Background: Overactive bladder (OAB) is characterized by the symptoms of urinary urgency or urge incontinence, which appear without a local pathological or metabolic explanation. OAB is defined by symptoms and the evaluation of treatment effectiveness should be based upon patient perceptions. The Overactive Bladder Questionnaire-Short Form (OAB-q SF) is a brief, self-administered patient-reported outcomes tool with two scales assessing symptom bother and health-related quality of life (HR-QOL) in patients with OAB.
Objective: This study aimed to adapt the OAB-q SF into Spanish and to estimate its psychometric properties in patients with symptomatic overactive bladder.
Methods: The Spanish version of the OAB-q SF was administered on two occasions, 3 months apart, to a set of patients of both sexes, over 18 years of age, diagnosed with OAB, scoring ≥8 on the OAB-V8 scale (a self-reported 8-item OAB screening and awareness tool), and able to understand patient-reported-outcome instruments written in Spanish. Patients were recruited consecutively at urology clinics. Feasibility, internal consistency (Cronbach's alpha), test-retest reliability, structure of instrument, criteria and construct validity and responsiveness were examined using classic test theory statistics.
Results: Data from 246 OAB patients (mean age 57.7 years, 76% women, 99% Caucasian, 37% workers and 36% with a primary education) were evaluated. Floor and ceiling effects ranged between 0.8% and 33%, and missing items were below 2%. Cronbach's alphas attained 0.811 and 0.922 for symptom-bother and HR-QOL domains, respectively. These two subscales matched the original structure and explained variances above 50%, which correlated moderately with EQ-5D (EuroQol) [r = -0.28 and r = +0.31, respectively (p < 0.001 in both cases)]. A significant change in OAB-q SF mean domain scores (-23.8; 95% CI -26.3, -21.3; and +17.7; 95% CI 15.4, 20.6; p < 0.001 in both cases; [effect sizes: 1.32 and 0.98]) was observed after 3 months of medical treatment.
Conclusion: The Spanish version of the OAB-q SF demonstrated sufficiently strong psychometric properties of reliability, validity and responsiveness to be used in the measurement of OAB symptom severity and HR-QOL.