The study aimed to compare willingness-to-pay (WTP) and health utility measured by time-trade-off (TTO) in psoriasis.
A pooled sample from a community-based cohort, a hospital, and an online registry were used. WTP was elicited for control and for cure. Psoriasis Area and Severity Index (PASI) and Dermatology Life Quality Index (DLQI) were used as references. Data distribution, concurrent validity, and area under the receiver operating characteristic curve (AUC) were compared.
A total of 479 patients were enrolled. WTP for control demonstrated a positive association with PASI among mild psoriasis, while TTO showed an inverse correlation to DLQI. The AUC of WTP for control (0.66) was higher than that of TTO (0.48) in discriminating PASI>10, and the AUC of TTO (0.64) was higher than that of WTP for control (0.62) in discriminating DLQI>10.
WTP for control shows superiority in detecting objective severity, while TTO may be more sensitive in measuring impaired quality of life.