Sensitivity to change of the Dermatology Life Quality Index in adult females with facial acne vulgaris: a validation study

Background The postadolescent form of acne papulopustulosa, also referred to as ‘acne tarda’ can have substantial negative impact on Quality of Life, especially in adult female patients. Objective Although the Dermatology Life Quality Index (DLQI) is widely used, empirical evidence about its performance in adult female acne patients is lacking. Methods In this prospective cohort study, we have investigated the sensitivity to change of the DLQI in 53 female adult acne patients with mild to moderate facial acne treated with azelaic acid (AzA) 15% gel twice daily over 24 weeks. Results Mean Investigator Static Global Assessment (ISGA) score was 2.3 (SD 0.5) at baseline and ranged from 0.9 (SD 0.3) to 2.1 (SD 0.4) at the end of the study in the ‘Highly Improved’ and ‘Unchanged’ responder groups respectively. The mean baseline DLQI score was 5.1 (SD 4.2). The Effect Size in the responder group ‘Highly Improved’ was 0.66; in group ‘Improved’ 0.62 and 0.23 in group ‘Unchanged’. At the end of study, the mean DLQI score ranged from 1.1 (SD 1.5) in the ‘Highly Improved’ group to 3.7 (SD 6.0) in the ‘Unchanged’ group. Conclusion The results support the sensitivity to change of the DLQI in this population.