Short-Form OAB questionnaire validated

Researchers from the USA have developed a short form (SF) version of the overactive bladder questionnaire (OAB-q), which they say can capture the full spectrum of symptom bother and quality of life impact, while being more convenient than the full version of the test.

“Although the 33-item OAB-q is not an unusually long questionnaire, clinicians, and researchers may benefit from a short-form that could be used when patient burden is an issue and detailed information on individual HRQL [health-related quality of life] domains is not needed,” comment study authors Karin Coyne (Evidera, Bethesda, Maryland).

The team used data from a 12-week open-label clinical trial involving 865 patients with OAB to determine which items should be kept in the Symptom Bother and HRQL SF scales. Using Rasch analysis, a type of item response theory modelling, they selected six items and 13 items, respectively, for each of the scales. Only a minority (<2.5%) of patients had extreme scores on either of the scales, which the researchers say indicates the capacity of the SF questionnaire to cover the full range of OAB symptom bother and HRQL impact.

The team also performed confirmatory factor analyses, which demonstrated the good fit of the two scales to the data. And, using additional data from a case–control study involving 396 OAB patients, they confirmed that the two scales had excellent internal consistency.

Also using this data, the team correlated OAB-q SF with results from the Center for Epidemiologic Studies Depression Scale, SF-36 and Medical Outcomes Study Sleep scale, which showed moderate associations. Using longitudinal data they confirmed that the questionnaire shows good reproducibility and responsiveness to change. They also found that it could easily differentiate between control patients and OAB patients.

“The demonstration of good psychometric properties in this diverse representation of participants highlights the ability of the OAB-q SF to capture a wide spectrum of OAB symptoms,” comment Coyne et al.

The team write in Neurourology and Urodynamics: “In order for a [patient reported outcome] to be widely used and effective, it must be brief, easy to complete, and appropriate for the setting in which it is being used, as well as possess reasonable estimation precision along the construct being used.

“The OAB-q SF fulfils these criteria and is a promising tool for settings in which completing the full 33-item OAB-q may be too burdensome for patients and physicians.”

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