Turkish translation and validation of the Xerostomia Inventory
Sezin Yüce Sarı1, Melek Tuğce Yılmaz1, Ayşenur Elmalı1, Levent Kılıç2, Deniz Yüce3, Gökhan Özyiğit1, Mustafa Cengiz1, Gözde Yazıcı1
1Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey
2Department of Internal Medicine, Division of Rheumatology, Hacettepe University Faculty of Medicine, Ankara, Turkey
3Department of Preventive Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey
Keywords: Head and neck cancer, Sjögren syndrome, validity, xerostomia.
Objectives: The Xerostomia Inventory (XI) was developed to assess the severity of dryness in patients with xerostomia. It has a long and a short form with three- and five-point Guttman-type response options. In this study, we aimed to translate the XI into Turkish, to assess the validity and reliability of both response options in patients with head & neck cancer (HNC) or Sjögren syndrome (SS), and to select the optimal version for Turkish patients.
Patients and methods: Between January 2019 and June 2019, the XI was translated into Turkish (XI-T) and applied to patients aged ≥18 years with HNC and SS. All patients were applied two tests including both the three- and five-point options. The internal consistency was assessed by Cronbach alpha and test-retest reliability by intraclass correlation coefficients (ICCs). Content validity was based on expert opinion and patient reviews.
Results: A total of 186 patients (109 males, 77 females; median age: 54 years; range, 19 to 78 years) answered the XI-T. The number of patients with HNC and SS was 143 (77%) and 43 (23%), respectively. Median XI-T score was 17 for the three-point, and 24 for the five-point option, respectively. Overall internal consistency was satisfactory for both options (a=0.81 and a=0.89, respectively). Overall test-retest reliability was satisfactory and ICCs ranged between 0.71 and 0.92 for the three-point, and 0.36 and 0.94 for the five-point option, respectively. Assessments based on expert opinions and patient reviews also favored the content validity of the scale.
Conclusion: The XI-T with both three- and five-point options is a valid and reliable tool to evaluate the presence and severity of dryness in patients with HNC and SS who experience xerostomia. The three-point option is more comprehensible and can be preferred over the five-point option in the Turkish population.