The Italian version of the National Institutes of Health Chronic Prostatitis Symptom Index.

Abstract

To perform the Italian version of the National Institutes of Health Chronic Prostatitis Symptom Index (NHI-CPSI), and to study its linguistic validity and its correlations with the Visual Analogue Scale for pain (VAS) and the Italian version of International Prostatic Symptom Score (I-PSS) in men with chronic pelvic pain syndrome (CPPS) and healthy controls. A rigorous double-back translation of the original English NHI-CPSI was performed by a staff composed of 3 professional bilingual experts and 3 urologists. The study population consisted of 160 male CPPS patients and 125 healthy controls, who were asked to self complete the Italian version of the NHI-CPSI together with the VAS and the Italian I-PSS. The discriminatory power, psychometric properties, internal correlations and convergent validity of the questionnaire were tested. Of the 285 enrolled patients, 223 patients (142 with CPPS and 81 healthy patients) were definitively considered for the study. The overall Italian NIH-CPSI scores and each subscale differed significantly (p<0.001) between the two groups, and so that the index proved a good discriminant validity. High correlations were found between the VAS and the pain domain (0.88) and between I-PSS and void domain (0.94), suggesting a good convergent validity of the Italian version of the NIH-CPSI. The questionnaire proved to have a high internal consistency. The Italian NIH-CPSI is a reliable symptom index that can be self-administrated in about 5 minutes in daily clinical practice for the follow-up of the Italian patients with chronic prostatitis.