title: Riboflavin as an independent and accurate biomarker for adherence in a randomized double-blind and placebo-controlled clinical trial.
abstract: BACKGROUND
  Medication adherence is critical for success of clinical trials.
  
  
  OBJECTIVE
  To assess oral riboflavin is an adherence marker.
  
  
  METHODS
  Riboflavin was incorporated into active treatment and placebo pills for a clinical trial lasting for 2 years.
  
  
  RESULTS
  The accuracy (area under the receiver operating curve) of urinary riboflavin was 0.91 as a binary classifier of adherence, and was similar or better than for two active study ingredients daidzein (0.92) and genistein (0.87) (all p < 0.0001). Decreased adherence over time was similar in the two study groups.
  
  
  CONCLUSIONS
  Riboflavin is an accurate and useful biomarker for study pill ingestion.
authors.affiliation: a Department of Preventive Medicine and Community Health , The University of Texas Medical Branch , Galveston , TX , USA.
authors.forename: V-M S
authors.initials: VS
authors.lastname: Ramanujam
authors.affiliation: a Department of Preventive Medicine and Community Health , The University of Texas Medical Branch , Galveston , TX , USA.
authors.forename: Fatima
authors.initials: F
authors.lastname: Nayeem
authors.affiliation: a Department of Preventive Medicine and Community Health , The University of Texas Medical Branch , Galveston , TX , USA.
authors.forename: Karl E
authors.initials: KE
authors.lastname: Anderson
authors.affiliation: a Department of Preventive Medicine and Community Health , The University of Texas Medical Branch , Galveston , TX , USA.
authors.forename: Yong-Fang
authors.initials: YF
authors.lastname: Kuo
authors.affiliation: a Department of Preventive Medicine and Community Health , The University of Texas Medical Branch , Galveston , TX , USA.
authors.forename: Nai-Wei
authors.initials: NW
authors.lastname: Chen
authors.affiliation: a Department of Preventive Medicine and Community Health , The University of Texas Medical Branch , Galveston , TX , USA.
authors.forename: Hyunsu
authors.initials: H
authors.lastname: Ju
authors.affiliation: a Department of Preventive Medicine and Community Health , The University of Texas Medical Branch , Galveston , TX , USA.
authors.forename: Lee-Jane W
authors.initials: LW
authors.lastname: Lu
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine; D004311:Double-Blind Method; D005260:Female; D019833:Genistein; D006801:Humans; D007529:Isoflavones; D055118:Medication Adherence; D017697:Premenopause; D012256:Riboflavin / Q000652:urine*
chemical_list: D015415:Biomarkers; D007529:Isoflavones; C004742:daidzein; D019833:Genistein; D012256:Riboflavin
keywords: Biomarker; accuracy; adherence; clinical trial; daidzein; genistein; medication compliance; receiver operating curve; riboflavin; sensitivity; specificity