Treatment satisfaction, willingness to pay and quality of life in Japanese patients with psoriasis

There is a range of psoriasis treatments available, from topical applications to biologic therapy, with corresponding cost variations. The efficacy of each treatment is usually evaluated by objective measures such as the Psoriasis Area and Severity Index (PASI) or subjective measures such as the Dermatology Life Quality Index (DLQI). However, the social and economic impacts of psoriasis, including cost-effectiveness, have not been assessed in Japan. The EuroQol 5-Dimension (EQ-5D) is a generic instrument used worldwide to calculate quality-adjusted life years, on which calculations of treatment cost-effectiveness are based. We conducted a pilot study to determine the cost-effectiveness of psoriasis treatment in Japan. We administered a questionnaire to 133 patients with psoriasis (105 men and 28 women) who visited four university hospitals in Fukuoka Prefecture. The questionnaire covered medical costs, satisfaction and willingness to pay (WTP), and we investigated the relationships between these items. PASI was evaluated by physicians. More participants indicated satisfaction with treatment in the group paying less than ¥5000/month. WTP, PASI and EQ-5D showed little correlation. However, the DLQI and EQ-5D showed a moderate correlation (r = 0.472). WTP seemed more dependent on participants' economic backgrounds. We found that it was difficult to reflect the PASI with the EQ-5D. However, the DLQI may be used to estimate the cost–benefit relationship in patients with psoriasis. This is the first study to evaluate the EQ-5D in patients with psoriasis in Japan.