title: Feasibility, reliability and validity of a questionnaire on healthcare consumption and productivity loss in patients with a psychiatric disorder (TiC-P).
abstract: BACKGROUND
  Patient self-report allows collecting comprehensive data for the purpose of performing economic evaluations. The aim of the current study was to assess the feasibility, reliability and a part of the construct validity of a commonly applied questionnaire on healthcare utilization and productivity losses in patients with a psychiatric disorder (TiC-P).
  
  
  METHODS
  Data were derived alongside two clinical trials performed in the Netherlands in patients with mental health problems. The response rate, average time of filling out the questionnaire and proportions of missing values were used as indicators of feasibility of the questionnaire. Test-retest analyses were performed including Cohen's kappa and intra class correlation coefficients to assess reliability of the data. The construct validity was assessed by comparing patient reported data on contacts with psychotherapists and reported data on long-term absence from work with data derived from registries.
  
  
  RESULTS
  The response rate was 72%. The mean time needed for filling out the first TiC-P was 9.4 minutes. The time needed for filling out the questionnaire was 2.3 minutes less for follow up measurements. Proportions of missing values were limited (< 2.4%) except for medication for which in 10% of the cases costs could not be calculated. Cohen's kappa was satisfactory to almost perfect for most items related to healthcare consumption and satisfactory for items on absence from work and presenteeism. Comparable results were shown by the ICCs on variables measuring volumes of medical consumption and productivity losses indicating good reliability of the questionnaire.Absolute agreement between patient-reported data and data derived from medical registrations of the psychotherapists was satisfactory. Accepting a margin of +/- seven days, the agreement on reported and registered data on long-term absence from work was satisfactory. The validity of self-reported data using the TiC-P is promising.
  
  
  CONCLUSIONS
  The results indicate that the TiC-P is a feasible and reliable instrument for collecting data on medical consumption and productivity losses in patients with mild to moderate mental health problems. Additionally, the construct validity of questions related to contacts with psychotherapist and long-term absence from work was satisfactory.
authors.affiliation: Institute for Medical Technology Assessment, Erasmus University Rotterdam, PO Box 1738, 3000 DR Rotterdam, The Netherlands. bouwmans@bmg.eur.nl
authors.forename: Clazien
authors.initials: C
authors.lastname: Bouwmans
authors.forename: Kim
authors.initials: K
authors.lastname: De Jong
authors.forename: Reinier
authors.initials: R
authors.lastname: Timman
authors.forename: Moniek
authors.initials: M
authors.lastname: Zijlstra-Vlasveld
authors.forename: Christina
authors.initials: C
authors.lastname: Van der Feltz-Cornelis
authors.forename: Siok
authors.initials: S
authors.lastname: Tan Swan
authors.forename: Leona
authors.initials: L
authors.lastname: Hakkaart-van Roijen
mesh_terms: D000041:Absenteeism; D000328:Adult; D003695:Delivery of Health Care / Q000706:statistics & numerical data; D004526:Efficiency; D005240:Feasibility Studies; D005260:Female; D017048:Health Care Costs; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000191:economics* / Q000453:epidemiology; D008875:Middle Aged; D009426:Netherlands; D011594:Psychometrics / Q000295:instrumentation*; D011788:Quality of Life; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*