Objective: To develop an oral health-related quality of life index in Thai children and evaluate its psychometric properties.
Design: Cross-sectional study of children aged 11-12 years, attending the final year of primary school (grade-six). Development and evaluation process was conducted on non-random sample in U-thong District, Suphan-buri province, Thailand. Re-evaluation of the index included all target group children in a municipal area of Suphan-buri province, Thailand. The psychometric properites evaluated in this study refer to face, content and concurrent validity and internal and test-retest reliability.
Participants: 513 children in the development process. 1,100 children in the re-evaluation.
Results: Throughout the development process, the OIDP index was modified and its psychometric properties evaluated. The final test revealed excellent validity and reliability. Weighted kappa was 0.93. There was no negative correlation between any item, corrected item-total correlation coefficients were between 0.4-0.7, Standardised Cronbach's alpha coefficient was 0.82. The index showed very significant associations with perceived oral treatment need (p < 0.001) and perceived oral health problems (p < 0.001). The validity and reliability of the index was confirmed by similar results in the re-evaluation study.
Conclusions: This study has demonstated that the CHILD-OIDP index is a valid, reliable and practical measure of oral health-related quality of life in 12 year old Thai children.