The Norwegian version of the Quality of Life Scale (QOLS-N). A validation and reliability study in patients suffering from psoriasis

Abstract

The aim of this study was to adapt, validate, and test for reliability the Quality of Life Scale in Norwegian (QOLS-N) for patients suffering from psoriasis. Two hundred and eighty-two patients with psoriasis were included in the study. Self-reported health was measured using the SF-36. Disease severity was also measured in 95 patients using the Psoriasis Area and Severity Index (PASI). The reliability of the QOLS-N was computed using the internal consistency reliability (Cronbach's alpha) and the test-retest reliability test. Face and content validity and construct discriminant ability of the QOLS-N were assessed. The results indicated that the QOLS-N has highly satisfactory rates of test-retest reliability (r = 0.83) and internal consistency reliability (alpha 0.86). As expected, the QOLS-N had a lower correlation with physical health (r = 0.24, p < 0.000) and self-reported symptoms (r = -0.20, p < 0.001), and a higher correlation with mental health (r = 0.52, p < 0.000). The correlation with disease severity was not significant (-0.06). The results reported in the present paper are in accordance with those derived in other validation studies. The QOLS-N seems to be a reliable and valid measure of global quality of life in patients suffering from psoriasis.