug therapy; D016032:Randomized Controlled Trials as Topic / Q000523:psychology*; D035842:Research Subjects / Q000523:psychology*; D028024:Serenoa
chemical_list: D010919:Placebos; D010936:Plant Extracts; C040972:saw palmetto extract
references: Prostaglandins Leukot Essent Fatty Acids. 2002 Apr;66(4):393-5
references: 12054908
references: Ann Intern Med. 2001 Apr 17;134(8):663-94
references: 11304107
references: Pain. 2002 Sep;99(1-2):91-9
references: 12237187
references: BJU Int. 2011 Mar;107(6):946-54
references: 21332630
references: N Engl J Med. 2005 Jul 28;353(4):341-8
references: 16049208
references: Radiology. 2010 Oct;257(1):219-25
references: 20851942
references: Am J Epidemiol. 2005 Aug 1;162(3):199-200
references: 15987728
references: N Engl J Med. 2006 Feb 9;354(6):557-66
references: 16467543
references: JAMA. 2002 Apr 10;287(14):1807-14
references: 11939866
references: N Engl J Med. 2003 Dec 18;349(25):2387-98
references: 14681504
references: J Subst Abuse Treat. 2008 Mar;34(2):234-41
references: 17600649
references: JAMA. 2011 Sep 28;306(12):1344-51
references: 21954478
references: J Urol. 1995 Nov;154(5):1770-4
references: 7563343
references: J Urol. 1992 Nov;148(5):1549-57; discussion 1564
references: 1279218
references: Clin Trials. 2009 Dec;6(6):628-36
references: 20007408
references: BJU Int. 2011 Aug;108(3):388-94
references: 21631695
references: Clin Pharmacol Ther. 2011 Nov;90(5):732-6
references: 21993424
references: J Child Adolesc Psychopharmacol. 2006 Feb-Apr;16(1-2):219-25
references: 16553542