The validity and reliability of the Indonesian version of the Summated Xerostomia Inventory

Abstract

Objective: To validate and determine the reliability of the Indonesian version of the Summated Xerostomia Inventory (SXI-ID) questionnaire.

Background: Xerostomia is a common problem in older people, and the SXI is increasingly being used to measure it.

Materials and methods: The SXI questionnaire was cross-culturally adapted to create an Indonesian version (SXI-ID), which was assessed for validity and reliability in a cross-sectional study of older adults living in nursing homes in Jakarta, Indonesia. Each participant signed an informed consent and was interviewed with the SXI-ID. A subset of participants was interviewed again after two weeks. A standard question was used to check criterion-related validity, by plotting the mean SXI-ID scale scores against the ordinal response categories of the standard question. The reliability check included Cronbach's alpha, total and inter-item correlation, and intraclass correlation for internal consistency, along with test-retest reliability.

Results: A total of 110 older adults participated. Cronbach's alpha value for the SXI-ID was .85, and the intraclass correlation coefficient value for test and retest in 15 participants was .9. The SXI-ID total score showed a strong positive correlation (.87) with the global question. There was a consistent ascending gradient in mean SXI-ID scores across the ordinal response categories of the global item.

Conclusion: The SXI-ID is psychometrically valid and reliable for measuring xerostomia in the Indonesian population.

Keywords: Indonesia; Summated Xerostomia Inventory; validity and reliability; xerostomia.