Psychometric validation of a German language version of a PROM for urethral stricture surgery and preliminary testing of supplementary ED and UI constructs.

Abstract

To validate a German language version of the patient-reported outcome measurement (PROM) following urethral stricture surgery (USS) in a cohort of men undergoing one-stage buccal mucosa graft urethroplasty (BMGU) for urethral stricture. Furthermore, to explore the responsiveness of erectile function (EF) and urinary incontinence (UI) constructs in the context of this intervention. The USS-PROM captures voiding symptoms (ICIQ-MLUTS) and health-related quality of life (HRQoL) (EQ-5D). To evaluate EF and UI, the IIEF-5 and ICIQ-UI SF were included. Between March 2012 and April 2013, all patients undergoing BMGU at our institution were prospectively enrolled in this study. Psychometric assessment included internal consistency, test-retest reliability, criterion validity and responsiveness. Ninety-three men completed the USS-PROM before and 3 months after surgery, with 40 (43 %) also completing the USS-PROM 6 months after surgery to assess reliability. Internal consistency: for the ICIQ-MLUTS, Cronbach's α was 0.83. The test-retest intraclass correlation coefficient was 0.94. There was a negative correlation between change in ICIQ-MLUTS total score and change in Q max (r = -0.40). All values exceeded our predefined thresholds. Significant improvements of voiding symptoms and HRQoL demonstrate responsiveness to change (all p values <0.001). While ICIQ-UI scores did not change (p > 0.05), IIEF-5 scores improved significantly (p = 0.048). The German language USS-PROM shows similar psychometric properties to the English language version. This instrument can be improved by assessing EF by the use of IIEF-5. Further studies with larger patient cohorts are needed to evaluate the significance of measuring UI in urethroplasty patients.