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

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 κ 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); κ 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.