Reliability and validity of the King's Health Questionnaire for lower urinary tract symptoms in both genders

To investigate the reliability and validity of the King's Health Questionnaire (KHQ) in both genders, which was originally developed as a health-related quality of life (HRQoL) questionnaire for female urinary incontinence for general lower urinary tract symptoms (LUTS). Data from the International Prostate Symptom Score (IPSS) and KHQ obtained from 179 men and 75 women consulting urologists (Sample A) were analysed. Cronbach's alpha coefficient and inter-domain correlation were calculated for reliability and validity assessment, respectively. Factor analysis was used to explore the underlying factor structure of the KHQ. KHQ scores of sample A were compared with those of 330 men and 418 women consulting general practitioners (Sample B). Internal consistency of KHQ was acceptable with a Crohnbach's alpha of 0.721-0.915 in the total population of sample A. Correlation analysis showed convergent validity among 'Physical Limitations', 'Role Limitation' and 'Social Limitations' and discriminant validity among 'Personal Relationship', 'Emotion's and 'Sleep/Energy'. Factor analysis showed three underlying components to explain convergent and discriminant validity. In both sample A and sample B, HRQoL was impaired in the eight domains according to IPSS severity. KHQ scores of domains other than 'General Health Perception' in sample B were lower than those in sample A. The KHQ can be used as a HRQoL questionnaire for LUTS in both genders. In the future, it is expected that the KHQ could be used in clinical studies for benign prostate hyperplasia and other conditions.