Reliability and validity of the National Institutes of Health Chronic Prostatitis Symptom Index questionnaire in the Turkish Population

Background/aim: To develop the first Turkish version of the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) questionnaire and to investigate its validity and reliability in men with chronic prostatitis/chronic pelvic pain syndrome (CP/ CPPS) and healthy controls. Material and methods: A total of 204 patients, 116 CP/CPPS and a control group which consisted of 88 healthy individuals were included in this prospective study. The NIH-CPSI form was first translated into Turkish and later on back into English. Using the Turkish version of the NIH CPSI, 40 patients completed the same questionnaires twice at 2-week intervals for test-retest concordance. To evaluate internal consistency and test-retest reliability, Cronbach's alpha value, and the Spearman correlation test were utilized respectively. Results: Our findings demonstrated statistically significant differences in NIH-CPSI scores between the patients and control groups (P < 0.001). Cronbach's alpha coefficient value of NIH-CPSI was 0.864. Reliability of test-retest was 0.909 (P < 0.001). Additionally, the Spearman correlation test showed that the results obtained using the Turkish NIH-CPSI were significantly correlated. Conclusion: The first Turkish version of the NIH-CPSI was found to be a reliable and valid instrument for Turkish patients with chronic prostatitis in both clinical and research settings.