Is the EQ-5D a Valid Instrument to Assess Health Related Quality of Life of Psoriasis Patients?

The purpose of this paper was to investigate whether EQ-5D is a valid measure of Health Related Quality of Life of psoriasis patients. The objective was carried out by investigating the correlation between the EuroQol EQ-5D and two other Health Related Quality of Life measures, Dermatology Life Quality Index and a Visual Analogue Scale assessed by the patient, as well as two clinical outcome measures assessed by the physician. Furthermore, the objective was to investigate whether the EQ-5D systematically differs from the other Health Related Quality of Life measures. The quality of life was measured in 2085 patients with psoriasis in PsoReg, a national registry for psoriasis patients in Sweden. Dermatology Life Quality Index has shown to be a valid measure in psoriasis patients in previous research and it correlated moderately with the EQ-5D in this study. There was a low significant correlation between the EQ-5D and the clinical outcome measures. Limited evidence implies that the EQ- 5D differs systematically from the other quality of life measures regarding age. This study suggests that the EQ-5D is a valid measure of Health Related Quality of life of psoriasis patients. Nevertheless, both generic and disease-specific instruments can contribute in the assessment of quality of life of patients with psoriasis.