Cost of illness study for adult atopic dermatitis in Japan: A cross-sectional Web-based survey

Atopic dermatitis is a pruritic, eczematous dermatitis, the symptoms of which chronically fluctuate with remissions and relapses. Although a high psychosomatic and economic burden caused by atopic dermatitis is expected, few studies have been conducted estimating the cost of illness, including the self-medication costs and productivity loss due to atopic dermatitis. The aim of this study was to conduct a cross-sectional, Web-based survey of the direct medical costs, self-medication costs and productivity loss for adult atopic dermatitis patients, and estimate the burden of Japanese adult atopic dermatitis patients by disease severity. In a physician survey, the medical resource consumption related to medical treatments was surveyed by disease severity. The direct medical costs were calculated by multiplying the medical resource consumption and medical fee corresponding to each treatment. Based on the results of a patient survey, the self-medication costs and productivity loss were estimated by sex and disease severity. Atopic dermatitis-related productivity loss was calculated based on absenteeism, presenteeism, overall work impairment for employed workers and activity impairment for housewives. The nationwide estimations were calculated based on the estimated number of atopic dermatitis patients, employed workers with atopic dermatitis, and housewives with atopic dermatitis in their 20s-50s in Japan. Based on the surveys, all costs per patient and the scores increased with disease severity. The cost of illness for adult atopic dermatitis patients in Japan was estimated to be approximately JPY 3 trillion/year. Considering the physical and mental burdens, the burden of illness for adult atopic dermatitis was demonstrated to be vast.