Validation of a quality of life questionnaire (King's Health Questionnaire) in Brazilian women with urinary incontinence

Purpose: the proposal of the present study was to translate and to validate King's Health Questionnaire (KHQ) for Brazilian women with urinary incontinence. Methods: a hundred and thirty-four patients with urinary incontinence, confirmed by urodynamic study, were enrolled from the outpatient clinic of Uroginecology. Initially, we translated the KHQ into the Brazilian Portuguese language in agreement with international criteria. Due to language and cultural differences we performed a cultural, structural, conceptual, and semantic adaptation of the KHQ, in order to make sure that patients were able to fully understand the questions. All patients answered the KHQ twice on the same day, within an interval of 30 min, applied by two different interviewers. After 7 to 14 days, on a second visit, the questionnaire was applied again. Reliability (intra-and interobserver internal consistency), construct and discriminative validity were tested. Results: several cultural adaptations were necessary until we reached the final version. The intra-observer internal consistency (alpha of Cronbach) of the several dimensions varied from moderate to high (0.77-0.90), and the interobserver internal consistency varied from 0.66 to 0.94. Moderate to strong correlation was detected among the specific KHQ urinary incontinence dominions and clinical urinary incontinence manifestations known to affect the quality of life of these patients. Conclusion: KHQ was adapted to the Portuguese language and to the Brazilian culture, showing great reliability and validity. It should be included and used in any Brazilian urinary incontinence clinical trial.