Validity and Reliability of the Greek Version of the Neurogenic Bladder Symptom Score (NBSS) Questionnaire in a Sample of Greek Patients with Multiple Sclerosis - Beyond the Abstract

Urinary tract symptoms are a common complaint in patients with multiple sclerosis (MS) and comprise a great burden for this group of patients, affecting health-related quality of life. The quantification of such symptoms is not an easy task for both the clinician and patient and is mostly performed via the utilization of patient-reported outcome tools, such as questionnaires. Neurogenic Bladder Symptom Score (NBSS), originally developed by Welk et al,1 consists of 24 questions assessing the following domains: incontinence, storage, voiding, and consequences, while the last question covers an overall quality of life aspect. In order to apply these tools in daily clinical practice worldwide, cross-cultural adaptation is an essential step. In order to make a solid assumption regarding the validity of a translated questionnaire, the research team should follow strict methodological steps, as proposed by appropriate guidelines.2 We focused on a group of MS patients in Greece in order to produce a validated version of NBSS in the Greek language.


The translation was performed by two bilingual translators and back translation was also conducted according to guidelines.2 The authors evaluated the final product for any inconsistencies, and a scientific committee with expertise in neurourology reviewed the final version until more than 90% of consensus was achieved. Finally, a pilot study on a small group of patients was done in order to examine the patient perspective and understanding of the translated questionnaire and minor corrections were made accordingly. Adult patients with MS were asked to complete the questionnaire independently from their treating physician and they were asked to return in two weeks to re-answer the questionnaire, without receiving any new intervention in the meanwhile. Patients were also asked to complete the Multiple Sclerosis International Quality of Life (MusiQoL) questionnaire in order to correlate the score with the quality of life question of NBSS.

NBSS sub-domains exhibited high internal consistency for overall score (Cronbach’s alpha coefficient of 0.91), incontinence (Cronbach’s alpha 0.92), storage symptoms (Cronbach’s alpha 0.88), and consequences (Cronbach’s alpha 0.74), while test-retest reliability was satisfactory with an intraclass correlation coefficient of 0.85 for overall score, 0.90 for incontinence, 0.83 for storage symptoms and 0.90 for consequences. Similar results were found by Welk et al in their study assessing the validity and reliability of NBSS.3 Evaluation of construct validity was performed with Pearson’s correlation between question 24 of NBSS and MusiQoL score and revealed a moderate correlation with r=0.64. Finally, content validity was confirmed by two independent urologists, with clinical and research expertise on neuro-urology.

Our results indicate that the Greek version of NBSS shows sufficient internal consistency, reliability, construct and content validity, in order to be used as a clinical tool for assessment of MS patients with urinary tract symptoms.

Written by: Lazaros Tzelves, Ioannis Glykas, Charalampos Fragkoulis, Dimos-Dimitrios Mitsikostas, Andreas Skolarikos, Blayne Welk, Athanasios Dellis

2nd Department of Urology, School of Medicine, Sismanoglio Hospital, National and Kapodistrian University of Athens, Athens, Greece., Department of Urology, General Hospital of Athens G. Gennimatas, Athens, Greece. ., Department of Urology, General Hospital of Athens G. Gennimatas, Athens, Greece., 1st Department of Neurology, School of Medicine, Aiginiteio Hospital, National and Kapodistrian University of Athens, Athens, Greece., Department of Surgery and Epidemiology and Biostatistics, Western University, London, ON, Canada., 2nd Department of Surgery, School of Medicine, Aretaieion Hospital, National and Kapodistrian University of Athens, Athens, Greece.

References:

  1. Welk, Blayne, Sarah A. Morrow, Wendy Madarasz, Patrick Potter, and Keith Sequeira. "The conceptualization and development of a patient-reported neurogenic bladder symptom score." Research and reports in urology 5 (2013): 129.
  2. Beaton, Dorcas E., Claire Bombardier, Francis Guillemin, and Marcos Bosi Ferraz. "Guidelines for the process of cross-cultural adaptation of self-report measures." Spine 25, no. 24 (2000): 3186-3191.
  3. Welk, Blayne, Sarah Morrow, Wendy Madarasz, Richard Baverstock, Jennifer Macnab, and Keith Sequeira. "The validity and reliability of the neurogenic bladder symptom score." The Journal of urology 192, no. 2 (2014): 452-457.
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