title: Initiation, Switching, and Cessation of Psoriasis Treatments Among Patients with Moderate to Severe Psoriasis in the United States.
abstract: BACKGROUND
  Psoriasis patients frequently switch among multiple therapies while managing their psoriasis. Determining treatment transitions is fundamental to understanding how patients access and use treatments.
  
  
  OBJECTIVE
  We aimed to identify patterns of treatment transitions of US patients with moderate to severe psoriasis over 5 years.
  
  
  METHODS
  This was a retrospective, longitudinal cohort study in which US patients aged ≥18 years who had at least one psoriasis claim (International Classification of Diseases, Ninth Revision [ICD-9] diagnosis) were continuously enrolled in a health plan between October 2007 and September 2012. Data from eligible patients were projected to reflect the total US insured population with moderate to severe psoriasis, and the proportions of patients who started, stopped, switched, and restarted treatment at any time between September 2011 and September 2012 were analyzed. Treatment categories were biologics, traditional oral systemics, topicals, phototherapy, lapsed from treatment, and treatment-naive.
  
  
  RESULTS
  There were 8.9 million patients in the claims database, of whom 0.9 million (10.4%) had a psoriasis diagnosis and 46,369 (0.5%) met the inclusion criteria. When projected, 1.7 million insured patients had moderate to severe psoriasis. Of these, an estimated 807,000 patients had lapsed treatment, an additional 346,000 were receiving treatment, and 547,000 were defined as being treatment-naive. A total of 81,000 of 346,000 patients had switched treatment in the preceding year. In addition, many patients stopped (438,000) and restarted (384,000) treatment in the 12-month period.
  
  
  CONCLUSIONS
  Based on health claims data, undertreatment of moderate to severe psoriasis appeared to be common.
authors.affiliation: Department of Dermatology, University of Southern California, Los Angeles, CA, USA.
authors.forename: April W
authors.initials: AW
authors.lastname: Armstrong
authors.affiliation: Kantar Insights, Wellington, New Zealand.
authors.forename: J Will
authors.initials: JW
authors.lastname: Koning
authors.affiliation: Vanguard Strategy, London, UK.|Capita plc, London, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Rowse
authors.affiliation: Pfizer Inc., Groton, CT, USA. Huaming.Tan@pfizer.com.|Global Product Development, Pfizer Inc., 445 Eastern Point Road, Groton, CT, 06340, USA. Huaming.Tan@pfizer.com.
authors.forename: Huaming
authors.initials: H
authors.lastname: Tan
authors.affiliation: Pfizer Inc., Groton, CT, USA.
authors.forename: Carla
authors.initials: C
authors.lastname: Mamolo
authors.affiliation: Pfizer Inc., Collegeville, PA, USA.
authors.forename: Mandeep
authors.initials: M
authors.lastname: Kaur
mesh_terms: D000328:Adult; D000368:Aged; D001688:Biological Products / Q000008:administration & dosage*; D015331:Cohort Studies; D016208:Databases, Factual / Q000639:trends; D057915:Drug Substitution / Q000379:methods / Q000639:trends*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010789:Phototherapy / Q000379:methods / Q000639:trends*; D011565:Psoriasis / Q000453:epidemiology / Q000628:therapy*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D028761:Withholding Treatment / Q000639:trends*; D055815:Young Adult
chemical_list: D001688:Biological Products