Reliability, validity and responsiveness of a new leisure index: The Patient-Specific Leisure Scale (PSLS).
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Objectives: To investigate the reliability, validity and responsiveness of a new Patient-Specific Leisure Scale (PSLS), constructed to identify goals and outcomes for individual patients with rheumatoid arthritis (RA).Methods: Forty-nine patients with RA were used to evaluate test-retest reliability, and 100 consecutive RA patients were used for construct validity. Twenty-five RA patients, commencing with treatment on tumour necrosis factor (TNF) inhibitors, were evaluated before the start and after three months of therapy, to test responsiveness. The most important leisure activity (as judged by the patients) was used when evaluating reliability and validity. The perceived difficulty with each activity was scored from 0 to 10 (0 = able to perform activity without difficulty, 10 = unable to perform activity).Results: Test-retest reliability indicated a good agreement (0.62-0.87) using weighted kappa. Construct validity was demonstrated by modest positive correlation between leisure activity and Health Assessment Questionnaire (HAQ) (r(s) = 0.27, p = 0.005) visual analogue scale (VAS) pain (r(s) = 0.28, p = 0.004) VAS global (r(s) = 0.22, p = 0.027), VAS fatigue (r(s) = 0.24, p = 0.013), joint index of 28 swollen joints (r(s) = 0.22, p = 0.027) and negative correlations with short-form-36 (SF-36) physical functioning (r(s) = -0.18, p = 0.008), bodily pain (r(s) = -0.31, p < 0.001), general health (r(s) = -0.23, p = 0.019), vitality (r(s) = -0.31, p < 0.001), social function (r(s) = -0.24, p = 0.016) and role-emotional (r(s) = -0.28, p = 0.005). Mean improvement for the most important leisure activity was 1.36, (p = 0.036, 95% confidence interval 0.10-2.62). Standardized response mean and effect size for the most important activity in PSLS was 1.05 and 0.72, respectively, and for HAQ 0.34 and 0.28, respectively.Conclusions: PSLS appears to be feasible, reliable, valid and responsive for measuring leisure activities in RA. It provides both an individual result which is useful in clinical work, and results at a group level. Copyright (c) 2009 John Wiley & Sons, Ltd.