Validity and reliability of the Greek version of the neurogenic bladder symptom score (NBSS) questionnaire in a sample of Greek patients with multiple sclerosis

Background and objectives: There is no data regarding validity and reliability of the Greek version of Neurogenic Bladder Symptom Score (NBSS) questionnaire. In this study we investigated these parameters using a sample of Greek patients with multiple sclerosis (MS).

Materials and methods: Patients with different types and severity of multiple sclerosis were recruited from a single center in Greece prospectively. All patients completed the MusiQoL and NBSS questionnaires at baseline and 20 days later, without receiving any new treatment. Construct validity, internal consistency and test-retest reliability were tested. Internal consistency was investigated using Cronbach's alpha coefficient, while test-retest reliability using Intraclass Correlation Coefficient (ICC). Construct validity was assessed by comparing NBSS quality of life question 24 with MusiQoL questionnaire.

Results: A total of 91 patients were evaluated. The dimensions of NBSS exhibited high internal consistency, both for overall questionnaire score (Cronbach's alpha coefficient of 0.91) and for every subdomain separately (Cronbach's alpha coefficient of 0.95 for incontinence, 0.88 for storage symptoms and 0.74 for consequences). Test-retest reliability was satisfactory both for overall score [ICC of 0.85, (0.35-0.94), p < 0.001] and for every subdomain separately (ICC of 0.90 for incontinence, 0.83 for storage symptoms and 0.90 for consequences). Pearson's correlation coefficient of question number 24 of the NBSS questionnaire regarding quality of life with the MusiQoL questionnaire revealed a moderate correlation [r = 0.64, (0.48-0.80), p < 0.0001].

Conclusions: The Greek version of NBSS appears to be a valid and reliable instrument for assessing neurogenic bladder symptoms in Greek population suffering from multiple sclerosis.