Reliability and validity of the Overactive Bladder Symptom Score in Spanish (OABSS-S)

Abstract

Purpose: To validate the Spanish translation of the Overactive Bladder Symptom Score (OABSS) questionnaire.

Materials and methods: The OABSS was translated into Spanish (OABSS-S) and back translated. The OABSS-S was self-administered to subjects, following internal IRB and ISPOR Good Practices guidelines. Spanish speaking patients >18 years of age were recruited from primary care clinics. Content validity was achieved by having the first 25 subjects complete the questionnaire in privacy; afterwards they were interviewed and the clarity of each question was discussed with the patient. All subjects recruited, including the first 25, were divided into two groups by the presence of OAB as determined by a previously validated intake question. Subjects completed the OABSS-S in privacy on two occasions within 10 days. Patients were excluded if their symptoms changed between the first and second administration of the questionnaire. Internal consistency was determined with Cronbach's alpha. Test-retest was determined by Spearman's rho. Discriminant validity was assessed between each group using one-way ANOVA and the Tukey post hoc test.

Results: One hundred and seventeen of 128 enrolled subjects completed this study (mean age 55; SD 18). Of 117, 74 (63%) were women 29 with OAB and 45 without OAB. There were 43 men (37%), 18 with OAB and 25 without OAB. A high level of consistency was observed among the seven items answered at visit 1 and 2, with a Cronbach's raw alpha statistic of 0.92. No differences in OABSS-S with age or gender were noted. However, subgroup analysis showed patients in the OAB group were significantly older and post-test analysis showed they had higher scores both for each individual question as well as overall symptom severity scores. Spearman's rank order correlation coefficients showed that there was significant difference between the seven items of the OABSS-S; a strong association (Spearman's rho) was also observed between the total seven-item score at visits 1 and 2 for the total score of all subjects r = 0.84, with OAB: r = 0.81, and without OAB: r = 0.83. Comparison of average total scores obtained for all patients at visits 1 and 2 was not significant (10.47 ± 6.53 vs. 11.02 ± 0.66). Discriminant validity testing revealed that there were significant differences in the responses between all diagnostic groups at visits 1 and 2: with OAB versus without OAB; total versus with OAB; total versus without OAB.

Conclusion: The Spanish version of the OABSS is valid and reliable and will allow health care providers to easily and quickly assess a Spanish-speaking patient's symptoms.