Background: Psoriasis has a negative impact on patient's' quality of life, which may reflect the physical and psychosocial impact of the disease. However, little is known about the perceived burden of disease. Pictorial Representation of Illness and Self Measure (PRISM), a pictorial tool, was developed to measure this global suffering. Capturing quality of life impairments in psoriasis is an integral part of assessing the overall disease severity and planning effective treatment strategies.
Objective: To validate Pictorial Representation of Illness and Self Measure (PRISM) in psoriasis patients.
Methods: An investigator initiated, prospective cohort study was performed in 108 outpatients with psoriasis to validate PRISM as an appropriate tool; Reliability was assessed in a cohort with controlled stable disease, repeated after 1 hour and after a 3-month follow-up phase; Convergent validity determined by correlation against measures of life quality (DLQI) and reported severity of psoriasis (PASI, PGA and BSA) was performed.
Results: For PRISM, we found a high reliability for short-term measurements (ICC = 0.98, P < 0.001) and for follow-up assessments at 3 months (ICC = 0.76, P < 0.001). Our investigation showed significant differences between patients with clear to minimal (PGA 0, 1), mild (PGA 2) and moderate-to-severe disease (PGA 3, 4) and significant (P < 0.001) correlation with DLQI, PGA, PASI and BSA (ρ = -0.62, -0.54, -0.44 and -0.39 respectively).
Conclusion: PRISM is a highly reliable tool and new approach to assess perceived burden of patients with psoriasis. It is easy to use and we recommend the application as an additional outcome measure in clinical trial settings.
© 2015 European Academy of Dermatology and Venereology.