title: Psychometric evaluation of the Persian version of the Type 2 Diabetes and Health Promotion Scale (T2DHPS): a diabetes-specific measure of lifestyle.
abstract: BACKGROUND
  A healthy lifestyle is important for maintaining health and preventing complications in patients with type 2 diabetes, and yet, few instruments are available to measure this.
  
  
  OBJECTIVE
  The aim of the present study was to examine the psychometrics of a recently developed tool that can be used to screen for a health-promoting lifestyle in patients with type 2 diabetes.
  
  
  METHODS
  Data were collected from outpatients attending diabetes clinics. The Type 2 Diabetes and Health Promotion Scale (T2DHPS), EQ-5D, medical records and a demographic questionnaire were administered to 368 participants. Forward-backward translation of the original English version was used to develop a Persian version. Internal consistency of the scale was assessed by Cronbach's alpha and item-to-total correlation. Acceptability was measured by assessing floor and ceiling effects for each item and subscale. The item scaling test was used to examine the convergent and discriminant validity of the measure. Pearson correlation was used to determine the predictive validity of the scale. An explanatory factor analysis and known-group method were used to establish construct validity.
  
  
  RESULTS
  Adjusted item-total correlations were higher than 0.20. Cronbach's alpha for the 28-item scale was 0.88 and for subscales ranged from 0.53 to 0.94. Correlations between the total score and subscale scores were significant (<0.01) and adequate (r's ≥ 0.53). There were significant relationships between the T2DHPS and both the EQ-5D and indicators of glycaemic control. Convergent and discriminant validity of the scale was established. Significant differences in lifestyle dimensions were present between different groups of patients, demonstrating known-group validity. A six-factor solution was obtained that explained 54.6% of the total variance.
  
  
  CONCLUSIONS
  The T2DHPS is a valid and reliable tool for investigating lifestyle behaviours in patients with type 2 diabetes. Further studies to establish the psychometric properties of the scale in other languages and cultures are suggested.
authors.affiliation: Health Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.|Health Education Department, School of Health, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Saffari
authors.affiliation: Health Education Department, School of Health, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors.forename: Tooba
authors.initials: T
authors.lastname: Karimi
authors.affiliation: Duke University Medical Center, Durham, NC, USA.|Department of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Harold G
authors.initials: HG
authors.lastname: Koenig
authors.affiliation: Department of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Faten
authors.initials: F
authors.lastname: Al-Zaben
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D003469:Culture; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis*; D005260:Female; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D007492:Iran; D008019:Life Style; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D011594:Psychometrics; D011788:Quality of Life; D015203:Reproducibility of Results; D014175:Translating; D014177:Translations
keywords: lifestyle; reliability; type 2 diabetes; validity