Health utility by Psoriasis Area and Severity Index response status after biologic induction therapy in Chinese...

Aim: Psoriasis severely affects quality of life, particularly in patients with moderate to severe psoriasis. This study aims to estimate health utility by Psoriasis Area and Severity Index (PASI) response after biologic induction therapy in Chinese patients with moderate to severe psoriasis. Materials & methods: Based on an established mapping algorithm between the Dermatology Life Quality Index and EuroQol 5 Dimension 5 Level utility score, the retrospective Dermatology Life Quality Index total scores before and after biologic induction therapy in 512 patients were converted into health utility scores to assess the associations between PASI response and post-induction utility using a multivariate generalized linear regression model. The constructed regression model was further applied to estimate post-induction utility by PASI response for a representative patient cohort, including 300 moderate to severe psoriasis patients from five tertiary hospitals. Results: When compared with baseline utility, the post-induction utility increased significantly irrespective of PASI response status. The multivariate regression analysis indicated that higher PASI response status was significantly correlated with higher utility score when compared with PASI <50 (coefficient: 0.050-0.124, p < 0.001). Relative to the baseline utility before treatment (0.653) in the representative patient cohort, the estimated post-induction utility increased by 0.174 for PASI <50, 0.224 for PASI 50-74, 0.275 for PASI 75-89, 0.280 for PASI 90-99 and 0.298 for PASI 100, respectively. Conclusion: As the extent of PASI improvement increases in Chinese patients with moderate to severe psoriasis, their health utility values rise significantly. However, the improvement in quality of life above PASI 75 is relatively limited when compared with PASI 75.