Background: the Irritable Bowel Syndrome Severity Score (IBSSS) is a questionnaire only available in English that classifies IBS patients according to the severity of their symptoms and can be used to guide and monitor the treatment.
Aims: to adapt and validate into Spanish the English version of the IBSSS questionnaire.
Methods: the Spanish version of the questionnaire was obtained through a process of translation-evaluation of the comprehensibility and back translation. In a later phase we evaluated the applicability(n = 15), reproducibility (n = 31) and sensitivity to change (n = 40) of the Spanish version of the questionnaire. Finally we evaluated an alternative version of the ISBSS using a numerical scoring system instead of the original analog visual scale (n = 40).
Results: the Spanish version of the IBSSS showed an excellent reproducibility (r = 0.81 for global score) and an adequate sensitivity to change: a decrease of 45 points or more identified worsening of IBS with a 70.6% sensitivity and 87.5% specificity; an increase of 45 points or more identified improvement of IBS with a 85.7% sensitivity and 87.5% specificity. The severity score was practically the same regardless of the scoring system used (r = 0.96).
Conclusions: the Spanish version of the IBSSS is a reproducible tool that is able to identify relevant changes over the course of the disease. The use of a numerical scoring system is a valid alternative to the visual scale that improves the applicability of the questionnaire to situations when the written communication is limited or not possible.