title: Measuring the positive psychological well-being of people with rheumatoid arthritis: a cross-sectional validation of the subjective vitality scale.
abstract: BACKGROUND
  People with rheumatoid arthritis (RA) frequently suffer from compromised physical and psychological health, however, little is known about positive indicators of health, due to a lack of validated outcome measures. This study aims to validate a clinically relevant outcome measure of positive psychological well-being for people with RA. The first study examined the reliability and factorial validity of the Subjective Vitality Scale (SVS), whilst study 2 tested the instruments convergent validity.
  
  
  METHODS
  In study 1, National Rheumatoid Arthritis Society members (N = 333; M age = 59.82 years SD = 11.00) completed a postal questionnaire. For study 2, participants (N = 106; M age = 56 years, SD = 12 years) were those recruited to a randomized control trial comparing two physical activity interventions who completed a range of health-related questionnaires.
  
  
  RESULTS
  The SVS had a high level of internal consistency (α = .93, Rho = .92). Confirmatory factor analysis supported the uni-dimensional factor structure of the questionnaire among RA patients [χ = 1327 (10), CFI = 1.0, SRMSR = .01 and RMSEA = .00 (.00 - .08)]. Support for the scales convergent validity was revealed by significant (p < .05) relationships, in expected directions, with health related quality of life (r = .59), physical function (r = .58), feelings of fatigue (r = -.70), anxiety (r = -.57) and depression (r = -.73).
  
  
  CONCLUSIONS
  Results from two studies have provided support for the internal consistency, factorial structure and convergent validity of the Subjective Vitality Scale. Researchers and healthcare providers may employ this clinically relevant, freely available and brief assessment with the confidence that it is a valid and reliable measure of positive psychological well-being for RA patients.
  
  
  BACKGROUND
  ClinicalTrials.gov ISRCTN04121489 . Registered 5 September 2012.
authors.affiliation: Department for Health, University of Bath, Bath, BA2 7AY, UK. p.c.rouse@bath.ac.uk.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Rouse
authors.affiliation: School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK. j.j.veldhuijzenvanzant@bham.ac.uk.|Department of Rheumatology, Dudley Group of Hospitals NHS Trust, Russells Hall Hospital, Dudley, West Midlands, UK. j.j.veldhuijzenvanzant@bham.ac.uk.
authors.forename: Jet J J C S
authors.initials: JJ
authors.lastname: Veldhuijzen Van Zanten
authors.affiliation: Health Psychology & Behavioural Medicine Research Group, School of Psychology & Speech Pathology, Curtin University, Perth, Western Australia. nikos.ntoumanis@curtin.edu.au.
authors.forename: Nikos
authors.initials: N
authors.lastname: Ntoumanis
authors.affiliation: Department of Rheumatology, Dudley Group of Hospitals NHS Trust, Russells Hall Hospital, Dudley, West Midlands, UK. G.Metsios@wlv.ac.uk.|Department of Physical Activity, Exercise and Health, University of Wolverhampton, Walsall, West Midlands, UK. G.Metsios@wlv.ac.uk.
authors.forename: George S
authors.initials: GS
authors.lastname: Metsios
authors.affiliation: School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK. CXY094@bham.ac.uk.
authors.forename: Chen-an
authors.initials: CA
authors.lastname: Yu
authors.affiliation: School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK. kitas@dgh.nhs.uk.|Department of Rheumatology, Dudley Group of Hospitals NHS Trust, Russells Hall Hospital, Dudley, West Midlands, UK. kitas@dgh.nhs.uk.
authors.forename: George D
authors.initials: GD
authors.lastname: Kitas
authors.affiliation: School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK. J.L.duda@bham.ac.uk.
authors.forename: Joan L
authors.initials: JL
authors.lastname: Duda
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000523:psychology* / Q000534:rehabilitation; D003430:Cross-Sectional Studies; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011581:Psychological Tests; D011788:Quality of Life; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires