Measuring patient-relevant benefits in pruritus treatment: development and validation of a specific outcomes tool

Background The assessment of patient-relevant benefit is gaining importance in evaluating treatments. The 'Patient Benefit Index, standard version' questionnaire (PBI-S) is a validated instrument to assess patients' treatment needs and benefits in skin diseases. Before therapy, the patient rates the importance of predefined treatment goals; after therapy, he rates the extent to which these goals have been achieved. Thus far, no such instrument has been developed specifically for pruritus. Objectives Development and validation of a patient-relevant benefit questionnaire in the treatment of pruritus. Methods Fifty patients with pruritus were questioned on impairments due to pruritus and treatment needs. Four treatment objectives not already covered by the PBI-S were added to obtain a disease-specific instrument. This was tested for feasibility by 36 patients with pruritus and validated in a sample of 100 patients with pruritus. Results The instrument was feasible in clinical practice. There were < 2% missing values. Cronbach's alpha of the needs questionnaire was 0.93. Convergent validity was demonstrated with respect to reduction of pruritus and quality of life. Conclusions The PBI for pruritus is a feasible, reliable and valid instrument that is highly accepted in daily routine for recording patient-reported benefit.