title: Can physician's self-estimates be used as a valid instrument to determine prescription frequencies of anti-psoriatic drugs? Comparison of the results of a cross-sectional study using self-estimates with actual prescription behavior documented in a cohort study.
abstract: OBJECTIVE
  Physicians' self-estimates of their own prescription behavior can be used as a tool to gather information on prescription frequencies. Self-estimates as a tool for health-care research on prescription frequencies need to be validated as a suitable method before it can be used widely.
  
  
  METHODS
  We performed a cross-sectional study inviting all dermatologists in Berlin and Brandenburg to give self-estimates of their own prescription behavior of anti-psoriatic drugs. The results were compared with the results from a consecutive 8-months cohort study with the same participants documenting their actual treatment choices during every visit of a psoriasis patient on a standardized documentation sheet. Differences between self-estimates and documented prescription patterns were analyzed with respect to systemic anti-psoriatic drugs and UV treatment.
  
  
  RESULTS
  Fifty-one dermatologists participated. They documented an average of 91 patient visits each. Absolute differences between the self-estimates and the documented actual prescription behavior ranged from -2.5% to 1.4% for systemic treatments. For psoralen plus ultravioloet A (PUVA) treatment, the absolute difference was 3.3% and for ultraviolet B (UVB) 4.7%.
  
  
  CONCLUSIONS
  Self-estimates were surprisingly exact. Self-estimates may be suggested as one tool to assess prescription frequencies, but further studies are needed to confirm their validity.
authors.affiliation: Division of Evidence Based Medicine (dEBM), Klinik für Dermatologie, Charité-Universitätsmedizin Berlin, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Nast
authors.forename: Stefanie
authors.initials: S
authors.lastname: Rosumeck
authors.forename: Ricardo
authors.initials: R
authors.lastname: Erdmann
authors.forename: Ricardo N
authors.initials: RN
authors.lastname: Werner
mesh_terms: D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003625:Data Collection / Q000379:methods; D003879:Dermatologic Agents / Q000627:therapeutic use*; D003880:Dermatology / Q000706:statistics & numerical data; D004282:Documentation; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D011701:PUVA Therapy / Q000706:statistics & numerical data; D010820:Physicians / Q000706:statistics & numerical data*; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D011565:Psoriasis / Q000188:drug therapy*; D057566:Self Report
chemical_list: D003879:Dermatologic Agents
keywords: drug prescriptions; evaluation studies; pharmacoepidemiology; psoriasis; surveys; treatment