Quality of life measures in psoriasis: a critical appraisal of their quality.

In recent years, the importance of patient-generated evaluations in assessing the impact of healthcare has been recognized. A plethora of quality of life (QoL) instruments have been developed to measure the burden of psoriasis and its treatment on the patient. We review the QoL measures and provide a critical appraisal of their quality. There is considerable variation in how the instruments have been constructed, the categories and items included, and the methods by which their reliability and validity have been examined. In order to guide investigators in their choice of instrument, further head-to-head comparisons of measures should be undertaken. When QoL measures are compared, a Pearson or rank-order correlation coefficient is not sufficient to indicate agreement. Methods that examine agreement, rather than association, are available and should be used. In the future, we will need to demonstrate whether these measurement tools are ready for widespread implementation in clinical trials or routine patient follow-up.