Presentation Authors: Blayne Welk*, London, Canada, John Stoffel, Ann Arbor, MI, Sean Elliott, Minnesota, MN, Sara Lenherr, Chong Zhang, Jeremy Myers, Salt Lake City, UT
Introduction: The Neurogenic Bladder Symptom Score (NBSS) is a 24-item questionnaire that assesses symptom burden in patients with SCI, multiple sclerosis, or spina bifida. It has been validated in multiple data sets, used in several studies, and licensed to >40 investigators in 16 countries. Our objective was to develop a short form.
Methods: We used three previous published datasets. First, we selected the questions within each of the domains (incontinence, storage/voiding, and consequences) with the highest level of responsiveness (measured by the standardized response mean, SRM) and acceptable face validity. Internal validity of the NBSS-SF was assessed using Cronbach's alpha. External validity was assessed by evaluating hypothesized relationships with other questionnaires (AUASS, SCI-QOL, and Qualiveen-SF) and testing correlations with the full NBSS domains. Test-retest reliability of the NBSS-SF domains was determined using an intraclass coefficient (ICC2,1).
Results: Using data from a prior responsiveness study, questions with the highest SRM and perceived importance were selected from the incontinence domain (three), storage/voiding domain (three), consequences domain (two) to create the NBSS-SF. We used the original NBSS validation cohort of 220 patients with MS, SCI, or spina bifida to calculate Cronbach's alpha of 0.76; the external validity was high, with correlations between specific NBSS-SF domains/total scores and the Qualiveen-SF, ICIQ, and AUASS, and between the NBSS-SF domains and the full NBSS domains. In the subset of 120 patients who completed the test-retest reliability assessment, the ICC for the NBSS-SF total score was 0.84. These results were then confirmed in a second independent dataset of 1479 SCI patients: Cronbach's alpha for the NBSS-SF total was 0.75 and external validity was again demonstrated with a moderate correlation between the calculated NBSS-SF total and the SCI-QOL Bladder complications score, and strong correlations between the NBSS-SF domains/total score and the full NBSS domains/total.
Conclusions: The total score of the eight question NBSS-SF has appropriate validity and reliability, and could be used in patient care settings. The full NBSS is better suited when researchers want to evaluate individual NBSS domains in addition to the total score.
Source of Funding: PCORI grant CER14092138