Absolute and relative psoriasis area and severity index (PASI) treatment goals and their association with health-related quality of life

Background: Relative Psoriasis Area and Severity Index (PASI) improvement, also called 'PASI response', is recommended in major guidelines for assessment of treatment response in psoriasis patients. However, under certain circumstances it has some limitations, e.g. when baseline values are missing or during long-term treatment. Improvement of health-related quality of life (HrQoL) can be measured by the Dermatology Life Quality Index (DLQI). Objective: To evaluate the association of HrQoL and relative and absolute PASI outcomes during therapy. Material and methods: Data of plaque psoriasis patients of two clinical trials (CLEAR and SCULPTURE) were pooled. The rates of patients achieving DLQI 0/1 at week 16 were compared for different categories of absolute PASI and PASI response values. The correlation of DLQI and absolute or relative PASI goals was assessed over 52 weeks. Results: One thousand and fifty-four patients with available assessments of PASI and DLQI were included. 76% of the patients with an absolute PASI <= 2 (N = 548) and patients with a 90% improvement in PASI (N = 559) achieved DLQI 0/1 at week 16. Achievement of DLQI 0/1 was equally reflected by absolute PASI and PASI response. Conclusion: Absolute PASI appeared to be a feasible alternative to PASI response for determining treatment success, reflecting HrQoL improvements in an equal manner.