Abstract
Background: Xerostomia is a common complication in patients with head and neck cancer (HNC) during and after radiotherapy. The lack of a simply-administered and well-validated self-reported instrument has hampered the assessment and management of xerostomia for research and clinical purposes in China.
Objective: This study aimed to evaluate the content validity and psychometric properties of the Xerostomia Questionnaire (XQ) in Chinese patients with HNC undergoing radiotherapy.
Methods: This psychometric evaluation study enrolled 80 patients and was conducted in 2 stages: translation and evaluation of content validity and psychometric evaluation. Cognitive interviews (n = 10) were conducted using the Participant Interview Form. The psychometric evaluation (n = 80) included score distribution, homogeneity (interitem and item-total correlations), factor structure (exploratory factor analysis), internal consistency (Cronbach's [alpha]), criterion-related validity (person correlation), and test-retest reliability (intraclass correlations).
Results: Content validity was supported by cognitive interviews. The factor analysis resulted in a 1-factor solution with strong factor loadings (0.84-0.91) that explained 75.6% of the total variance. The internal consistency was excellent, with a Cronbach's [alpha] of .95. The XQ correlated strongly with other measures of xerostomia (0.70-0.80), which supports criterion-related validity. The test-retest reliability was excellent (intraclass correlation coefficient = 0.92).
Conclusions: The result provides evidence for the validity and reliability of the XQ in a sample of Chinese patients with HNC.
Implications for Practice: The XQ can be used in both clinical practice and research as a valuable tool to screen for problems with xerostomia, monitor the xerostomia level, and evaluate the effects of treatment and interventions among patients with HNC.