Translating the Science of Quality of Life into Practice: What Do Dermatology Life Quality Index Scores Mean?

Abstract

This study's aim was to determine the relationship between Dermatology Life Quality Index (DLQI) scores and a Global Question (GQ) concerning patients' views of the overall impairment of their skin-related quality of life (QoL), and to express this relationship by identifying bands of DLQI scores equivalent to each GQ descriptor. A DLQI questionnaire and the GQ were mailed to 3834 adult general dermatology outpatients. There were 1993 (52%) responses: male 841; female 1152. Mean DLQI score = 4.86 (range 0-30, standard deviation (SD) = 5.83). Mean GQ score = 1.22 (range 0-4, SD = 1.20). The mean, mode, and median of the GQ scores for each DLQI score were used to devise several sets of bands of DLQI scores, and kappa coefficients of agreement calculated. The set proposed for adoption is: DLQI scores 0-1 = no effect on patient's life (GQ = 0, n = 754); DLQI scores 2-5 = small effect on patient's life (GQ = 1, n = 611); DLQI scores 6-10 = moderate effect on patient's life (GQ = 2, n = 327); DLQI scores 11-20 = very large effect on patient's life (GQ = 3, n = 242); DLQI scores 21-30 = extremely large effect on patient's life (GQ = 4, n = 59); kappa coefficient 0.489. Banding of the DLQI will aid the clinical interpretation of an individual's DLQI score and allow DLQI scores to inform clinical decisions.