French-Canadian linguistic validation of the NIH Chronic Prostatitis Symptom Index

The NIH Chronic Prostatitis Symptom Index (CPSI) is recommended in the clinical evaluation of men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). However, its use is not possible in French speakers, as it has not been validated in this population. We performed a linguistic validation of the CPSI.

Linguistic translation followed the forward-backward-forward technique and relied on professional medical translators, bilingual health professionals, and patient input. Along with the SF-12, the translated version was administered to a convenience sample of men presenting for pre-vasectomy visits (controls) and to consecutive patients with established CP/CPPS (cases). Men with CP/CPPS were subsequently asked to complete a 14-day retest questionnaire. Psychometric testing addressed standard reliability and validity characteristics.

Thirty-six cases and 38 controls with respective mean ages of 46.5 and 44.0 years participated and 33 (91.2%) cases completed the retest questionnaire. Pain (p<0.001), urinary (p<0.001) and quality-of-life (QOL) scale (p<0.001) score means differed between cases and controls. For the same scales, Cronbach's alphas for cases were respectively 0.70, 0.72 and 0.79 versus 0.80, 0.57, and 0.88 for controls. The retest product-moments were 0.83 for pain, 0.55 for urinary, and 0.83 for QOL scales. In cases, strong correlation was noted between QOL and pain scales (r=0.7), and between urinary and pain scales (r=0.6), versus moderate correlation between QOL and urinary scales (r=0.4). Negative correlation was recorded between CPSI scales and SF-12 scales, which ranged from -0.2 to -0.4.

When applied to CPPS and control subjects, the French Canadian CPSI translation demonstrates excellent discriminant properties. Moreover, its reliability and validity characteristics confirm the qualities of the CPSI as a standard evaluative tool for men with CPPS.