title: Nail Assessment in Psoriasis and Psoriatic Arthritis (NAPPA): development and validation of a tool for assessment of nail psoriasis outcomes.
abstract: BACKGROUND
  Existing tools for nail psoriasis are complex and may not adequately measure outcomes that are important to patients.
  
  
  OBJECTIVE
  We have developed and validated a new tool, the Nail Assessment in Psoriasis and Psoriatic Arthritis (NAPPA), with three components: a questionnaire assessing quality of life (NAPPA-QoL), a two-part questionnaire assessing patient-relevant treatment benefits (the Patient Benefit Index, NAPPA-PBI) and a psoriasis Clinical Assessment of Severity (NAPPA-CLIN).
  
  
  METHODS
  Development of the questionnaires involved multiple steps: (i) collection of items about nail psoriasis-related impairments and treatment goals; (ii) selection of 48 items by an expert panel, including patients; (iii) translation into eight languages; (iv) feasibility testing and (v) longitudinal validation in six countries.
  
  
  RESULTS
  Patients found the questionnaires clear (84%) and comprehensible (95%). NAPPA-QoL and NAPPA-PBI scores correlated moderately with clinical outcomes [e.g. Nail Psoriasis Severity Index (NAPSI)] and markedly with other quality-of-life questionnaires (e.g. EQ-5D™). Both questionnaires were sensitive to change. Internal consistency was good (Cronbach α ≥ 0.88 for all scales). The NAPPA-CLIN, a brief version of NAPSI that involves assessment of only four digits rather than all 20, was found to correlate highly with total NAPSI score (r = 0.97, P < 0.001).
  
  
  CONCLUSIONS
  Overall, the three-component NAPPA tool is a valid, reliable and practical instrument to assess patient-relevant nail psoriasis outcomes.
authors.affiliation: University Medical Center Hamburg-Eppendorf, Institute for Health Services Research in Dermatology and Nursing, Hamburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Augustin
authors.forename: C
authors.initials: C
authors.lastname: Blome
authors.forename: A
authors.initials: A
authors.lastname: Costanzo
authors.forename: E
authors.initials: E
authors.lastname: Dauden
authors.forename: C
authors.initials: C
authors.lastname: Ferrandiz
authors.forename: G
authors.initials: G
authors.lastname: Girolomoni
authors.forename: R
authors.initials: R
authors.lastname: Gniadecki
authors.forename: L
authors.initials: L
authors.lastname: Iversen
authors.forename: A
authors.initials: A
authors.lastname: Menter
authors.forename: K
authors.initials: K
authors.lastname: Michaelis-Wittern
authors.forename: A
authors.initials: A
authors.lastname: Morita
authors.forename: H
authors.initials: H
authors.lastname: Nakagawa
authors.forename: K
authors.initials: K
authors.lastname: Reich
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015535:Arthritis, Psoriatic / Q000523:psychology / Q000628:therapy; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009260:Nail Diseases / Q000523:psychology / Q000628:therapy*; D063868:Patient Outcome Assessment; D017060:Patient Satisfaction; D011565:Psoriasis / Q000523:psychology / Q000628:therapy*; D011788:Quality of Life; D016896:Treatment Outcome; D055815:Young Adult