Translation into Spanish and field-testing of a new score for evaluating psoriasis severity: The Simplified Psoriasis Index (SPI).

Background: The simplified psoriasis index (SPI) was developed in the United Kingdom to provide a simple summary measure for monitoring changes in psoriasis severity and associated psychosocial impact as well as for obtaining information about past disease behavior and treatment. Two complementary versions of the SPI allow for self-assessment by the patient or professional assessment by a doctor or nurse. Both versions have proven responsive to change, reliable, and interpretable, and to correlate well with assessment tools that are widely used in clinical trials - the Psoriasis Area and Severity Index and the Dermatology Quality of Life Index. The SPI has already been translated into several languages, including French, Brazilian Portuguese, Dutch, Arabic, and Thai.

Objective: To translate the professional and self-assessment versions of the SPI to Spanish and to field test the translations.

Method: A medically qualified native Spanish speaker translated both versions of the SPI into Spanish. The Spanish translations were discussed by comparing them to blinded back translations into English undertaken by native English speakers; the Spanish texts were then revised in an iterative process involving the translators, 4 dermatologists, and 20 patients. The patients scored their own experience of psoriasis with the self-assessment version and commented on it. The process involved checking the conceptual accuracy of the translation, language-related differences, and subtle gradations of meaning in a process involving all translators and a panel of both Spanish- and English-speaking dermatologists, including a coauthor of the SPI.

Results: The final self-assessment and professional Spanish versions of the SPI are presented in this manuscript.

Conclusions: Castilian Spanish translations of both versions of the SPI are now available for monitoring disease changes in Spanish-speaking patients with psoriasis under routine clinical care.