title: Validity and reliability of short form-12 questionnaire in Iranian hemodialysis patients.
abstract: BACKGROUND
  The aim of the study was to assess the validity and reliability of the SF-12 questionnaire in a sample of Iranian patients undergoing hemodialysis.
  
  
  METHODS
  One hundred and forty-four hemodialysis patients were included from dialysis centers in Zanjan, Iran, and were asked to complete the SF-12 and SF-36 questionnaires. An initial test-retest reliability evaluation was performed on a sample of 70 patients from the total group, with a retest interval of 14 days. Reliability was estimated by internal consistency and validity was assessed using known-group comparisons and construct validity on the patient group as a whole. A linear regression analysis was used to assess any variation in the physical component summary and mental component summary scores of the SF-36 with the respective component summary scores of the SF-12. In addition, the factor structure of the questionnaire was extracted by performing a confirmatory factor analysis.
  
  
  RESULTS
  Cronbach alpha for physical and mental component summaries were 0.89 and 0.90, respectively. The SF-12 showed a good discriminatory ability between subgroups of patients based on demographic and clinical variables. The confirmatory factor analysis for the original two-factor structure showed a good fit index (chi2 = 23.30, degrees of freedom = 13), goodness-of-fit index = 0.96, and root mean squared error of approximation = 0.079).
  
  
  CONCLUSIONS
  In general, the SF-12 has good psychometric properties and can be used as a shorter version of the SF-36 questionnaire in future studies involving Iranian patients undergoing hemodialysis.
authors.affiliation: Department of Public Health, Qazvin University of Medical Sciences, Qazvin, Iran. pakpour_amir@yahoo.com
authors.forename: Amir H
authors.initials: AH
authors.lastname: Pakpour
authors.forename: Saeedeh
authors.initials: S
authors.lastname: Nourozi
authors.forename: Stig
authors.initials: S
authors.lastname: Molsted
authors.forename: Adrian P
authors.initials: AP
authors.lastname: Harrison
authors.forename: Khadije
authors.initials: K
authors.lastname: Nourozi
authors.forename: Bengt
authors.initials: B
authors.lastname: Fridlund
mesh_terms: D005260:Female; D006801:Humans; D007492:Iran; D007676:Kidney Failure, Chronic / Q000523:psychology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life; D006435:Renal Dialysis / Q000523:psychology*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*