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

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 pso riasis. Two hundred and eighty-two patients with psoriasis were included in the study. Self-reported health was measured using the SF-36. Disease seve rity was also measured in 95 patients using the Psoriasis Area and Severity Index (PASI). The reliability of the QOLS-N was computed using the interva l consistency reliability (Cronbach's alpha) and the test-retest reliabilit y test. Face and content validity and construct discriminant ability of the QOLS-N were assessed. The results indicated that the QOLS-N has highly sat isfactory rates of test-retest reliability (r = 0.83) and internal consiste ncy reliability (alpha 0.86). As expected, the QOLS-N had a lower correlati on 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 der ived in other validation studies. The QOLS-N seems to be a reliable and val id measure of global quality of life in patients suffering from psoriasis.