Health-related quality of life in psoriasis : an analysis of Psocare project patients

Aim. Psoriasis is a common, chronic, immune-mediated skin disorder that may be complicated by psoriatic arthritis in up to one-third of patients. Psoriasis treatments are increasingly effective, yet more expensive, thus requiring rational decision-making on interventional priorities. The ability to perform cost-utility analyses is hindered by the lack of algorithms that allow the inference of utility measures, like QALY, from specific dermatological health-related quality-of-life (HR-QoL) measures (e.g. Dermatology Life Quality Index [DLQI]). This study aimed to assess whether psoriasis-related HR-QoL data (DLQI) could be used to obtain utility measures for use in economic analyses. Methods. Psoriasis patients attending 11 Italian Psocare project treatment centers over a 19-day period were enrolled and completed a questionnaire, including several HR-QoL scales and sociodemographic/clinical data, and underwent a clinical examination. Data were subjected to a Multiple Correspondence Analysis and multiple regression analysis to determine the contribution of single items to the HR-QoL. Results. DLQI and Psychological General Well-Being Index (PGWBI) scores were most closely correlated with the EuroQol health status index. Age and gender were considered confounding factors, while pain and arthritis contributed significantly to HR-QoL deterioration. For disease severity, the need for hospitalization and the number of examinations, but not the Psoriasis Area Severity Index (PASI), contributed to HR-QoL deterioration. Conclusion. Recent historical clinical and HR-QoL data from psoriasis patients can reproducibly define a health status index, such as the EuroQol SD-SQ, that could be used reliably to estimate QALYs for use in cost-utility analyses to compare the cost-benefit profiles of competing therapies.