Reliability, Validity and Measurement Invariance of the WHO’s Quality of Life Scale among Women of Reproductive Age Living with HIV in Ethiopia - a Quasi-Experimental Study
Despite its widespread global adoption and use, studies have not examined measurement invariance of the 31-question World Health Organization Quality of Life–HIV BREF scale among HIV/AIDS patients. The current study seeks to (a) evaluate the scale’s internal consistency reliability, and concurrent validity, and (b) test if the same latent construct of quality of life was consistently measured at two time-points, for a sample of HIV-positive women from two sites in Addis Ababa, Ethiopia. The study used data from two cross-sectional interviews with 926 HIV-positive women of reproductive age who participated in a quasi-experimental study. All participants were receiving antiretroviral therapy and related treatment support services from 51 service providers in two non-contiguous sub-cities. We used One-Way ANOVA, chi square test and Kruskal Wallis test to compare demographic characteristics and quality of life scores of study participants. Further, we used Cronbach’s coefficient alpha (α) to assess internal consistency reliability and Pearson product-moment correlation (r) to assess concurrent validity. Finally, multiple-group confirmatory factor analysis with maximum likelihood estimation was used to assess measurement invariance of the quality of life scale. Findings suggest that the WHOQOL-HIV BREF exhibited acceptable psychometric properties. There was evidence for strong internal consistency reliability demonstrated by Cronbach’s α >0.80 and coefficient ω >0.80. The scale’s six domains also exhibited good concurrent validity, with coefficient r = 0.63–0.82. In measurement invariance analysis, configural invariance was found for the scale’s six domains, suggesting measurement noninvariance for factor loadings, item intercepts and factor variances when comparing QOL among participants in the two sites at baseline and follow-up. Our findings suggest that the WHOQOL-HIV BREF has internal consistency reliability and concurrent validity in this study sample. The differences in the levels of observed responses for QOL across intervention and non-intervention groups at baseline and follow-up suggest participants had dissimilar understanding, interpretation, and responses to the scale’s items, which may have resulted from significant measurement, cultural, and developmental differences between study groups. The WHOQOL-HIV BREF exhibited internal consistency reliability, concurrent validity and configural invariance. However, strong invariance was not achieved, making it difficult to compare levels of QOL between groups in this study sample.
Agala, CB; Fried, BJ; Thomas, JC; Reynolds, HW; Lich, KH; Whetten, K; Zimmer, C; Morrissey, JP
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