title: Treatment response to pregabalin in fibromyalgia pain: effect of patient baseline characteristics.
abstract: OBJECTIVE
  The objective of this study was to evaluate the effect of patients' characteristics at baseline on the magnitude of pain response to pregabalin in patients with fibromyalgia.
  
  
  METHODS
  Data from four randomized, multicenter, placebo-controlled clinical studies of pregabalin in patients with fibromyalgia were used for the analysis. Approved doses (300 and 450 mg/day) were pooled to enhance the sensitivity of the interaction tests. A centered covariate interaction model was used to assess the treatment effects; a noncentered model was used for estimated mean pain changes and least square means across different levels of baseline covariates. The interaction was considered significant if p < 0.10.
  
  
  RESULTS
  In total, 2061 patients (median age, 49 years; median pain score, 7.0; median duration of fibromyalgia, 83 months) were included in this analysis. No significant interaction was observed between treatment and anxiety, depression, or duration of fibromyalgia. Significant treatment by baseline mean pain (p = 0.037), treatment by baseline sleep score (p = 0.071), and treatment by age (p = 0.051) interactions were observed.
  
  
  CONCLUSIONS
  The magnitude of response to pregabalin in terms of changes in pain may depend on age, pain, and sleep levels at baseline in patients with fibromyalgia.
authors.affiliation: Statistics, Primary Care Business Unit, Pfizer, Inc., 235 East 42nd Street, New York, NY 10017-5755, USA. birol.emir@pfizer.com
authors.forename: Birol
authors.initials: B
authors.lastname: Emir
authors.forename: Thomas Kevin
authors.initials: TK
authors.lastname: Murphy
authors.forename: Danielle Lauren
authors.initials: DL
authors.lastname: Petersel
authors.forename: Ed
authors.initials: E
authors.lastname: Whalen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000700:Analgesics / Q000627:therapeutic use*; D001007:Anxiety / Q000150:complications / Q000523:psychology; D003863:Depression / Q000150:complications / Q000523:psychology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005356:Fibromyalgia / Q000150:complications / Q000188:drug therapy* / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy* / Q000209:etiology / Q000523:psychology; D010147:Pain Measurement; D000069583:Pregabalin; D012893:Sleep Wake Disorders / Q000150:complications / Q000523:psychology; D016896:Treatment Outcome; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D000700:Analgesics; D000069583:Pregabalin; D005680:gamma-Aminobutyric Acid