The Finnish version of The National Institutes Of Health Chronic Prostatitis Symptom Index correlates well with the visual pain scale: translation and results of a modified linguistic validation study

Abstract

Authors from Finland have assessed a version in their language of the National Institutes of Health-Chronic Prostatitis Symptom Index; they found that their translated version was valid and easily understandable in the management of the symptoms of chronic pelvic pain syndrome. They felt it should be used as a primary outcome measure in studies with these patients. There are three papers in this issue relating to the effect of drugs on LUTS; the first of these is a pooled analysis of three double-blind placebo-controlled studies into the safety and efficacy of the 10 mg dose of alfuzosin. The second evaluates the effect on quality-of-life issues of treatment with dutasteride. Finally, authors from Australia compare the effect of a Serenoa repens extract with placebo for LUTS.

Objectives: To provide a fluent and easily comprehensible Finnish version of the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) and to study its linguistic validity and correlation with a visual pain scale (VAS).

Patients and methods: The double-back translation method with two interim modifications was used to produce the Finnish version of the NIH-CPSI. The validity was tested by presenting the questionnaire to 155 men with clinically confirmed chronic pelvic pain syndrome (CPPS) and 12 controls with no previous urological symptoms. Convergent validity of the NIH-CPSI was tested by determining the correlation between the Finnish NIH-CPSI and VAS. Patients' and urologists' opinions about the utility of the Finnish NIH-CPSI were also reviewed.

Results: The total Finnish NIH-CPSI scores and the pain domain and voiding symptom domain scores differed significantly (P < 0.001) between the groups, suggesting good discriminant validity of the symptom index. The NIH-CPSI scores correlated well with the VAS (Pearson's correlation 0.76). The preciseness and comprehensibility of the questionnaire were consistently evaluated to be 'good' or 'excellent' both by patients and urologists.

Conclusions: The Finnish version of the NIH-CPSI is valid and easily comprehensible for measuring CPPS symptoms. In addition, it provides good discriminant and convergent validity in distinguishing CPPS symptoms and should be used as primary outcome measure in CPPS studies.