Objective: 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).
Subjects and methods: 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).
Results: 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.
Conclusion: 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.