Cross-National Validation of a Health-Related Quality of Life Measure in Five Latin American Countries: Invariance of the 8-Item Short Form Health Survey (SF-8) and Proposed 6-Item Version (SF-6).

The objective was to analyze the factorial structure, reliability, and cross-national measurement invariance of the 8-item Short Form Health Survey (SF-8) in 1,940 individuals from five Latin American countries (El Salvador, Honduras, Guatemala, Colombia, and Venezuela). Five CFA models were estimated based on previous findings and considerations of the content validity. The results indicated that the two-factor model (physical and mental health) without items 1 and 5 provided the best fit across all countries. Item 5 was removed due to low factor loadings in all estimated models and across all countries, while item 1 was removed because it was too general, making it difficult to determine whether it measured physical or mental health. The six-item version (SF-6) demonstrated adequate reliability and strict invariance across all countries in the invariance sequence models. The reported differences in physical and mental health dimensions were negligible and minor among all countries. In conclusion, a 6-item version of the Short Form Health Survey (SF-6) was proposed, which is better represented by two dimensions (physical and mental health) and is invariant across Latin American countries.