title: Psychometric properties of the HIT-6 among patients in a headache-specialty practice.
abstract: OBJECTIVE
  To evaluate the performance and score interpretability of the Headache Impact Test (HIT-6) questionnaire in a headache patient population.
  
  
  BACKGROUND
  The HIT-6 is a standardized questionnaire designed to assess headache-related disability. Norms have been established using randomly sampled respondents from the general population. This study evaluated the psychometric properties of the HIT-6 scale among new adult patients who presented for treatment at a university headache-specialty practice.
  
  
  METHODS
  Participants were 309 new patients who presented for treatment at a headache-specialty clinic in an academic medical center.
  
  
  RESULTS
  Respondents ranged in age from 18 to 91 years, with an average age of 41 years (SD = 13 years) and were predominantly female (77%). Over half (57%) experienced chronic daily headache. Scores ranged from 38 to 78, with an average of 65.6 (SD = 7.0) and the majority (87%) had "severe impact" (60 or higher). The scale showed high reliability (alpha= 0.87) and an exploratory factor analysis showed large loadings from |0.57| to |0.86| and suggested a single disability factor. Scores were moderately negatively correlated with Short Form Health Survey (SF-36) subscales, ranging from -0.22 for mental health to -0.57 for social functioning. Item response theory analyses showed that half of the items functioned well across the disability continuum, while the remaining items discriminated between low and high levels of headache impact.
  
  
  CONCLUSIONS
  These findings suggest that the HIT-6 is useful for assessing headache-related disability among patients who seek headache-specialty care.
authors.affiliation: Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Ariane K
authors.initials: AK
authors.lastname: Kawata
authors.forename: Remy R
authors.initials: RR
authors.lastname: Coeytaux
authors.forename: Robert F
authors.initials: RF
authors.lastname: Devellis
authors.forename: Alan G
authors.initials: AG
authors.lastname: Finkel
authors.forename: J Douglas
authors.initials: JD
authors.lastname: Mann
authors.forename: Kevin
authors.initials: K
authors.lastname: Kahn
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006261:Headache / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018710:Pain Clinics; D011594:Psychometrics / Q000295:instrumentation*; D015203:Reproducibility of Results; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires / Q000592:standards*