title: Treatment adherence and persistence with duloxetine, venlafaxine XR, and escitalopram among patients with major depressive disorder and chronic pain-related diseases.
abstract: OBJECTIVE
  Chronic pain is prevalent in patients with major depressive disorder (MDD). This study compared adherence and persistence rates among MDD patients with comorbid chronic pain-related diseases (CPD, including fibromyalgia, diabetes with neurological manifestations, osteoarthritis, low back pain, and headache) for three antidepressants: duloxetine, venlafaxine XR, and escitalopram.
  
  
  METHODS
  A retrospective analysis was conducted of 15,523 adult MDD patients with CPD in the MarketScan Commercial Claims and Encounters Database who started on one of the study medications between 07/01/06 and 06/30/07. Patients were followed-up for 6 months. Adherence was reported using a medication possession ratio ≥0.8. Persistence was measured using persistence rates (proportions of patients who continuously refilled prescriptions during 6 months) and duration of therapy (number of days patients remained on the study medication before a prescription gap over 30 days). Multivariate logistic regression on adherence and persistence rates and linear regression on duration of therapy adjusting for patient and prescription characteristics were conducted.
  
  
  RESULTS
  Patients on duloxetine had a higher adherence rate (46.03%) than those on venlafaxine XR (42.94%; p = 0.0033) or escitalopram (37.27%; p < 0.0001). Patients on duloxetine also had a higher persistence rate and longer duration of therapy (43.66%, 117.82 days) than did patients treated with venlafaxine XR (40.38%; p = 0.0017; 114.24 days; p = 0.009) or escitalopram (33.86%; p < 0.0001; 105.73 days; p < 0.0001). These differences were still significant after adjusting for patient and prescription characteristics (p < 0.05). Sensitivity analyses found similar patterns using an allowable gap for refill of 15 days.
  
  
  CONCLUSIONS
  Among commercially insured MDD patients with CPD, duloxetine-treated patients had higher adherence and persistence rates than did patients treated with venlafaxine XR or escitalopram during 6 months after medication initiation. Future studies should examine the clinical and economic implications of these differences.
  
  
  CONCLUSIONS
  This study has limitations such as possible selection bias using secondary database analysis.
authors.affiliation: University of Tennessee College of Pharmacy, Memphis, TN 38163, USA. jwang26@uthsc.edu
authors.forename: Junling
authors.initials: J
authors.lastname: Wang
authors.forename: Xianchen
authors.initials: X
authors.lastname: Liu
authors.forename: C Daniel
authors.initials: CD
authors.lastname: Mullins
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D000928:Antidepressive Agents / Q000008:administration & dosage / Q000627:therapeutic use; D002908:Chronic Disease; D015283:Citalopram / Q000627:therapeutic use*; D003511:Cyclohexanols / Q000008:administration & dosage / Q000627:therapeutic use*; D003865:Major Depressive Disorder / Q000150:complications / Q000188:drug therapy*; D004304:Dosage Forms; D000068736:Duloxetine Hydrochloride; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000150:complications / Q000188:drug therapy*; D012189:Retrospective Studies; D013001:Somatoform Disorders / Q000188:drug therapy; D013876:Thiophenes / Q000627:therapeutic use*; D000069470:Venlafaxine Hydrochloride; D055815:Young Adult; D016903:Drug Monitoring
chemical_list: D000928:Antidepressive Agents; D003511:Cyclohexanols; D004304:Dosage Forms; D013876:Thiophenes; D015283:Citalopram; D000069470:Venlafaxine Hydrochloride; D000068736:Duloxetine Hydrochloride