Reliability and validity of Turkish versions of the interstitial cystitis symptom index and interstitial cystitis...

To validate the Turkish versions of the interstitial cystitis symptom index (ICSI) and interstitial cystitis problem index (ICPI) for use in Turkish speaking patients with bladder pain syndrome/interstitial cystitis (BPS/IC).

After translation of the original ICSI and ICPI into the Turkish language, Turkish versions of ICSI and ICPI were self-administered to all participants. Test-retest reliability (intraclass correlation coefficient) was evaluated at 2 weeks intervals in the BPS/IC group. Internal consistency was evaluated using Cronbach's alpha. Scores of ICSI and ICPI was compared between BPS/IC and control groups to examine discriminant validity. Criterion validity was examined via investigating the correlations between bladder diary data (24-hour frequency and nocturia), visual analogue scale (VAS) scores, and results to the corresponding questions in ICSI and ICPI.

Results of 79 patients with BPS/IC and 50 control patients were analyzed. Both indices showed high internal consistency (Cronbach's α for ICSI and ICPI was 0.879 and 0.923, respectively). The test-retest reliability of ICSI and ICPI was high for total scores and subdomains of both indices (intraclass correlation coefficient was 0.722 for ICSI and 0.777 for ICPI). Scores of both indices were significantly higher in BPS/IC group than the control group (P < .001). Statistically significant correlations were found between 24-hour frequency, nocturia, VAS scores, and corresponding questions in the indices. A statistically significant and strong correlation was observed between ICSI and ICPI scores (P < .001, r_S  = .632).

Turkish versions of ICSI and ICPI are reliable, consistent, and valid instruments to evaluate symptoms of Turkish speaking patients with BPS/IC.