259 Comparing willingness-to-pay and time-trade-off as the measures of burden of psoriasis: A pooled analysis of community, hospital, and web-based samples

Abstract

Listen

Translate article

The willingness-to-pay (WTP) and time-trade-off (TTO) have been widely used as the measures of disease burden; however, for mild and temporary diseases such as the majority of skin diseases, the sensitivity of the two metrics have not been compared. The study aimed to compare the WTP (for cure and for control) and TTO regarding the sensitivity in measuring the burden of psoriasis. A pooled sample of patients with psoriasis from a population-based cohort, a tertiary hospital in Changsha, and the largest psoriasis online registry in China were used for the comparison. The evaluation of WTP and TTO were referred to the Psoriasis Area and Severity Index (PASI) as the indicator of clinical severity, and the Dermatology Life Quality Index (DLQI) as the measure of impaired Quality-of-life (QoL). Data distribution, concurrent validity, and capability of discriminating moderate-to-severe psoriasis (area under the receiver operating characteristic curve, AUC) were compared among WTPcure, WTPcontrol, and the TTO. A total of 479 diagnosed patients were enrolled from the hospital (175), the cohort (88 out of 16,758 participants), and the online registry (216), respectively. The median WTPcontrol was significantly higher in patients with PASI>10 than those with PASI<10, while the median TTO was significantly higher in those with DLQI>10 than those with DLQI<10. WTPcontrol demonstrated a positive association with PASI only among mild psoriasis, while TTO showed an inverse correlation to DLQI across all severity levels. The AUC of WTPcontrol (0.66) was significantly higher than that of TTO (0.48) in discriminating PASI>10, and the AUC of TTO (0.64) was significantly higher than that of WTPcontrol (0.62) in discriminating DLQI>10. WTPcure demonstrated no significant results. TTO is more sensitive in measuring the impaired QoL, while WTPcontrol is superior in detecting the clinical severity of psoriasis.