Modern psychometric evaluation of Thai WHOQOL-BREF and its shorter versions in patients undergoing warfarin in Thailand: Rasch analysis

Rasch analysis was employed to investigate the psychometric properties of the World Health Organization Quality of Life-BREF (WHOQOL-BREF) and its shorter versions (EUROHIS-QOL-8 and WHOQOL-5) within the context of patients undergoing warfarin in Thailand. A group of 260 patients were recruited from three public hospitals and tasked with completing the WHOQOL-BREF questionnaire. Rasch analysis showed that the WHOQOL-BREF, structured into four-domain subtests, achieved a commendable fit to the Rasch model (chi 2[16] = 12.26, p = 0.73), met the criterion of unidimensionality (7.31% significant t-tests; lower bound confidence interval, 4.66), and demonstrated satisfactory reliability (PSI = 0.87). The adoption of a subtest approach facilitated an acceptable fit to the Rasch model for each domain of the WHOQOL-BREF, except for the social domain. However, the presence of local dependency of the three-item social domain was detected, so the reliability was not reported. The WHOQOL-5 proved to be unidimensional, fitting the Rasch model acceptably, and had satisfactory reliability. Conversely, the EUROHIS-QOL-8 presented local dependency; thus, reliability was not reported. Consequently, the WHOQOL-BREF in its four-domain subtests is recommended for pre- and post-HRQoL measurements, whereas the WHOQOL-5 can effectively measure HRQoL levels in between-group analyses.